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--- back2root:ibm-pc-ms-dos:interrupts:old:ms_interrupt_list-21 [2023/01/05 04:01] – supprimée - modification externe (Unknown date) 127.0.0.1
+++ back2root:ibm-pc-ms-dos:interrupts:old:ms_interrupt_list-21 [2023/01/05 04:01] (Version actuelle) – créée - modification externe 127.0.0.1
@@ Ligne 1: / Ligne 1: @@
+====== MSDOS - Interrupt List 21h ======
+===== 00h - DOS 1+ - TERMINATE PROGRAM =====
+<code>
+	AH = 00h
+	CS = PSP segment
+</code>
+<WRAP round box>
+Microsoft recomments using INT 21/AH=4Ch for DOS 2+ execution continues at address stored in INT 22 after DOS performs whatever cleanup it needs to do
+if the PSP is its own parent, the process's memory is not freed; if INT 22 additionally points into the terminating program, the process is effectively NOT terminated
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=26h,AH=31h,AH=4Ch,INT 20,INT 22
+===== 01h - DOS 1+ - READ CHARACTER FROM STANDARD INPUT, WITH ECHO =====
+<code>
+	AH = 01h
+</code>
+<code>
+Return: AL = character read
+</code>
+<WRAP round box>
+^C/^Break are checked, and INT 23 executed if read
+character is echoed to standard output
+standard input is always the keyboard and standard output the screen under DOS 1.x, but they may be redirected under DOS 2+
+</WRAP>
+SeeAlso: AH=06h,AH=07h,AH=08h,AH=0Ah
+===== 02h - DOS 1+ - WRITE CHARACTER TO STANDARD OUTPUT =====
+	AH = 02h
+	DL = character to write
+Return: AL = last character output (despite the official docs which state
+		nothing is returned) (at least DOS 3.3-5.0)
+Notes:	^C/^Break are checked, and INT 23 executed if pressed
+	standard output is always the screen under DOS 1.x, but may be
+	  redirected under DOS 2+
+	the last character output will be the character in DL unless DL=09h
+	  on entry, in which case AL=20h as tabs are expanded to blanks
+SeeAlso: AH=06h,AH=09h
+===== 03h - DOS 1+ - READ CHARACTER FROM STDAUX =====
+	AH = 03h
+Return: AL = character read
+Notes:	keyboard checked for ^C/^Break, and INT 23 executed if detected
+	STDAUX is usually the first serial port
+SeeAlso: AH=04h,INT 14/AH=02h,INT E0/CL=03h
+===== 04h - DOS 1+ - WRITE CHARACTER TO STDAUX =====
+	AH = 04h
+	DL = character to write
+Notes:	keyboard checked for ^C/^Break, and INT 23 executed if detected
+	STDAUX is usually the first serial port
+	if STDAUX is busy, this function will wait until it becomes free
+SeeAlso: AH=03h,INT 14/AH=01h,INT E0/CL=04h
+===== 05h - DOS 1+ - WRITE CHARACTER TO PRINTER =====
+	AH = 05h
+	DL = character to print
+Notes:	keyboard checked for ^C/^Break, and INT 23 executed if detected
+	STDPRN is usually the first parallel port, but may be redirected under
+	  DOS 2+
+	if the printer is busy, this function will wait
+SeeAlso: INT 17/AH=00h
+===== 06h - DOS 1+ - DIRECT CONSOLE OUTPUT =====
+	AH = 06h
+	DL = character (except FFh)
+Return: AL = character output (despite official docs which state nothing is
+		returned) (at least DOS 3.3-5.0)
+Notes:	does not check ^C/^Break
+	writes to standard output, which is always the screen under DOS 1.x,
+	  but may be redirected under DOS 2+
+SeeAlso: AH=02h,AH=09h
+===== 06h - FFh - DOS 1+ - DIRECT CONSOLE INPUT =====
+	AH = 06h
+	DL = FFh
+Return: ZF set if no character available
+	ZF clear if character available
+	    AL = character read
+Notes:	^C/^Break are NOT checked
+	if the returned character is 00h, the user pressed a key with an
+	  extended keycode, which will be returned by the next call of this
+	  function
+	reads from standard input, which is always the keyboard under DOS 1.x,
+	  but may be redirected under DOS 2+
+SeeAlso: AH=0Bh
+===== 07h - DOS 1+ - DIRECT CHARACTER INPUT, WITHOUT ECHO =====
+	AH = 07h
+Return: AL = character read from standard input
+Notes:	does not check ^C/^Break
+	standard input is always the keyboard under DOS 1.x, but may be
+	  redirected under DOS 2+
+	if the interim console flag is set (see AX=6301h), partially-formed
+	  double-byte characters may be returned
+SeeAlso: AH=01h,AH=06h,AH=08h,AH=0Ah
+===== 08h - DOS 1+ - CHARACTER INPUT WITHOUT ECHO =====
+	AH = 08h
+Return: AL = character read from standard input
+Notes:	^C/^Break are checked, and INT 23 executed if detected
+	standard input is always the keyboard under DOS 1.x, but may be
+	  redirected under DOS 2+
+	if the interim console flag is set (see AX=6301h), partially-formed
+	  double-byte characters may be returned
+SeeAlso: AH=01h,AH=06h,AH=07h,AH=0Ah,AH=64h
+===== 09h - DOS 1+ - WRITE STRING TO STANDARD OUTPUT =====
+	AH = 09h
+	DS:DX -> '$'-terminated string
+Return: AL = 24h (the '$' terminating the string, despite official docs which
+		state that nothing is returned) (at least DOS 3.3-5.0)
+Notes:	^C/^Break checked, and INT 23 called if pressed
+	standard output is always the screen under DOS 1.x, but may be
+	  redirected under DOS 2+
+SeeAlso: AH=02h,AH=06h"OUTPUT"
+===== 0Ah =====
+==== 0Ah - DOS 1+ - BUFFERED INPUT ====
+	AH = 0Ah
+	DS:DX -> buffer (see below)
+Return: buffer filled with user input
+Notes:	^C/^Break checked, and INT 23 called if detected
+	reads from standard input, which may be redirected under DOS 2+
+	if the maximum buffer size (see below) is set to 00h, this call returns
+	  immediately without reading any input
+SeeAlso: AH=0Ch,INT 2F/AX=4810h
+Format of input buffer:
+Offset	Size	Description
+h	BYTE	maximum characters buffer can hold
+h	BYTE	(input) number of chars from last input which may be recalled
+		(return) number of characters actually read, excluding CR
+h  N BYTEs	actual characters read, including the final carriage return
+==== 0A00h - WCED v1.6 - INSTALLATION CHECK ====
+	AX = 0A00h
+	DS:DX -> 6-byte buffer whose first two bytes must be 00h
+Return: buffer offset 02h-05h filled with "Wced" if installed
+Note:	WCED is a free command-line editor and history utility by Stuart
+	  Russell
+SeeAlso: AH=FFh"CED"
+===== 0Bh =====
+==== 0Bh - DOS 1+ - GET STDIN STATUS ====
+	AH = 0Bh
+Return: AL = 00h if no character available
+	   = FFh if character is available
+Notes:	^C/^Break checked, and INT 23 called if pressed
+	standard input is always the keyboard under DOS 1.x, but may be
+	  redirected under DOS 2+
+	if the interim console flag is set (see AX=6301h), this function
+	  returns AL=FFh if a partially-formed double-byte character is
+	  available
+SeeAlso: AH=06h"INPUT",AX=4406h
+==== 0B56h - VIRUS - "Perfume" - INSTALLATION CHECK ====
+	AX = 0B56h
+Return: AX = 4952h if resident
+SeeAlso: AX=0D20h
+===== 0Ch - DOS 1+ - FLUSH BUFFER AND READ STANDARD INPUT =====
+	AH = 0Ch
+	AL = STDIN input function to execute after flushing buffer
+	other registers as appropriate for the input function
+Return: as appropriate for the specified input function
+Note:	if AL is not one of 01h,06h,07h,08h, or 0Ah, the buffer is flushed but
+	  no input is attempted
+SeeAlso: AH=01h,AH=06h"INPUT",AH=07h,AH=08h,AH=0Ah
+===== 0Dh =====
+==== 0Dh - DOS 1+ - DISK RESET ====
+	AH = 0Dh
+Notes:	writes all modified disk buffers to disk, but does not update directory
+	  information (that is only done when files are closed or a SYNC call
+	  is issued)
+SeeAlso: AX=5D01h,INT 13/AH=00h,INT 2F/AX=1120h
+==== 0D20h - VIRUS - "Crazy Imp" - INSTALLATION CHECK ====
+	AX = 0D20h
+Return: AX = 1971h if resident
+SeeAlso: AX=0B56h,AH=30h/DX=ABCDh
+===== 0Eh - DOS 1+ - SELECT DEFAULT DRIVE =====
+	AH = 0Eh
+	DL = new default drive (00h = A:, 01h = B:, etc)
+Return: AL = number of potentially valid drive letters
+Notes:	under Novell NetWare, the return value is always 32, the number of
+	  drives that NetWare supports
+	under DOS 3+, the return value is the greatest of 5, the value of
+	  LASTDRIVE= in CONFIG.SYS, and the number of drives actually present
+	on a DOS 1.x/2.x single-floppy system, AL returns 2 since the floppy
+	  may be accessed as either A: or B:
+	otherwise, the return value is the highest drive actually present
+	DOS 1.x supports a maximum of 16 drives, 2.x a maximum of 63 drives,
+	  and 3+ a maximum of 26 drives
+SeeAlso: AH=19h,AH=3Bh,AH=DBh
+===== 0Fh - DOS 1+ - OPEN FILE USING FCB =====
+<code>
+	AH = 0Fh
+	DS:DX -> unopened File Control Block (see below)
+</code>
+<code>
+Return: AL = status
+h successful
+	    FFh file not found or access denied
+</code>
+<WRAP round box>
+(DOS 3.1+) file opened for read/write in compatibility mode
+an unopened FCB has the drive, filename, and extension fields filled in and all other bytes cleared
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=10h,AH=16h,AH=3Dh
+=== Format of File Control Block: ===
+^  Offset  ^  Size    ^ Description                                                                       ^
+| -7       | BYTE     | extended FCB if FFh                                                               |
+| -6       | 5 BYTEs  | reserved                                                                          |
+| -1       | BYTE     | file attribute if extended FCB                                                    |
+| 00h      | BYTE     | drive number (0 = default, 1 = A, etc)                                            |
+| 01h      | 8 BYTEs  | blank-padded file name                                                            |
+| 09h      | 3 BYTEs  | blank-padded file extension                                                       |
+| 0Ch      | WORD     | current block number                                                              |
+| 0Eh      | WORD     | logical record size                                                               |
+| 10h      | DWORD    | file size                                                                         |
+| 14h      | WORD     | date of last write (see AX=5700h)                                                 |
+| 16h      | WORD     | time of last write (see AX=5700h) (DOS 1.1+)                                      |
+| 18h      | 8 BYTEs  | reserved (see below)                                                              |
+| 20h      | BYTE     | record within current block                                                       |
+| 21h      | DWORD    | random access record number (if record size is > 64 bytes, high byte is omitted)  |
+<WRAP round box>
+to use an extended FCB, you must specify the address of the FFh flag at offset -7, rather than the address of the drive number field
+</WRAP>
+=== Format of reserved field for DOS 1.0: ===
+^  Offset  ^  Size  ^ Description                                                        ^
+| 16h      | WORD   | location in directory (if high byte = FFh, low byte is device ID)  |
+| 18h      | WORD   | number of first cluster in file                                    |
+| 1Ah      | WORD   | last cluster number accessed (absolute)                            |
+| 1Ch      | WORD   | relative current cluster number                                    |
+| 1Eh      | BYTE   | dirty flag (00h = not dirty)                                       |
+| 1Fh      | BYTE   | unused                                                             |
+=== Format of reserved field for DOS 1.10-1.25: ===
+^  Offset  ^  Size  ^ Description                                                                                   ^
+| 18h      | BYTE   | bit 7: set if logical device\\ bit 6: not dirty\\ bits 5-0: disk number or logical device ID  |
+| 19h      | WORD   | starting cluster number                                                                       |
+| 1Bh      | WORD   | absolute current cluster number                                                               |
+| 1Dh      | WORD   | relative current cluster number                                                               |
+| 1Fh      | BYTE   | unused                                                                                        |
+=== Format of reserved field for DOS 2.x: ===
+^  Offset  ^  Size  ^ Description                                                           ^
+|18h |BYTE | bit 7: set if logical device\\ bit 6: set if open???\\ bits 5-0: ???  |
+|19h |WORD | starting cluster number                                               |
+|1Bh |WORD | ???                                                                   |
+|1Dh |BYTE | ???                                                                   |
+|1Eh |BYTE | ???                                                                   |
+|1Fh |BYTE | ???                                                                   |
+=== Format of reserved field for DOS 3.x: ===
+^Offset ^ Size ^Description^
+| 18h	|BYTE	|number of system file table entry for file|
+| 19h	|BYTE	|attributes\\ bits 7,6: \\   * 00 = SHARE.EXE not loaded, disk file\\   * 01 = SHARE.EXE not loaded, character device\\   * 10 = SHARE.EXE loaded, remote file\\   * 11 = SHARE.EXE loaded, local file\\ bits 5-0:\\   * low six bits of device attribute word---SHARE.EXE loaded, local file (DOS 3.x and 5.0)---|
+| 1Ah	|WORD	|starting cluster of file|
+| 1Ch	|WORD	|(DOS 3.x) offset within SHARE of sharing record (see AH=52h)\\(DOS 5.0) unique sequence number of sharing record|
+| 1Eh	|BYTE	|file attribute|
+| 1Fh	|BYTE	|???|
+|---SHARE.EXE loaded, remote file---|||
+| 1Ah	|WORD	|number of sector containing directory entry|
+| 1Ch	|WORD	|relative cluster within file of last cluster accessed|
+| 1Eh	|BYTE	|absolute cluster number of last cluster accessed|
+| 1Fh	|BYTE	|???|
+|---SHARE.EXE not loaded---|||
+| 1Ah	|BYTE	|(low byte of device attribute word AND 0Ch) OR open mode|
+| 1Bh	|WORD	|starting cluster of file|
+| 1Dh	|WORD	|number of sector containing directory entry|
+| 1Fh	|BYTE	|number of directory entry within sector|
+<WRAP round box >
+if FCB opened on character device, DWORD at 1Ah is set to the address of the device driver header, then the BYTE at 1Ah is overwritten.
+</WRAP>
+===== 10h - DOS 1+ - CLOSE FILE USING FCB =====
+	AH = 10h
+	DS:DX -> File Control Block (see AH=0Fh)
+Return: AL = status
+h successful
+	    FFh failed
+Notes:	a successful close forces all disk buffers used by the file to be
+	  written and the directory entry to be updated
+	not supported by MS Windows 3.0 DOSX.EXE DOS extender
+SeeAlso: AH=0Fh,AH=16h,AH=3Eh
+===== 11h - DOS 1+ - FIND FIRST MATCHING FILE USING FCB =====
+<code>
+	AH = 11h
+	DS:DX -> unopened FCB (see AH=0Fh), may contain '?' wildcards
+</code>
+<code>
+Return: AL = status
+h successful
+		[DTA] unopened FCB for first matching file
+	    FFh no matching filename, or bad FCB
+</code>
+<WRAP round box>
+the type of the returned FCB depends on whether the input FCB was a normal or an extended FCB
+for extended FCBs with search attribute 08h, the volume label (if any) will be returned even if the current directory is not the root dir.
+DOS 3+ also allows the '*' wildcard
+the search FCB must not be modified if AH=12h will be used to continue searching; DOS 3.3 has set the following parts of the FCB:
+<code>
+Ch	BYTE	???
+Dh	WORD	directory entry number of matching file
+Fh	WORD	cluster number of current directory
+h  4 BYTEs	???
+h	BYTE	drive number (1=A:)
+</code>
+at least for DOS 3.3, the unopened FCB in the DTA is actually the drive number followed by the file's directory entry
+</WRAP>
+===== 12h - DOS 1+ - FIND NEXT MATCHING FILE USING FCB =====
+<code>
+	AH = 12h
+	DS:DX -> unopened FCB (see AH=0Fh)
+</code>
+<code>
+Return: AL = status
+h successful
+		[DTA] = unopened FCB
+	    FFh no more matching filenames
+</code>
+<WRAP round box>
+(see AH=11h)
+assumes that successful FindFirst executed on search FCB before call
+</WRAP>
+SeeAlso: AH=1Ah,AH=4Fh,INT 2F/AX=111Ch
+===== 13h - DOS 1+ - DELETE FILE USING FCB =====
+<code>
+	AH = 13h
+	DS:DX -> unopened FCB (see AH=0Fh), filename filled with template for deletion ('?' wildcards allowed)
+</code>
+<code>
+Return: AL = status
+h one or more files successfully deleted
+	    FFh no matching files or all were read-only or locked
+</code>
+<WRAP round box>
+DOS 1.25+ deletes everything in the current directory (including subdirectories) and sets the first byte of the name to 00h (entry never used) instead of E5h if called on an extended FCB with filename '???????????' and bits 0-4 of the attribute set (bits 1 and 2 for DOS 1.x). This may have originally been an optimization to minimize directory searching after a mass deletion (DOS 1.25+ stop the directory search upon encountering a never-used entry), but can corrupt the filesystem under DOS 2+ because subdirectories are removed without deleting the files they contain.
+currently-open files should not be deleted
+</WRAP>
+SeeAlso: AH=41h,INT 2F/AX=1113h
+===== 14h - DOS 1+ - SEQUENTIAL READ FROM FCB FILE =====
+<code>
+	AH = 14h
+	DS:DX -> opened FCB (see AH=0Fh)
+</code>
+<code>
+Return: AL = status
+h successful
+h end of file (no data)
+h segment wrap in DTA
+h end of file, partial record read
+	[DTA] = record read from file
+</code>
+<WRAP round box>
+reads a record of the size specified in the FCB beginning at the current file position, then updates the current block and current record fields in the FCB
+if a partial record was read, it is zero-padded to the full size not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=0Fh,AH=15h,AH=1Ah,AH=3Fh,INT 2F/AX=1108h
+===== 15h - DOS 1+ - SEQUENTIAL WRITE TO FCB FILE =====
+<code>
+	AH = 15h
+	DS:DX -> opened FCB (see AH=0Fh)
+	[DTA] = record to write
+</code>
+<code>
+Return: AL = status
+h successful
+h disk full
+h segment wrap in DTA
+</code>
+<WRAP round box>
+Notes:	writes a record of the size specified in the FCB beginning at the current file position, then updates the current block and current record fields in the FCB
+	if less than a full sector is written, the data is placed in a DOS buffer to be written out at a later time
+	not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=0Fh,AH=14h,AH=1Ah,AH=40h,INT 2F/AX=1109h
+===== 16h - DOS 1+ - CREATE OR TRUNCATE FILE USING FCB =====
+	AH = 16h
+	DS:DX -> unopened FCB (see AH=0Fh), wildcards not allowed
+Return: AL = status
+h successful
+	    FFh directory full or file exists and is read-only or locked
+Notes:	if file already exists, it is truncated to zero length
+	if an extended FCB is used, the file is given the attribute in the
+	  FCB
+	not supported by MS Windows 3.0 DOSX.EXE DOS extender
+SeeAlso: AH=0Fh,AH=10h,AH=3Ch
+===== 17h - DOS 1+ - RENAME FILE USING FCB =====
+<code>
+	AH = 17h
+	DS:DX -> modified FCB (see also AH=0Fh)
+		the old filename ('?' wildcards OK) is in the standard location	while the new filename ('?' wildcards OK) is stored in the 11 bytes beginning at offset 11h
+<code>
+</code>
+Return:	AL = status
+h successfully renamed
+	    FFh no matching files,file is read-only, or new name already exists
+</code>
+<WRAP round box>
+subdirectories may be renamed using an extended FCB with the appropriate attribute
+</WRAP>
+SeeAlso: AH=0Fh,AH=13h,AH=56h,INT 2F/AX=1111h
+===== 18h - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY =====
+<code>
+	AH = 18h
+</code>
+<code>
+Return: AL = 00h
+</code>
+<WRAP round box>
+corresponds to the CP/M BDOS function "get bit map of logged drives", which is meaningless under MSDOS
+</WRAP>
+SeeAlso: AH=1Dh,AH=1Eh,AH=20h,AX=4459h
+===== 19h - DOS 1+ - GET CURRENT DEFAULT DRIVE =====
+<code>
+	AH = 19h
+</code>
+<code>
+Return: AL = drive (00h = A:, 01h = B:, etc)
+</code>
+SeeAlo: AH=0Eh,AH=47h
+===== 1Ah - DOS 1+ - SET DISK TRANSFER AREA ADDRESS =====
+<code>
+	AH = 1Ah
+	DS:DX -> Disk Transfer Area (DTA)
+</code>
+<WRAP round box>
+the DTA is set to PSP:0080h when a program is started
+</WRAP>
+SeeAlso: AH=11h,AH=12h,AH=2Fh,AH=4Eh,AH=4Fh
+===== 1Bh - DOS 1+ - GET ALLOCATION INFORMATION FOR DEFAULT DRIVE =====
+<code>
+	AH = 1Bh
+</code>
+<code>
+Return: AL = sectors per cluster (allocation unit)
+	CX = bytes per sector
+	DX = total number of clusters
+	DS:BX -> media ID byte (see below)
+</code>
+<WRAP round box>
+under DOS 1.x, DS:BX points at an actual copy of the FAT; later versions return a pointer to a copy of the FAT's ID byte
+</WRAP>
+SeeAlso: AH=1Ch,AH=36h
+Values for media ID byte:
+|FFh|floppy, double-sided, 8 sectors per track (320K)|
+|FEh|floppy, single-sided, 8 sectors per track (160K)|
+|FDh|floppy, double-sided, 9 sectors per track (360K)|
+|FCh|floppy, single-sided, 9 sectors per track (180K)|
+|F9h|floppy, double-sided, 15 sectors per track (1.2M)|
+|F8h|hard disk|
+|F0h|other|
+===== 1Ch - DOS 1+ - GET ALLOCATION INFORMATION FOR SPECIFIC DRIVE =====
+<code>
+	AH = 1Ch
+	DL = drive (00h = default, 01h = A:, etc)
+</code>
+<code>
+Return: AL = sectors per cluster (allocation unit)
+	CX = bytes per sector
+	DX = total number of clusters
+	DS:BX -> media ID byte (see AH=1Bh)
+</code>
+<WRAP round box>
+under DOS 1.x, DS:BX points at an actual copy of the FAT; later versions return a pointer to a copy of the FAT's ID byte
+</WRAP>
+SeeAlso: AH=1Bh,AH=36h
+===== 1Dh - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY =====
+<code>
+	AH = 1Dh
+</code>
+<code>
+Return: AL = 00h
+</code>
+<WRAP round box>
+corresponds to the CP/M BDOS function "get bit map of read-only drives", which is meaningless under MSDOS
+</WRAP>
+SeeAlso: AH=18h,AH=1Eh,AH=20h,AX=4459h
+===== 1Eh - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY =====
+<code>
+	AH = 1Eh
+</code>
+<code>
+Return: AL = 00h
+</code>
+<WRAP round box>
+corresponds to a CP/M BDOS function which is meaningless under MSDOS
+</WRAP>
+SeeAlso: AH=18h,AH=1Dh,AH=20h
+===== 1Fh - DOS 1+ - GET DRIVE PARAMETER BLOCK FOR DEFAULT DRIVE =====
+<code>
+	AH = 1Fh
+</code>
+<code>
+Return: AL = status
+h successful
+		DS:BX -> Drive Parameter Block (DPB) (see below for DOS 1.x,
+			AH=32h for DOS 2+)
+	    FFh invalid drive
+</code>
+<WRAP round box>
+documented for DOS 5.0, but undocumented in prior versions
+</WRAP>
+SeeAlso: AH=32h
+Format of DOS 1.1 and MSDOS 1.25 drive parameter block:
+^ Offset ^ Size ^Description^
+|00h|BYTE|sequential device ID|
+|01h|BYTE|logical drive number (0=A:)|
+|02h|WORD|bytes per sector|
+|04h|BYTE|highest sector number within a cluster|
+|05h|BYTE|shift count to convert clusters into sectors|
+|06h|WORD|starting sector number of first FAT|
+|08h|BYTE|number of copies of FAT|
+|09h|WORD|number of directory entries|
+|0Bh|WORD|number of first data sector|
+|0Dh|WORD|highest cluster number (number of data clusters + 1)|
+|0Fh|BYTE|sectors per FAT|
+|10h|WORD|starting sector of directory|
+|12h|WORD|address of allocation table|
+<WRAP round box>
+the DOS 1.0 table is the same except that the first and last fields are missing
+</WRAP>
+===== 20h - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY =====
+<code>
+	AH = 20h
+</code>
+<code>
+Return: AL = 00h
+</code>
+<WRAP round box>
+corresponds to the CP/M BDOS function "get/set default user number", which is meaningless under MSDOS
+</WRAP>
+SeeAlso: AH=18h,AH=1Dh,AH=1Eh,AX=4459h
+===== 21h - DOS 1+ - READ RANDOM RECORD FROM FCB FILE =====
+<code>
+	AH = 21h
+	DS:DX -> opened FCB (see AH=0Fh)
+</code>
+<code>
+Return: AL = status
+h successful
+h end of file, no data read
+h segment wrap in DTA, no data read
+h end of file, partial record read
+	[DTA] = record read from file
+</code>
+<WRAP round box>
+the record is read from the current file position as specified by the random record and record size fields of the FCB
+the file position is not updated after reading the record
+if a partial record is read, it is zero-padded to the full size
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=14h,AH=22h,AH=27h,AH=3Fh
+===== 22h - DOS 1+ - WRITE RANDOM RECORD TO FCB FILE =====
+<code>
+	AH = 22h
+	DS:DX -> opened FCB (see AH=0Fh)
+	[DTA] = record to write
+</code>
+<code>
+Return: AL = status
+h successful
+h disk full
+h segment wrap in DTA
+</code>
+<WRAP round box>
+the record is written to the current file position as specified by the random record and record size fields of the FCB
+the file position is not updated after writing the record
+if the record is located beyond the end of the file, the file is extended but the intervening data remains uninitialized
+if the record only partially fills a disk sector, it is copied to a DOS disk buffer to be written out to disk at a later time
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=15h,AH=21h,AH=28h,AH=40h
+===== 23h - DOS 1+ - GET FILE SIZE FOR FCB =====
+<code>
+	AH = 23h
+	DS:DX -> unopened FCB (see AH=0Fh), wildcards not allowed
+</code>
+<code>
+Return: AL = status
+h successful (matching file found)
+		FCB random record field filled with size in records, rounded up
+		to next full record
+	    FFh failed (no matching file found)
+</code>
+<WRAP round box>
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=42h
+===== 24h - DOS 1+ - SET RANDOM RECORD NUMBER FOR FCB =====
+<code>
+	AH = 24h
+	DS:DX -> opened FCB (see AH=0Fh)
+</code>
+<WRAP round box>
+computes the random record number corresponding to the current record number and record size, then stores the result in the FCB
+normally used when switching from sequential to random access
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=21h,AH=27h,AH=42h
+===== 25h - DOS 1+ - SET INTERRUPT VECTOR =====
+<code>
+	AH = 25h
+	AL = interrupt number
+	DS:DX -> new interrupt handler
+</code>
+<WRAP round box>
+this function is preferred over direct modification of the interrupt vector table
+</WRAP>
+SeeAlso: AH=35h
+===== 25xxh - Phar Lap 386/DOS-Extender =====
+==== 2501h - Phar Lap 386/DOS-Extender - RESET 386/DOS-EXTENDER DATA STRUCTURES ====
+<code>
+	AX = 2501h
+</code>
+<code>
+Return: CF clear
+</code>
+Note:	Phar Lap uses INT 21/AH=25h as the entry point for all 386/DOS-Extender
+	  system calls.	 Only available when directly using 386/DOS-Extender,
+	  or when using a product that was created using 386-DOS/Extender
+SeeAlso: AH=30h"Phar Lap"
+==== 2502h - Phar Lap 386/DOS-Extender - GET PROTECTED-MODE INTERRUPT VECTOR ====
+	AX = 2502h
+	CL = interrupt number
+Return: ES:EBX -> 48-bit address of protected-mode interrupt handler
+	CF clear
+SeeAlso: AX=2503h,AX=2504h,INT 31/AX=0204h
+==== 2503h - Phar Lap 386/DOS-Extender - GET REAL-MODE INTERRUPT VECTOR ====
+	AX = 2503h
+	CL = interrupt number
+Return: EBX = 32-bit address of real-mode interrupt handler
+	CF clear
+SeeAlso: AX=2502h,AX=2504h,AH=35h,INT 31/AX=0200h
+==== 2504 - Phar Lap 386/DOS-Extender - SET PROTECTED-MODE INTERRUPT VECTOR ====
+	AX = 2504h
+	CL = interrupt number
+	DS:EDX -> 48-bit address of protected-mode interrupt handler
+Return: CF clear
+SeeAlso: AX=2502h,AX=2505h,INT 31/AX=0205h
+==== 2505h - Phar Lap 386/DOS-Extender - SET REAL-MODE INTERRUPT VECTOR ====
+	AX = 2505h
+	CL = interrupt number
+	EBX = 32-bit address of real-mode interrupt handler
+Return: CF clear
+SeeAlso: AX=2503h,AX=2504h,INT 31/AX=0201h
+==== 2506h - Phar Lap 386/DOS-Extender - SET INT TO ALWAYS GAIN CONTRL IN PROT MODE ====
+	AX = 2506h
+	CL = interrupt number
+	DS:EDX -> 48-bit address of protected-mode interrupt handler
+Return: CF clear
+Note:	This function modifies both the real-mode low-memory interrupt
+	  vector table and the protected-mode Interrupt Descriptor Table (IDT)
+	Interrupts occurring in real mode are resignaled in protected mode.
+==== 2507h - Phar Lap 386/DOS-Extender - SET REAL- & PROTECTED-MODE INT VECTORS ====
+	AX = 2507h
+	CL = interrupt number
+	DS:EDX -> 48-bit address of protected-mode interrupt handler
+	EBX = 32-bit address of real-mode interrupt handler
+Return: CF clear
+Note:	interrupts are disabled until both vectors have been modified
+SeeAlso: AX=2504h,AX=2505h
+==== 2508h - Phar Lap 386/DOS-Extender - GET SEGMENT LINEAR BASE ADDRESS ====
+	AX = 2508h
+	BX = segment selector
+Return: CF clear if successful
+	    ECX = linear base address of segment
+	CF set if invalid segment selector
+==== 2509h - Phar Lap 386/DOS-Extender - CONVERT LINEAR TO PHYSICAL ADDRESS ====
+	AX = 2509h
+	EBX = linear address to convert
+Return: CF clear if successful
+	    ECX = physical address (carry flag clear)
+	CF set if linear address not mapped in page tables
+==== 250Ah - Phar Lap 386/DOS-Extender - MAP PHYSICAL MEMORY AT END OF SEGMENT ====
+	AX = 250Ah
+	ES = segment selector in the Local Descriptor Table (LDT) of segment
+	     to modify
+	EBX = physical base address of memory to map (multiple of 4K)
+	ECX = number of physical 4K pages to map
+Return: CF clear if successful
+	    EAX = 32-bit offset in segment of mapped memory
+	CF set on error
+	    EAX = error code
+h insufficient memory to create page tables
+h invalid segment selector
+SeeAlso: INT 31/AX=0800h
+==== 250Ch - Phar Lap 386/DOS-Extender - GET HARDWARE INTERRUPT VECTORS ====
+	AX = 250Ch
+Return: CF clear
+	AL = base interrupt vector for IRQ0-IRQ7
+	AH = base interrupt vector for IRQ8-IRQ15
+	BL = interrupt vector for BIOS print screen function
+SeeAlso: INT 31/AX=0400h
+==== 250Dh - Phar Lap 386/DOS-Extender - GET REAL-MODE LINK INFORMATION ====
+	AX = 250Dh
+Return: CF clear
+	EAX = 32-bit address of real-mode 386/DOS-Extender proc that will call
+	      through from real mode to a protected-mode routine
+	EBX = 32-bit real-mode address of intermode call data buffer
+	ECX = size in bytes of intermode call data buffer
+	ES:EDX -> protected-mode address of intermode call data buffer
+==== 250Eh - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE ====
+	AX = 250Eh
+	EBX = 32-bit address of real-mode procedure to call
+	ECX = number of two-byte words to copy from protected-mode stack
+	      to real-mode stack
+Return: CF clear if successful
+	    all segment registers unchanged
+	    all general registers contain values set by real-mode procedure
+	    all other flags set as they were left by real-mode procedure
+	CF set on error
+	    EAX = error code
+h not enough real-mode stack space
+SeeAlso: AH=E1h"OS/286",INT 31/AX=0301h
+==== 250Fh - Phar Lap 386/DOS-Extender - CONVERT PROTECTED-MODE ADDRESS TO MS-DOS ====
+	AX = 250Fh
+	ES:EBX -> 48-bit protected-mode address to convert
+	ECX = length of data, in bytes
+Return: CF clear if successful
+	    ECX = 32-bit MS-DOS address
+	CF set on error
+	    ECX destroyed
+SeeAlso: AX=2510h
+==== 2510h - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE, REGISTERS ====
+	AX = 2510h
+	EBX = 32-bit address of real-mode procedure to call
+	ECX = number of two-byte words to copy to protected-mode stack to
+	      real-mode stack
+	DS:EDX -> pointer to parameter block (see below)
+Return: CF clear if successful
+	    all segment registers unchanged,
+	    EDX unchanged
+	    all other general registers contain values set by real-mode proc
+	    all other flags are set as they were left by real-mode procedure
+	    real-mode register values are returned in the parameter block
+	CF set on error
+	    EAX = error code
+h not enough real-mode stack space
+SeeAlso: AX=250Fh
+Format of parameter block:
+Offset	Size	Description
+h	WORD	real-mode DS value
+h	WORD	real-mode ES value
+h	WORD	real-mode FS value
+h	WORD	real-mode GS value
+h	DWORD	real-mode EAX value
+Ch	DWORD	real-mode EBX value
+h	DWORD	real-mode ECX value
+h	DWORD	real-mode EDX value
+==== 2511h - Phar Lap 386/DOS-Extender - ISSUE REAL-MODE INTERRUPT ====
+	AX = 2511h
+	DS:EDX -> pointer to parameter block (see below)
+Return: all segment registers unchanged
+	EDX unchanged
+	all other registers contain values set by the real-mode int handler
+	the flags are set as they were left by the real-mode interrupt handler
+	real-mode register values are returned in the parameter block
+SeeAlso: AX=2503h,AX=2505h,AH=E3h"OS/286",INT 31/AX=0300h
+Format of parameter block:
+Offset	Size	Description
+h	WORD	interrupt number
+h	WORD	real-mode DS value
+h	WORD	real-mode ES value
+h	WORD	real-mode FS value
+h	WORD	real-mode GS value
+Ah	DWORD	real-mode EAX value
+Eh	DWORD	real-mode EDX value
+Note: all other real-mode values set from protected-mode registers
+==== 2512h - Phar Lap 386/DOS-Extender - LOAD PROGRAM FOR DEBUGGING ====
+	AX = 2512h
+	DS:EDX -> pointer to ASCIIZ program name
+	ES:EBX -> pointer to parameter block (see below)
+	ECX = size in bytes of LDT buffer
+Return: CF clear if successful
+	    EAX = number of segment descriptors in LDT
+	CF set on error
+	    EAX = error code
+h file not found or path invalid
+h access denied
+h insufficient memory
+Ah environment invalid
+Bh invalid file format
+h LDT too small
+Format of parameter block:
+Offset	Size	Description
+Input:
+h	DWORD	32-bit offset of environment string
+h	WORD	segment of environment string
+h	DWORD	32-bit offset of command-tail string
+Ah	WORD	segment of command-tail string
+Ch	DWORD	32-bit offset of LDT buffer (size in ECX)
+h	WORD	segment of LDT buffer
+Output:
+h	WORD	real-mode paragraph address of PSP (see also AH=26h)
+h	WORD	real/protected mode flag
+h  real mode
+h  protected mode
+h	DWORD	initial EIP value
+Ah	WORD	initial CS value
+Ch	DWORD	initial ESP value
+h	WORD	initial SS value
+h	WORD	initial DS value
+h	WORD	initial ES value
+h	WORD	initial FS value
+h	WORD	initial GS value
+==== 2513h - Phar Lap 386/DOS-Extender - ALIAS SEGMENT DESCRIPTOR ====
+	AX = 2513h
+	BX = segment selector of descriptor in GDT or LDT
+	CL = access-rights byte for alias descriptor
+	CH = use-type bit (USE16 or USE32) for alias descriptor
+Return: CF clear if successful
+	    AX = segment selector for created alias
+	CF set on error
+	    EAX = error code
+h insufficient memory (can't grow LDT)
+h invalid segment selector in BX
+==== 2514h - Phar Lap 386/DOS-Extender - CHANGE SEGMENT ATTRIBUTES ====
+	AX = 2514h
+	BX = segment selector of descriptor in GDT or LDT
+	CL = new access-rights byte
+	CH = new use-type bit (USE16 or USE32)
+Return: CF clear if successful
+	CF set on error
+	    EAX = error code
+h invalid selector in BX
+SeeAlso: AX=2515h,INT 31/AX=0009h
+==== 2515h - Phar Lap 386/DOS-Extender - GET SEGMENT ATTRIBUTES ====
+	AX = 2515h
+	BX = segment selector of descriptor in GDT or LDT
+Return: CF clear if successful
+	    CL = access-rights byte for segment
+	    CH = use-type bit (USE16 or USE32)
+	ECX<16-31> destroyed
+	CF set on error
+	    EAX = error code
+h invalid segment selector in BX
+SeeAlso: AX=2514h
+==== 2516h - Phar Lap 386/DOS-Extender - FREE ALL MEMORY OWNED BY LDT ====
+	AX = 2516h
+	???
+Return: ???
+==== 2517h - Phar Lap 386/DOS-Extender - GET INFO ON DOS DATA BUFFER ====
+	AX = 2517h
+	???
+Return: ???
+==== 2518h - Phar Lap 386/DOS-Extender - SPECIFY HANDLER FOR MOVED SEGMENTS ====
+	AX = 2518h
+	???
+Return: ???
+==== 2519h - Phar Lap 386/DOS-Extender VMM - GET ADDITIONAL MEMORY ERROR INFO ====
+	AX = 2519h
+Return: CF clear
+	EAX = error code
+h  no error
+h  out of physical memory
+h  out of swap space (unable to grow swap file)
+h  out of LDT entries and unable to grow LDT
+h  unable to change extended memory allocation mark
+	    FFFFFFFFh	paging disabled
+Note:	VMM is the Virtual Memory Manager option
+==== 251Ah - Phar Lap 386/DOS-Extender VMM - LOCK PAGES IN MEMORY ====
+	AX = 251Ah
+	EDX = number of 4k pages to lock
+	if BL = 00h
+	    ECX = linear address of first page to lock
+	if BL = 01h
+	    ES:ECX -> pointer to first page to lock
+Return: CF clear if successful
+	CF set on error
+	    EAX = error code
+h insufficient memory
+h invalid address range
+SeeAlso: AX=251Bh,AX=EB06h,INT 31/AX=0600h
+==== 251Bh - Phar Lap 386/DOS-Extender VMM - UNLOCK PAGES ====
+	AX = 251Bh
+	EDX = number of pages to unlock
+	if BL = 00h
+	    ECX = linear address of first page to unlock
+	if BL = 01h
+	    ES:ECX -> pointer to first page to unlock
+Return: CF clear if successful
+	CF set on error
+	    EAX = error code
+h invalid address range
+SeeAlso: AX=251Ah,AX=EB07h,INT 31/AX=0601h
+==== 251Dh - Phar Lap 386/DOS-Extender VMM - READ PAGE-TABLE ENTRY ====
+	AX = 251Dh
+	???
+Return: ???
+SeeAlso: AX=251Eh,AX=EB00h,INT 31/AX=0506h
+==== 251Eh - Phar Lap 386/DOS-Extender VMM - WRITE PAGE-TABLE ENTRY ====
+	AX = 251Eh
+	???
+Return: ???
+SeeAlso: AX=251Dh,INT 31/AX=0507h
+==== 251Fh - Phar Lap 386/DOS-Extender VMM - EXHANGE TWO PAGE-TABLE ENTRIES ====
+	AX = 251Fh
+	???
+Return: ???
+SeeAlso: AX=251Dh,AX=251Eh
+==== 2520h - Phar Lap 386/DOS-Extender VMM - GET MEMORY STATISTICS ====
+	AX = 2520h
+	DS:EDX -> pointer to buffer at least 100 bytes in size (see below)
+	BL = 0 (don't reset VM stats), 1 (reset VM stats)
+Return: carry flag clear
+Format of VM stats buffer:
+Offset	Size	Description
+h	DWORD	VM status
+h VM subsystem is present
+h VM not present
+h	DWORD	"nconvpg" number of conventional memory pages available
+h	DWORD	"nbimpg" number of Compaq built-in memory pages available
+Ch	DWORD	"nextpg" total number of extended memory pages
+h	DWORD	"extlim" extender memory pages limit
+h	DWORD	"aphyspg" number of physical memory pages allocated to appl
+h	DWORD	"alockpg" number of locked pages owned by application
+Ch	DWORD	"sysphyspg" number physical memory pages allocated to system
+h	DWORD	"nfreepg" number of free physical pages; approx if EMS VCPI
+h	DWORD	linear address of beginning of application address space
+h	DWORD	linear address of end of application address space
+Ch	DWORD	number of seconds since last time VM stats were reset
+h	DWORD	number of page faults since last time
+h	DWORD	number of pages written to swap file since last time
+h	DWORD	number of reclaimed pages (page faults on swapped pages)
+Ch	DWORD	number of virtual pages allocated to the application
+h	DWORD	size in pages of swap file
+h	DWORD	number of system pages allocated with EMS calls
+h	DWORD	minimum number of conventional memory pages
+Ch	DWORD	maximum size in bytes to which swap file can be increased
+h	DWORD	"vmflags" bit 0 = 1 if page fault in progress
+h 16 BYTEs	reserved for future expansion (set to zero)
+==== 2521h - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S EXTENDED MEMORY USAGE ====
+	AX = 2521h
+	EBX = max 4k pages of physical extended memory which program may use
+Return: CF clear if successful
+	   EBX = maximum limit in pages
+	   ECX = minimum limit in pages
+	CF set on error
+	    EAX = error code
+h insufficient memory or -nopage switch used
+SeeAlso: AX=2522h
+==== 2522h - Phar Lap 386/DOS-Extender VMM - SPECIFY ALTERNATE PAGE-FAULT HANDLER ====
+	AX = 2522h
+	???
+Return: ???
+SeeAlso: AX=2523h
+==== 2523h - Phar Lap 386/DOS-Extender VMM - SPECIFY OUT-OF-SWAP-SPACE HANDLER ====
+	AX = 2523h
+	???
+Return: ???
+SeeAlso: AX=2522h
+==== 2524h - Phar Lap 386/DOS-Extender VMM - INSTALL PAGE-REPLACEMENT HANDLERS ====
+	AX = 2524h
+	???
+Return: ???
+==== 2525h - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S CONVENTIONAL MEM USAGE ====
+	AX = 2525h
+	EBX = limit in 4k pages of physical conventional memory which program
+	      may use
+Return: CF clear if successful
+	    EBX = maximum limit in pages
+	    ECX = minimum limit in pages
+	CF set on error
+	    EAX = error code
+h insufficient memory or -nopage switch used
+SeeAlso: AX=2521h
+==== 2526h - Phar Lap 386/DOS-Extender - GET CONFIGURATION INFORMATION ====
+	AX = 2526h
+	???
+Return: ???
+==== 25C0h - Phar Lap 386/DOS-Extender - ALLOCATE MS-DOS MEMORY BLOCK ====
+	AX = 25C0h
+	BX = number of 16-byte paragraphs of MS-DOS memory requested
+Return: CF clear if successful
+	    AX = real-mode paragraph address of memory
+	CF set on error
+	    AX = error code
+h MS-DOS memory control blocks destroyed
+h insufficient memory
+	    BX = size in paragraphs of largest available memory block
+SeeAlso: AX=25C1h,AX=25C2h
+==== 25C1h - Phar Lap 386/DOS-Extender - RELEASE MS-DOS MEMORY BLOCK ====
+	AX = 25C1h
+	CX = real-mode paragraph address of memory block to free
+Return: CF clear if successful
+	    EAX destroyed
+	CF set on error
+	    AX = error code
+h MS-DOS memory control blocks destroyed
+h invalid memory block address in CX
+SeeAlso: AX=25C0h,AX=25C2h
+==== 25C2h - Phar Lap 386/DOS-Extender - MODIFY MS-DOS MEMORY BLOCK ====
+	AX = 25C2h
+	BX = new requested block size in paragraphs
+	CX = real-mode paragraph address of memory block to modify
+Return: CF clear if successful
+	    EAX destroyed
+	CF set on error
+	    AX = error code
+h MS-DOS memory control blocks destroyed
+h insufficient memory
+h invalid memory block address in CX
+	    BX = size in paragraphs of largest available memory block
+SeeAlso: AX=25C0h,AX=25C1h
+==== 25C3h - Phar Lap 386/DOS-Extender - EXECUTE PROGRAM ====
+	AX = 25C3h
+	ES:EBX -> pointer to parameter block (see below)
+	DS:EDX -> pointer to ASCIIZ program filename
+Return: CF clear if successful
+	    all registers unchanged
+	CF set on error
+	    EAX = error code
+h function code in AL is invalid ???
+h file not found or path invalid
+h access denied
+h insufficient memory to load program
+Ah environment invalid
+Bh invalid file format
+Format of parameter block:
+Offset	Size	Description
+h	DWORD	32-bit offset of environment string
+h	WORD	segment selector of environment string
+h	DWORD	32-bit offset of command-tail string
+Ah	WORD	segment selector of command-tail string
+===== 26h - DOS 1+ - CREATE NEW PROGRAM SEGMENT PREFIX =====
+<code>
+	AH = 26h
+	DX = segment at which to create PSP (see below for format)
+</code>
+<WRAP round box>
+new PSP is updated with memory size information; INTs 22h, 23h, 24h taken from interrupt vector table
+(DOS 2+) DOS assumes that the caller's CS is the segment of the PSP to copy
+</WRAP>
+SeeAlso: AH=4Bh,AH=50h,AH=51h,AH=55h,AH=62h,AH=67h
+== Format of PSP: ==
+^ Offset ^ Size ^Description^
+|00h|2 BYTEs	|INT 20 instruction for CP/M CALL 0 program termination|
+|02h|WORD	|segment of first byte beyond memory allocated to program|
+|04h|BYTE	|unused filler|
+|05h|BYTE	|CP/M CALL 5 service request (FAR JMP to 000C0h)\\ BUG: (DOS 2+) PSPs created by INT 21/AH=4Bh point at 000BEh|
+|06h|WORD	|CP/M compatibility--size of first segment for .COM files|
+|08h|2 BYTEs	|remainder of FAR JMP at 05h|
+|0Ah|DWORD	|stored INT 22 termination address|
+|0Eh|DWORD	|stored INT 23 control-Break handler address|
+|12h|DWORD	|DOS 1.1+ stored INT 24 critical error handler address|
+|16h|WORD	|segment of parent PSP|
+|18h|20 BYTEs	|DOS 2+ Job File Table, one byte per file handle, FFh = closed|
+|2Ch|WORD	|DOS 2+ segment of environment for process|
+|2Eh|DWORD	|DOS 2+ process's SS:SP on entry to last INT 21 call|
+|32h|WORD	|DOS 3+ number of entries in JFT (default 20)|
+|34h|DWORD	|DOS 3+ pointer to JFT (default PSP:0018h)|
+|38h|DWORD	|DOS 3+ pointer to previous PSP (default FFFFFFFFh in 3.x)\\ used by SHARE in DOS 3.3|
+|3Ch |4 BYTEs	|unused by DOS versions <= 5.00|
+|40h |2 BYTEs	|DOS 5.0 version to return on INT 21/AH=30h|
+|42h |6 BYTEs	|unused by DOS versions <= 5.00|
+|48h|BYTE	|(MSWindows3) bit 0 set if non-Windows application|
+|49h |7 BYTEs	|unused by DOS versions <= 5.00|
+|50h |3 BYTEs	|DOS 2+ service request (INT 21/RETF instructions)|
+|53h |9 BYTEs	|unused in DOS versions <= 5.00|
+|5Ch |16 BYTEs	|first default FCB, filled in from first commandline argument overwrites second FCB if opened|
+|6Ch |16 BYTEs	|second default FCB, filled in from second commandline argument overwrites beginning of commandline if opened|
+|7Ch |4 BYTEs	|unused|
+|80h |128 BYTEs	|commandline / default DTA\\ command tail is BYTE for length of tail, N BYTEs for the tail, followed by a BYTE containing 0Dh|
+<WRAP round box>
+in DOS versions 3.0 and up, the limit on simultaneously open files may be increased by allocating memory for a new open file table, filling it with FFh, copying the first 20 bytes from the default table, and adjusting the pointer and count at 34h and 32h.  However, DOS versions through  at least 3.30 will only copy the first 20 file handles into a child PSP (including the one created on EXEC).
+network redirectors based on the original MS-Net implementation use values of 80h-FEh in the open file table to indicate remote files
+MSDOS 5.00 incorrectly fills the FCB fields when loading a program high; the first FCB is empty and the second contains the first parameter
+</WRAP>
+== Format of environment block: ==
+^  Offset       ^  Size    ^ Description                                                   ^
+| 00h           | N BYTEs  | first environment variable, ASCIZ string of form "var=value"  |
+|               | N BYTEs  | second environment variable, ASCIZ string                     |
+|  ...                                                                                   |||
+|               | N BYTEs  | last environment variable, ASCIZ string of form "var=value"   |
+|               | BYTE     | 00h                                                           |
+| ---DOS 3+---                                                                           |||
+|               | WORD     | number of strings following environment (normally 1)          |
+|               | N BYTEs  | ASCIZ full pathname of program owning this environment        |
+|               |          | other strings may follow                                      |
+===== 27h - DOS 1+ - RANDOM BLOCK READ FROM FCB FILE =====
+<code>
+	AH = 27h
+	CX = number of records to read
+	DS:DX -> opened FCB (see AH=0Fh)
+</code>
+<code>
+Return: AL = status
+h successful, all records read
+h end of file, no data read
+h segment wrap in DTA, no data read
+h end of file, partial read
+	[DTA] = records read from file
+	CX = number of records read (return AL = 00h or 03h)
+</code>
+<WRAP round box>
+read begins at current file position as specified in FCB; the file position is updated after reading
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=21h,AH=28h,AH=3Fh
+===== 28h - DOS 1+ - RANDOM BLOCK WRITE TO FCB FILE =====
+<code>
+	AH = 28h
+	CX = number of records to write
+	DS:DX -> opened FCB (see AH=0Fh)
+	[DTA] = records to write
+</code>
+<code>
+Return: AL = status
+h successful
+h disk full or file read-only
+h segment wrap in DTA
+	CX = number of records written
+</code>
+<WRAP round box>
+write begins at current file position as specified in FCB; the file position is updated after writing
+if CX = 0000h on entry, no data is written; instead the file size is adjusted to be the same as the file position specified by the random record and record size fields of the FCB
+if the data to be written is less than a disk sector, it is copied into a DOS disk buffer, to be written out to disk at a later time
+not supported by MS Windows 3.0 DOSX.EXE DOS extender
+</WRAP>
+SeeAlso: AH=22h,AH=27h,AH=40h,AH=59h
+===== 29h - DOS 1+ - PARSE FILENAME INTO FCB =====
+<code>
+	AH = 29h
+	AL = parsing options
+	    bit 0: skip leading separators
+	    bit 1: use existing drive number in FCB if no drive is specified,
+		   instead of setting field to zero
+	    bit 2: use existing filename in FCB if no base name is specified,
+		   instead of filling field with blanks
+	    bit 3: use existing extension in FCB if no extension is specified,
+		   instead of filling field with blanks
+	    bits 4-7: reserved (0)
+	DS:SI -> filename string (both '*' and '?' wildcards OK)
+	ES:DI -> buffer for unopened FCB
+</code>
+<code>
+Return: AL = result code
+h successful parse, no wildcards encountered
+h successful parse, wildcards present
+	    FFh failed (invalid drive specifier)
+	DS:SI -> first unparsed character
+	ES:DI buffer filled with unopened FCB (see AH=0Fh)
+</code>
+<WRAP round box>
+asterisks expanded to question marks in the FCB
+all processing stops when a filename terminator is encountered
+cannot be used with filespecs which include a path (DOS 2+)
+</WRAP>
+SeeAlso: AH=0Fh,AH=16h,AH=26h
+===== 2Ah - DOS 1+ - GET SYSTEM DATE =====
+<code>
+	AH = 2Ah
+</code>
+<code>
+Return: CX = year (1980-2099)
+	DH = month
+	DL = day
+---DOS 1.10+---
+	AL = day of week (00h=Sunday)
+</code>
+SeeAlso: AH=2Bh"DOS",AH=2Ch,AH=E7h,INT 1A/AH=04h,INT 2F/AX=120Dh
+===== 2Bh =====
+==== 2Bh - DOS 1+ - SET SYSTEM DATE ====
+<code>
+	AH = 2Bh
+	CX = year (1980-2099)
+	DH = month
+	DL = day
+</code>
+<code>
+Return: AL = status
+h successful
+	    FFh invalid date, system date unchanged
+</code>
+<WRAP round box>
+DOS 3.3+ also sets CMOS clock
+</WRAP>
+SeeAlso: AH=2Ah,AH=2Dh,INT 1A/AH=05h
+==== 2Bh - AI Architects - ??? - INSTALLATION CHECK ====
+<code>
+	AH = 2Bh
+	CX = 4149h ('AI')
+	DX = 413Fh ('A?')
+</code>
+<code>
+Return: AL <> FFh if installed
+</code>
+<WRAP round box>
+Borland's TKERNEL makes this call
+</WRAP>
+==== 2Bh - PC Tools v5.x PC-Cache - INSTALLATION CHECK ====
+<code>
+	AH = 2Bh
+	CX = 4358h ('CX')
+</code>
+<code>
+Return: AL = FFh if PC-Cache not installed
+	AL = 00h if installed
+	    CX = 6378h ('cx')
+	    BX = ???
+	    DX = ???
+</code>
+SeeAlso: INT 16/AX=FFA5h/CX=1111h
+==== 2Bh - DESQview - INSTALLATION CHECK ====
+<code>
+	AH = 2Bh
+	CX = 4445h ('DE')
+	DX = 5351h ('SQ')
+	AL = subfunction (DV v2.00+)
+h get version
+		Return: BX = version (BH = major, BL = minor)
+		Note: early copies of v2.00 return 0002h
+h get shadow buffer info, and start shadowing
+		Return: BH = rows in shadow buffer
+			BL = columns in shadow buffer
+			DX = segment of shadow buffer
+h get shadow buffer info
+		Return: BH = rows in shadow buffer
+			BL = columns in shadow buffer
+			DX = segment of shadow buffer
+h stop shadowing
+</code>
+<code>
+Return: AL = FFh if DESQview not installed
+</code>
+<WRAP round box>
+in DESQview v1.x, there were no subfunctions; this call only identified	whether or not DESQview was loaded
+</WRAP>
+SeeAlso: INT 10/AH=FEh,INT 10/AH=FFh,INT 15/AX=1024h,INT 15/AX=DE30h
+==== 2Bh - ELRES v1.1 - INSTALLATION CHECK ====
+<code>
+	AH = 2Bh
+	CX = 454Ch ('EL')
+	DX = 5253h ('RS')
+</code>
+<code>
+Return: ES:BX -> ELRES history structure (see below)
+	DX = DABEh (signature, DAve BEnnett)
+</code>
+<WRAP round box>
+ELRES is an MSDOS return code (errorlevel) recorder by David H. Bennett which stores recent errorlevel values, allows them to be retrieved for use in batch files, and can place them in an environment variable
+</WRAP>
+SeeAlso: AH=4Bh"ELRES",AH=4Dh
+== Format of ELRES history structure: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|number of return codes which can be stored by following buffer|
+|02h|WORD|current position in buffer (treated as a ring)|
+|04h|N BYTEs|ELRES buffer|
+==== 2Bh - TAME v2.10+ - INSTALLATION CHECK ====
+<code>
+	AX = 2B01h
+	CX = 5441h ('TA')
+	DX = 4D45h ('ME')
+---v2.60---
+	BH = ???
+h skip ???, else do
+</code>
+<code>
+Return: AL = 02h if installed
+	ES:DX -> data area in TAME-RES (see below)
+</code>
+<WRAP round box>
+TAME is a shareware program by David G. Thomas which gives up CPU time to other partitions under a multitasker when the current partition's program incessantly polls the keyboard or system time
+</WRAP>
+== Format of TAME 2.10-2.20 data area: ==
+^ Offset ^ Size  ^Description^
+| 00h	|BYTE	|data structure minor version number (01h in TAME 2.20)|
+| 01h	|BYTE	|data structure major version number (07h in TAME 2.20)|
+| 02h	|DWORD	|number of task switches|
+| 06h	|DWORD	|number of keyboard polls|
+| 0Ah	|DWORD	|number of time polls|
+| 0Eh	|DWORD	|number of times DESQview told program runs only in foreground|
+| 12h	|DWORD	|original INT 10h|
+| 16h	|DWORD	|original INT 14h|
+| 1Ah	|DWORD	|original INT 15h|
+| 1Eh	|DWORD	|original INT 16h|
+| 22h	|DWORD	|original INT 17h|
+| 26h	|DWORD	|original INT 21h|
+| 2Ah	|DWORD	|original INT 28h|
+| 2Eh	|WORD	|offset of TAME INT 10h handler|
+| 30h	|WORD	|offset of TAME INT 14h handler|
+| 32h	|WORD	|offset of TAME INT 15h handler|
+| 34h	|WORD	|offset of TAME INT 16h handler|
+| 36h	|WORD	|offset of TAME INT 17h handler|
+| 38h	|WORD	|offset of TAME INT 21h handler|
+| 3Ah	|WORD	|offset of TAME INT 28h handler|
+| 3Ch	|WORD	|X in /max:X,Y or /freq:X,Y|
+| 3Eh	|WORD	|Y in /max:X,Y or /freq:X,Y|
+| 40h	|WORD	|number of polls remaining before next task switch|
+| 42h	|WORD	|/KEYIDLE value|
+| 44h	|BYTE	|flags for interrupts already grabbed by TAME\\ bit 0: INT 10h\\ bit 1: INT 14h\\ bit 2: INT 15h\\ bit 3: INT 16h\\ bit 4: INT 17h\\ bit 5: INT 21h\\ bit 6: INT 28h|
+| 45h	|BYTE	|flags for interrupts which may be acted on (same bits as above)|
+| 46h	|BYTE	|TAME enabled (01h) or disabled (00h)|
+| 47h	|BYTE	|/TIMEPOLL (01h) or /NOTIMEPOLL (00h)|
+| 48h	|BYTE	|/NOTIMER (01h) or /TIMER (00h)|
+| 49h	|BYTE	|window or task number for this task|
+| 4Ah	|BYTE	|multitasker type ???\\ 01h DESQview\\ 02h DoubleDOS\\ 03h TopView\\ ???|
+| 4Bh	|BYTE	|type of task switching selected\\ bit 0: DESQview???\\ bit 1: DoubleDOS???\\ bit 2: TopView???\\ bit 3: KeySwitch\\ bit 4: HLT instruction|
+| 4Ch	|BYTE	|???|
+| 4Dh	|BYTE	|flags\\	bit 1: /FREQ instead of /MAX|
+| 4Eh	|BYTE	|/FG: value|
+| 4Fh	|BYTE	|task switches left until next FGONLY DESQview API call|
+| 50h	|BYTE	|???|
+== Format of TAME 2.30 data area: ==
+^ Offset ^ Size ^Description^
+| 00h	|BYTE	|data structure minor version number (02h in TAME 2.30)|
+| 01h	|BYTE	|data structure major version number (0Ah in TAME 2.30)|
+| 02h	|DWORD	|number of task switches|
+| 06h	|DWORD	|number of keyboard polls|
+| 0Ah	|DWORD	|number of time polls|
+| 0Eh	|DWORD	|number of times DESQview told program runs only in foreground|
+| 12h	|DWORD	|time of last /CLEAR or TAME-RES load|
+| 16h	|DWORD	|time yielded|
+| 1Ah	|DWORD	|time spent polling|
+| 1Eh	|DWORD	|time spent waiting on key input with INT 16/AH=01h,11h|
+| 22h	|DWORD	|original INT 10h|
+| 26h	|DWORD	|original INT 14h|
+| 2Ah	|DWORD	|original INT 15h|
+| 2Eh	|DWORD	|original INT 16h|
+| 32h	|DWORD	|original INT 17h|
+| 36h	|DWORD	|original INT 21h|
+| 3Ah	|DWORD	|original INT 28h|
+| 3Eh	|WORD	|offset of TAME INT 10h handler|
+| 40h	|WORD	|offset of TAME INT 14h handler|
+| 42h	|WORD	|offset of TAME INT 15h handler|
+| 44h	|WORD	|offset of TAME INT 16h handler|
+| 46h	|WORD	|offset of TAME INT 17h handler|
+| 48h	|WORD	|offset of TAME INT 21h handler|
+| 4Ah	|WORD	|offset of TAME INT 28h handler|
+| 4Ch	|WORD	|X in /max:X,Y or /freq:X,Y|
+| 4Eh	|WORD	|Y in /max:X,Y or /freq:X,Y|
+| 50h	|WORD	|number of polls remaining before next task switch|
+| 52h	|WORD	|/KEYIDLE value|
+| 54h	|WORD	|/FG: value|
+| 56h	|WORD	|task switches left until next FGONLY DESQview API call|
+| 58h	|WORD	|multitasker version|
+| 5Ah	|WORD	|virtual screen segment|
+| 5Ch	|BYTE	|flags for interrupts already grabbed by TAME\\ bit 0: INT 10h\\ bit 1: INT 14h\\ bit 2: INT 15h\\ bit 3: INT 16h\\ bit 4: INT 17h\\ bit 5: INT 21h\\ bit 6: INT 28h|
+| 5Dh	|BYTE	|flags for interrupts which may be acted on (same bits as above)|
+| 5Eh	|BYTE	|window or task number for this task|
+| 5Fh	|BYTE	|multitasker type\\ 01h DESQview\\ 02h DoubleDOS\\ 03h TopView\\ 04h OmniView\\ 05h VM/386|
+| 60h	|BYTE	|type of task switching selected (bit flags)\\ bit 0: DESQview\\ bit 1: DoubleDOS\\ bit 2: TopView\\ bit 3: OmniView\\ bit 4: KeySwitch\\ bit 5: HLT instruction|
+| 61h	|BYTE	|watch_DOS|
+| 62h	|BYTE	|bit flags\\ bit 0: TAME enabled\\ bit 1: /FREQ instead of /MAX (counts in 3Ch and 3Eh per tick)\\ bit 2: /TIMEPOLL\\ bit 3: /KEYPOLL\\ bit 4: inhibit timer\\ bit 5: enable status monitoring|
+| 63h	|BYTE	|old status|
+| 64h	|WORD	|signature DA34h|
+== Format of TAME 2.60 data area: ==
+^ Offset ^ Size ^Description^
+| 00h|BYTE|data structure minor version number (02h in TAME 2.60)|
+| 01h|BYTE|data structure major version number (0Bh in TAME 2.60)|
+| 02h|DWORD|number of task switches|
+| 06h|DWORD|number of keyboard polls|
+| 0Ah|DWORD|number of time polls|
+| 0Eh|DWORD|number of times DESQview told program runs only in foreground|
+| 12h|DWORD|time of last /CLEAR or TAME-RES load|
+| 16h|DWORD|time yielded|
+| 1Ah|DWORD|time spent polling|
+| 1Eh|DWORD|time spent waiting on key input with INT 16/AH=01h,11h|
+| 22h|4 BYTEs|???|
+| 26h|DWORD|original INT 10h|
+| 2Ah|DWORD|original INT 14h|
+| 2Eh|DWORD|original INT 15h|
+| 32h|DWORD|original INT 16h|
+| 36h|DWORD|original INT 17h|
+| 3Ah|DWORD|original INT 21h|
+| 3Eh|DWORD|original INT 28h|
+| 42h|WORD|offset of TAME INT 10h handler|
+| 44h|WORD|offset of TAME INT 14h handler|
+| 46h|WORD|offset of TAME INT 15h handler|
+| 48h|WORD|offset of TAME INT 16h handler|
+| 4Ah|WORD|offset of TAME INT 17h handler|
+| 4Ch|WORD|offset of TAME INT 21h handler|
+| 4Eh|WORD|offset of TAME INT 28h handler|
+| 50h|WORD|X in /max:X,Y or /freq:X,Y|
+| 52h|WORD|Y in /max:X,Y or /freq:X,Y|
+| 54h|WORD|number of polls remaining before next task switch|
+| 56h|WORD|/KEYIDLE value|
+| 58h|4 BYTEs|???|
+| 5Ch|WORD|X in /boost:X,Y|
+| 5Eh|WORD|Y in /boost:X,Y|
+| 60h|WORD|/FG: value|
+| 62h|WORD|task switches left until next FGONLY DESQview API call|
+| 64h|WORD|multitasker version ???|
+| 66h|WORD|virtual screen segment|
+| 68h|BYTE|flags for interrupts already grabbed by TAME\\ bit 0: INT 10h\\ bit 1: INT 14h\\ bit 2: INT 15h\\ bit 3: INT 16h\\ bit 4: INT 17h\\ bit 5: INT 21h\\ bit 6: INT 28h|
+| 69h|BYTE|flags for interrupts which may be acted on (same bits as above)|
+| 6Ah|BYTE|window or task number for this task|
+| 6Bh|BYTE|multitasker type\\ 01h DESQview\\ 02h DoubleDOS\\ 03h TopView\\ 04h OmniView\\ 05h VM/386|
+| 6Ch|BYTE|type of task switching selected (bit flags)\\ bit 0: DESQview\\ bit 1: DoubleDOS\\ bit 2: TopView\\ bit 3: OmniView\\ bit 4: KeySwitch\\ bit 5: HLT instruction|
+| 6Dh|BYTE|watch_DOS|
+| 6Eh|BYTE|bit flags\\ bit 0: TAME enabled\\ bit 1: /FREQ instead of /MAX (counts in 50h and 52h per tick)\\ bit 2: /TIMEPOLL\\ bit 3: /KEYPOLL\\ bit 4: inhibit timer\\ bit 5: enable status monitoring|
+| 6Fh|BYTE|old status|
+| 70h|WORD|signature DA34h\
+==== 2Bh - pcANYWHERE IV/LAN - INSTALLATION CHECK ====
+<code>
+	AX = 2B44h ('D')
+	BX = 4D41h ('MA')
+	CX = 7063h ('pc')
+	DX = 4157h ('AW')
+</code>
+<code>
+Return: AX = 4F4Bh ('OK') if large host resident
+	   = 6F6Bh ('ok') if small host resident
+	CX:DX -> API entry point
+</code>
+SeeAlso: INT 16/AH=79h
+<code>
+Call API entry point with:
+	AX = 0000h get pcANYWHERE IV version
+	    DS:SI -> BYTE buffer for host type code
+	    Return: AH = version number
+		    AL = revision number
+		    DS:DI buffer byte filled with
+h full-featured host
+h limited-feature LAN host
+			other API may not be supported
+	AX = 0001h initialize operation
+	    DS:SI -> initialization request structure (see below)
+	    Return: AX = function status (see below)
+	AX = 0002h get status
+	    Return: AH = current operating mode (see init req structure below)
+		    AL = current connection status
+			bit 0: a physical connection is active
+			bit 1: remove screen updating is active
+			bit 2: connection checking is active
+			bit 3: hot key detection is active
+			bit 4: background file transfer is active
+	AX = 0003h suspend remote screen updates
+	    Return: AX = function status (see below)
+	AX = 0004h resume screen updates
+	    Return: AX = function status (see below)
+	AX = 0005h end current remote access session
+	    DS:SI -> termination request structure (see below)
+	    Return: AX = function status (see below)
+	AX = 0006h remove pcANYWHERE IV from memory
+	    Return: AX = status
+h successful
+			FFD2h unable to release allocated memory
+			FFD1h unable to release interrupt vectors
+	AX = 8000h read data from communications channel
+	    DS:BX -> buffer
+	    CX = buffer size
+	    Return: AX >= number of characters read/available
+		    AX < 0 on error
+	AX = 8001h write data to communications channel
+	    DS:BX -> buffer
+	    CX = buffer size
+	    Return: AX >= number of characters written
+		    AX < 0 on error
+	AX = 8002h get connection status
+	    Return: AX = status
+			> 0000h if connection active
+			= 0000h if connection lost
+			< 0000h on error
+</code>
+== Format of initialization request structure: ==
+^ Offset ^ Size ^Description^
+|00h|BYTE|operating mode: \\ 00h wait for a call\\ 01h hot key activates\\ 02h incoming call activates\\ 03h initiate a call|
+|01h|3 BYTEs|user ID to append to config file names|
+|04h|WORD|DS-relative pointer to path for config files|
+|06h|WORD|DS-relative pointer to path for program files|
+== Format of termination request structure: ==
+^ Offset ^ Size ^Description^
+|00h|BYTE| operating mode after termination:\\ 00h wait for a call\\ 01h hot key activates\\ 02h incoming call activates\\ 80h use current mode\\ FFh remove from memory|
+== Values for function status: ==
+| 0000h |function completed successfully|
+| FFF2h |unable to establish a connection when operating mode is "Initiate a call"|
+| FFF3h |modem configuration is invalid (corrupt config)|
+| FFF4h |modem initialization failed (no modem response)|
+| FFF5h |the communications device could not be initialized|
+| FFF6h |the host operator aborted the function|
+| FFF7h |the communications driver type specified in the configuration file is different than the one loaded when pcANYWHERE IV was initially started|
+| FFF9h |the configuration file is invalid|
+| FFFAh |the configuration file could not be found|
+| FFFBh |no session is active|
+| FFFCh |a remote access session is active|
+| FFFDh |the specified operating mode is invalid|
+===== 2Ch - DOS 1+ - GET SYSTEM TIME =====
+<code>
+	AH = 2Ch
+</code>
+<code>
+Return: CH = hour
+	CL = minute
+	DH = second
+	DL = 1/100 seconds
+</code>
+<WRAP round box>
+on most systems, the resolution of the system clock is about 5/100sec, so returned times generally do not increment by 1
+on some systems, DL may always return 00h
+</WRAP>
+SeeAlso: AH=2Ah,AH=2Dh,AH=E7h,INT 1A/AH=00h,INT 1A/AH=02h,INT 1A/AH=FEh
+SeeAlso: INT 2F/AX=120Dh
+===== 2Dh - DOS 1+ - SET SYSTEM TIME =====
+<code>
+	AH = 2Dh
+	CH = hour
+	CL = minute
+	DH = second
+	DL = 1/100 seconds
+</code>
+Return: AL = result
+h successful
+	    FFh invalid time, system time unchanged
+</code>
+<WRAP round box>
+DOS 3.3+ also sets CMOS clock
+</WRAP>
+SeeAlso: AH=2Bh"DOS",AH=2Ch,INT 1A/AH=01h,INT 1A/AH=03h,INT 1A/AH=FFh"AT&T"
+===== 2Eh - DOS 1+ - SET VERIFY FLAG =====
+<code>
+	AH = 2Eh
+	DL = 00h (DOS 1.x/2.x only)
+	AL = new state of verify flag
+h off
+h on
+</code>
+<WRAP round box>
+default state at system boot is OFF
+when ON, all disk writes are verified provided the device driver supports read-after-write verification
+</WRAP>
+SeeAlso: AH=54h
+==== 2Fh - DOS 2+ - GET DISK TRANSFER AREA ADDRESS ====
+<code>
+	AH = 2Fh
+</code>
+<code>
+Return: ES:BX -> current DTA
+</code>
+SeeAlso: AH=1Ah
+===== 30h - DOS 2+ - GET DOS VERSION =====
+<code>
+	AH = 30h
+---DOS 5.0---
+	AL = what to return in BH
+h OEM number (as for DOS 2.0-4.0x)
+h version flag
+</code>
+<code>
+Return: AL = major version number (00h if DOS 1.x)
+	AH = minor version number
+	BL:CX = 24-bit user serial number (most versions do not use this)
+---if DOS <5 or AL=00h---
+	BH = OEM number
+h IBM
+h Zenith
+h DEC
+h Olivetti
+h Toshiba
+Dh	Hewlett-Packard
+h	STARLITE architecture (OEM DOS, NETWORK DOS, SMP DOS)
+	    FFh Microsoft, Phoenix
+---if DOS 5.0 and AL=01h---
+	BH = version flag
+h DOS is in ROM
+h DOS is in HMA
+</code>
+<WRAP round box>
+the OS/2 v1.x Compatibility Box returns major version 0Ah
+the OS/2 v2.x Compatibility Box returns major version 14h
+DOS 4.01 and 4.02 identify themselves as version 4.00
+generic MSDOS 3.30, Compaq MSDOS 3.31, and others identify themselves as PC-DOS by returning OEM number 00h
+the version returned under DOS 4.0x may be modified by entries in the special program list (see AH=52h)
+the version returned under DOS 5.0 may be modified by SETVER; use AX=3306h to get the true version number
+</WRAP>
+SeeAlso: AX=3306h,INT 2F/AX=122Fh
+===== 30h - Phar Lap 386/DOS-Extender, Intel Code Builder - INSTALLATION CHECK =====
+	AH = 30h
+	EAX = 00003000h
+	EBX = 50484152h ("PHAR")
+Return: AL = major DOS version
+	AH = minor DOS version
+	EAX bits 31-16 = 4458h ('DX') if 386/DOS-extender installed
+	    BL = ASCII major version number
+	EAX bits 31-16 = 4243h ('BC') if Intel Code Builder installed
+	    EDX = address of GDA
+SeeAlso: AX=2501h,AX=FF00h
+===== 30h -  VIRUS - "Possessed" - INSTALLATION CHECK =====
+	AH = 30h
+	DX = ABCDh
+Return: DX = DCBAh if installed
+SeeAlso: AX=0D20h,AX=30F1h
+===== 3000h Btrieve Multi-User - INSTALLATION CHECK =====
+<code>
+	AX = 3000h
+</code>
+<code>
+Return: AL >= 03h if INT 2F handler installed
+</code>
+SeeAlso: INT 2F/AX=AB00h,INT 7B"Btrieve",INT 7F/AX=0200h
+===== 3000h - CTask 2.0+ - INSTALLATION CHECK =====
+<code>
+	AX = 3000h
+	BX = 1234h
+	DS:DX -> 8-byte version string (DX < FFF0h) "CTask21",00h for v2.1-2.2
+</code>
+<code>
+Return: AL = DOS major version
+	AH = DOS minor version
+	CX:BX -> Ctask global data block
+</code>
+<WRAP round box>
+if first eight bytes of returned data block equal eight bytes passed in, CTask is resident
+CTask is a multitasking kernel for C written by Thomas Wagner
+</WRAP>
+===== 30F1h - VIRUS - "Dutch-555"/"Quit 1992" - INSTALLATION CHECK =====
+<code>
+	AX = 30F1h
+</code>
+<code>
+Return: AL = 00h if resident
+</code>
+SeeAlso: AH=30h/DX=ABCDh,AX=330Fh
+===== 31h - DOS 2+ - TERMINATE AND STAY RESIDENT =====
+<code>
+	AH = 31h
+	AL = return code
+	DX = number of paragraphs to keep resident
+</code>
+<code>
+Return: never
+</code>
+<WRAP round box>
+the value in DX only affects the memory block containing the PSP; additional memory allocated via AH=48h is not affected
+the minimum number of paragraphs which will remain resident is 11h for DOS 2.x and 06h for DOS 3+
+most TSRs can save some memory by releasing their environment block before terminating (see AH=26h,AH=49h)
+</WRAP>
+SeeAlso: AH=00h,AH=4Ch,AH=4Dh,INT 20,INT 22,INT 27
+===== 32h - DOS 2+ - GET DOS DRIVE PARAMETER BLOCK FOR SPECIFIC DRIVE =====
+<code>
+	AH = 32h
+	DL = drive number (00h = default, 01h = A:, etc)
+</code>
+<code>
+Return: AL = status
+h successful
+		DS:BX -> Drive Parameter Block (DPB) for specified drive
+	    FFh invalid or network drive
+</code>
+<WRAP round box>
+the OS/2 compatibility box supports the DOS 3.3 version of this call except for the DWORD at offset 12h
+this call updates the DPB by reading the disk; the DPB may be accessed via the DOS list of lists (see AH=52h) if disk access is not desirable.
+documented for DOS 5.0, but undocumented in prior versions
+</WRAP>
+SeeAlso: AH=1Fh,AH=52h
+== Format of DOS Drive Parameter Block: ==
+Offset	Size	Description
+h	BYTE	drive number (00h = A:, 01h = B:, etc)
+h	BYTE	unit number within device driver
+h	WORD	bytes per sector
+h	BYTE	highest sector number within a cluster
+h	BYTE	shift count to convert clusters into sectors
+h	WORD	number of reserved sectors at beginning of drive
+h	BYTE	number of FATs
+h	WORD	number of root directory entries
+Bh	WORD	number of first sector containing user data
+Dh	WORD	highest cluster number (number of data clusters + 1)
+Fh	BYTE	number of sectors per FAT
+h	WORD	sector number of first directory sector
+h	DWORD	address of device driver header
+h	BYTE	media ID byte
+h	BYTE	00h if disk accessed, FFh if not
+h	DWORD	pointer to next DPB
+---DOS 2.x---
+Ch	WORD	cluster containing start of current directory, 0000h=root,
+		FFFFh = unknown
+Eh 64 BYTEs	ASCIZ pathname of current directory for drive
+---DOS 3.x---
+Ch	WORD	cluster at which to start search for free space when writing
+Eh	WORD	number of free clusters on drive, FFFFh = unknown
+---DOS 4.0-5.0---
+Fh	WORD	number of sectors per FAT
+h	WORD	sector number of first directory sector
+h	DWORD	address of device driver header
+h	BYTE	media ID byte
+h	BYTE	00h if disk accessed, FFh if not
+h	DWORD	pointer to next DPB
+Dh	WORD	cluster at which to start search for free space when writing
+Fh	WORD	number of free clusters on drive, FFFFh = unknown
+===== 33h - DOS 2+ - EXTENDED BREAK CHECKING =====
+<code>
+	AH = 33h
+	AL = subfunction
+h get current extended break state
+		Return: DL = current state, 00h = off, 01h = on
+h set state of extended ^C/^Break checking
+		DL = 00h off, check only on character I/O functions
+h on, check on all DOS functions
+</code>
+<WRAP round box>
+under DOS 3.1+, this function does not use any of the DOS-internal and may thus be called at any time
+</WRAP>
+SeeAlso: AX=3302h
+===== 33xxh =====
+==== 3302h - DOS 3.x+ internal - GET AND SET EXTENDED CONTROL-BREAK CHECKING STATE ====
+<code>
+	AX = 3302h
+	DL = new state
+h for OFF or 01h for ON
+</code>
+<code>
+Return: DL = old state of extended BREAK checking
+</code>
+<WRAP round box>
+this function does not use any of the DOS-internal stacks and may thus be called at any time
+</WRAP>
+SeeAlso: AH=33h
+==== 3305h - DOS 4+ - GET BOOT DRIVE ====
+<code>
+	AX = 3305h
+</code>
+<code>
+Return: DL = boot drive (1=A:,...)
+</code>
+<WRAP round box>
+fully reentrant
+NEC 9800-series PCs always call the boot drive A: and assign the other drive letters sequentially to the other drives in the system
+</WRAP>
+==== 3306h - DOS 5.0 - GET TRUE VERSION NUMBER ====
+<code>
+	AX = 3306h
+</code>
+<code>
+Return:	BL = major version
+	BH = minor version
+	DL = revision (bits 2-0, all others 0)
+	DH = version flags
+	    bit 3: DOS is in ROM
+	    bit 4: DOS in in HMA
+</code>
+<WRAP round box>
+Notes:	this function always returns the true version number, unlike AH=30h, whose return value may be changed with SETVER
+because of the conflict from the CBIS PowerLAN redirector (see next entry), programs should check whether BH is less than 100 (64h) and BL is at least 5 before accepting the returned BX as the true version number; however, even this is not entirely reliable when  that redirector is loaded
+fully reentrant
+</WRAP>
+<WRAP round important>
+DR-DOS 5.0 returns CF set/AX=0001h for INT 21/AH=33h subfunctions other than 00h-02h and 05h, while MS-DOS returns AL=FFh for invalid  subfunctions
+</WRAP>
+SeeAlso: AH=30h
+==== 3306h - CBIS POWERLAN - NETWORK REDIRECTOR - ??? ====
+<code>
+	AX = 3306h
+</code>
+<code>
+Return: AX = 3306h
+	BL = ??? (usually 00h)
+	BH = ??? (usually 00h or FFh)
+</code>
+<WRAP round box>
+unknown function, is in conflict with DOS 5.0 version call
+</WRAP>
+SeeAlso: AX=3306h"DOS"
+==== 330Fh - VIRUS - "Burghofer" - INSTALLATION CHECK ====
+<code>
+	AX = 330Fh
+</code>
+<code>
+Return: AL = 0Fh if resident (DOS returns AL=FFh)
+</code>
+SeeAlso: AX=30F1h,AX=33E0h
+==== 33E0h - VIRUS - "Oropax" - INSTALLATION CHECK ====
+<code>
+	AX = 33E0h
+</code>
+<code>
+Return: AL = E0h if resident (DOS returns AL=FFh)
+</code>
+SeeAlso: AX=330Fh,AX=357Fh
+===== 34h - DOS 2+ - GET ADDRESS OF INDOS FLAG =====
+<code>
+	AH = 34h
+</code>
+<code>
+Return: ES:BX -> one-byte InDOS flag
+</code>
+<WRAP round box>
+the value of InDOS is incremented whenever an INT 21 function begins and decremented whenever one completes during an INT 28 call, it is safe to call some INT 21 functions even though InDOS may be 01h instead of zero
+InDOS alone is not sufficient for determining when it is safe to enter DOS, as the critical error handling decrements InDOS and increments the critical error flag for the duration of the critical error. Thus, it is possible for InDOS to be zero even if DOS is  busy.
+the critical error flag is the byte immediately following InDOS in DOS 2.x, and the byte BEFORE the InDOS flag in DOS 3+ (except COMPAQ DOS 3.0, where the critical error flag is located 1AAh bytes BEFORE the critical section flag)
+For DOS 3.1+, an undocumented call exists to get the address of the critical error flag (see AX=5D06h)
+</WRAP>
+SeeAlso: AX=5D06h,AX=5D0Bh,INT 28
+===== 35h - DOS 2+ - GET INTERRUPT VECTOR =====
+<code>
+	AH = 35h
+	AL = interrupt number
+</code>
+<code>
+Return: ES:BX -> current interrupt handler
+</code>
+SeeAlso: AH=25h,AX=2503h
+==== 357Fh - VIRUS - "Agiplan"/"Month 4-6" - INSTALLATION CHECK ====
+<code>
+	AX = 357Fh
+</code>
+<code>
+Return: DX = FFFFh if installed
+</code>
+SeeAlso: AX=33E0h,AX=3DFFh
+===== 36h - DOS 2+ - GET FREE DISK SPACE =====
+<code>
+	AH = 36h
+	DL = drive number (00h = default, 01h = A:, etc)
+</code>
+<code>
+Return: AX = FFFFh if invalid drive
+	else
+	    AX = sectors per cluster
+	    BX = number of free clusters
+	    CX = bytes per sector
+	    DX = total clusters on drive
+</code>
+<WRAP round box>
+free space on drive in bytes is AX * BX * CX
+total space on drive in bytes is AX * CX * DX
+"lost clusters" are considered to be in use
+according to Dave Williams' MSDOS reference, the value in DX is incorrect for non-default drives after ASSIGN is run
+</WRAP>
+SeeAlso: AH=1Bh,AH=1Ch
+===== 37h =====
+==== 3700h - DOS 2+ - "SWITCHAR" - GET SWITCH CHARACTER ====
+	AX = 3700h
+Return: AL = status
+h successful
+		DL = current switch character
+	    FFh unsupported subfunction
+Desc:	Determine the character which is used to introduce command switches.
+	  This setting is ignored by DOS commands in version 4.0 and higher,
+	  but is honored by many third-party programs.
+Notes:	documented in some OEM versions of some releases of DOS
+	supported by OS/2 compatibility box
+	always returns DL=2Fh for DOS 5.0
+SeeAlso: AX=3701h
+==== 3701h - DOS 2+ - "SWITCHAR" - SET SWITCH CHARACTER ====
+	AX = 3701h
+	DL = new switch character
+Return: AL = status
+h successful
+	    FFh unsupported subfunction
+Notes:	documented in some OEM versions of some releases of DOS
+	supported by OS/2 compatibility box
+	ignored by DOS 5.0
+SeeAlso: AX=3700h
+==== 37h - DOS 2.x and 3.3+ only - "AVAILDEV" - SPECIFY \DEV\ PREFIX USE ====
+	AH = 37h
+	AL = subfunction
+h get availdev flag
+		Return: DL = 00h \DEV\ must precede character device names
+			   = nonzero \DEV\ is optional
+h set availdev flag
+		DL = 00h	\DEV\ is mandatory
+		   = nonzero	\DEV\ is optional
+Return: AL = status
+h successful
+	    FFh unsupported subfunction
+Notes:	all versions of DOS from 2.00 allow \DEV\ to be prepended to device
+	  names without generating an error even if the directory \DEV does
+	  not actually exist (other paths generate an error if they do not
+	  exist).
+	although DOS 3.3+ accepts these calls, they have no effect, and
+	  AL=02h always returns DL=FFh
+===== 38h - DOS 2+ - GET COUNTRY-SPECIFIC INFORMATION =====
+	AH = 38h
+--DOS 2.x--
+	AL = 00h get current-country info
+	DS:DX -> buffer for returned info (see below)
+Return: CF set on error
+	    AX = error code (02h)
+	CF clear if successful
+	    AX = country code (MSDOS 2.11 only)
+	    buffer at DS:DX filled
+--DOS 3+--
+	AL = 00h for current country
+	AL = 01h thru 0FEh for specific country with code <255
+	AL = 0FFh for specific country with code >= 255
+	   BX = 16-bit country code
+	DS:DX -> buffer for returned info (see below)
+Return:	CF set on error
+	    AX = error code (02h)
+	CF clear if successful
+	    BX = country code
+	    DS:DX buffer filled
+SeeAlso: AH=65h,INT 10/AX=5001h,INT 2F/AX=110Ch,INT 2F/AX=1404h
+Format of PCDOS 2.x country info:
+Offset	Size	Description
+h	WORD	date format  0 = USA	mm dd yy
+= Europe dd mm yy
+= Japan	yy mm dd
+h	BYTE	currency symbol
+h	BYTE	00h
+h	BYTE	thousands separator char
+h	BYTE	00h
+h	BYTE	decimal separator char
+h	BYTE	00h
+h 24 BYTEs	reserved
+Format of MSDOS 2.x,DOS 3+ country info:
+Offset	Size	Description
+h	WORD	date format (see above)
+h  5 BYTEs	ASCIZ currency symbol string
+h  2 BYTEs	ASCIZ thousands separator
+h  2 BYTEs	ASCIZ decimal separator
+Bh  2 BYTEs	ASCIZ date separator
+Dh  2 BYTEs	ASCIZ time separator
+Fh	BYTE	currency format
+		bit 2 = set if currency symbol replaces decimal point
+		bit 1 = number of spaces between value and currency symbol
+		bit 0 = 0 if currency symbol precedes value
+if currency symbol follows value
+h	BYTE	number of digits after decimal in currency
+h	BYTE	time format
+		bit 0 = 0 if 12-hour clock
+if 24-hour clock
+h	DWORD	address of case map routine
+		(FAR CALL, AL = character to map to upper case [>= 80h])
+h  2 BYTEs	ASCIZ data-list separator
+h 10 BYTEs	reserved
+Values for country code:
+h	United States
+h	Canadian-French
+h	Latin America
+Fh	Netherlands
+h	Belgium
+h	France
+h	Spain
+h	Hungary (not supported by DR-DOS 5.0)
+h	Yugoslavia (not supported by DR-DOS 5.0)
+h	Italy
+h	Switzerland
+Ah	Czechoslovakia (not supported by DR-DOS 5.0)
+Bh	Austria (DR-DOS 5.0)
+Ch	United Kingdom
+Dh	Denmark
+Eh	Sweden
+Fh	Norway
+h	Poland (not supported by DR-DOS 5.0)
+h	Germany
+h	Brazil (not supported by DR-DOS 5.0)
+Dh	International English [Australia in DR-DOS 5.0]
+h	Japan (DR-DOS 5.0)
+h	Korea (DR-DOS 5.0)
+Fh	Portugal
+h	Finland
+h	Middle East (DR-DOS 5.0)
+CCh	Israel (DR-DOS 5.0)
+===== 38h - DOS 3+ - SET COUNTRY CODE =====
+	AH = 38h
+	AL = 01h thru 0FEh for specific country with code <255
+	AL = FFh for specific country with code >= 255
+	   BX = 16-bit country code
+	DX = FFFFh
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	not supported by OS/2
+SeeAlso: INT 2F/AX=1403h
+===== 39h - DOS 2+ - "MKDIR" - CREATE SUBDIRECTORY =====
+	AH = 39h
+	DS:DX -> ASCIZ pathname
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (03h,05h) (see AH=59h)
+Notes:	all directories in the given path except the last must exist
+	fails if the parent directory is the root and is full
+	DOS 2.x-3.3 allow the creation of a directory sufficiently deep that
+	  it is not possible to make that directory the current directory
+	  because the path would exceed 64 characters
+SeeAlso: AH=3Ah,AH=3Bh,INT 2F/AX=1103h
+===== 3Ah - DOS 2+ - "RMDIR" - REMOVE SUBDIRECTORY =====
+	AH = 3Ah
+	DS:DX -> ASCIZ pathname of directory to be removed
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (03h,05h,06h,10h) (see AH=59h)
+Note:	directory must be empty (contain only '.' and '..' entries)
+SeeAlso: AH=39h,AH=3Bh,INT 2F/AX=1101h
+===== 3Bh - DOS 2+ - "CHDIR" - SET CURRENT DIRECTORY =====
+	AH = 3Bh
+	DS:DX -> ASCIZ pathname to become current directory (max 64 bytes)
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (03h) (see AH=59h)
+Notes:	if new directory name includes a drive letter, the default drive is
+	  not changed, only the current directory on that drive
+	changing the current directory also changes the directory in which
+	  FCB file calls operate
+SeeAlso: AH=47h,INT 2F/AX=1105h
+===== 3Ch - DOS 2+ - "CREAT" - CREATE OR TRUNCATE FILE =====
+<code>
+	AH = 3CH
+	CX = file attribute
+	    bit 0: read-only
+: hidden
+: system
+: volume label (ignored)
+: reserved, must be zero (directory)
+: archive bit
+: if set, file is shareable under Novell NetWare
+	DS:DX -> ASCIZ filename
+</code>
+<code>
+Return: CF clear if successful
+	    AX = file handle
+	CF set on error
+	    AX = error code (03h,04h,05h) (see AH=59h)
+</code>
+<WRAP round box>
+if a file with the given name exists, it is truncated to zero length
+</WRAP>
+SeeAlso: AH=16h,AH=3Dh,AH=5Ah,AH=5Bh
+===== 3Dh - DOS 2+ - "OPEN" - OPEN EXISTING FILE =====
+<code>
+	AH = 3Dh
+	AL = access and sharing modes
+	    bits 2-0: access mode
+read only
+write only
+read/write
+	    bit 3: reserved (0)
+	    bits 6-4: sharing mode (DOS 3+)
+compatibility mode
+"DENYALL" prohibit both read and write access by others
+"DENYWRITE" prohibit write access by others
+"DENYREAD" prohibit read access by others
+"DENYNONE" allow full access by others
+	    bit 7: inheritance
+		if set, file is private to current process and will not be inherited by child processes
+	DS:DX -> ASCIZ filename
+	CL = attribute mask of files to look for (server call only)
+</code>
+<code>
+Return: CF clear if successful
+	    AX = file handle
+	CF set on error
+	    AX = error code (01h,02h,03h,04h,05h,0Ch) (see AH=59h)
+</code>
+<WRAP round box>
+file pointer is set to start of file
+file handles which are inherited from a parent also inherit sharing and access restrictions
+files may be opened even if given the hidden or system attributes
+</WRAP>
+SeeAlso: AH=0Fh,AH=3Ch,AX=4301h,AX=5D00h,INT 2F/AX=1226h
+File sharing behavior:
+|              |  Second and subsequent Opens                                                                                                                                                                                                                                                                                                                                                                                                                                      ||||||||||||||||
+|  First Open  |                               |  Compat                                                                            |||  Deny All                                                                          |||  Deny Write                                                                        |||  Deny Read                                                                         |||  Deny None                                                                         |||
+|              |                               |  R                         |  W                         |  RW                        |  R                         |  W                         |  RW                        |  R                         |  W                         |  RW                        |  R                         |  W                         |  RW                        |  R                         |  W                         |  RW                        |
+|  Compat      |  R                            |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  1                         |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  1                         |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+| :::          |  W                            |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+| :::          |  RW                           |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |||||||||||||||||
+|  Deny All    |  R                            |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+| :::          |  W                            |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+| :::          |  RW                           |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |||||||||||||||||
+|  Deny Write  |  R                            |  2                         |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+| :::          |  W                            |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+| :::          |  RW                           |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |
+|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |||||||||||||||||
+|  Deny Read   |  R                            |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |
+| :::          |  W                            |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |
+| :::          |  RW                           |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |
+|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |||||||||||||||||
+|  Deny None   |  R                            |  2                         |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |
+| :::          |  W                            |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |
+| :::          |  RW                           |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #00a2e8>C</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #ed1c24>N</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |  <color #22b14c>Y</color>  |
+Legend:
+  Y = open succeeds,
+  N = open fails with error code 05h
+  C = open fails, INT 24 generated
+= open succeeds if file read-only, else fails with error code
+= open succeeds if file read-only, else fails with INT 24
+=====3DFFh - VIRUS - "JD-448" - INSTALLATION CHECK =====
+	AX = 3DFFh
+Return: AX = 4A44h if resident
+SeeAlso: AX=357Fh,AX=4203h
+===== 3E - DOS 2+ - "CLOSE" - CLOSE FILE =====
+<code>
+	AH = 3Eh
+	BX = file handle
+</code>
+<code>
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (06h) (see AH=59h)
+</code>
+<WRAP round box>
+if the file was written to, any pending disk writes are performed, the time and date stamps are set to the current time, and the directory entry is updated
+</WRAP>
+SeeAlso: AH=10h,AH=3Ch,AH=3Dh,INT 2F/AX=1106h,INT 2F/AX=1227h
+===== 3Fh - DOS 2+ - "READ" - READ FROM FILE OR DEVICE =====
+<code>
+	AH = 3Fh
+	BX = file handle
+	CX = number of bytes to read
+	DS:DX -> buffer for data
+</code>
+<code>
+Return: CF clear if successful
+	    AX = number of bytes actually read (0 if at EOF before call)
+	CF set on error
+	    AX = error code (05h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+data is read beginning at current file position, and the file position is updated after a successful read
+the returned AX may be smaller than the request in CX if a partial read occurred
+if reading from CON, read stops at first CR
+</WRAP>
+SeeAlso: AH=27h,AH=40h,INT 2F/AX=1108h,INT 2F/AX=1229h
+===== 3Fh - Turbo Debug HARDWARE BREAKPOINTS - READ STATUS BLOCK =====
+<code>
+	AH = 3Fh
+	BX = handle for character device "TDHDEBUG"
+	CX = number of bytes to read
+	DS:DX -> buffer for status block (see below)
+</code>
+<code>
+Return: CF clear if successful
+	    AX = number of bytes actually read
+	CF set on error
+	    AX = error code (05h,06h) (see AH=59h)
+</code>
+SeeAlso: AH=40h"Turbo Debug"
+Format of status block:
+^ Offset                        ^ Size  ^ Description                                                                                                                                                                                                                                    ^
+| 00h                           | BYTE  | status of command                                                                                                                                                                                                                              |
+|                               |       | 00h successful                                                                                                                                                                                                                                 |
+|                               |       | 01h invalid handle                                                                                                                                                                                                                             |
+|                               |       | 02h no more breakpoints available                                                                                                                                                                                                              |
+|                               |       | 03h hardware does not support specified breakpoint type                                                                                                                                                                                        |
+|                               |       | 04h previous command prevents execution                                                                                                                                                                                                        |
+|                               |       | 05h debugger hardware not found                                                                                                                                                                                                                |
+|                               |       | 06h hardware failure                                                                                                                                                                                                                           |
+|                               |       | 07h invalid command                                                                                                                                                                                                                            |
+|                               |       | 08h driver not initialized yet                                                                                                                                                                                                                 |
+|                               |       | FEh recursive entry (hardware breakpoint inside hw bp handler)                                                                                                                                                                                 |
+| ---status for command 01h---                                                                                                                                                                                                                                                         |||
+| 01h                           | WORD  | device driver interface version number (currently 1)                                                                                                                                                                                           |
+| 03h                           | WORD  | device driver software version                                                                                                                                                                                                                 |
+| 05h                           | BYTE  | maximum simultaneous hardware breakpoints                                                                                                                                                                                                      |
+| 06h                           | BYTE  | configuration bits\\  * 0: CPU and DMA accesses are distinct\\  * 1: can detect DMA transfers\\  * 2: supports data mask\\  * 3: hardware pass counter on breakpoints\\  * 4: can match on data as well as addresses                           |
+| 07h                           | BYTE  | supported breakpoint types\\  * 0: memory read\\  * 1 : memory write\\  * 2: memory read/write\\  * 3: I/O read\\  * 4: I/O write\\  * 5: I/O read/write\\  * 6: instruction fetch                                                             |
+| 08h                           | WORD  | supported addressing match modes\\  * 0: any address\\  * 1: equal to test value\\  * 2: not equal\\  * 3: above test value\\  * 4: below test value\\  * 5: below or equal\\  * 6: above or equal\\  * 7: within range\\  * 8: outside range  |
+| 0Ah                           | WORD  | supported data matches\\  * 0: any data\\  * 1: equal to test value\\  * 2: not equal\\  * 3: above test value\\  * 4: below test value\\  * 5: below or equal\\  * 6: above or equal\\  * 7: within range\\  * 8: outside range               |
+| 0Ch                           | BYTE  | maximum data match length (01h, 02h, or 04h)                                                                                                                                                                                                   |
+| 0Dh                           | WORD  | size of onboard memory (in K)                                                                                                                                                                                                                  |
+| 0Fh                           | WORD  | maximum number of trace-back events                                                                                                                                                                                                            |
+| 11h                           | WORD  | hardware breakpoint enable byte address segment (0000h if not supported)                                                                                                                                                                       |
+| ---status for command 04h---                                                                                                                                                                                                                                                         |||
+| 01h                           | BYTE  | handle to use when referring to the just-set breakpoint                                                                                                                                                                                        |
+===== 3Fh - PC/TCP IPCUST.SYS - READ CONFIGURATION DATA =====
+<code>
+	AH = 3Fh
+	BX = handle for character device "$IPCUST"
+	CX = number of bytes to read
+	DS:DX -> buffer for configuration data (see below)
+</code>
+<code>
+Return: CF clear if successful
+	    AX = number of bytes actually read
+	CF set on error
+	    AX = error code (05h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+if less than the entire data is read or written, the next read/write continues where the previous one ended; IOCTL calls AX=4402h and AX=4403h both reset the location at which the next operation starts to zero
+the data pointer is also reset to zero if the previous read or write reached or exceeded the end of the data, when the current function is read and the previous was write, or vice versa
+</WRAP>
+SeeAlso: AH=40h"IPCUST",AX=4402h"IPCUST"
+Format of configuration data:
+^  Offset  ^  Size      ^  Description                                                                           ^
+| 00h      | 12 BYTEs   | IPCUST.SYS device driver header                                                        |
+| 12h      | BYTE       | ???                                                                                    |
+| 13h      | BYTE       | ???                                                                                    |
+| 14h      | WORD       | ???                                                                                    |
+| 16h      | BYTE       | bit flags\\ bit 0: send BS rather than DEL for BackSpace key\\ bit 1: wrap long lines  |
+| 17h      | BYTE       | ???                                                                                    |
+| 18h      | 64 BYTEs   | ASCIZ hostname                                                                         |
+| 58h      | 64 BYTEs   | ASCIZ domain name\\ (fully qualified domain name is hostname.domain-name)              |
+| 98h      | 16 BYTEs   | ASCIZ username                                                                         |
+| A8h      | 64 BYTEs   | ASCIZ full name                                                                        |
+| E8h      | 64 BYTEs   | ASCIZ office address                                                                   |
+| 128h     | 32 BYTEs   | ASCIZ phone number                                                                     |
+| 148h     | WORD       | offset from GMT in minutes                                                             |
+| 14Ah     | 4 BYTEs    | ASCIZ timezone name                                                                    |
+| 14Eh     | WORD       | number of time servers                                                                 |
+| 150h     | ? DWORDs   | IP addresses for time servers (big-endian)                                             |
+|          | ???        |                                                                                        |
+| 164h     | WORD       | number of old-style name servers                                                       |
+| 166h     | 3 DWORDs   | IP addresses for name servers (big-endian)                                             |
+| 172h     | WORD       | number of domain name servers                                                          |
+| 174h     | 3 DWORDs   | IP addresses for domain name servers (big-endian)                                      |
+| 180h     | DWORD      | IP address of default gateway (big-endian)                                             |
+| 184h     | DWORD      | IP address of log server (big-endian)                                                  |
+| 188h     | DWORD      | IP address of cookie server (big-endian)                                               |
+| 18Ch     | DWORD      | IP address of lpr server (big-endian)                                                  |
+| 190h     | DWORD      | IP address of imagen print server                                                      |
+| 194h     | 54 BYTEs   | ???                                                                                    |
+| 1E8h     | WORD       | TCP default window size in bytes                                                       |
+| 1EAh     | WORD       | TCP low window size                                                                    |
+| 1ECh     | 64 BYTEs   | ASCIZ host tabel filename                                                              |
+| 22Ch     | 2 BYTEs    | ???                                                                                    |
+| 22Eh     | 80 BYTEs   | ASCIZ mail relay host name                                                             |
+| 27Eh     | BYTE       | ???                                                                                    |
+| 27Fh     | BYTE       | ??? bit flags                                                                          |
+| 280h     | 44 BYTEs   | ???                                                                                    |
+| 2ACh     | WORD       | ???                                                                                    |
+| 2AEh     | 202 BYTEs  | ???                                                                                    |
+===== 40h - DOS 2+ - "WRITE" - WRITE TO FILE OR DEVICE =====
+<code>
+	AH = 40h
+	BX = file handle
+	CX = number of bytes to write
+	DS:DX -> data to write
+</code>
+<code>
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (05h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+if CX is zero, no data is written, and the file is truncated or extended to the current position
+data is written beginning at current file position, and the file position is updated after a successful write
+the usual cause for AX < CX on return is a full disk
+</WRAP>
+SeeAlso: AH=28h,AH=3Fh,INT 2F/AX=1109h
+===== 40h - Turbo Debug HARDWARE BREAKPOINTS - SEND CMD TO HARDWARE BRKPNT DRIVER =====
+<code>
+	AH = 40h
+	BX = handle for character device "TDHDEBUG"
+	CX = number of bytes to write
+	DS:DX -> hardware breakpoint command (see below)
+</code>
+<code>
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (05h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+results are retrieved by reading from the device
+</WRAP>
+SeeAlso: AH=3Fh"Turbo Debug"
+Format of hardware breakpoint commands:
+^ Offset                  ^ Size   ^ Description                                                                                                                                                                                                                                                                         ^
+| 00h                     | BYTE   | command code                                                                                                                                                                                                                                                                        |
+|                         |        | 00h install interrupt vectors                                                                                                                                                                                                                                                       |
+|                         |        | 01h get hardware capabilities                                                                                                                                                                                                                                                       |
+|                         |        | 02h enable hardware breakpoints                                                                                                                                                                                                                                                     |
+|                         |        | 03h disable hardware breakpoints                                                                                                                                                                                                                                                    |
+|                         |        | 04h set hardware breakpoint                                                                                                                                                                                                                                                         |
+|                         |        | 05h clear hardware breakpoint                                                                                                                                                                                                                                                       |
+|                         |        | 06h set I/O base address and reset hardware                                                                                                                                                                                                                                         |
+|                         |        | 07h restore interrupt vectors                                                                                                                                                                                                                                                       |
+| ---command code 00h---                                                                                                                                                                                                                                                                                               |||
+| 01h                     | DWORD  | pointer to Turbo Debugger entry point to be jumped to on hardware breakpoint; call with CPU state the same as on the breakpoint except for pushing AX and placing an entry code (FFh if breakout button or breakpoint handle) in AH                                                 |
+| ---command code 04h---                                                                                                                                                                                                                                                                                               |||
+| 01h                     | BYTE   | breakpoint type:\\ 00h memory read\\ 01h memory write\\ 02h memory read/write\\ 03h I/O read\\04h I/O write\\ 05h I/O read/write\\ 06h instruction fetch                                                                                                                            |
+| 02h                     | BYTE   | address matching mode: \\ 00h any address\\ 01h equal to test value\\ 02h different from test value\\ 03h above test value\\ 04h below test value\\ 05h below or equal to test value\\ 06h above or equal to test value\\ 07h within inclusive range\\ 08h outside specified range  |
+| 03h                     | DWORD  | 32-bit linear low address                                                                                                                                                                                                                                                           |
+| 07h                     | DWORD  | 32-bit linear high address                                                                                                                                                                                                                                                          |
+| 0Bh                     | WORD   | pass count                                                                                                                                                                                                                                                                          |
+| 0Dh                     | BYTE   | data size (01h, 02h, or 04h)                                                                                                                                                                                                                                                        |
+| 0Eh                     | BYTE   | source of matched bus cycle\\ 01h CPU\\ 02h DMA\\ 03h either                                                                                                                                                                                                                        |
+| 0Fh                     | BYTE   | data-matching mode\\ 00h match any\\ 01h equal to test value\\ 02h different from test value\\ 03h above test value\\ 04h below test value\\ 05h below or equal to test value\\ 06h above or equal to test value\\ 07h within specified range\\ 08h outside specified range         |
+| 10h                     | DWORD  | low data value                                                                                                                                                                                                                                                                      |
+| 14h                     | DWORD  | high data value                                                                                                                                                                                                                                                                     |
+| 18h                     | DWORD  | data mask specifying which bits of the data are tested                                                                                                                                                                                                                              |
+| ---command code 05h---                                                                                                                                                                                                                                                                                               |||
+| 01h                     | BYTE   | handle of breakpoint to clear (breakpoint returned from command 04h)                                                                                                                                                                                                                |
+| ---command code 06h---                                                                                                                                                                                                                                                                                               |||
+| 01h                     | WORD   |                                                                                                                                                                                                                                                                                     |
+===== 40h - PC/TCP IPCUST.SYS - WRITE CONFIGURATION DATA =====
+<code>
+	AH = 40h
+	BX = handle for character device "$IPCUST"
+	CX = number of bytes to write
+	DS:DX -> buffer for configuration data (AH=3Fh"IPCUST")
+</code>
+<code>
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (05h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+if less than the entire data is read or written, the next read/write continues where the previous one ended; IOCTL calls AX=4402h and AX=4403h both reset the location at which the next operation starts to zero
+the data pointer is also reset to zero if the previous read or write reached or exceeded the end of the data, when the current function is read and the previous was write, or vice versa
+</WRAP>
+SeeAlso: AH=3Fh"IPCUST",AX=4402h"IPCUST"
+===== 4000 - FARTBELL.EXE - INSTALLATION CHECK =====
+<code>
+	AX = 4000h
+	BX = 0002h
+	CX = 0000h
+	DS:DX = 0000h:0000h
+</code>
+<code>
+Return: CF clear if installed
+	    AX = CS of resident code
+</code>
+<WRAP round box>
+FARTBELL is a joke program by Guenther Thiele which makes various noises when programs output a bell
+</WRAP>
+SeeAlso: AX=4001h
+===== 4001 - FARTBELL.EXE - FORCE NOISE =====
+<code>
+	AX = 4001h
+	BX = 0002h
+	CX = 0000h
+	DS:DX = 0000h:0000h
+</code>
+<WRAP round box>
+FARTBELL is a joke program by Guenther Thiele which makes various noises when programs output a bell
+</WRAP>
+SeeAlso: AX=4000h
+===== 41 - DOS 2+ - "UNLINK" - DELETE FILE =====
+<code>
+	AH = 41h
+	DS:DX -> ASCIZ filename (no wildcards, but see below)
+	CL = attribute mask for deletion (server call only, see below)
+</code>
+<code>
+Return: CF clear if successful
+	    AX destroyed (DOS 3.3) AL seems to be drive of deleted file
+	CF set on error
+	    AX = error code (02h,03h,05h) (see AH=59h)
+</code>
+<WRAP round box>
+(DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case the filespec must be canonical (as returned by AH=60h), and only files matching the attribute mask in CL are deleted
+DOS does not erase the file's data; it merely becomes inaccessible because the FAT chain for the file is cleared
+deleting a file which is currently open may lead to filesystem corruption. Unless SHARE is loaded, DOS does not close the handles referencing the deleted file, thus allowing writes to a nonexistant file.
+</WRAP>
+SeeAlso: AH=13h,AX=4301h,AX=5D00h,AH=60h,INT 2F/AX=1113h
+===== 4101 - SoftLogic Data Guardian - ??? =====
+<code>
+	AX = 4101h
+	DX = FFFEh
+</code>
+<code>
+Return: AX = 0000h if installed
+</code>
+Note:	resident code sets several internal variables on this call
+===== 42h - DOS 2+ - "LSEEK" - SET CURRENT FILE POSITION =====
+<code>
+	AH = 42h
+	AL = origin of move
+h start of file
+h current file position
+h end of file
+	BX = file handle
+	CX:DX = offset from origin of new file position
+</code>
+<code>
+Return: CF clear if successful
+	    DX:AX = new file position in bytes from start of file
+	CF set on error
+	    AX = error code (01h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+for origins 01h and 02h, the pointer may be positioned before the start of the file; no error is returned in that case, but subsequent attempts at I/O will produce errors
+if the new position is beyond the current end of file, the file will be extended by the next write (see AH=40h)
+</WRAP>
+SeeAlso: AH=24h,INT 2F/AX=1228h
+===== 4203h - VIRUS - "Shake" - INSTALLATION CHECK =====
+<code>
+	AX = 4203h
+</code>
+<code>
+Return: AX = 1234h if resident
+</code>
+SeeAlso: AX=3DFFh,AX=4243h
+===== 4243h - VIRUS - "Invader" - INSTALLATION CHECK =====
+<code>
+	AX = 4243h
+</code>
+<code>
+Return: AX = 5678h if resident
+</code>
+SeeAlso: AX=4203h,AX=4B04h
+===== 43h =====
+==== 4300h - DOS 2+ - GET FILE ATTRIBUTES ====
+<code>
+	AX = 4300h
+	DS:DX -> ASCIZ filename
+</code>
+<code>
+Return: CF clear if successful
+	    CX = attributes (see AX=4301h)
+	    AX = CX (DR-DOS 5.0)
+	CF set on error
+	    AX = error code (01h,02h,03h,05h) (see AH=59h)
+</code>
+SeeAlso: AX=4301h,AH=B6h,INT 2F/AX=110Fh
+==== 4301h - DOS 2+ - "CHMOD" - SET FILE ATTRIBUTES ====
+<code>
+	AX = 4301h
+	CX = new attributes
+	    bit 8: shareable (Novell NetWare)
+: unused
+: unused
+: archive
+: directory
+: volume label
+: system
+: hidden
+: read-only
+	DS:DX -> ASCIZ filename
+</code>
+<code>
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (01h,02h,03h,05h) (see AH=59h)
+</code>
+<WRAP round box>
+will not change volume label or directory attribute bits, but will change the other attribute bits of a directory (the directory bit must be cleared to successfully change the other attributes of a directory, but the directory will not be changed to a normal file as a result)
+	MSDOS 4.01 reportedly closes the file if it is currently open
+</WRAP>
+SeeAlso: AX=4300h,INT 2F/AX=110Eh
+==== 4302h - DR-DOS 3.41+ internal - GET ACCESS RIGHTS ====
+<code>
+	AX = 4302h
+	DS:DX -> ASCIZ pathname
+</code>
+<code>
+Return: CF clear if successful
+	    CX = access rights
+		bit 0 delete requires password
+		bit 2 write requires password
+		bit 3 read requires password
+		bits 4-7=equal to bits 0-3
+		bits 8-11=equal to bits 0-3
+	    AX = CX (DR-DOS 5.0)
+	CF set on error
+	    AX = error code
+<code>
+<WRAP round box>
+Determine which operations the calling program may perform on a specified file without being required to provide a password.
+</WRAP>
+SeeAlso: AX=4303h
+==== 4303h - DR-DOS 3.41+ internal - SET ACCESS RIGHTS AND PASSWORD ====
+<code>
+	AX = 4303h
+	CX = access rights
+	     bit 0 delete requires password
+	     bit 2 write requires password
+	     bit 3 read requires password
+	     bits 4-7=equal to bits 0-3
+	     bits 8-11=equal to bits 0-3
+	     bit 15 new password is to be set
+	DS:DX -> ASCIZ pathname
+	[DTA] = new password if CX bit 15 is set (blank-padded to 8 characters)
+</code>
+<code>
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+</code>
+<WRAP round box>
+if the file is already protected, the old password must be added after the pathname, separated by a ";"
+</WRAP>
+SeeAlso: AX=4302h,AX=4454h
+==== 4304h - DR-DOS 5.0 internal - GET ??? ====
+<code>
+	AX = 4304h
+	???
+</code>
+<code>
+Return: CF clear if successful
+	    CX = AX = ???
+	CF set on error
+	    AX = error code (see AH=59h)
+</code>
+SeeAlso: AX=4305h
+==== 4305h - DR-DOS 5.0 internal - SET ??? ====
+<code>
+	AX = 4305h
+	???
+</code>
+<code>
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (see AH=59h)
+/code>
+SeeAlso: AX=4304h
+===== 4400h -  DOS 2+ - IOCTL - GET DEVICE INFORMATION =====
+<code>
+	AX = 4400h
+	BX = handle
+</code>
+<code>
+Return: CF clear if successful
+	    DX = device information word
+		character device
+: device driver can process IOCTL requests (see AX=4402h)
+: output until busy supported
+: driver supports OPEN/CLOSE calls
+: set (indicates device)
+: EOF on input
+: raw (binary) mode
+: device is special (uses INT 29)
+: clock device
+: NUL device
+: standard output
+: standard input
+		disk file
+: file is remote (DOS 3+)
+: don't set file date/time on closing (DOS 3+)
+: media not removable
+: (DOS 4+) generate INT 24 if no disk space on write
+: clear (indicates file)
+: file has not been written
+-0: drive number (0 = A:)
+	    AX destroyed
+	CF set on error
+	    AX = error code (01h,05h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+value in DH corresponds to high byte of device driver's attribute word if handle refers to a character device
+</WRAP>
+SeeAlso: AX=4401h,INT 2F/AX=122Bh
+===== 44h =====
+==== 4401h - DOS 2+ - IOCTL - SET DEVICE INFORMATION ====
+<code>
+	AX = 4401h
+	BX = handle (must refer to character device)
+	DX = device information word (see AX=4400h)
+	    (DH must be zero)
+</code>
+<code>
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+</code>
+SeeAlso: AX=4400h,INT 2F/AX=122Bh
+===== 4402h - DOS 2+ - IOCTL - READ FROM CHARACTER DEVICE CONTROL CHANNEL =====
+	AX = 4402h
+	BX = file handle referencing character device
+	CX = number of bytes to read
+	DS:DX -> buffer
+Return: CF clear if successful
+	    AX = number of bytes actually read
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	format of data is driver-specific (see below for some specific cases)
+SeeAlso: AX=4400h,AX=4403h,AX=4404h,INT 2F/AX=122Bh
+===== 4402h - Network Driver Interface Spec 2.0.1 - PROTOCOL MANAGER =====
+	AX = 4402h
+	BX = file handle for device "PROTMAN$"
+	DS:DX -> request block (see below)
+	CX = 000Eh (size of request block)
+== Format of request block for GetProtocolManagerInfo: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|01h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|returned pointer to structure representing parsed user config|
+|08h|DWORD|unused|
+|0Ch|WORD|returned BCD version of NDIS on which Protocol Manager is based|
+== Format of request block for RegisterModule: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|02h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|pointer to module's common characteristics table (see below)|
+|08h|DWORD|pointer to list of modules to which the module is to be bound|
+|0Ch|WORD|unused|
+== Format of request block for BindAndStart: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|03h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|caller's virtual address in FailingModules structure|
+|08h|DWORD|unused|
+|0Ch|WORD|unused|
+== Format of request block for GetProtocolManagerLinkage: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|04h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|returned dispatch point|
+|08h|DWORD|unused|
+|0Ch|WORD|returned protocol manager DS|
+<WRAP round box>
+the dispatch point may be called as follows instead of using this IOCTL
+<code>
+STACK: WORD  protocol manager DS
+       DWORD pointer to request block
+</code>
+<code>
+Return: AX = returned status
+	STACK popped
+</code>
+</WRAP>
+== Format of request block for GetProtocolIniPath: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|05h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|pointer to a buffer for the ASCIZ pathname of PROTOCOL.INI|
+|08h|DWORD|unused|
+|0Ch|WORD|buffer length|
+== Format of request block for RegisterProtocolManagerInfo: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|06h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|pointer to structure containing parsed user config file|
+|08h|DWORD|unused|
+|0Ch|WORD|length of structure|
+== Format of request block for InitAndRegister: ==
+^ Offset ^ Size ^Description^
+|00h|WORD|07h|
+|02h|WORD|returned status (see below)|
+|04h|DWORD|unused|
+|08h|DWORD|poitner to ASCIZ name of the module to be prebind initialized|
+|0Ch|WORD|unused|
+== Format of request block for UnbindAndStop: ==
+^  Offset  ^  Size  ^ Description                                                                                                                                       ^
+| 00h      | WORD   | 08h                                                                                                                                               |
+| 02h      | WORD   | returned status (see below)                                                                                                                       |
+| 04h      | DWORD  | failing modules as for BindAndStart                                                                                                               |
+| 08h      | DWORD  | if not 0000h:0000h, pointer to ASCIZ name of module to unbind\\ if 0000h:0000h, terminate a set of previously dynamically bound protocol modules  |
+| 0Ch      | WORD   |                                                                                                                                                   |
+== Format of request block for BindStatus: ==
+^  Offset  ^  Size  ^ Description                                           ^
+| 00h      | WORD   | 09h                                                   |
+| 02h      | WORD   | returned status (see below)                           |
+| 04h      | DWORD  | must be 0000h:0000h\\ on return, points to root tree  |
+| 08h      | DWORD  | 0000h:0000h                                           |
+| 0Ch      | WORD   | unused under DOS                                      |
+== Format of request block for RegisterStatus: ==
+^  Offset  ^  Size  ^ Description                                        ^
+| 00h      | WORD   | 0Ah                                                |
+| 02h      | WORD   | returned status (0000h, 0008h, 002Ch) (see below)  |
+| 04h      | DWORD  | 0000h:0000h                                        |
+| 08h      | DWORD  | pointer to 16-byte ASCIZ module name               |
+| 0Ch      | WORD   | 0000h                                              |
+== Values of status code: ==
+| 0000h |success|
+| 0001h |wait for release--protocol has retained control of the data buffer|
+| 0002h |request queued|
+| 0003h |frame not recognized|
+| 0004h |frame rejected|
+| 0005h |frame should be forwarded|
+| 0006h |out of resource|
+| 0007h |invalid parameter|
+| 0008h |invalid function|
+| 0009h |not supported|
+| 000Ah |hardware error|
+| 000Bh |transmit error|
+| 000Ch |unrecognized destination|
+| 000Dh |buffer too small|
+| 0020h |already started|
+| 0021h |binding incomplete|
+| 0022h |driver not initialized|
+| 0023h |hardware not found|
+| 0024h |hardware failure|
+| 0025h |configuration failure|
+| 0026h |interrupt conflict|
+| 0027h |MAC incompatible|
+| 0028h |initialization failed|
+| 0029h |no binding|
+| 002Ah |network may be disconnected|
+| 002Bh |incompatible OS version|
+| 002Ch |already registered|
+| 002Dh |path not found|
+| 002Eh |insufficient memory|
+| 002Fh |info not found|
+| 00FFh |general failure|
+| F000h-|FFFFh reserved for vendor-specific codes, treated as general failure|
+== Format of common characteristics table: ==
+^  Offset  ^  Size     ^ Description                                                                                                                                                                     ^
+| 00h      | WORD      | size of table in bytes                                                                                                                                                          |
+| 02h      | BYTE      | NDIS major version                                                                                                                                                              |
+| 03h      | BYTE      | NDIS minor version                                                                                                                                                              |
+| 04h      | WORD      | reserved                                                                                                                                                                        |
+| 06h      | BYTE      | module major version                                                                                                                                                            |
+| 07h      | BYTE      | module minor version                                                                                                                                                            |
+| 08h      | DWORD     | module function flag bits\\ bit 0: binding at upper boundary supported\\ bit 1: binding at lower boundary supported\\ bit 2: dynamically bound\\ bits 3-31 reserved, must be 0  |
+| 0Ch      | 16 BYTEs  | ASCIZ module name                                                                                                                                                               |
+| 1Ch      | BYTE      | upper boundary protocol level\\ 01h Media Access Control\\ 02h Data link\\ 03h network\\ 04h transport\\ 05h session\\ FFh not specified                                        |
+| 1Dh      | BYTE      | upper boundary interface type\\ for MACs: 1 = MAC\\ for data links and transports: to be defined\\ for session: 1 = NCB\\ any level: 0 = private (ISV-defined)                  |
+| 1Eh      | BYTE      | lower boundary protocol level\\ 00h physical\\ 01h Media Access Control\\ 02h Data link\\ 03h network\\ 04h transport\\ 05h session\\ FFh not specified                         |
+| 1Fh      | BYTE      | lower boundary interface type same as offset 1Dh                                                                                                                                |
+| 20h      | WORD      | module ID filled in by protocol manager                                                                                                                                         |
+| 22h      | WORD      | module DS                                                                                                                                                                       |
+| 24h      | DWORD     | system request entry point                                                                                                                                                      |
+| 28h      | DWORD     | pointer to service-specific characteristics \\ 0000h:0000h if none                                                                                                              |
+| 2Ch      | DWORD     | pointer to service-specific status \\ 0000h:0000h if none                                                                                                                       |
+| 30h      | DWORD     | pointer to upper dispatch table (see below) \\ 0000h:0000h if none                                                                                                              |
+| 34h      | DWORD     | pointer to lower dispatch table (see below) \\ 0000h:0000h if none                                                                                                              |
+| 38h      | DWORD     | reserved, must be 0                                                                                                                                                             |
+| 3Ch      | DWORD     | reserved, must be 0                                                                                                                                                             |
+<WRAP round box>
+for compatibility with NDIS 1.x.x, a major version of 00h is interpreted as 01h
+</WRAP>
+== Format of MAC Service-Specific Characteristics Table: ==
+^  Offset  ^  Size     ^ Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    ^
+| 00h      | WORD      | length of table in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+| 02h      | 16 BYTEs  | ASCIZ MAC type name, "802.3", "802.4", "802.5", "802.6", "DIX", "DIX+802.3", "APPLETALK", "ARCNET", "FDDI", "SDLC", "BSC", "HDLC", or "ISDN"                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
+| 12h      | WORD      | length of station addresses in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+| 14h      | 16 BYTEs  | permanent station address                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
+| 24h      | 16 BYTEs  | current station address                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+| 34h      | DWORD     | current functional adapter address (00000000h if none)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
+| 38h      | DWORD     | pointer to multicast address list                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+| 3Ch      | DWORD     | link speed in bits/sec                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
+| 40h      | DWORD     | service flags\\ bit  0: supports broadcast\\ bit  1: supports multicast\\ bit  2: supports functional/group addressing\\ bit  3: supports promiscuous mode\\ bit  4: station address software settable\\ bit  5: statistics always current\\ bit  6: supports InitiateDiagnostics\\ bit  7: supports loopback\\ bit  8: MAC does primarily ReceiveChain indications instead of ReceiveLookahead indications\\ bit  9: supports IBM source routing\\ bit 10: supports MAC reset\\ bit 11: supports Open/Close adapter\\ bit 12: supports interrupt request\\ bit 13: supports source routing bridge\\ bit 14: supports GDT virtual addresses (OS/2 version)\\ bit 15: multiple TransferDatas allowed durign a single indication\\ bit 16: MAC normally sets FrameSize = 0 in ReceiveLookahead\\ bit 17-31: reserved, must be 0  |
+| 44h      | WORD      | maximum frame size which may be both sent and received                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
+| 46h      | DWORD     | total transmit buffer capacity in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+| 4Ah      | WORD      | transmit buffer allocation block size in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
+| 4Ch      | DWORD     | total receive buffer capacity in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
+| 50h      | WORD      | receive buffer allocation block size in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+| 52h      | 3 BYTEs   | IEEE vendor code                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
+| 55h      | BYTE      | vendor adapter code                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+| 56h      | DWORD     | pointer to ASCIZ vendor adapter description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+| 5Ah      | WORD      | IRQ used by adapter                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+| 5Ch      | WORD      | transmit queue depth                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+| 5Eh      | WORD      | maximum supported number of data blocks in buffer descriptors                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+| 60h      | N BYTEs   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
+== Format of NetBIOS Service-Specific Characteristics Table: ==
+^ Offset ^ Size ^Description^
+| 00h|WORD	|length of table in bytes|
+| 02h |16 BYTEs	|ASCIZ type name of NetBIOS module|
+| 12h|WORD	|NetBIOS module code|
+| 14h |N BYTEs	|vendor-specific info|
+== Format of MAC Service-Specific Status Table: ==
+^  Offset  ^  Size    ^ Description                                                                                                                                                                                                                                                                                                                                                                                                      ^
+| 00h      | WORD     | length of table in bytes                                                                                                                                                                                                                                                                                                                                                                                         |
+| 02h      | DWORD    | seconds since 0:00 1/1/70 when diagnostics last run (FFFFFFFFh = never)                                                                                                                                                                                                                                                                                                                                          |
+| 06h      | DWORD    | MAC status bits\\ bits 0-2: \\   * 000 hardware not installed\\   * 001 hardware failed startup diagnostics\\   * 010 hardware configuration problem\\   * 011 hardware fault\\   * 100 operating marginally due to soft faults\\   * 101 reserved\\   * 110 reserved\\   * 111 hardware fully operational\\ bit  3:	  MAC bound\\ bit  4:	  MAC open\\ bit  5:	  diagnostics in progress\\ bits 6-31: reserved  |
+| 0Ah      | WORD     | current packet filter flags\\ bit 0: directed/multicast or group/functional\\ bit 1: broadcast\\ bit 2: promiscuous\\ bit 3: all source routing\\ bit 4-15: reserved, must be zero                                                                                                                                                                                                                               |
+| 0Ch      | DWORD    | pointer to media-specific status table or 0000h:0000h                                                                                                                                                                                                                                                                                                                                                            |
+| 10h      | DWORD    | seconds past 0:00 1/1/70 of last ClearStatistics                                                                                                                                                                                                                                                                                                                                                                 |
+| 14h      | DWORD    | total frames received (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                                  |
+| 18h      | DWORD    | frames with CRC error (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                                  |
+| 1Ch      | DWORD    | total bytes received (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                                   |
+| 20h      | DWORD    | frames discarded--no buffer space (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                      |
+| 24h      | DWORD    | multicast frames received (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                              |
+| 28h      | DWORD    | broadcast frames received (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                              |
+| 2Ch      | DWORD    | frames with errors (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                                     |
+| 30h      | DWORD    | overly large frames (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                                    |
+| 34h      | DWORD    | frames less than minimum size (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                          |
+| 38h      | DWORD    | multicast bytes received (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                               |
+| 3Ch      | DWORD    | broadcast bytes received (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                               |
+| 40h      | DWORD    | frames discarded--hardware error (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                       |
+| 44h      | DWORD    | total frames transmitted (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                               |
+| 48h      | DWORD    | total bytes transmitted (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                                |
+| 4Ch      | DWORD    | multicast frames transmitted (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                           |
+| 50h      | DWORD    | broadcast frames transmitted (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                           |
+| 54h      | DWORD    | broadcast bytes transmitted (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                            |
+| 58h      | DWORD    | multicast bytes transmitted (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                            |
+| 5Ch      | DWORD    | frames not transmitted--timeout (FFFFFFFFh = not counted)                                                                                                                                                                                                                                                                                                                                                        |
+| 60h      | DWORD    | frames not transmitted--hardware error (FFFFFFFFh = not countd)                                                                                                                                                                                                                                                                                                                                                  |
+| 64h      | N BYTEs  | vendor-specific info                                                                                                                                                                                                                                                                                                                                                                                             |
+==== 4402h - U - IBM SYSTEM 36/38 WORKSTATION EMULATION - VDI.SYS - GET ??? ====
+	AX = 4402h
+	BX = handle for character device "GDMS"
+	CX = number of bytes to read (>= 4)
+	DS:DX -> buffer (see below)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    AX = number of bytes read
+Format of returned data:
+Offset	Size	Description
+h  4 BYTEs	???
+h	DWORD	pointer to ???
+h  4 BYTEs	???
+==== 4402h - U - LASTBYTE.SYS v1.19 - IOCTL - GET ??? TABLE ====
+	AX = 4402h
+	BX = handle for device "LA$TBYTE"
+	CX = 0004h
+	DS:DX -> DWORD to hold address of 39-byte table of ???
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    AX = number of bytes read
+Note:	LASTBYTE.SYS is part of "The Last Byte" by Key Software Products
+SeeAlso: AX=4402h"HIGHUMM"
+==== 4402h - HIGHUMM.SYS v1.17+ - IOCTL - GET API ADDRESS ====
+	AX = 4402h
+	BX = handle for device "KSP$UMM"
+	CX = 0004h
+	DS:DX -> DWORD to hold entry point
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    AX = number of bytes read
+Note:	HIGHUMM.SYS is part of "The Last Byte" by Key Software Products
+SeeAlso: AX=4402h"LASTBYTE"
+Call HIGHUMM.SYS entry point with:
+	AH = 00h allocate UMB (same as XMS function 10h) (see INT 2F/AX=4310h)
+	    DX = size in paragraphs
+	    Return: BX = segment number (if successful)
+		    DX = size of requested block/size of largest block
+	AH = 01h deallocate UMB (same as XMS func 11h) (see INT 2F/AX=4310h)
+	    DX = segment number of UMB
+	AH = 02h request a bank-switched memory block
+	    DX = size in paragraphs
+	    Return: BX = segment number (if successful)
+		    DX = size of requested block/size of largest block
+	AH = 03h release a bank-switched memory block
+	    DX = segment number
+	AH = 04h transfer data to/from high memory
+	    DS:SI -> source
+	    ES:DI -> destination
+	    CX = length in bytes
+	    Note: enables bank-switched memory, does the copy, then disables
+		bank-switched memory
+	AH = 05h get a word from bank-switched memory
+	    ES:DI -> word to read
+	    Return: DX = word
+	AH = 06h put a word to bank-switched memory
+	    ES:DI -> word to write
+	    DX = word
+	AH = 07h put a byte to bank-switched memory
+	    ES:DI -> byte to write
+	    DL = byte
+	AH = 08h enable bank-switched memory
+	    DS:SI -> 6-byte status save area
+	AH = 09h disable bank-switched memory
+	    DS:SI -> 6-byte save area from enable call (AH=08h)
+	AH = 0Ah assign name to UMB or high bank-switched block
+	    DX = segment number
+	    DS:SI -> 8-byte blank-padded name
+	AH = 0Bh locate UMB block by name
+	    DS:SI -> 8-byte blank-padded name
+	    Return: BX = segment number (if successful)
+		    DX = size of block
+	AH = 0Ch locate bank-switched block by name
+	    DS:SI -> 8-byte blank-padded name
+	    Return: BX = segment number (if successful)
+		    DX = size of block
+Return: AX = status code
+h successful
+h failed
+		BL = error code
+h not implemented
+		    B0h insufficient memory, smaller block available
+		    B1h insufficient memory, no blocks available
+		    B2h invalid segment number
+Note:	only functions 00h and 01h are always available; the remaining
+	  functions are only enabled if the proper commandline switch is given
+==== 4402h - SMARTDRV.SYS - IOCTL - GET CACHE STATUS ====
+	AX = 4402h
+	BX = file handle for device "SMARTAAR"
+	CX = number of bytes to read (min 28h)
+	DS:DX -> buffer for status record (see below)
+Return: CF clear if successful
+	    AX = number of bytes actually read
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4403h"SMARTDRV",INT 2F/AX=4A10h
+Format of SMARTDRV status record:
+Offset	Size	Description
+h	BYTE	write-through flag (always 01h)
+h	BYTE	writes should be buffered (always 00h)
+h	BYTE	cache enabled if 01h
+h	BYTE	driver type (01h extended memory, 02h expanded)
+h	WORD	clock ticks between cache flushes (currently unused)
+h	BYTE	cache contains locked tracks if nonzero
+h	BYTE	flush cache on INT 19 reboot if nonzero
+h	BYTE	cache full track writes if nonzero
+h	BYTE	double buffering (for VDS) state (00h off, 01h on, 02h dynamic)
+Ah	DWORD	original INT 13 vector
+Eh	BYTE	minor version number
+Fh	BYTE	major version number
+h	WORD	unused
+h	WORD	sectors read			\
+h	WORD	sectors already in cache	 > may be scaled rather than
+h	WORD	sectors already in track buffer /  absolute counts
+h	BYTE	cache hit rate in percent
+h	BYTE	track buffer hit rate in percent
+Ah	WORD	total tracks in cache
+Ch	WORD	number of tracks in use
+Eh	WORD	number of locked tracks
+h	WORD	number of dirty tracks
+h	WORD	current cache size in 16K pages
+h	WORD	original (maximum) cache size in 16K pages
+h	WORD	minimum cache size in 16K pages
+h	DWORD	pointer to byte flag to increment for locking cache contents
+==== 4402h - CD-ROM device driver - IOCTL INPUT ====
+	AX = 4402h
+	BX = file handle referencing character device for CD-ROM driver
+	CX = number of bytes to read
+	DS:DX -> control block (see below)
+Return: CF clear if successful
+	    AX = number of bytes actually read
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	the data returned depends on the first byte of the control block; the
+	  remainder of the control block is filled by the driver
+SeeAlso: AX=4403h"CD-ROM",INT 2F/AX=0802h
+Format of control block:
+Offset	Size	Description
+h	BYTE	data being requested
+h device driver header address
+h drive head location
+h reserved
+h error statistics
+h audio channel info
+h raw drive bytes (uninterpreted and device-specific)
+h device status
+h sector size
+h volume size
+h media change status
+Ah audio disk info
+Bh audio track info
+Ch audio Q-Channel info
+Dh audio sub-channel info
+Eh UPC code
+---function 00h---
+h	DWORD	device driver header address (see also AH=52h)
+---function 01h---
+h	BYTE	addressing mode
+h HSG
+h Red Book
+h	DWORD	current location of drive's head
+		logical sector number in HSG mode
+		frame/second/minute/unused in Red Book mode
+		(HSG sector = minute * 4500 + second * 75 + frame - 150)
+---function 03h---
+h  N BYTEs	undefined as of 5 Aug 88 specification
+---function 04h---
+h	BYTE	input channel (0-3) for output channel 0
+h	BYTE	volume for output channel 0
+h	BYTE	input channel (0-3) for output channel 1
+h	BYTE	volume for output channel 1
+h	BYTE	input channel (0-3) for output channel 2
+h	BYTE	volume for output channel 2
+h	BYTE	input channel (0-3) for output channel 3
+h	BYTE	volume for output channel 3
+Notes:	output channels 0 and 1 are left and right, 2 and 3 are left prime and
+	  right prime; a volume of 00h is off
+	the default setting is for each input channel to be assigned to the
+	  same-numbered output channel at full (FFh) volume
+---function 05h---
+h	BYTE	number of bytes read
+h 128 BYTEs	buffer for drive bytes
+---function 06h---
+h	DWORD	device parameters
+		bit 0: door open
+: door unlocked
+: supports raw reading in addition to cooked
+: writable
+: can play audio/video tracks
+: supports interleaving
+: reserved
+: supports prefetch requests
+: supports audio channel control
+: supports Red Book addressing in addition to HSG
+: audio is playing
+---function 07h---
+h	BYTE	read mode
+h cooked
+h raw
+h	WORD	sector size in bytes
+---function 08h---
+h	DWORD	volume size in sectors
+---function 09h---
+h	BYTE	media change status
+h don't know
+h media unchanged
+		FFh media has been changed
+---function 0Ah---
+h	BYTE	lowest audio track number
+h	BYTE	highest audio track number
+h	DWORD	start address of lead-out track (Red Book format)
+--function 0Bh---
+h	BYTE	track number (set by caller)
+h	DWORD	starting point of track (Red Book format)
+h	BYTE	track control info
+		bits 15,14,12: track type (notice: bits not contiguous!)
+two audio channels, no pre-emphasis
+two audio channels with pre-emphasis
+data track
+four audio channels, no pre-emphasis
+four audio channels with pre-emphasis
+			other reserved
+		bit 13: digital copy permitted
+---function 0Ch---
+h	BYTE	CONTROL and ADR byte (as received from drive)
+h	BYTE	track number
+h	BYTE	point or index
+h	BYTE	minute	\
+h	BYTE	second	 > running time within track
+h	BYTE	frame	/
+h	BYTE	zero
+h	BYTE	"AMIN" or "PMIN"     \
+h	BYTE	"ASEC" or "PSEC"      > running time on disk
+Ah	BYTE	"AFRAME" or "PFRAME" /
+---function 0Dh---
+h	DWORD	starting frame address (Red Book format)
+h	DWORD	transfer address
+h	DWORD	number of sectors to read
+Note:	copies 96 bytes of sub-channel info per sector into buffer
+---function 0Eh---
+h	BYTE	CONTROL and ADR byte
+h  7 BYTEs	UPC/EAN code (13 BCD digits,low-order nybble of last byte is 0)
+h	BYTE	zero
+Ah	BYTE	"AFRAME"
+==== 4402h - U - Quarterdeck - QEMM-386 v5+ - GET API ENTRY POINT ====
+	AX = 4402h
+	BX = file handle for device "QEMM386$"
+	CX = 0004h
+	DS:DX -> DWORD buffer for API entry point
+Return: CF clear if successful
+	    buffer filled (see INT 67/AH=3Fh for entry point parameters)
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4402h"HOOKROM",INT 2F/AX=D201h/BX=5145h,INT 67/AH=3Fh
+==== 4402h - U - Quarterdeck - QEMM-386 v6+ - GET ??? ====
+	AX = 4402h
+	BX = file handle for device "EMMXXXX0"
+	CX = 0006h (size of buffer in bytes)
+	DS:DX -> buffer for ???
+		first byte must be 01h on entry
+Return: CF clear if successful
+	    buffer filled (see INT 67/AH=3Fh function 1B00h)
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	this call always returns an error if Windows3 support has been disabled
+	  with the NW3 switch to QEMM386.SYS
+SeeAlso: INT 2F/AX=D201h/BX=5145h,INT 67/AH=3Fh
+==== 4402h -  U - Quarterdeck - HOOKROM.SYS - GET HOOKED VECTOR TABLE ====
+	AX = 4402h
+	BX = file handle for device "HOOKROM$"
+	CX = 0004h
+	DS:DX -> DWORD buffer for address of hooked vector table (see below)
+Return: CF clear if successful
+	    DS:DX buffer filled
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4402h"QEMM"
+Format of hooked vector table entry:
+Offset	Size	Description
+h  5 BYTEs	FAR jump to actual interrupt handler
+ 		(end of table if first byte is not EAh)
+h	BYTE	interrupt vector number
+==== 4402h - Advanced SCSI Programming Interface (ASPI) - INTERFACE ====
+	AX = 4402h
+	BX = file handle for device "SCSIMGR$"
+	CX = 0004h
+	DS:DX -> buffer for function address
+Return: CF clear if successful
+	    AX = 0004h
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	the function address is called with the address of a SCSI Request
+	  Block on the stack and the caller must clean up the stack
+SeeAlso: AX=440Ch"ASPITAPE",INT 11/AH=FFh"WD7000"
+Format of SCSI Request Block (64 bytes):
+Offset	Size	Description
+h	BYTE	request number
+h "HA_INQ"     host adapter inquiry
+h "GET_TYPE"   get device type
+h "EXEC_SIO"   execute SCSI I/O
+h "ABORT_SRB"  abort SRB
+h "RESET_DEV"  reset SCSI device
+h "SET_HAPRMS" set host adapter parameters
+h	BYTE	request status
+h not done yet
+h aborted
+h SCSI I/O error
+h invalid
+h no adapter
+h no device attached
+		else status
+h	BYTE	host adapter ID
+h	BYTE	request flags
+ 		bit 3: ???
+h	DWORD	reserved
+---request 00h---
+h	BYTE	(returned) number of host adapters
+h	BYTE	(returned) target adapter ID
+Ah 16 BYTEs	(returned) manager ID
+Ah 16 BYTEs	(returned) adapter ID
+Ah 16 BYTEs	(returned) parameters
+---request 01h---
+h	BYTE	target ID
+h	BYTE	logical unit number
+Ah	BYTE	(returned) device type
+h streamer
+---request 02h---
+h	BYTE	target ID
+h	BYTE	logical unit number
+Ah	DWORD	data allocation length
+Eh	BYTE	sense allocation length
+Fh	DWORD	data buffer pointer
+h	DWORD	next request pointer (for linking)
+h	BYTE	CDB length
+h	BYTE	(returned) host adapter status
+h select timeout
+h data overrun
+h bus error
+h bus failure
+h	BYTE	(returned) target status
+h sense data stored in SRB
+h target busy
+h reservation error
+Ah	DWORD	post routine address
+Eh	WORD	real mode Post DS
+h	DWORD	SRB pointer
+h	WORD	reserved
+h	DWORD	SRB physical address
+Ah 22 BYTEs	SCSIMGR$ workspace
+h  N BYTEs	CCB (20-24 bytes)
+---request 04h---
+h	BYTE	target ID
+h	BYTE	logical unit number
+Ah 14 BYTEs	reserved
+h	BYTE	(returned) host adapter status (see above)
+h	BYTE	(returned) target status (see above)
+Ah	DWORD	post routine address
+Eh 34 BYTEs	workspace
+Format of CCB:
+Offset	Size	Description
+h	BYTE	command code
+h rewind
+h get block size limits
+h read
+Ah write
+h write file marks
+h SCSI Space (set position?)
+h SCSI Inquire
+h erase
+Bh load/unload media
+h	BYTE	flags
+ 		bits 4-0: vary by function
+		bits 7-5: logical unit number
+h	BYTE	"adr_1"
+h	BYTE	"adr_0"
+h	BYTE	length
+h	BYTE	control
+ 	...
+h/0Ah 14 BYTEs buffer for sense data
+==== 4402h - U - Qualitas 386MAX v6.00+ - IOCTL INPUT - GET STATE ====
+	AX = 4402h
+	BX = file handle for device "386MAX$$"
+	CX = 005Ah
+	DS:DX -> 386MAX state buffer (see below)
+Return: CF clear if successful
+	    buffer filled
+	    AX = number of bytes actually copied
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Notes:	the buffer must be one byte larger than the value given in CX; if the
+	  value is less than 5Ah, only a partial state record will be returned
+	the state is 40h bytes for 386MAX (actually ASTEMM) v2.20 ("386MAX$$"
+	  did not exist yet, use "QMMXXXX0" and then "EMMXXXX0" instead) and
+h bytes for v5.11.
+	to invoke 386MAX API functions, push DX onto the stack, load DX with
+	  the word at offset 25h in the returned state, load all other
+	  registers as needed for the desired function, and execute an
+	  OUT DX,AL or OUT DX,AX; DX will be set to the pushed value on return
+	  if it is not otherwise modified by the API function.
+SeeAlso: AX=4403h"386MAX",INT 67/AH=03h,INT 67/AH=3Fh
+Format of 386MAX v6.01 state:
+Offset	Size	Description
+h	BYTE	version number of state structure (must be set on entry;
+		  v6.01 returns an error if not 03h)
+h  6 BYTEs	signature "386MAX"
+h  4 BYTEs	version string "N;NN" (i.e. "6;01" for v6.01)
+Bh	WORD	segment of low-memory portion of 386MAX.SYS
+Dh  2 BYTEs	???
+Fh	WORD	segment of ??? memory block or 0000h
+h	WORD	bit flags
+		bit 1: ???
+		bit 2: ???
+		bit 3: ??? (cleared by calling INT 67 functions)
+		bit 5: ???
+		bit 6: 386MAX active???
+		bit 7: 386MAX is providing EMS services
+		bit 8: ???
+		bit 9: ??? (see INT 15/AX=2402h)
+		bit 10: ???
+		bit 11: ???
+		bit 12: ???
+		bit 13: QPMS has been used
+		bit 14: ???
+		bit 15: ???
+h	WORD	starting address of video memory in K
+h  8 BYTEs	???
+Dh	WORD	KBytes extended memory used by 386MAX
+Fh  2 BYTEs	???
+h	WORD	???
+h	WORD	IO port to write (OUT DX,AL) to invoke 386MAX INT 15 functions
+h	WORD	IO port to write (OUT DX,AL) to invoke 386MAX API functions
+h	WORD	???
+h  2 BYTEs	???
+Bh	DWORD	???
+Fh  4 BYTEs	???
+h	WORD	system configuration??? flags
+ 		bit 1: ROM compressed???
+ 		bit 3: ???
+		bit 5: 386MAX loaded into high memory
+ 		bit 11: PC/XT (thus only single 8259 interrupt controller
+				present, DMA only in 1st megabyte, etc)
+h	WORD	??? bit flags
+h  4 BYTEs	???
+Bh	WORD	segment of first MCB in high memory chain???
+Dh	WORD	flags
+ 		bit 2: no DPMI services
+ 		bit 11: don't backfill holes in video memory area
+		bit 12: don't backfill below video memory???
+Fh	WORD	flags
+ 		bit 7: ???
+h	WORD	flags
+ 		bit 0: Windows3 support enabled
+		bit 8: ???
+h  2 BYTEs	???
+h	WORD	amount of memory to report available on INT 15/AH=88h
+h  4 BYTEs	???
+Bh	WORD	???
+Dh  2 BYTEs	???
+Fh	WORD	???
+h	WORD	bit flags
+ 		bit 12: ???
+h	DWORD	old INT 21h
+h	DWORD	pointer to 386MAX's EMS (INT 67h) handler
+Format of high memory info record:
+Offset	Size	Description
+h	WORD	segment address of memory region
+h	WORD	size of memory region in paragraphs
+h	BYTE	type or flags???
+h if locked out
+h if EMS page frame
+h if high RAM
+h if ROM
+h	BYTE	???
+Format of ROM shadowing record:
+Offset	Size	Description
+h	WORD	segment of ROM???
+h	WORD	segment of ROM???
+h  2 BYTEs	???
+h	WORD	size of shadowed ROM in paragraphs
+h  4 BYTEs	???
+Values for memory type:
+h unused by EMS
+h DOS
+h page frame overlapping ROM???
+h high memory
+h page frame???
+h video ROM???
+Note:	the type may be 00h (unused) if the 16K page is split among different
+	  uses (such as ROM and high RAM)
+Call 386MAX API (via OUT DX,AL) with:
+	STACK: WORD value for DX
+	AH = 01h get high memory information
+		ES:DI -> buffer for array of high memory info records
+			(see above)
+		Return: CX = number of records placed in buffer
+	AH = 02h get shadowed ROM info???
+		ES:DI -> buffer for array of ROM shadowing records (see above)
+		Return: CX = number of records placed in buffer
+	AH = 03h get 386MAX state
+		ES:DI -> 90-byte buffer for state (see above)
+		Return: AH = 00h (successful)
+			buffer filled
+		Note:	unlike INT 21/AX=4402h"386MAX", this function omits
+			  the first byte specifying the state buffer version
+	AH = 04h get memory types???
+		ES:DI -> buffer for memory type info (array of bytes, one per
+K page) (see above)
+		Return:	CX = number of bytes placed in buffer
+	AH = 05h get ???
+		AL = subfunction
+h invoke INT 15/AX=2401h first
+h don't invoke INT 15/AX=2401h first
+		CX = number of bytes to copy (0000h for default)
+		SI = ???
+		ES:DI -> buffer for ???
+		Return: CX = number of bytes actually copied
+			???
+	AH = 06h get memory speed info
+		ES:DI -> buffer for memory speed records (see below)
+		Return: AH = 00h (successful)
+			CX = number of bytes placed in buffer
+		Note:	this function can take over a second to execute
+	AH = 07h ???
+		???
+		Return:	???
+	AH = 08h ???
+		AL = ??? (00h or nonzero)
+	AH = 09h toggle ??? flags
+		BX = bitmask of bits of ??? flags (word at state+11h) to toggle
+		Return: AH = 00h (successful)
+		Note: invokes INT 15/AX=2401h first
+	AH = 0Ah toggle ??? flags
+		BX = bitmask of bits of ??? (word at state+33h) to toggle
+		Return: AH = 00h (successful)
+		Notes:	invokes INT 15/AX=2401h first
+			does ??? if bit 3 on after specified bits are toggled
+	AH = 0Bh toggle ??? flags
+		BX = bitmask of bits of ??? (word at state+35h) to toggle
+		Return: AH = 00h (successful)
+		Note: invokes INT 15/AX=2401h first
+	AH = 0Ch toggle ??? flags
+		BX = bitmask of bits of ??? (word at state+41h) to toggle
+		Return: AH = 00h (successful)
+		Note: invokes INT 15/AX=2401h first
+	AH = 0Dh specify 386MAX high-memory location
+		BX = segment address of high-memory real-mode portion of 386MAX
+		???
+		Return: AH = status (00h successful)
+			???
+	AH = 0Eh CRT controller register virtualization
+		AL = subfunction
+h allow access to CRTC I/O ports 03B4h/03B5h, 03D4h/03D5h
+h trap accesses to CRTC I/O ports
+	AH = 0Fh reboot system
+		Return: never
+	AH = 11h get high memory information
+		ES:DI -> 96-byte buffer for high memory info
+		Return: AH = 00h (successful)
+			ES:DI buffer filled
+		Notes:	each byte in buffer contains bit flags for a 4K page in
+			  the A000h-FFFFh region
+				bit 0: ???
+				bit 1: physical address same as linear address
+				bit 2: EMS page frame
+				bit 6: ???
+			this function can take over a second to execute
+	AH = 12h ???
+		AL = subfunction
+h ???
+h ???
+		???
+		Return: AH = 00h (successful) if AL=00h or 01h
+			AH = 8Fh otherwise
+	AH = 13h page protection???
+		AL = subfunction
+h set all ??? 4K pages to read-only???
+h set all ??? 4K pages to read-write???
+		???
+		Return: AH = 00h (successful) if AL=00h or 01h
+			AH = 8Fh otherwise
+	AH = 15h ???
+		???
+		Return: ???
+	AH = 16h get 386MAX memory usage screen
+		ES:DI -> buffer for memory info display
+		CX = size of buffer in bytes
+		Return:	ES:DI buffer filled with '$'-terminated string (if
+				large enough to hold entire usage screen)
+	AH = 17h Windows 3 startup/termination
+		AL = subfunction
+h Windows3 initializing
+			DX (on stack) = Windows startup flags
+			DI = Windows version number (major in upper byte)
+			ES:BX = 0000h:0000h
+			DS:SI = 0000h:0000h
+			Return: CX = 0000h if OK for Windows to load
+				   <> 0 if Windows should not load
+				ES:BX -> startup info structure
+				DS:SI -> Virtual86 mode enable/disable callback
+h Windows3 terminating
+		    	ES:BX -> ???
+			DX (on stack) = Windows exit flags
+			Return: ???
+	AH = 18h QPMS (Qualitas Protected Memory Services)
+		AL = subfunction
+h get QPMS configuration
+		    	Return: BX = starting segment of QPMS memory window
+				CX = number of 4K pages reserved for QPMS???
+				DX = number of 4K pages in QPMS window???
+h map QPMS memory page???
+		    	BX = 4K page number within memory reserved for QPMS???
+			CL = 4K page number within QPMS memory window???
+h mark all QPMS memory read-only
+h mark all QPMS memory read-write
+		Return: AH = status (00h,8Ah,8Bh,8Fh)
+	AH = 19h get linear address for physical address
+		EDX = physical address (low word on stack)
+		Return: AH = status
+h successful
+			    	EDX = linear address at which physical address
+					may be accessed
+Bh physical address currently not addressable
+		Note: calls INT 15/AX=2401h first
+	AH = 1Ah set page table entry???
+		EDX = new page table entry??? (low word on stack)
+		ESI = linear address of page???
+		Return: AH = status (00h,8Bh)
+		Note: calls INT 15/AX=2401h first
+	AH = 1Bh get ???
+		Return: AH = status
+			BX = ???
+			CX = ???
+			EDX = physical address of ???
+	AH = 1Ch get original interrupt vector
+		AL = interrupt vector (00h-7Fh)
+		Return: AH = 00h (successful)
+			EDX = original vector before 386MAX loaded (segment in
+				high word, offset in low word)
+		Note:	no range checking is performed; requests for INTs 80h-
+			  FFh will return random values
+	AH = 1Dh display string???
+		SI = ???
+		Return: AH = 00h (successful)
+			???
+	AH = 1Eh ???
+		ES:DI -> ???
+		???
+		Return: ???
+	AH = 1Fh ???
+		???
+		Return: AX = 0000h if successful
+			BX = ??? (0001h for 386MAX v6.01)
+			CL = ???
+			DL = ??? (5Ah for 386MAX v6.01)
+			DH = ??? (00h for 386MAX v6.01)
+			SI = ???
+			ES???:DI -> ???
+	AH = 40h-5Dh EMS services (see INT 67/AH=40h etc)
+	AH = DEh VCPI services (see INT 67/AX=DE00h etc)
+Return: AH = status (as for EMS INT 67 calls)
+h successful
+h internal error
+h hardware malfunction
+h invalid handle
+h	undefined function
+Ah invalid logical page nuber
+Bh illegal physical page number
+Fh undefined subfunction
+	    A4h access denied
+	    etc.
+	STACK popped (value placed in DX if no specific return value for DX)
+Format of memory speed record:
+Offset	Size	Description
+h	DWORD	page table entry for 4K page
+h	WORD	number of microticks (840ns units) required for REP LODSD of
+ 		entire 4K page
+==== 4402h - PGS1600.DEV - IOCTL - GET CONFIGURATION INFO ====
+	AX = 4402h
+	BX = file handle for device "PGS1600$"
+	CX = 0018h (size of buffer)
+	DS:DX -> configuration buffer (see below)
+Return: CF clear if successful
+	    buffer filled
+	    AX = number of bytes actually copied
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	PGS1600.DEV is a device driver for the Cornerstone Technology PG1600
+	  display adapter, which provides a 1600x1200 monochrome display as
+	  well as one of two emulations, MDA or CGA.
+SeeAlso: AX=4403h"PGS1600"
+Format of configuration information:
+Offset	Size	Description
+h	WORD	version (high byte = major, low byte = minor)
+h	WORD	board initialisation mode
+h	WORD	board I/O address
+D0h CGA emulation
+B0h MDA emulation
+h no emulation
+h no emulation, alternate
+h	WORD	emulation buffer segment
+ 		B800h   CGA emulation
+		B000h   MDA emulation
+h   no emulation
+h	WORD	PG1600 graphics buffer segment
+Ah	WORD	number of bytes between consecutive graphic rows
+Ch	WORD	horizontal pixel size
+Eh	WORD	vertical pixel size
+h	WORD	horizontal dots per inch
+h	WORD	vertical dots per inch
+h	WORD	graphics buffer bits per pixel
+h	WORD	monitor bits per pixel
+==== 4402h - PC/TCP IPCUST.SYS - RESET CONFIGURATION DATA READ POINTER ====
+	AX = 4402h
+	BX = file handle referencing device "$IPCUST"
+	CX, DS:DX ignored
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	there are a total of 378h bytes of configuration data for IPCUST.SYS
+	  version 2.05.  If less than the entire data is read or written,
+	  the next read/write continues where the previous one ended; this
+	  call and AX=4403h both reset the location at which the next
+	  operation starts to zero
+SeeAlso: AH=3Fh"IPCUST",AH=40h"IPCUST",AX=4403h"IPCUST"
+----------214403-----------------------------
+INT 21 - DOS 2+ - IOCTL - WRITE TO CHARACTER DEVICE CONTROL CHANNEL
+	AX = 4403h
+	BX = file handle referencing character device
+	CX = number of bytes to write
+	DS:DX -> data to write
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Notes:	format of data is driver-specific (see below for some specific cases)
+	if the file handle refers to "4DOSSTAK", the 4DOS (v2.x-3.03)
+	  KEYSTACK.SYS driver will push the specified characters on the
+	  keyboard stack; similarly for "NDOSSTAK", the NDOS KEYSTACK.SYS
+	  driver will push the characters onto the keyboard stack
+SeeAlso: AX=4400h,AX=4402h,AX=4405h,INT 2F/AX=122Bh,INT 2F/AX=D44Dh
+SeeAlso: INT 2F/AX=D44Fh
+----------214403-----------------------------
+INT 21 - SMARTDRV.SYS - IOCTL - CACHE CONTROL
+	AX = 4403h
+	BX = handle for device "SMARTAAR"
+	CX = number of bytes to write
+	DS:DX -> SMARTDRV control block (see below)
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	       = 0000h if control block too small for given command
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4402h"SMARTDRV",INT 2F/AX=4A10h
+Format of SMARTDRV control block:
+Offset	Size	Description
+h	BYTE	function code
+h flush cache
+h flush and discard cache
+h disable caching (flushes and discards cache first)
+h enable caching
+h control write caching
+h set flushing tick count
+h lock cache contents
+h unlock cache contents
+h set flush-on-reboot flag
+h unused
+Ah control full-track caching
+Bh reduce cache size
+Ch increase cache size
+Dh set INT 13 chain address
+---function 04h---
+h	BYTE	write caching control action
+h turn off write-through
+h turn on write-through
+h turn off write buffering (also flushes cache)
+h turn on write buffering (also flushes cache)
+---function 05h---
+h	WORD	number of timer ticks between cache flushes
+---function 08h---
+h	BYTE	new flush-on-reboot flag (00h off, 01h on)
+---function 0Ah---
+h	BYTE	full-track writes are
+h not cached
+h cached
+---functions 0Bh,0Ch---
+h	WORD	number of 16K pages by which to increase/reduce cache size
+---function 0Dh---
+h	DWORD	new address to which to chain on INT 13
+Note:	the previous address is not preserved
+----------214403-----------------------------
+INT 21 - CD-ROM device driver - IOCTL OUTPUT
+	AX = 4403h
+	BX = file handle referencing character device for CD-ROM driver
+	CX = number of bytes to write
+	DS:DX -> control block (see below)
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4402h"CD-ROM",INT 2F/AX=0802h
+Format of control block:
+Offset	Size	Description
+h	BYTE	function code
+h eject disk
+h lock/unlock door
+h reset drive
+h control audio channel
+h write device control string
+h close tray
+---functions 00h,02h,05h---
+ no further fields
+---function 01h---
+h	BYTE	lock function
+h unlock door
+h lock door
+---function 03h---
+h	BYTE	input channel (0-3) for output channel 0
+h	BYTE	volume for output channel 0
+h	BYTE	input channel (0-3) for output channel 1
+h	BYTE	volume for output channel 1
+h	BYTE	input channel (0-3) for output channel 2
+h	BYTE	volume for output channel 2
+h	BYTE	input channel (0-3) for output channel 3
+h	BYTE	volume for output channel 3
+Note:	output channels 0 and 1 are left and right, 2 and 3 are left prime and
+	  right prime; a volume of 00h is off
+---function 04h---
+h  N BYTEs	bytes to send directly to the CD-ROM drive without
+		interpretation
+----------214403-----------------------------
+INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS
+	AX = 4403h
+	BX = handle for device "SCSITAPE"
+	CX = number of bytes to write
+	DS:DX -> SCSITAPE control block (see below)
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4405h"ST-01",INT 78/AH=10h
+Format of SCSITAPE control block:
+Offset	Size	Description
+h	WORD	command type
+		'F' Format (argument 1 = interleave, argument 2 = format type)
+		'E' Erase
+		'R' Rewind
+		'L' Load
+		'N' No Load
+		'S' Space (argument 1 = count, argument 2 = type)
+		'M' File Mark (argument 1 = count)
+		'A' Reassign
+h	WORD	argument 1
+h	WORD	argument 2
+h	WORD	segment of command buffer
+h	WORD	offset of command buffer
+Ah	WORD	length of command buffer
+----------214403-----------------------------
+INT 21 U - AI Architects - OS/x86??? - API
+	AX = 4403h
+	BX = handle for device "AIA_OS"
+	CX = number of bytes to write (ignored)
+	DS:DX -> 12-byte buffer, first byte is command:
+h installation check
+h get API entry point
+h uninstall
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Ch,0Dh) (see AH=59h)
+Notes:	these functions are only available if the DOS extender was loaded as a
+	  device driver in CONFIG.SYS
+	called by TKERNEL (a licensed version of AI Architects/Ergo OS/x86)
+SeeAlso: INT 2F/AX=FBA1h/BX=0081h,INT 2F/AX=FBA1h/BX=0082h
+Format of buffer on return:
+Offset	Size	Description
+h  4 BYTEs	signature "IABH"
+---if func 81h---
+ (no additional fields)
+---if func 82h---
+h	DWORD	pointer to API entry point (see INT 2F/AX=FBA1h/BX=0082h)
+---if func 84h---
+h	WORD	success indicator
+h	WORD	segment of ???
+h	WORD	segment of ??? memory block to free if nonzero
+Ah	WORD	segment of ??? memory block to free if nonzero
+----------214403-----------------------------
+INT 21 U - Qualitas 386MAX v6.01 - SET STATE
+	AX = 4403h
+	BX = handle for device "386MAX$$"
+	CX = number of bytes to copy (up to 5Ah)
+	DS:DX -> 386MAX state buffer (see AX=4402h"386MAX")
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	the first byte of the buffer must be either 01h, 02h, or 03h
+	  (specifying the version of the state record) and the buffer must
+	  contain CX bytes AFTER the initial byte
+SeeAlso: AX=4402h"386MAX"
+----------214403-----------------------------
+INT 21 - PGS1600.DEV - IOCTL - SET CONFIGURATION???
+	AX = 4403h
+	BX = file handle for device "PGS1600$"
+	CX = 0018h (size of buffer)
+	DS:DX -> configuration buffer (see AX=4402h"PGS1600")
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	PGS1600.DEV is a device driver for the Cornerstone Technology PG1600
+	  display adapter, which provides a 1600x1200 monochrome display as
+	  well as one of two emulations, MDA or CGA.
+SeeAlso: AX=4402h"PGS1600"
+----------214403-----------------------------
+INT 21 - PC/TCP IPCUST.SYS - RESET CONFIGURATION DATA READ POINTER
+	AX = 4403h
+	BX = file handle referencing device "$IPCUST"
+	CX, DS:DX ignored
+Return: CF clear if successful
+	    AX destroyed
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	there are a total of 378h bytes of configuration data for IPCUST.SYS
+	  version 2.05.  If less than the entire data is read or written,
+	  the next read/write continues where the previous one ended; this
+	  call and AX=4402h both reset the location at which the next
+	  operation starts to zero
+SeeAlso: AH=3Fh"IPCUST",AH=40h"IPCUST",AX=4402h"IPCUST"
+----------214404-----------------------------
+INT 21 - DOS 2+ - IOCTL - READ FROM BLOCK DEVICE CONTROL CHANNEL
+	AX = 4404h
+	BL = drive number (00h = default, 01h = A:, etc)
+	CX = number of bytes to read
+	DS:DX -> buffer
+Return: CF clear if successful
+	    AX = number of bytes actually read
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	format of data is driver-specific
+SeeAlso: AX=4402h,AX=4405h,INT 2F/AX=122Bh
+----------214404-----------------------------
+INT 21 - Stacker - GET DEVICE DRIVER ADDRESS AND SET VOLUME NUMBER
+	AX = 4404h
+	BL = drive number (00h = default, 01h = A:, etc)
+	CX = 0004h
+	DS:DX -> DWORD buffer to receive device driver address
+Note:	In addition to returning the address of the Stacker device driver,
+	  this call also sets the volume number at offset 3Eh in the device
+	  driver (see INT 25/AX=CDCDh)
+SeeAlso: INT 25/AX=CDCDh
+----------214404-----------------------------
+INT 21 - Stacker - GET STACVOL FILE SECTORS
+	AX = 4404h
+	BL = drive number (0 is current drive)
+	CX = byte count (i.e., 200h = 1 sector)
+	DS:DX -> buffer (see below)
+Return:	Data Buffer contains the number of sectors requested from the
+	  STACVOL physical file for the drive specified.
+Format of stacker buffer:
+Offset	Size	Description
+h	WORD	01CDh
+h	WORD	sector count
+h	DWORD	number of starting sector
+h	DWORD	far pointer to Data Buffer
+----------214405-----------------------------
+INT 21 - DOS 2+ - IOCTL - WRITE TO BLOCK DEVICE CONTROL CHANNEL
+	AX = 4405h
+	BL = drive number (00h = default, 01h = A:, etc)
+	CX = number of bytes to write
+	DS:DX -> data to write
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	format of data is driver-specific
+SeeAlso: AX=4403h,AX=4404h,INT 2F/AX=122Bh
+----------214405-----------------------------
+INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS
+	AX = 4405h
+	BX = drive number (00h = default, 01h = A:, etc)
+	CX = number of bytes to write
+	DS:DX -> SCSIDISK control block (see AX=4403h"ST-01")
+Return: CF clear if successful
+	    AX = number of bytes actually written
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+SeeAlso: AX=4403h"ST-01"
+----------214406-----------------------------
+INT 21 - DOS 2+ - IOCTL - GET INPUT STATUS
+	AX = 4406h
+	BX = file handle
+Return: CF clear if successful
+	    AL = input status
+h not ready (device) or at EOF (file)
+		FFh ready
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	files may not register as being at EOF if positioned there by AH=42h
+SeeAlso: AX=4407h,INT 2F/AX=122Bh
+----------214407-----------------------------
+INT 21 - DOS 2+ - IOCTL - GET OUTPUT STATUS
+	AX = 4407h
+	BX = file handle
+Return: CF clear if successful
+	    AL = input status
+h not ready
+		FFh ready
+	CF set on error
+	    AX = error code (01h,05h,06h,0Dh) (see AH=59h)
+Note:	for DOS 2+, files are always ready for output, even if the disk is
+	  full or no media is in the drive
+SeeAlso: AX=4406h,INT 2F/AX=122Bh
+----------214408-----------------------------
+INT 21 - DOS 3.0+ - IOCTL - CHECK IF BLOCK DEVICE REMOVABLE
+	AX = 4408h
+	BL = drive number (00h = default, 01h = A:, etc)
+Return: CF clear if successful
+	    AX = 0000h if removable
+	       = 0001h if fixed
+	CF set on error
+	    AX = error code (01h,0Fh) (see AH=59h)
+SeeAlso: AX=4400h,AX=4409h,INT 2F/AX=122Bh
+----------214409-----------------------------
+INT 21 - DOS 3.1+ - IOCTL - CHECK IF BLOCK DEVICE REMOTE
+	AX = 4409h
+	BL = drive number (00h = default, 01h = A:, etc)
+Return: CF clear if successful
+	    DX = device attribute word
+		bit 15: drive is SUBSTituted
+		bit 12: drive is remote
+		bit  9: direct I/O not allowed
+	CF set on error
+	    AX = error code (01h,0Fh) (see AH=59h)
+Note:	on local drives, DX bits not listed above are the attribute word from
+	  the device driver header (see AH=52h); for remote drives, the other
+	  bits appear to be undefined
+SeeAlso: AX=4400h,AX=4408h,AX=440Ah,INT 2F/AX=122Bh
+----------21440A-----------------------------
+INT 21 - DOS 3.1+ - IOCTL - CHECK IF HANDLE IS REMOTE
+	AX = 440Ah
+	BX = handle
+Return: CF clear if successful
+	    DX = attribute word (as stored in SFT)
+		bit 15: set if remote
+		bit 14: date/time not set on close
+	CF set on error
+	    AX = error code (01h,06h) (see AH=59h)
+Note:	if file is remote, Novell Advanced NetWare 2.0 returns the number of
+	  the file server on which the handle is located in CX
+SeeAlso: AX=4400h,AX=4409h,AH=52h,INT 2F/AX=122Bh
+----------21440B-----------------------------
+INT 21 - DOS 3.1+ - IOCTL - SET SHARING RETRY COUNT
+	AX = 440Bh
+	CX = pause between retries (default 1)
+	DX = number of retries (default 3)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h) (see AH=59h)
+Notes:	delay is dependent on processor speed (value in CX specifies number of
+K-iteration empty loops to execute)
+	if DX=0000h on entry, the retry count is left unchanged
+SeeAlso: AH=52h,INT 2F/AX=1224h,INT 2F/AX=122Bh
+----------21440C-----------------------------
+INT 21 - DOS 3.2+ - IOCTL - GENERIC CHARACTER DEVICE REQUEST
+	AX = 440Ch
+	BX = device handle
+	CH = category code
+h unknown (DOS 3.3+)
+h COMn: (DOS 3.3+)
+h CON (DOS 3.3+)
+h LPTn:
+Eh Media Access Control driver (STARLITE)
+	CL = function
+h MAC driver Bind (STARLITE)
+h set iteration count
+Ah select code page
+Ch start code-page preparation
+Dh end code-page preparation
+Fh set display information (DOS 4.0)
+h get iteration count
+Ah query selected code page
+Bh query prepare list
+Fh get display information (DOS 4.0)
+	DS:DX -> (DOS) parameter block (see below)
+	SI:DI -> (OS/2 comp box) parameter block (see below)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    DS:DX -> iteration count if CL=65h
+	DS:DX -> (OS/2 comp box) data block
+SeeAlso: AX=440Dh,INT 2F/AX=0802h,INT 2F/AX=122Bh,INT 2F/AX=1A01h
+Format of parameter block for function 00h:
+Offset	Size	Description
+h  8 BYTEs	ASCIZ signature "STARMAC"
+h	WORD	version
+Ah	WORD	flags
+		bit 0: media requires connect or listen request before use
+		bit 1: network is a LAN (broadcast/multicast supported)
+		bit 2: point-to-point network
+Ch	WORD	handle for use with MAC driver's private interface (filled in
+		by MAC driver)
+Eh	WORD	context
+h	WORD	approximate speed in KB/sec (filled in by MAC driver)
+h	WORD	approximate cost in cents per hour (filled in by MAC driver)
+h	WORD	maximum packet size in bytes (filled in by MAC driver)
+h	WORD	addressing format (filled in by MAC driver)
+h general addressing
+h Ethernet addressing
+h Token Ring addressing
+h Token Bus addressing
+h	DWORD	Send entry point (filled in by MAC driver)
+Ch	DWORD	RegisterEventHandler entry point (filled in by MAC driver)
+h	DWORD	SetPacketFilter entry point (filled in by MAC driver)
+h	DWORD	UnBind entry point (filled in by MAC driver)
+Format of parameter block for function 45h:
+Offset	Size	Description
+h	WORD	number of times output is attempted before driver assumes
+		device is busy
+Format of parameter block for functions 4Ah and 6Ah:
+Offset	Size	Description
+h	WORD	length of data
+h	WORD	code page ID
+h 2N BYTEs	DCBS (double byte character set) lead byte range
+		  start/end for each of N ranges (DOS 4.0)
+	WORD	0000h  end of data (DOS 4.0)
+Format of parameter block for function 4Dh:
+Offset	Size	Description
+h	WORD	length of data
+h	WORD	code page ID
+Format of parameter block for function 4Ch:
+Offset	Size	Description
+h	WORD	flags
+		DISPLAY.SYS = 0000h
+		PRINTER.SYS bit 0 clear to prepare downloaded font, set to
+			prepare cartridge selection
+h	WORD	length of remainder of parameter block
+h	WORD	number of code pages following
+h  N WORDs	code page 1,...,N
+Format of parameter block for functions 5Fh and 7Fh:
+Offset	Size	Description
+h	BYTE	level (0 for DOS 4.x and 5.0)
+h	BYTE	reserved (0)
+h	WORD	length of following data (14)
+h	WORD	control flags
+		  bit 0 set for blink, clear for intensity
+		  bits 1 to 15 reserved
+h	BYTE	mode type (1=text, 2=graphics)
+h	BYTE	reserved (0)
+h	WORD	colors
+= monochrome
+		   else N bits per pixel
+Ah	WORD	pixel columns
+Ch	WORD	pixel rows
+Eh	WORD	character columns
+h	WORD	character rows
+Format of parameter block for function 6Bh:
+Offset	Size	Description
+h	WORD	length of following data
+h	WORD	number of hardware code pages
+h  N WORDs	hardware code pages 1,...,N
+	WORD	number of prepared code pages
+      N WORDs	prepared code pages 1,...,N
+----------21440C-----------------------------
+INT 21 - Greg Shenaut ASPITAPE.SYS - INTERFACE
+	AX = 440Ch
+	BX = device handle
+	CH = category code
+h tape (ASPITAPE.SYS)
+	CL = function
+h "mtop" - perform tape operation
+h "mtget" - get tape status
+h ignore end-of-tape errors
+h enable end-of-tape errors
+	DS:DX -> parameter block (see below)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    DS:DX -> data block
+Notes:	This device driver is a simple DOS interface to the Adaptec Advanced
+	  SCSI Programming Interface (ASPI).  It provides the following device
+	  names as access to the SCSI tape, 'RMTx' (rewind on close) and
+	  'NRMTx' (NO rewind on close) where x can go from 0 to 3.  There may
+	  also be the following names 'MTx' and 'NMTx' which default to 1024
+	  byte blocks.	The names may also have a '$' appended to try and make
+	  them unique from file names of 'RMT0' etc.
+	once opend these devices must be put into RAW mode
+SeeAlso: AX=4402h"ASPI"
+Format of mtop parameter block:
+Offset	Size	Description
+h	WORD	operation code
+h "MTWEOF" - write an end-of-file record
+h "MTFSF" - forward space file
+h "MTBSF" - backward space file
+h "MTFSR" - forward space record
+h "MTBSR" - backward space record
+h "MTREW" - rewind
+h "MTOFFL" - rewind and unload
+h "MTNOP" - perform TEST UNIT READY
+h	DWORD	repetition count
+Format of mtget parameter block:
+Offset	Size	Description
+h	BYTE	ASPI host ID
+h	BYTE	SCSI target ID
+h	BYTE	SCSI logical unit number
+h	BYTE	device parameters
+		bit 0: drive must use fixed-block read and write
+		bit 7: drive is an ASPI device
+h	BYTE	current device state
+		bit 0: device currently opened in buffered mode
+		bit 1: drive currently opened in nonbuffered mode
+		bit 2: rewind drive on last close
+		bit 3: drive has been written on
+		bit 4: drive has been read from
+		bit 5: next read will return 0 bytes
+		bit 6: EOM will resemble EOF
+		bit 7: drive may be busy rewinding
+h	BYTE	unit number within driver
+h	WORD	fixed block blocksize
+h	BYTE	last SCSI status
+h	BYTE	last SCSI sense key
+Ah	WORD	last SCSI opcode (packed)
+		bits 0-7: SCSI operation (SCSI packet byte 0)
+		bits 8-10: SCSI flags (SCSI packet byte 1)
+		bits 11-12: ASPI "Direction Bits" (ASPI SRB byte 3)
+Ch	WORD	residual bytes from SCSI opcode
+----------21440D-----------------------------
+INT 21 - DOS 3.2+ - IOCTL - GENERIC BLOCK DEVICE REQUEST
+	AX = 440Dh
+	BL = drive number (00h=default,01h=A:,etc)
+	CH = category code
+h disk drive
+	CL = function
+h set device parameters
+h write logical device track
+h format and verify logical device track
+h (DOS 4+) set volume serial number (see also AH=69h)
+h (DOS 4+) set access flag
+h get device parameters
+h read logical device track
+h verify logical device track
+h (DOS 4+) get volume serial number (see also AH=69h)
+h (DOS 4+) get access flag
+h (DOS 5+) sense media type
+	DS:DX -> (DOS) parameter block (see below)
+	SI:DI -> (OS/2 comp box) parameter block (see below)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    DS:DX -> data block if CL=60h or CL=61h
+Notes:	DOS 4.01 seems to ignore the high byte of the number of directory
+	  entries in the BPB for diskettes.
+	functions 46h and 66h undocumented in DOS 4.x, documented for DOS 5.0
+SeeAlso: AX=440Ch,AH=69h,INT 2F/AX=0802h,INT 2F/AX=122Bh
+Format of parameter block for functions 40h, 60h:
+Offset	Size	Description
+h	BYTE	special functions
+		bit 0 set if function to use current BPB, clear if Device
+			BIOS Parameter Block field contains new default BPB
+		bit 1 set if function to use track layout fields only
+			must be clear if CL=60h
+		bit 2 set if all sectors in track same size (should be set)
+		bits 3-7 reserved
+h	BYTE	device type
+h  320K/360K disk
+h  1.2M disk
+h  720K disk
+h  single-density 8-inch disk
+h  double-density 8-inch disk
+h  fixed disk
+h  tape drive
+h  (DOS 3.3+) 1.44M floppy
+h  read/write optical disk
+h  (DOS 5.0) 2.88M floppy
+Ah  other type of block device
+h	WORD	device attributes
+		bit 0 set if nonremovable medium
+		bit 1 set if door lock supported
+		bits 2-15 reserved
+h	WORD	number of cylinders
+h	BYTE	media type
+		for 1.2M drive
+h 1.2M disk (default)
+h 320K/360K disk
+		always 00h for other drive types
+h 31 BYTEs	device BPB (see AH=53h), bytes after BPB offset 1Eh omitted
+h	WORD	number of sectors per track (start of track layout field)
+		not used by function 60h
+h  N word pairs: number,size of each sector in track
+Format of parameter block for functions 41h, 61h:
+Offset	Size	Description
+h	BYTE	special functions (reserved, must be zero)
+h	WORD	number of disk head
+h	WORD	number of disk cylinder
+h	WORD	number of first sector to read/write
+h	WORD	number of sectors
+h	DWORD	transfer address
+Format of parameter block for functions 42h, 62h:
+Offset	Size	Description
+h	BYTE	reserved, must be zero (DOS <3.2)
+		  bit 0=0: format/verify track
+: format status call (DOS 3.2+)
+		  bits 1-7 reserved, must be zero
+		on return (DOS 4.x):
+		  bit 0: set if specified tracks, sectors/track supported
+		  bit 1: set if function not supported by BIOS
+		  bit 2: set if specified tracks, sectors/track not supported
+		  bit 3: set if no disk in drive
+h	WORD	number of disk head
+h	WORD	number of disk cylinder
+Format of parameter block for functions 46h, 66h:
+Offset	Size	Description
+h	WORD	info level (00h)
+h	DWORD	disk serial number (binary)
+h 11 BYTEs	volume label or "NO NAME    "
+h  8 BYTEs	filesystem type "FAT12	 " or "FAT16   " (CL=66h only)
+Format of parameter block for functions 47h, 67h:
+Offset	Size	Description
+h	BYTE	special-function field (must be zero)
+h	BYTE	disk-access flag, nonzero if access allowed by driver
+Format of parameter block for function 68h:
+Offset	Size	Description
+h	BYTE	01h for default media type, 00h for any other media type
+h	BYTE	02h for 720K, 07h for 1.44M, 09h for 2.88M
+----------21440E-----------------------------
+INT 21 - DOS 3.2+ - IOCTL - GET LOGICAL DRIVE MAP
+	AX = 440Eh
+	BL = drive number (00h=default,01h=A:,etc)
+Return: CF set on error
+	    AX = error code (01h,0Fh) (see AH=59h)
+	CF clear if successful
+	    AL = 00h block device has only one logical drive assigned
+..26 the last letter used to reference the drive (1=A:,etc)
+SeeAlso: AX=440Fh,INT 2F/AX=122Bh
+----------21440F-----------------------------
+INT 21 - DOS 3.2+ - IOCTL - SET LOGICAL DRIVE MAP
+	AX = 440Fh
+	BL = physical drive number (00h=default,01h=A:,etc))
+Return: CF set on error
+	    AX = error code (01h,0Fh) (see AH=59h)
+	CF clear if successful
+	    drive now responds to next logical drive number
+Note:	maps logical drives to physical drives, similar to DOS's treatment of
+	  a single physical floppy drive as both A: and B:
+SeeAlso: AX=440Eh,INT 2F/AX=122Bh
+----------214410-----------------------------
+INT 21 - DOS 5.0 - IOCTL - QUERY GENERIC IOCTL CAPABILITY (HANDLE)
+	AX = 4410h
+	BX = handle for device
+	CH = category code (see AX=440Ch)
+	CL = function code
+Return: CF clear if successful
+	    AX = 0000h	specified IOCTL function is supported
+	CF set on error
+	    AL = 01h	IOCTL capability not available
+Note:	a program which wishes to use Generic IOCTL calls beyond those in the
+	  standard DOS 3.2 set may use this call first to see whether a
+	  particular call is supported
+SeeAlso: AX=440Ch,AX=440Dh,AX=4411h
+----------214410BXFFFF-----------------------
+INT 21 U - NewSpace - ENABLE DRIVER
+	AX = 4410h
+	BX = FFFFh
+Notes:	NewSpace is a TSR by Isogon Corporation which automatically compresses
+	  all files as they are written and decompresses them as they are read
+	compressed files are not accessible unless the driver is enabled
+SeeAlso: AX=4411h/BX=FFFFh
+----------214411-----------------------------
+INT 21 - DOS 5.0 - IOCTL - QUERY GENERIC IOCTL CAPABILITY (DRIVE)
+	AX = 4411h
+	BL = drive number
+	CH = category code (see AX=440Dh)
+	CL = function code
+Return: CF clear if successful
+	    AX = 0000h	specified IOCTL function is supported
+	CF set on error
+	    AL = 01h	IOCTL capability not available
+Note:	a program which wishes to use Generic IOCTL calls beyond those in the
+	  standard DOS 3.2 set may use this call first to see whether a
+	  particular call is supported
+SeeAlso: AX=440Ch,AX=440Dh,AX=4410h
+----------214411BXFFFF-----------------------
+INT 21 U - NewSpace - DISABLE DRIVER
+	AX = 4411h
+	BX = FFFFh
+Notes:	NewSpace is a TSR by Isogon Corporation which automatically compresses
+	  all files as they are written and decompresses them as they are read
+	compressed files are not accessible unless the driver is enabled
+SeeAlso: AX=4410h/BX=FFFFh
+----------214412-----------------------------
+INT 21 - DR-DOS 5.0 - DETERMINE DOS TYPE
+	AX = 4412h
+	CF set
+Return: CF set if not DR DOS
+	    AX = error code (see AH=59h)
+	CF clear if DR DOS
+	    DX = AX = version code
+h = ???
+h = DR-DOS 3.41 ???
+h = DR-DOS 5.0
+h = DR-DOS 6.0
+Note:	this call is identical to AX=4452h
+SeeAlso: AX=4452h
+----------214412BXFFFF-----------------------
+INT 21 U - NewSpace - INSTALLATION CHECK???
+	AX = 4412h
+	BX = FFFFh
+Return: AX = PSP segment of NewRes (resident driver for NewSpace)
+	BX:DX -> ???
+	CX = ???
+SeeAlso: AX=4411h/BX=FFFFh
+----------214413BXFFFF-----------------------
+INT 21 U - NewSpace - GET ???
+	AX = 4413h
+	BX = FFFFh
+Return: AX = code segment of NewRes (resident driver for NewSpace)
+	BX = offset of ???
+SeeAlso: AX=4412h/BX=FFFFh
+----------214414-----------------------------
+INT 21 U - DR-DOS 5.0 - SET GLOBAL PASSWORD
+	AX = 4414h
+	DS:DX -> password string (blank-padded to 8 characters)
+Desc:	Specify the master password for accessing files.
+Note:	this call is identical to AX=4454h
+SeeAlso: AX=4454h
+----------214414BXFFFF-----------------------
+INT 21 U - NewSpace - DEBUGGING DUMP
+	AX = 4414h
+	BX = FFFFh
+Return:	debugging dump written to X:\NEWSPACE.SMP
+SeeAlso: AX=4413h/BX=FFFFh,AX=44FFh/BX=FFFFh
+----------2144-------------------------------
+INT 21 U - DR-DOS 5.0
+	AH = 44h
+	AL = 16h to 18h
+Note:	these subfunctions are identical to AX=4456h to 4458h
+SeeAlso: AX=4456h,AX=4457h,AX=4458h
+----------214451-----------------------------
+INT 21 - Concurrent DOS v3.2+ - INSTALLATION CHECK
+	AX = 4451h
+Return: CF set if not Concurrent DOS
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    AH = 14h
+	    AL = version (high nybble = major version, low nybble = minor ver)
+SeeAlso: AX=4452h,AX=4459h
+----------214452-----------------------------
+INT 21 - DR DOS 3.41+ - DETERMINE DOS TYPE/GET DR-DOS VERSION
+	AX = 4452h
+	CF set
+Return: CF set if not DR DOS
+	    AX = error code (see AH=59h)
+	CF clear if DR DOS
+	    DX = AX = version code
+h = ???
+h = DR-DOS 3.41 ???
+h = DR-DOS 5.0
+h = DR-DOS 6.0
+Notes:	the DR-DOS version is stored in the environment variable VER
+SeeAlso: AX=4412h,AX=4451h,AX=4459h
+----------214454-----------------------------
+INT 21 U - DR-DOS 3.41+ - SET GLOBAL PASSWORD
+	AX = 4454h
+	DS:DX -> password string (blank-padded to 8 characters)
+Desc:	Specify the master password for accessing files.
+SeeAlso: AX=4303h,AX=4414h
+----------214456-----------------------------
+INT 21 U - DR-DOS 5.0+ - ???
+	AX = 4456h
+	DL = flag
+	    bit 0: ???
+Return: AL = ???
+Note:	This was seen called by COMMAND.COM of DR-DOS 6.0
+----------214457-----------------------------
+INT 21 U - DR-DOS 5.0+ - ???
+	AX = 4457h
+	DH = subfunction
+h ???
+	    	DL = 00h ???
+		   = 01h ???
+		   else Return: AX = ???
+h
+	   	Return: AX = ???
+h
+	   	DL = ???
+		Return: AX = ???
+	    other
+	   	Return: AX = ???
+Note:	This was seen called by COMMAND.COM of DR-DOS 6.0
+----------214458-----------------------------
+INT 21 U - DR DOS 5.0+ internal - GET POINTER TO TABLE OF ???
+	AX = 4458h
+Return: ES:BX -> internal table (see below)
+	AX = ??? (0B50h for DR-DOS 5.0, 0A56h for DR-DOS 6.0)
+SeeAlso: AX=4452h
+Format of internal table:
+Offset	Size	Description
+h	DWORD	pointer to ???
+h  7 BYTEs	???
+Bh	WORD	K of extended memory at startup
+Dh	BYTE	number of far jump entry points
+Eh	WORD	segment containing far jumps to DR-DOS entry points (see below)
+h	WORD	???
+h	WORD	pointer to segment of environment variables set in CONFIG,
+		or 0000h if already used (DR-DOS 6.0 only)
+h	???	???
+Note:	the segment used for the DR-DOS 6.0 CONFIG environment variables
+	  (excluding COMSPEC, VER and OS) is only useful for programs/drivers
+	  called from CONFIG.SYS. The word is set to zero later and the area
+	  lost.
+Format of jump table for DR-DOS 5.0-6.0:
+Offset	Size	Description
+h  5 BYTEs	far jump to entry point corresponding to CP/M CALL 5
+h  5 BYTEs	far jump to entry point corresponding to INT 20
+Ah  5 BYTEs	far jump to entry point corresponding to INT 21
+Fh  5 BYTEs	far jump to entry point corresponding to ???
+h  5 BYTEs	far jump to entry point corresponding to ???
+h  5 BYTEs	far jump to entry point corresponding to ???
+Eh  5 BYTEs	far jump to entry point corresponding to ???
+h  5 BYTEs	far jump to entry point corresponding to ???
+h  5 BYTEs	far jump to entry point corresponding to ???
+Dh  5 BYTEs	far jump to entry point corresponding to ???
+h  5 BYTEs	far jump to entry point corresponding to ??? (IRET)
+h  5 BYTEs	far jump to entry point corresponding to ??? (IRET)
+Ch  5 BYTEs	far jump to entry point corresponding to ??? (IRET)
+h  5 BYTEs	far jump to entry point corresponding to ??? (IRET)
+h  5 BYTEs	far jump to entry point corresponding to ??? (IRET)
+Bh  5 BYTEs	far jump to entry point corresponding to ???
+----------214459-----------------------------
+INT 21 - DR MultiUser DOS 5.0 - API
+	AX = 4459h
+	CL = function (see INT E0"CP/M")
+	DS,DX = parameters
+Notes:	DR-DOS 5.0 returns CF set and AX=0001h
+	this API is also available on INT E0
+SeeAlso: AX=4452h,INT E0"CP/M"
+----------2144FFBXFFFF-----------------------
+INT 21 U - NewSpace - ???
+	AX = 44FFh
+	BX = FFFFh
+	DX = ???
+Note:	NewSpace is a TSR by Isogon Corporation which automatically compresses
+	  all files as they are written and decompresses them as they are read
+SeeAlso: AX=4414h/BX=FFFFh
+===== 45h - DOS 2+ - "DUP" - DUPLICATE FILE HANDLE =====
+<code>
+	AH = 45h
+	BX = file handle
+</code>
+<code>
+Return: CF clear if successful
+	    AX = new handle
+	CF set on error
+	    AX = error code (04h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+moving file pointer for either handle will also move it for the other, because both will refer to the same system file table
+for DOS versions prior to 3.3, file writes may be forced to disk by duplicating the file handle and closing the duplicate
+</WRAP>
+SeeAlso: AH=3Dh,AH=46h
+===== 46h - DOS 2+ - "DUP2", "FORCEDUP" - FORCE DUPLICATE FILE HANDLE =====
+<code>
+	AH = 46h
+	BX = file handle
+	CX = file handle to become duplicate of first handle
+</code>
+<code>
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (04h,06h) (see AH=59h)
+</code>
+<WRAP round box>
+closes file with handle CX if it is still open
+DOS 3.30 hangs if BX=CX on entry
+moving file pointer for either handle will also move it for the other, because both will refer to the same system file table
+</WRAP>
+SeeAlso: AH=3Dh,AH=45h
+===== 47h - DOS 2+ - "CWD" - GET CURRENT DIRECTORY =====
+<code>
+	AH = 47h
+	DL = drive number (00h = default, 01h = A:, etc)
+	DS:SI -> 64-byte buffer for ASCIZ pathname
+</code>
+<code>
+Return: CF clear if successful
+	    AX = 0100h (undocumented)
+	CF set on error
+	    AX = error code (0Fh) (see AH=59h)
+</code>
+<WRAP round box>
+the returned path does not include a drive or the initial backslash
+many Microsoft products for Windows rely on AX being 0100h on success
+</WRAP>
+SeeAlso: AH=19h,AH=3Bh
+===== 48h - DOS 2+ - ALLOCATE MEMORY =====
+<code>
+	AH = 48h
+	BX = number of paragraphs to allocate
+</code>
+<code>
+Return: CF clear if successful
+	    AX = segment of allocated block
+	CF set on error
+	    AX = error code (07h,08h) (see AH=59h)
+	    BX = size of largest available block
+</code>
+<WRAP round box>
+DOS 2.1-5.0 coalesces free blocks while scanning for a block to allocate
+.COM programs are initially allocated the largest available memory block, and should free some memory with AH=49h before attempting any allocations
+</WRAP>
+SeeAlso: AH=49h,AH=4Ah,AH=58h
+===== 49h - DOS 2+ - FREE MEMORY =====
+<code>
+	AH = 49h
+	ES = segment of block to free
+</code>
+<code>
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (07h,09h) (see AH=59h)
+</code>
+<WRAP round box>
+apparently never returns an error 07h, despite official docs; DOS 3.30 code contains only an error 09h exit
+DOS 2.1-5.0 does not coalesce adjacent free blocks when a block is freed, only when a block is allocated or resized
+</WRAP>
+SeeAlso: AH=48h,AH=4Ah
+===== 4Ah - DOS 2+ - RESIZE MEMORY BLOCK =====
+<code>
+	AH = 4Ah
+	BX = new size in paragraphs
+	ES = segment of block to resize
+</code>
+<code>
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (07h,08h,09h) (see AH=59h)
+	    BX = maximum paragraphs available for specified memory block
+</code>
+<WRAP round box>
+under DOS 2.1-5.0, if there is insufficient memory to expand the block as much as requested, the block will be made as large as possible
+DOS 2.1-5.0 coalesces any free blocks immediately following the block to be resized
+</WRAP>
+SeeAlso: AH=48h,AH=49h
+===== 4Bh =====
+==== 4Bh - DOS 2+ - "EXEC" - LOAD AND/OR EXECUTE PROGRAM ====
+<code>
+	AH = 4Bh
+	AL = type of load
+h load and execute
+h load but do not execute
+h load overlay
+h load and execute in background (European MSDOS 4.0 only)
+		(see also AH=80h)
+	DS:DX -> ASCIZ program name (must include extension)
+	ES:BX -> parameter block (see below)
+</code>
+<code>
+Return: CF clear if successful
+	    BX,DX destroyed
+	    if subfunction 01h, process ID set to new program's PSP; get with
+		INT 21/AH=62h
+	CF set on error
+	    AX = error code (01h,02h,05h,08h,0Ah,0Bh) (see AH=59h)
+</code>
+<WRAP round box>
+DOS 2.x destroys all registers, including SS:SP
+for functions 00h and 01h, the calling process must ensure that there is enough unallocated memory available; if necessary, by releasing memory with AH=49h or AH=4Ah
+for function 01h, the value to be passed to the child program is put on top of the child's stack
+for function 03h, DOS assumes that the overlay is being loaded into memory allocated by the caller
+function 01h has been documented for DOS 5+, but was undocumented in prior versions
+some versions (such as DR-DOS 6.0) check the parameters and parameter block and return an error if an invalid value (such as an offset of FFFFh) is found
+BUG:	DOS 2.00 assumes that DS points at the current program's PSP
+</WRAP>
+SeeAlso: AX=4B05h,AH=4Ch,AH=4Dh,AH=64h"OS/2",INT 2E
+=== Structures format ===
+== Format of EXEC parameter block for AL=00h,01h,04h: ==
+^  Offset  ^  Size  ^ Description                                                                            ^
+| 00h      | WORD   | segment of environment to copy for child process (copy caller's environment if 0000h)  |
+| 02h      | DWORD  | pointer to command tail to be copied into child's PSP                                  |
+| 06h      | DWORD  | pointer to first FCB to be copied into child's PSP                                     |
+| 0Ah      | DWORD  | pointer to second FCB to be copied into child's PSP                                    |
+| 0Eh      | DWORD  | (AL=01h) will hold subprogram's initial SS:SP on return                                |
+| 12h      | DWORD  | (AL=01h) will hold entry point (CS:IP) on return                                       |
+== Format of EXEC parameter block for AL=03h: ==
+^  Offset  ^  Size  ^ Description                                              ^
+| 00h      | WORD   | segment at which to load overlay                         |
+| 02h      | WORD   | relocation factor to apply to overlay if in .EXE format  |
+== Format of .EXE file header: ==
+^  Offset                                  ^  Size     ^ Description                                                                    ^
+| 00h                                      | 2 BYTEs   | .EXE signature, either "MZ" or "ZM" (5A4Dh or 4D5Ah)                           |
+| 02h                                      | WORD      | number of bytes in last 512-byte page of executable                            |
+| 04h                                      | WORD      | total number of 512-byte pages in executable (includes any partial last page)  |
+| 06h                                      | WORD      | number of relocation entries                                                   |
+| 08h                                      | WORD      | header size in paragraphs                                                      |
+| 0Ah                                      | WORD      | minimum paragraphs of memory to allocation in addition to executable's size    |
+| 0Ch                                      | WORD      | maximum paragraphs to allocate in addition to executable's size                |
+| 0Eh                                      | WORD      | initial SS relative to start of executable                                     |
+| 10h                                      | WORD      | initial SP                                                                     |
+| 12h                                      | WORD      | checksum (one's complement of sum of all words in executable)                  |
+| 14h                                      | DWORD     | initial CS:IP relative to start of executable                                  |
+| 18h                                      | WORD      | offset within header of relocation table (40h for New EXE)                     |
+| 1Ah                                      | WORD      | overlay number (normally 0000h = main program)                                 |
+| ---new executable---                                                                                                                |||
+| 1Ch                                      | 4 BYTEs   | ???                                                                            |
+| 20h                                      | WORD      | behavior bits                                                                  |
+| 22h                                      | 26        | BYTEs	reserved for additional behavior info                                    |
+| 3Ch                                      | DWORD     | offset of new executable header within disk file                               |
+| ---Borland TLINK---                                                                                                                 |||
+| 1Ch                                      | 2 BYTEs   | ??? (apparently always 01h 00h)                                                |
+| 1Eh                                      | BYTE      | signature FBh                                                                  |
+| 1Fh                                      | BYTE      | TLINK version (major in high nybble, minor in low nybble)                      |
+| 20h                                      | 2 BYTEs   | ??? (v2.0 apparently always 72h 6Ah, v3.0+ seems always 6Ah 72h)               |
+| ---ARJ self-extracting archive---                                                                                                   |||
+| 1Ch                                      | 4 BYTEs   | signature "RJSX"                                                               |
+| ---LZEXE 0.91 compressed executable---                                                                                              |||
+| 1Ch                                      | 4 BYTEs   | signature "LZ91"                                                               |
+| ---PKLITE compressed executable---                                                                                                  |||
+| 1Ch                                      | 2 BYTEs   | ???                                                                            |
+| 1Eh                                      | 6 BYTEs   | signature "PKLITE" (followed by copyright message)                             |
+| ---LHarc 1.x self-extracting archive---                                                                                             |||
+| 1Ch                                      | 4 BYTEs   | unused???                                                                      |
+| 20h                                      | 3 BYTEs   | jump to start of extraction code                                               |
+| 23h                                      | 2 BYTEs   | ???                                                                            |
+| 25h                                      | 12 BYTEs  | signature "LHarc's SFX "                                                       |
+| ---LHA 2.x self-extracting archive---                                                                                               |||
+| 1Ch                                      | 8 BYTEs   | ???                                                                            |
+| 24h                                      | 10 BYTEs  | signature "LHA's SFX "                                                         |
+| ---other linkers---                                                                                                                 |||
+| 1Ch                                      | var       | optional information                                                           |
+|  :                                       |           |                                                                                |
+|  N                                       | N DWORDs  | relocation items                                                               |
+== Format of new executable header: ==
+^ Offset ^  Size	^Description^
+| 00h  |2 BYTEs	|"NE" (4Eh 45h) signature|
+| 02h  |2 BYTEs	|linker version (major, then minor)|
+| 04h|	WORD	|offset from start of this header to entry table (see below)|
+| 06h|	WORD	|length of entry table in bytes|
+| 08h|	DWORD	|file load CRC (0 in Borland's TPW)|
+| 0Ch|	BYTE	|program flags\\ bits 0-1 DGROUP type\\   * 0 = none\\   * 1 = single shared\\   * 2 = multiple (unshared)\\   * 3 = (null)\\   * bit 2:	global initialization\\   * bit 3:	protected mode only\\   * bit 4:	8086 instructions\\   * bit 5:	80286 instructions\\   * bit 6:	80386 instructions\\   * bit 7:	80x87 instructions|
+| 0Dh|	BYTE	|application flags\\   * bits 0-2: application type\\   *     001 full screen (not aware of Windows/P.M. API)\\   *     010 compatible with Windows/P.M. API\\   *     011 uses Windows/P.M. API\\   * bit 3: is a Family Application (OS/2)\\   * bit 5: 0=executable, 1=errors in image\\   * bit 6: non-conforming program (valid stack is not maintained)\\   * bit 7: DLL or driver rather than application\\   * 	(SS:SP info invalid, CS:IP points at FAR init routine\\   * 	 called with AX=module handle which returns AX=0000h\\   * 	 on failure, AX nonzero on successful initialization)|
+| 0Eh|	WORD	|auto data segment index|
+| 10h|	WORD	|initial local heap size|
+| 12h|	WORD	|initial stack size (added to data seg, 0000h if SS != DS)|
+| 14h|	DWORD	|program entry point (CS:IP), "CS" is index into segment table|
+| 18h|	DWORD	|initial stack pointer (SS:SP), "SS" is segment index\\ if SS=automatic data segment and SP=0000h, the stack pointer is set to the top of the automatic data segment, just below the local heap|
+| 1Ch|	WORD	|segment count|
+| 1Eh|	WORD	|module reference count|
+| 20h|	WORD	|length of nonresident names table in bytes|
+| 22h|	WORD	|offset from start of this header to segment table (see below)|
+| 24h|	WORD	|offset from start of this header to resource table|
+| 26h|	WORD	|offset from start of this header to resident names table|
+| 28h|	WORD	|offset from start of this header to module reference table|
+| 2Ah|	WORD	|offset from start of this header to imported names table\\ (array of counted strings, terminated with a string of length 00h)|
+| 2Ch|	DWORD	|offset from start of file to nonresident names table|
+| 30h|	WORD	|count of moveable entry point listed in entry table|
+| 32h|	WORD	|file alignment size shift count\\ 0 is equivalent to 9 (default 512-byte pages)|
+| 34h|	WORD	|number of resource table entries|
+| 36h|	BYTE	|target operating system\\   * 00h unknown\\   * 01h OS/2\\   * 02h Windows\\   * 03h European MS-DOS 4.x\\   * 04h Windows 386\\   * 05h BOSS (Borland Operating System Services)|
+| 37h|	BYTE	|other EXE flags\\   * bit 0: supports long filenames\\   * bit 1: 2.X protected mode\\   * bit 2: 2.X proportional font\\   * bit 3: gangload area|
+| 38h|	WORD	|offset to return thunks or start of gangload area|
+| 3Ah|	WORD	|offset to segment reference thunks or length of gangload area|
+| 3Ch|	WORD	|minimum code swap area size|
+| 3Eh  |2 BYTEs	|expected Windows version (minor version first)|
+Format of Codeview trailer (at end of executable):
+^  Offset  ^  Size   ^ Description                          ^
+| 00h      |  WORD   | signature 4E42h ('NB')               |
+| 02h      |  WORD   | Microsoft debug info version number  |
+| 04h      |  DWORD  | Codeview header offset               |
+== Format of new executable segment table record: ==
+^Offset^	Size	^Description^
+| 00h|	WORD	|offset in file (shift left by alignment shift to get byte offs)|
+| 02h|	WORD	|length of image in file (0000h = 64K)|
+| 04h|	WORD	|attributes\\  * bit 0: data segment rather than code segment\\  * bit 1: unused???\\  * bit 2: real mode\\  * bit 3: iterated\\  * bit 4: movable\\  * bit 5: sharable\\  * bit 6: preloaded rather than demand-loaded\\  * bit 7: execute-only (code) or read-only (data)\\  * bit 8: relocations (directly following code for this segment)\\  * bit 9: debug info present\\  * bits 10,11: 80286 DPL bits\\  * bit 12:	    discardable\\  * bits 13-15: discard priority|
+| 06h|	WORD	|number of bytes to allocate for segment (0000h = 64K)|
+<WRAP round box>
+the first segment table entry is entry number 1
+</WRAP>
+== Format of new executable entry table item (list): ==
+^  Offset  ^  Size     ^ Description                                                                                                                           |||
+|  00h     | BYTE      | number of entry points (00h if end of entry table list)                                                                               |||
+|  01h     | BYTE      | segment number (00h if end of entry table list)                                                                                       |||
+|  02h     | 3N BYTEs  | entry records                                                                                                                         |||
+|                     |^  Offset                                                  ^  Size  ^  Description                                                        ^
+| :::                 | :::       |  00h                                                     | BYTE   | flags\\ bit 0: exported\\ bit 1: single data\\ bits 2-7: unused???  |
+| :::                 | :::       |  01h                                                     | WORD   | offset within segment                                               |
+== Format of new executable relocation data (immediately follows segment image): ==
+^ Offset  ^ Size      ^ Description                                                                                                                 |||
+| 00h     | WORD      | number of relocation items                                                                                                  |||
+| 02h     | 8N BYTEs  | relocation items                                                                                                            |||
+|                    |^  Offset                     ^  Size  ^ Description                                                                            ^
+| :::                | :::       | 00h                         | BYTE   | relocation type\\ 00h LOBYTE\\ 02h BASE\\ 03h PTR\\ 05h OFFS\\ 0Bh PTR48\\ 0Dh OFFS32  |
+| :::                | :::       | 01h                         | BYTE   | flags\\ bit 2: additive                                                                |
+| :::                | :::       | 02h                         | WORD   | offset within segment                                                                  |
+| :::                | :::       | 04h                         | WORD   | target address segment                                                                 |
+| :::                | :::       | 06h                         | WORD   | target address offset                                                                  |
+^  Offset  ^  Size      ^ Description                              ^
+| 00h      | WORD       | alignment shift count for resource data  |
+| 02h      | N RECORDs  | resources                                |
+== Format of resource record: ==
+^  Offset  ^  Size        ^ Description                                                                                                            ^
+| 00h      | WORD         | type ID                                                                                                                |
+|          |              | 0000h if end of resource records\\ >= 8000h if integer type\\ else offset from start of resource table to type string  |
+| 02h      | WORD         | number of resources of this type                                                                                       |
+| 04h      | DWORD        | reserved for runtime use                                                                                               |
+| 08h      | N Resources  | (see below)                                                                                                            |
+<WRAP round box>
+resource type and name strings are stored immediately following the resource table, and are not null-terminated
+</WRAP>
+== Format of new executable resource entry: ==
+^ Offset  ^  Size  ^ Description ^
+| 00h	|WORD	|offset in alignment units from start of file to contents of the resource data|
+| 02h	|WORD	|length of resource image in bytes|
+| 04h	|WORD	|flags\\ bit 4: moveable\\ bit 5: shareable\\ bit 6: preloaded|
+| 06h	|WORD	|resource ID\\ >= 8000h if integer resource\\ else offset from start of resource table to resource string|
+| 08h	|DWORD	|reserved for runtime use|
+<WRAP round box>
+resource type and name strings are stored immediately following the resource table, and are not null-terminated
+strings are counted strings, with a string of length 0 indicating the end of the resource table
+</WRAP>
+== Format of new executable module reference table [one bundle of entries]: ==
+^ Offset  ^ Size                      ^ Description                                                                                                                                                                                                                              ||
+| 00h     |  BYTE                     | number of records in this bundle (00h if end of table)                                                                                                                                                                                   ||
+| 01h     |  BYTE                     | segment indicator\\ 00h unused\\ FFh movable segment, segment number is in entry else segment number of fixed segment                                                                                                                    ||
+| 02h     | N RECORDs                                                                                                                                                                                                                                                           |||
+|         | Format of segment record                                                                                                                                                                                                                                            |||
+| :::     ^  Offset                   ^  Size                                                                                                                  ^ Description                                                                                                      ^
+| :::     |  00h                      |  BYTE                                                                                                                  | flags\\ bit 0: entry is exported\\ bit 1: entry uses global (shared) data\\ bits 7-3: number of parameter words  |
+| :::     | ---fixed segment---                                                                                                                                                                                                                                                 |||
+| :::     |  01h                      |  WORD                                                                                                                  | offset                                                                                                           |
+| :::     | ---moveable segment---                                                                                                                                                                                                                                              |||
+| :::     |  01h                      |  2 BYTEs                                                                                                               | INT 3F instruction (CDh 3Fh)                                                                                     |
+| :::     |  03h                      |  BYTE                                                                                                                  | segment number                                                                                                   |
+| :::     |  05h                      |  WORD                                                                                                                  | offset                                                                                                           |
+<WRAP round box>
+table entries are numbered starting from 1
+</WRAP>
+== Format of new executable resident/nonresident name table entry: ==
+^ Offset ^ Size	^Description^
+|00h	| BYTE	|length of string (00h if end of table)|
+| 01h  |N BYTEs	|ASCII text of string|
+| N+1	|WORD	|ordinal number (index into entry table)|
+<WRAP round box>
+the first string in the resident name table is the module name; the first entry in the nonresident name table is the module description
+the strings are case-sensitive; if the executable was linked with /IGNORECASE, all strings are in uppercase
+</WRAP>
+== Format of Linear Executable (enhanced mode executable) header: ==
+^  Offset  ^  Size     ^ Description                                                                                                                                                                                                                                                                                                                                                                                                                                                               ^
+|  00h     |  2 BYTEs  | "LE" (4Ch 45h) signature                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+|  02h     |  BYTE     | byte order (00h = little-endian, nonzero = big-endian)                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  03h     |  BYTE     | word order (00h = little-endian, nonzero = big-endian)                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  04h     |  DWORD    | executable format level                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
+|  08h     |  WORD     | CPU type (see also INT 15/AH=C9h)\\ 01h Intel 80286 or upwardly compatible\\ 02h Intel 80386 or upwardly compatible\\ 03h Intel 80486 or upwardly compatible\\ 04h Intel 80586 or upwardly compatible\\ 20h Intel i860 (N10) or compatible\\ 21h Intel "N11" or compatible\\ 40h MIPS Mark I (R2000, R3000) or compatible\\ 41h MIPS Mark II (R6000) or compatible\\ 42h MIPS Mark III (R4000) or compatible                                                              |
+|  0Ah     |  WORD     | target operating system\\ 01h OS/2\\ 02h Windows\\ 03h DOS4.x\\ 04h Windows 386                                                                                                                                                                                                                                                                                                                                                                                           |
+|  0Ch     |  DWORD    | module version                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+|  10h     |  DWORD    | module type\\ bit 2: initialization (only for DLLs)\\  * 0 = global\\  * 1 = per-process\\ bit 4: no internal fixups in executable image\\ bit 5: no external fixups in executable image\\ bits 8,9,10:\\  * 0 = unknown\\  * 1 = incompatible with PM windowing\\  * 2 = compatible with PM windowing\\  * 3 = uses PM windowing API\\ bit 13: module not loadable (only for programs)\\ bit 15: module is DLL rather than program\\ note bit 1,2,3 : only for programs  |
+|  14h     |  DWORD    | number of memory pages                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  18h     |           | Initial CS:EIP                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+|          |  DWORD    | object number                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
+|          |  DWORD    | offset                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  20h     |           | Initial SS:ESP                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+|          |  DWORD    | object number                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
+|          |  DWORD    | offset                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  28h     |  DWORD    | memory page size                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+|  2Ch     |  DWORD    | bytes on last page                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|  30h     |  DWORD    | fixup section size                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|  34h     |  DWORD    | fixup section checksum                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  38h     |  DWORD    | loader section size                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+|  3Ch     |  DWORD    | loader section checksum                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
+|  40h     |  DWORD    | offset of object table (see below)                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|  44h     |  DWORD    | object table entries                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
+|  48h     |  DWORD    | object page map table offset                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+|  4CH     |  DWORD    | object iterate data map offset                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+|  50h     |  DWORD    | resource table offset                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+|  54h     |  DWORD    | resource table entries                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  58h     |  DWORD    | resident names table offset                                                                                                                                                                                                                                                                                                                                                                                                                                               |
+|  5Ch     |  DWORD    | entry table offset                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|  60h     |  DWORD    | module directives table offset                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+|  64h     |  DWORD    | Module Directives entries                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
+|  68h     |  DWORD    | Fixup page table offset                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
+|  6Ch     |  DWORD    | Fixup record table offset                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
+|  70h     |  DWORD    | imported modules name table offset                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|  74h     |  DWORD    | imported modules count                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+|  78h     |  DWORD    | imported procedures name table offset                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+|  7Ch     |  DWORD    | per-page checksum table offset                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+|  80h     |  DWORD    | data pages offset                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
+|  84h     |  DWORD    | preload page count                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+|  88h     |  DWORD    | non-resident names table offset                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+|  8Ch     |  DWORD    | non-resident names table length                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+|  90h     |  DWORD    | non-resident names checksum                                                                                                                                                                                                                                                                                                                                                                                                                                               |
+|  94h     |  DWORD    | automatic data object                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+|  98h     |  DWORD    | debug information offset                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+|  9Ch     |  DWORD    | debug information length                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+|  A0h     |  DWORD    | preload instance pages number                                                                                                                                                                                                                                                                                                                                                                                                                                             |
+|  A4h     |  DWORD    | demand instance pages number                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+|  A8h     |  DWORD    | extra heap allocation                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+|  ACh     |  ???      | (at most 24 additional bytes here)                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+<WRAP round box>
+used by EMM386.EXE, QEMM, and Windows 3.0 Enhanced Mode drivers
+</WRAP>
+== Format of object table entry: ==
+^  Offset  ^  Size     ^ Description                                                                                                                                                                                                                                                                                                                                                                                                                                                     ^
+|  00h     |  DWORD    | virtual size in bytes                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+|  04h     |  DWORD    | relocation base address                                                                                                                                                                                                                                                                                                                                                                                                                                         |
+|  08h     |  DWORD    | object flags\\ bit 0: readable\\ bit 1: writable\\ bit 2: executable\\ bit 3: resource\\ bit 4: discardable\\ bit 5: shared\\ bit 6: preloaded\\ bit 7: invalid\\ bit 8-9: type\\  * 00 normal\\ * 01 zero-filled\\  * 10 resident\\  * 11 resident/contiguous\\ bit 10: "RESIDENT/LONG_LOCKABLE"\\ bit 11: reserved???\\ bit 12: "16:16_ALIAS"\\ bit 13: "BIG" (32-bit???)\\ bit 14: conforming\\ bit 15: "OBJECT_I/O_PRIVILEGE_LEVEL"\\ bits 16-31: reserved  |
+|  0Ch     |  DWORD    | page map index                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+|  10h     |  DWORD    | page map entries                                                                                                                                                                                                                                                                                                                                                                                                                                                |
+|  10h     |  4 BYTEs  | ??? (apparently always zeros)                                                                                                                                                                                                                                                                                                                                                                                                                                   |
+== Format of object page map table entry: ==
+^  Offset  ^  Size     ^ Description  ^
+|  00h     |  4 BYTEs  | ???          |
+== Format of resident names table entry: ==
+^  Offset  ^  Size     ^ Description     ^
+|  00h     |  BYTE     | length of name  |
+|  01h     |  N BYTEs  | name            |
+|  N+1     |  3 BYTEs  | ???             |
+== Format of linear executable entry table: ==
+^  Offset  ^  Size      ^ Description                                                                       |||
+|  00h     |  BYTE      | number of entries in table                                                        |||
+|  01h     |  10 BYTEs  | per entry                                                                         |||
+|                      |^  Offset                     ^  Size     ^ Description                               ^
+|  :::                 |  :::       |  00h                        |  BYTE     | bit flags\\ bit 1: 32-bit entry           |
+|  :::                 |  :::       |  01h                        |  WORD     | object number                             |
+|  :::                 |  :::       |  03h                        |  BYTE     | bit flags\\ bit 0: exported\\ bit 1: ???  |
+|  :::                 |  :::       |  04h                        |  DWORD    | offset of entry point                     |
+|  :::                 |  :::       |  08h                        |  2 BYTEs  | ???                                       |
+== Format of Borland debugging information header (following load image): ==
+^  Offset  ^  Size     ^ Description                                                                          ^
+|  00h     |  WORD     | signature 52FBh                                                                      |
+|  02h     |  WORD     | version ID                                                                           |
+|  04h     |  DWORD    | size of name pool in bytes                                                           |
+|  08h     |  WORD     | number of names in namem pool                                                        |
+|  0Ah     |  WORD     | number of type entries                                                               |
+|  0Ch     |  WORD     | number of structure members                                                          |
+|  0Eh     |  WORD     | number of symbols                                                                    |
+|  10h     |  WORD     | number of global symbols                                                             |
+|  12h     |  WORD     | number of modules                                                                    |
+|  14h     |  WORD     | number of locals (optional)                                                          |
+|  16h     |  WORD     | number of scopes in table                                                            |
+|  18h     |  WORD     | number of line-number entries                                                        |
+|  1Ah     |  WORD     | number of include files                                                              |
+|  1Ch     |  WORD     | number of segment records                                                            |
+|  1Eh     |  WORD     | number of segment/file correlations                                                  |
+|  20h     |  DWORD    | size of load image after removing uninitialized data and debug info                  |
+|  24h     |  DWORD    | debugger hook; pointer into debugged program whose meaning depends on program flags  |
+|  28h     |  BYTE     | program flags\\ bit 0: case-sensitive link\\ bit 1: pascal overlay program           |
+|  29h     |  WORD     | no longer used                                                                       |
+|  2Bh     |  WORD     | size of data pool in bytes                                                           |
+|  2Dh     |  BYTE     | padding                                                                              |
+|  2Eh     |  WORD     | size of following header extension (currently 00h, 10h, or 20h)                      |
+|  30h     |  WORD     | number of classes                                                                    |
+|  32h     |  WORD     | number of parents                                                                    |
+|  34h     |  WORD     | number of global classes (currently unused)                                          |
+|  36h     |  WORD     | number of overloads (currently unused)                                               |
+|  38h     |  WORD     | number of scope classes                                                              |
+|  3Ah     |  WORD     | number of module classes                                                             |
+|  3Ch     |  WORD     | number of coverage offsets                                                           |
+|  3Eh     |  DWORD    | offset relative to symbol base of name pool                                          |
+|  42h     |  WORD     | number of browser information records                                                |
+|  44h     |  WORD     | number of optimized symbol records                                                   |
+|  46h     |  WORD     | debugging flags                                                                      |
+|  48h     |  8 BYTEs  | padding                                                                              |
+<WRAP round box>
+additional information on the Borland debugging info may be found in Borland's Open Architecture Handbook
+</WRAP>
+==== 4Bh - ELRES v1.0 only - INSTALLATION CHECK ====
+	AH = 4Bh
+	DS:DX = 0000h:0000h
+Return: ES:BX -> ELRES history structure (see AH=2Bh/CX=454Ch)
+	DX = DABEh (signature, DAve BEnnett)
+Note:	ELRES is an MSDOS return code (errorlevel) recorder by David H. Bennett
+SeeAlso: AH=2Bh/CX=454Ch
+==== 4B04h - VIRUS - "MG", "699"/"Thirteen Minutes" - INSTALLATION CHECK ====
+<code>
+	AX = 4B04h
+</code>
+<code>
+Return: CF clear if "MG" resident
+	AX = 044Bh if "699"/"Thirteen Minutes" resident
+</code>
+SeeAlso: AX=4243h,AX=4B25h
+==== 4B43h - DOS 5.0 - SET EXECUTION STATE ====
+<code>
+	AX = 4B05h
+	DS:DX -> execution state structure (see below)
+</code>
+<code>
+Return: CF clear if successful
+	    AX = 0000h
+	CF set on error
+	    AX = error code (see AH=59h)
+</code>
+<WRAP round box>
+used by programs which intercept AX=4B00h to prepare new programs for execution (including setting the DOS version number). No DOS, BIOS or other software interrupt may be called after return from this call before commencement of the child process. If DOS is running in the HMA, A20 is turned off on return from this call.
+</WRAP>
+SeeAlso: AH=4Bh
+Format of execution state structure:
+Offset	Size	Description
+h	WORD	reserved (00h)
+h	WORD	type flags
+		bit 0: program is an .EXE
+: program is an overlay
+h	DWORD	pointer to ASCIZ name of program file
+h	WORD	PSP segment of new program
+Ah	DWORD	starting CS:IP of new program
+Eh	DWORD	program size including PSP
+==== 4B25h - VIRUS - "1063"/"Mono" - INSTALLATION CHECK ====
+	AX = 4B25h
+Return: DI = 1234h if resident
+SeeAlso: AX=4B04h,AX=4B40h
+==== 4B40h - VIRUS - "Plastique"/"AntiCad" - INSTALLATION CHECK ====
+	AX = 4B40h
+Return: AX = 5678h if resident
+SeeAlso: AX=4B25h,AX=4B41h,AX=4B4Ah
+==== 4B41h - VIRUS - "Plastique"/"AntiCad" - ??? ====
+	AX = 4B41h
+	???
+Return: ???
+SeeAlso: AX=4B40h
+==== 4B4Ah  - VIRUS - "Jabberwocky" - INSTALLATION CHECK ====
+	AX = 4B4Ah
+Return: AL = 57h if resident
+SeeAlso: AX=4B40h,AX=4B4Bh
+==== 4B4Bh - VIRUS - "Horse-2" - INSTALLATION CHECK ====
+	AX = 4B4Bh
+Return: CF clear if resident
+SeeAlso: AX=4B4Ah,AX=4B4Dh
+==== 4B4Dh - VIRUS - "Murphy-2", "Patricia"/"Smack" - INSTALLATION CHECK ====
+	AX = 4B4Dh
+Return: CF clear if resident
+SeeAlso: AX=4B4Ah,AX=4B50h
+==== 4B50h - VIRUS - "Plastique-2576"/"AntiCad-2576" - INSTALLATION CHECK ====
+	AX = 4B50h
+Return: AX = 1234h if resident
+SeeAlso: AX=4B4Dh,AX=4B53h,AX=4B60h
+==== 4B4Dh - VIRUS - "Horse" - INSTALLATION CHECK ====
+	AX = 4B53h
+Return: CF clear if resident
+SeeAlso: AX=4B50h,AX=4B55h
+==== 4B55h - VIRUS - "Sparse" - INSTALLATION CHECK ====
+	AX = 4B55h
+Return: AX = 1231h if resident
+SeeAlso: AX=4B53h,AX=4B59h
+==== 4B59h - VIRUS - "Murphy-1", "Murphy-4" - INSTALLATION CHECK ====
+	AX = 4B59h
+Return: CF clear if resident
+SeeAlso: AX=4B50h,AX=4B5Eh
+==== 4B5Eh - VIRUS - "Brothers" - INSTALLATION CHECK ====
+	AX = 4B5Eh
+Return: CF clear if resident
+SeeAlso: AX=4B59h,AX=4B87h
+==== 4B60h - VIRUS - "Plastique-2576"/"AntiCad-2576" - ??? ====
+	AX = 4B60h
+	???
+Return: ???
+SeeAlso: AX=4B50h
+==== 4B87h - VIRUS - "Shirley" - INSTALLATION CHECK ====
+	AX = 4B87h
+Return: AX = 6663h if resident
+SeeAlso: AX=4B5Eh,AX=4B95h
+==== 4B95h - VIRUS - "Zherkov-1882" - INSTALLATION CHECK ====
+	AX = 4B95h
+Return: AX = 1973h if resident
+SeeAlso: AX=4B87h,AX=4BA7h
+==== 4BA7h - VIRUS - "1876"/"Dash-em" - INSTALLATION CHECK ====
+	AX = 4BA7h
+Return: AX = B459h if resident
+SeeAlso: AX=4B95h,AX=4BAAh
+==== 4BAAh - VIRUS - "Nomenklatura" - INSTALLATION CHECK ====
+	AX = 4BAAh
+Return: CF clear if resident
+SeeAlso: AX=4BA7h,AX=4BAFh
+==== 4BAFh - VIRUS - "948"/"Screenplus1", "Magnitogorsk" - INSTALLATION CHECK ====
+	AX = 4BAFh
+Return: AL = AFh if "Magnitogorsk" resident
+	AL = FAh if "948"/"Screenplus1" resident
+SeeAlso: AX=4BAAh,AX=4BDDh
+==== 4BDDh - VIRUS - "Lozinsky"/"Zherkov" - INSTALLATION CHECK ====
+	AX = 4BDDh
+Return: AX = 1234h
+SeeAlso: AX=4BAFh,AX=4BFEh
+==== 4BEEh - F-DRIVER.SYS v1.14+ - GRAB INT 21 ====
+	AX = 4BEEh
+Return: AX = 1234h if grab successful
+	   = 2345h if failed (INT 21 grabbed previously)
+Notes:	F-DRIVER.SYS is part of the F-PROT virus/trojan protection package by
+	  Fridrik Skulason
+	when called the first time, this function moves the INT 21 monitoring
+	  code from its original location in the INT 21 chain to be the first
+	  thing called by INT 21.  This is the mechanism used by F-NET.
+SeeAlso: INT 2F/AX=4653h
+==== 4BF0h - DIET v1.10+ (Overlay Mode) - INSTALLATION CHECK ====
+	AX = 4BF0h
+Return: CF clear if installed
+	    AX = 899Dh
+Note:	DIET is an executable-compression program
+SeeAlso: AX=4BF1h
+==== 4BF1h - DIET v1.10+ (Overlay Mode) - EXPAND PROGRAM??? ====
+	AX = 4BF1h
+Return: ???
+SeeAlso: AX=4BF0h
+==== 4BFEh - VIRUS - "Hitchcock", "Dark Avenger-1028", "1193" - INSTALLATION CHECK ====
+	AX = 4BFEh
+Return: AX = 1234h if "Hitchcock" resident
+	AX = ABCDh if "1193"/"Copyright" resident
+	DI = 55BBh if "Dark Avenger-1028" resident
+SeeAlso: AX=4BDDh,AX=4BFFh"Justice"
+==== 4BFFh - VIRUS - "USSR-707", "Justice", "Europe 92" - INSTALLATION CHECK ====
+<code>
+	AX = 4BFFh
+</code>
+<code>
+Return: BL = FFh if "USSR-707" resident
+	DI = 55AAh if "Justice" resident
+	CF clear if "Europe 92" resident
+</code>
+SeeAlso: AX=4BFEh,AX=4BFFh"Cascade",AX=5252h
+==== 4BFFh -  VIRUS - "Cascade" - INSTALLATION CHECK ====
+<code>
+	AX = 4BFFh
+	SI = 0000h
+	DI = 0000h
+</code>
+<code>
+Return: DI = 55AAh if installed
+</code>
+SeeAlso: AX=4BFFh"Justice",AX=5252h
+===== 4Ch - DOS 2+ - "EXIT" - TERMINATE WITH RETURN CODE =====
+<code>
+	AH = 4Ch
+	AL = return code
+</code>
+<code>
+Return: never returns
+</code>
+<WRAP round box>
+unless the process is its own parent (see AH=26h, offset 16h in PSP), all open files are closed and all memory belonging to the process is freed
+all network file locks should be removed before calling this function
+</WRAP>
+SeeAlso: AH=00h,AH=26h,AH=4Bh,AH=4Dh,INT 15/AH=12h/BH=02h,INT 20,INT 22
+SeeAlso: INT 60/DI=0601h
+===== 4Dh - DOS 2+ - GET RETURN CODE =====
+<code>
+	AH = 4Dh
+</code>
+<code>
+Return: AH = termination type
+h normal (INT 20,INT 21/AH=00h, or INT 21/AH=4Ch)
+h control-C abort
+h critical error abort
+h terminate and stay resident (INT 21/AH=31h or INT 27)
+	AL = return code
+</code>
+<WRAP round box>
+the word in which DOS stores the return code is cleared after being read by this function, so the return code can only be retrieved once
+</WRAP>
+SeeAlso: AH=4Bh,AH=4Ch
+===== 4Eh - DOS 2+ - "FINDFIRST" - FIND FIRST MATCHING FILE =====
+<code>
+	AH = 4Eh
+	AL = special flag for use by APPEND (see note below)
+	CX = file attribute mask (see AX=4301h) (bits 0 and 5 ignored)
+	DS:DX -> ASCIZ file specification (may include path and wildcards)
+</code>
+<code>
+Return: CF clear if successful
+	    [DTA] = FindFirst data block (see below)
+	CF set on error
+	    AX = error code (02h,03h,12h) (see AH=59h)
+</code>
+<WRAP round box>
+for search attributes other than 08h, all files with at MOST the specified combination of hidden, system, and directory attributes will be returned.  Under DOS 2.x, searching for attribute 08h (volume label) will also return normal files, while under DOS 3+ only the volume label (if any) will be returned.
+this call also returns successfully if given the name of a character device without wildcards.  DOS 2.x returns attribute 00h, size 0, and the current date and time.  DOS 3+ returns attribute 40h and the current date and time.
+immediately after an INT 2F/AX=B711h (APPEND return found name), the name at DS:DX will be overwritten; if AL=00h on entry, the actual found pathname will be stored, otherwise, the actual found path will be prepended to the original filespec without a path.
+under LANtastic, this call may be used to obtain a list of a server's shared resources by searching for "\\SERVER\*.*"; a list of printerresources may be obtained by searching for "\\SERVER\@*.*"
+BUG:	under DOS 3.x and 4.x, the second and subsequent calls to this function with a character device name (no wildcards) and search attributes which include the volume-label bit (08h) will fail unless there is an intervening DOS call which implicitly or explicity performs a directory search without the volume-label bit. Such implicit searches are performed by CREATE (AH=3Ch), OPEN (AH=3Dh), UNLINK (AH=41h), and RENAME (AH=56h)
+</WRAP>
+SeeAlso: AH=11h,AH=4Fh,AX=4301h,INT 2F/AX=111Bh,INT 2F/AX=B711h
+Format of FindFirst data block:
+Offset	Size	Description
+---PCDOS 3.10, PCDOS 4.01, MSDOS 3.2/3.3/5.0---
+h	BYTE	drive letter
+h 11 BYTEs	search template
+Ch	BYTE	search attributes
+---DOS 2.x (and some DOS 3.x???)---
+h	BYTE	search attributes
+h	BYTE	drive letter
+h 11 BYTEs	search template
+---WILDUNIX.COM---
+h 12 BYTEs	15-character wildcard search pattern and drive letter (packed)
+Ch	BYTE	search attributes
+---DOS 2.x and most 3.x---
+Dh	WORD	entry count within directory
+Fh	DWORD	pointer to DTA???
+h	WORD	cluster number of start of parent directory
+---PCDOS 4.01, MSDOS 3.2/3.3/5.0---
+Dh	WORD	entry count within directory
+Fh	WORD	cluster number of start of parent directory
+h  4 BYTEs	reserved
+---all versions, documented fields---
+h	BYTE	attribute of file found
+h	WORD	file time
+		    bits 11-15: hour
+		    bits 5-10:	minute
+		    bits 0-4:	seconds/2
+h	WORD	file date
+		    bits 9-15:	year-1980
+		    bits 5-8:	month
+		    bits 0-4:	day
+Ah	DWORD	file size
+Eh 13 BYTEs	ASCIZ filename+extension
+----------214E-------------------------------
+INT 21 - WILDUNIX.COM internal - INSTALLATION CHECK
+	AH = 4Eh
+	DS:DX = 0000h:0000h
+Return:	AH = 99h if installed
+Note:	WILDUNIX.COM is a resident Unix-style wildcard expander by Steve
+	  Hosgood and Terry Barnaby
+----------214F-------------------------------
+INT 21 - DOS 2+ - "FINDNEXT" - FIND NEXT MATCHING FILE
+	AH = 4Fh
+	[DTA] = data block from previous FindFirst or FindNext call
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (12h) (see AH=59h)
+SeeAlso: AH=12h,AH=4Eh
+----------2150-------------------------------
+INT 21 - DOS 2+ internal - SET CURRENT PROCESS ID (SET PSP ADDRESS)
+	AH = 50h
+	BX = segment of PSP for new process
+Notes:	DOS uses the current PSP address to determine which processes own files
+	  and memory; it corresponds to process identifiers used by other OSs
+	under DOS 2.x, this function cannot be invoked inside an INT 28h
+	  handler without setting the Critical Error flag
+	under DOS 3+, this function does not use any of the DOS-internal stacks
+	  and may thus be called at any time, even during another INT 21h call
+	supported by OS/2 compatibility box
+	not documented for DOS 2.x-4.x, but newly documented for 5.0.
+SeeAlso: AH=26h,AH=51h,AH=62h
+----------2151-------------------------------
+INT 21 - DOS 2+ internal - GET CURRENT PROCESS ID (GET PSP ADDRESS)
+	AH = 51h
+Return: BX = segment of PSP for current process
+Notes:	DOS uses the current PSP address to determine which processes own files
+	  and memory; it corresponds to process identifiers used by other OSs
+	under DOS 2.x, this function cannot be invoked inside an INT 28h
+	  handler without setting the Critical Error flag
+	under DOS 3+, this function does not use any of the DOS-internal stacks
+	  and may thus be called at any time, even during another INT 21h call
+	supported by OS/2 compatibility box
+	identical to the documented AH=62h
+	undocumented for DOS 2.x-4.x, but newly documented for 5.0.
+SeeAlso: AH=26h,AH=50h,AH=62h
+----------2152-------------------------------
+INT 21 U - DOS 2+ internal - "SYSVARS" - GET LIST OF LISTS
+	AH = 52h
+Return: ES:BX -> DOS list of lists
+Note:	partially supported by OS/2 v1.1 compatibility box (however, most
+	  pointers are FFFFh:FFFFh, LASTDRIVE is FFh, and the NUL header "next"
+	  pointer is FFFFh:FFFFh).
+Format of List of Lists:
+Offset	Size	Description
+ -12	WORD	(DOS 3.1-3.3) sharing retry count (see AX=440Bh)
+ -10	WORD	(DOS 3.1-3.3) sharing retry delay (see AX=440Bh)
+ -8	DWORD	(DOS 3.x) pointer to current disk buffer
+ -4	WORD	(DOS 3.x) pointer in DOS code segment of unread CON input
+		when CON is read via a handle, DOS reads an entire line,
+		  and returns the requested portion, buffering the rest
+		  for the next read.  0000h indicates no unread input
+ -2	WORD	segment of first memory control block
+h	DWORD	pointer to first Drive Parameter Block (see AH=32h)
+h	DWORD	pointer to first System File Table (see below)
+h	DWORD	pointer to active CLOCK$ device's header
+Ch	DWORD	pointer to active CON device's header
+---DOS 2.x---
+h	BYTE	number of logical drives in system
+h	WORD	maximum bytes/block of any block device
+h	DWORD	pointer to first disk buffer (see below)
+h 18 BYTEs	actual NUL device driver header (not a pointer!)
+		NUL is always the first device on DOS's linked list of device
+		drivers. (see below for format)
+---DOS 3.0---
+h	BYTE	number of block devices
+h	WORD	maximum bytes/block of any block device
+h	DWORD	pointer to first disk buffer (see below)
+h	DWORD	pointer to array of current directory structures (see below)
+Bh	BYTE	value of LASTDRIVE command in CONFIG.SYS (default 5)
+Ch	DWORD	pointer to STRING= workspace area
+h	WORD	size of STRING area (the x in STRING=x from CONFIG.SYS)
+h	DWORD	pointer to FCB table
+h	WORD	the y in FCBS=x,y from CONFIG.SYS
+h 18 BYTEs	actual NUL device driver header (not a pointer!)
+		NUL is always the first device on DOS's linked list of device
+		drivers. (see below for format)
+---DOS 3.1-3.3---
+h	WORD	maximum bytes per sector of any block device
+h	DWORD	pointer to first disk buffer in buffer chain (see below)
+h	DWORD	pointer to array of current directory structures (see below)
+Ah	DWORD	pointer to system FCB tables (see below)
+Eh	WORD	number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y)
+h	BYTE	number of block devices installed
+h	BYTE	number of available drive letters (largest of 5, installed
+		block devices, and CONFIG.SYS LASTDRIVE=).  Also size of
+		current directory structure array.
+h 18 BYTEs	actual NUL device driver header (not a pointer!)
+		NUL is always the first device on DOS's linked list of device
+		drivers. (see below for format)
+h	BYTE	number of JOIN'ed drives
+---DOS 4.x---
+h	WORD	maximum bytes per sector of any block device
+h	DWORD	pointer to disk buffer info record (see below)
+h	DWORD	pointer to array of current directory structures (see below)
+Ah	DWORD	pointer to system FCB tables (see below)
+Eh	WORD	number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y)
+		(always 00h for DOS 5.0)
+h	BYTE	number of block devices installed
+h	BYTE	number of available drive letters (largest of 5, installed
+		block devices, and CONFIG.SYS LASTDRIVE=).  Also size of
+		current directory structure array.
+h 18 BYTEs	actual NUL device driver header (not a pointer!)
+		NUL is always the first device on DOS's linked list of device
+		drivers. (see below for format)
+h	BYTE	number of JOIN'ed drives???
+h	WORD	pointer within IBMDOS code segment to list of special program
+		names (see below)
+		(always 0000h for DOS 5.0)
+h	DWORD	pointer to FAR routine for resident IFS utility functions
+		(see below)
+		may be called by any IFS driver which does not wish to
+		service functions 20h or 24h-28h itself
+Bh	DWORD	pointer to chain of IFS (installable file system) drivers
+Fh	WORD	the x in BUFFERS x,y (rounded up to multiple of 30 if in EMS)
+h	WORD	the y in BUFFERS x,y
+h	BYTE	boot drive (1=A:)
+h	BYTE	01h if 80386+, 00h otherwise???
+h	WORD	extended memory size in K
+---DOS 5.0---
+h 39 BYTEs	as for DOS 4.x (see above)
+h	DWORD	pointer to SETVER program list or 0000h:0000h
+Bh	WORD	??? pointer to function in DOS CS
+Dh	WORD	??? apparently 0000h if DOS loaded low, PSP of most-recently
+		EXECed program if DOS in HMA
+Fh  8 BYTEs	as for DOS 4.x (see above)
+Format of memory control block (see also below):
+Offset	Size	Description
+h	BYTE	block type: 5Ah if last block in chain, otherwise 4Dh
+h	WORD	PSP segment of owner or
+h if free
+h if DR-DOS XMS UMB
+h if DR-DOS excluded upper memory ("hole")
+h if belongs to DOS
+		FFFAh if 386MAX UMB control block
+		FFFDh if 386MAX locked-out memory
+		FFFEh if 386MAX UMB (immediately follows its control block)
+h	WORD	size of memory block in paragraphs
+h  3 BYTEs	unused
+---DOS 2.x,3.x---
+h  8 BYTEs	unused
+---DOS 4+ ---
+h  8 BYTEs	ASCII program name if PSP memory block or DR-DOS UMB,
+		  else garbage
+		null-terminated if less than 8 characters
+Notes:	the next MCB is at segment (current + size + 1)
+	under DOS 3.1+, the first memory block is the DOS data segment,
+	  containing installable drivers, buffers, etc.  Under DOS 4+ it is
+	  divided into subsegments, each with its own memory control block
+	  (see below), the first of which is at offset 0000h.
+	for DOS 5.0, blocks owned by DOS may have either "SC" or "SD" in bytes
+h and 09h.	"SC" is system code or locked-out inter-UMB memory,
+	  "SD" is system data, device drivers, etc.
+	Some versions of DR-DOS use only seven characters of the program name,
+	  placing a NUL in the eighth byte.
+Format of MSDOS 5.0 UMB control block:
+Offset	Size	Description
+h	BYTE	type: 5Ah if last block in chain, 4Dh otherwise
+h	WORD	first available paragraph in UMB if control block at start
+		of UMB, 000Ah if control block at end of UMB
+h	WORD	length in paragraphs of following UMB or locked-out region
+h  3 BYTEs	unused
+h  8 BYTEs	block type name: "UMB" if start block, "SM" if end block in UMB
+Format of STARLITE memory control block:
+Offset	Size	Description
+h	BYTE	block type: 5Ah if last block in chain, otherwise 4Dh
+h	WORD	PSP segment of owner, 0000h if free, 0008h if belongs to DOS
+h	WORD	size of memory block in paragraphs
+h	BYTE	unused
+h	WORD	segment address of next memory control block (0000h if last)
+h	WORD	segment address of previous memory control block or 0000h
+Ah  6 BYTEs	reserved
+Format of DOS 4.x data segment subsegment control blocks:
+Offset	Size	Description
+h	BYTE	subsegment type (blocks typically appear in this order)
+		"D"  device driver
+		"E"  device driver appendage
+		"I"  IFS (Installable File System) driver
+		"F"  FILES=  control block storage area (for FILES>5)
+		"X"  FCBS=   control block storage area, if present
+		"C"  BUFFERS EMS workspace area (if BUFFERS /X option used)
+		"B"  BUFFERS=  storage area
+		"L"  LASTDRIVE=	 current directory structure array storage area
+		"S"  STACKS=  code and data area, if present (see below)
+		"T"  INSTALL= transient code
+h	WORD	paragraph of subsegment start (usually the next paragraph)
+h	WORD	size of subsegment in paragraphs
+h  3 BYTEs	unused
+h  8 BYTEs	for types "D" and "I", base name of file from which the driver
+		  was loaded (unused for other types)
+Format of data at start of STACKS code segment (if present):
+Offset	Size	Description
+h	WORD	???
+h	WORD	number of stacks (the x in STACKS=x,y)
+h	WORD	size of stack control block array (should be 8*x)
+h	WORD	size of each stack (the y in STACKS=x,y)
+h	DWORD	ptr to STACKS data segment
+Ch	WORD	offset in STACKS data segment of stack control block array
+Eh	WORD	offset in STACKS data segment of last element of that array
+h	WORD	offset in STACKS data segment of the entry in that array for
+		the next stack to be allocated (initially same as value in 0Eh
+		and works its way down in steps of 8 to the value in 0Ch as
+		hardware interrupts pre-empt each other)
+Note:	the STACKS code segment data may, if present, be located as follows:
+    DOS 3.2:	The code segment data is at a paragraph boundary fairly early
+		in the IBMBIO segment (seen at 0070:0190h)
+    DOS 3.3:	The code segment is at a paragraph boundary in the DOS data
+		segment, which may be determined by inspecting the segment
+		pointers of the vectors for those of interrupts 02h, 08h-0Eh,
+h, 72-77h which have not been redirected by device drivers or
+		TSRs.
+    DOS 4.x:	Identified by sub-segment control block type "S" within the DOS
+		data segment.
+Format of array elements in STACKS data segment:
+Offset	Size	Description
+h	BYTE	status: 00h=free, 01h=in use, 03h=corrupted by overflow of
+		higher stack.
+h	BYTE	not used
+h	WORD	previous SP
+h	WORD	previous SS
+h	WORD	ptr to word at top of stack (new value for SP). The word at the
+		top of the stack is preset to point back to this control block.
+SHARE.EXE hooks (DOS 3.1-5.00):
+(offsets from first system file table--pointed at by ListOfLists+04h)
+Offset	Size	Description
+-3Ch	DWORD	pointer to FAR routine for ???
+		Note: not called by MSDOS 3.3, set to 0000h:0000h by SHARE 3.3
+-38h	DWORD	pointer to FAR routine called on opening file
+		on call, internal DOS location points at filename(see AX=5D06h)
+		Return: CF clear if successful
+			CF set on error
+			    AX = DOS error code (24h) (see AH=59h)
+		Note: SHARE assumes DS=SS=DOS DS, direct-accesses DOS internals
+			to get name of file just opened
+-34h	DWORD	pointer to FAR routine called on closing file
+		ES:DI -> system file table
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+			does something to every lock record for file
+-30h	DWORD	pointer to FAR routine to close all files for given computer
+		(called by AX=5D03h)
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-2Ch	DWORD	pointer to FAR routine to close all files for given process
+		(called by AX=5D04h)
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-28h	DWORD	pointer to FAR routine to close file by name
+		(called by AX=5D02h)
+		DS:SI -> DOS parameter list (see AX=5D00h)
+		   DPL's DS:DX -> name of file to close
+		Return: CF clear if successful
+			CF set on error
+			    AX = DOS error code (03h) (see AH=59h)
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-24h	DWORD	pointer to FAR routine to lock region of file
+		call with BX = file handle
+			  CX:DX = starting offset
+			  SI:AX = size
+		Return: CF set on error
+			    AL = DOS error code (21h) (see AH=59h)
+		Note: not called if file is marked as remote
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-20h	DWORD	pointer to FAR routine to unlock region of file
+		call with BX = file handle
+			  CX:DX = starting offset
+			  SI:AX = size
+		Return: CF set on error
+			    AL = DOS error code (21h) (see AH=59h)
+		Note: not called if file is marked as remote
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-1Ch	DWORD	pointer to FAR routine to check if file region is locked
+		call with ES:DI -> system file table entry for file
+			CX = length of region from current position in file
+		Return: CF set if any portion of region locked
+			    AX = 0021h
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-18h	DWORD	pointer to FAR routine to get open file list entry
+		(called by AX=5D05h)
+		call with DS:SI -> DOS parameter list (see AX=5D00h)
+			DPL's BX = index of sharing record
+			DPL's CX = index of SFT in SFT chain of sharing rec
+		Return: CF set on error or not loaded
+			    AX = DOS error code (12h) (see AH=59h)
+			CF clear if successful
+			    ES:DI -> filename
+			    CX = number of locks owned by specified SFT
+			    BX = network machine number
+			    DX destroyed
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+-14h	DWORD	pointer to FAR routine for updating FCB from SFT???
+		call with DS:SI -> unopened FCB
+			  ES:DI -> system file table entry
+		Return: BL = C0h???
+		Note: copies following fields from SFT to FCB:
+		   starting cluster of file	  0Bh	 1Ah
+		   sharing record offset	  33h	 1Ch
+		   file attribute		  04h	 1Eh
+-10h	DWORD	pointer to FAR routine to get first cluster of FCB file ???
+		call with ES:DI -> system file table entry
+			  DS:SI -> FCB
+		Return: CF set if SFT closed or sharing record offsets
+				mismatched
+			CF clear if successful
+			    BX = starting cluster number from FCB
+-0Ch	DWORD	pointer to FAR routine to close file if duplicate for process
+		DS:SI -> system file table
+		Return: AX = number of handle in JFT which already uses SFT
+		Note: called during open/create of a file
+		Note: SHARE assumes SS=DOS DS, directly accesses DOS internals
+		Note: if SFT was opened with inheritance enabled and sharing
+			mode 111, does something to all other SFTs owned by
+			same process which have the same file open mode and
+			sharing record
+-08h	DWORD	pointer to FAR routine for ???
+		Note: SHARE assumes SS=DS=DOS DS, direct-accesses DOS internals
+		Note: closes various handles referring to file most-recently
+			opened
+-04h	DWORD	pointer to FAR routine to update directory info in related SFT
+		  entries
+		call with ES:DI -> system file table entry for file (see below)
+			  AX = subfunction (apply to each related SFT)
+h: update time stamp (offset 0Dh) and date
+				     stamp (offset 0Fh)
+h: update file size (offset 11h) and starting
+				     cluster (offset 0Bh).  Sets last-accessed
+				     cluster fields to start of file if file
+				     never accessed
+h: as function 01h, but last-accessed fields
+				     always changed
+h: do both functions 00h and 02h
+		Note: follows ptr at offset 2Bh in system file table entries
+		Note: NOP if opened with no-inherit or via FCB
+Format of sharing record:
+Offset	Size	Description
+h	BYTE	flag
+h free block
+h allocated block
+		FFh end marker
+h	WORD	size of block
+h	BYTE	checksum of pathname (including NUL)
+		if sum of ASCII values is N, checksum is (N/256 + N%256)
+h	WORD	offset in SHARE's DS of lock record (see below)
+h	DWORD	pointer to start of system file table chain for file
+Ah	WORD	unique sequence number
+Ch	var	ASCIZ full pathname
+Format of SHARE.EXE lock record:
+Offset	Size	Description
+h	WORD	offset in SHARE's DS of next lock table in list
+h	DWORD	offset in file of start of locked region
+h	DWORD	offset in file of end of locked region
+Ah	DWORD	pointer to System File Table entry for this file
+Eh	WORD	PSP segment of lock's owner
+Format of DOS 2.x system file tables:
+Offset	Size	Description
+h	DWORD	pointer to next file table
+h	WORD	number of files in this table
+h  28h bytes per file
+	Offset	Size	Description
+h	BYTE	number of file handles referring to this file
+h	BYTE	file open mode (see AH=3Dh)
+h	BYTE	file attribute
+h	BYTE	drive (0 = character device, 1 = A, 2 = B, etc)
+h 11 BYTEs	filename in FCB format (no path,no period,blank-padded)
+Fh	WORD	???
+h	WORD	???
+h	DWORD	file size???
+h	WORD	file date in packed format (see AX=5700h)
+h	WORD	file time in packed format (see AX=5700h)
+Bh	BYTE	device attribute (see AX=4400h)
+	---character device---
+Ch	DWORD	pointer to device driver
+	---block device---
+Ch	WORD	starting cluster of file
+Eh	WORD	relative cluster in file of last cluster accessed
+	------
+h	WORD	absolute cluster number of current cluster
+h	WORD	???
+h	DWORD	current file position???
+Format of DOS 3.0 system file tables and FCB tables:
+Offset	Size	Description
+h	DWORD	pointer to next file table
+h	WORD	number of files in this table
+h  38h bytes per file
+	Offset	Size	Description
+h-1Eh as for DOS 3.1+ (see below)
+Fh	WORD	byte offset of directory entry within sector
+h 11 BYTES	filename in FCB format (no path/period, blank-padded)
+Ch	DWORD	(SHARE.EXE) pointer to previous SFT sharing same file
+h	WORD	(SHARE.EXE) ??? network machine number
+h	WORD	PSP segment of file's owner
+h	WORD	(SHARE.EXE) offset in SHARE code seg of share record
+h	WORD	??? apparently always 0000h
+Format of DOS 3.1-3.3x system file tables and FCB tables:
+Offset	Size	Description
+h	DWORD	pointer to next file table
+h	WORD	number of files in this table
+h  35h bytes per file
+	Offset	Size	Description
+h	WORD	number of file handles referring to this file
+h	WORD	file open mode (see AH=3Dh)
+			bit 15 set if this file opened via FCB
+h	BYTE	file attribute (see AX=4301h)
+h	WORD	device info word (see AX=4400h)
+			bit 15 set if remote file
+			bit 14 set means do not set file date/time on closing
+			bit 12 set means don't inherit on EXEC
+h	DWORD	pointer to device driver header if character device
+			else pointer to DOS Drive Parameter Block (see AH=32h)
+Bh	WORD	starting cluster of file
+Dh	WORD	file time in packed format (see AX=5700h)
+Fh	WORD	file date in packed format (see AX=5700h)
+h	DWORD	file size
+	---system file table---
+h	DWORD	current offset in file (may be larger than size of
+			file; INT 21/AH=42h does not check new position)
+	---FCB table---
+h	WORD	counter for last I/O to FCB
+h	WORD	counter for last open of FCB
+			(these are separate to determine the times of the
+			latest I/O and open)
+	---
+h	WORD	relative cluster within file of last cluster accessed
+Bh	WORD	absolute cluster number of last cluster accessed
+h if file never read or written???
+Dh	WORD	number of sector containing directory entry
+Fh	BYTE	number of dir entry within sector (byte offset/32)
+h 11 BYTEs	filename in FCB format (no path/period, blank-padded)
+Bh	DWORD	(SHARE.EXE) pointer to previous SFT sharing same file
+Fh	WORD	(SHARE.EXE) network machine number which opened file
+h	WORD	PSP segment of file's owner (see AH=26h)
+h	WORD	offset within SHARE.EXE code segment of
+			sharing record (see above)  0000h = none
+Format of DOS 4.0-5.0 system file tables and FCB tables:
+Offset	Size	Description
+h	DWORD	pointer to next file table
+h	WORD	number of files in this table
+h  3Bh bytes per file
+	Offset	Size	Description
+h	WORD	number of file handles referring to this file
+h	WORD	file open mode (see AH=3Dh)
+			bit 15 set if this file opened via FCB
+h	BYTE	file attribute (see AX=4301h)
+h	WORD	device info word (see AX=4400h)
+			bit 15 set if remote file
+			bit 14 set means do not set file date/time on closing
+			bit 13 set if named pipe
+			bit 12 set if no inherit
+			bit 11 set if network spooler
+h	DWORD	pointer to device driver header if character device
+			else pointer to DOS Drive Parameter Block (see AH=32h)
+			or REDIR data
+Bh	WORD	starting cluster of file
+Dh	WORD	file time in packed format (see AX=5700h)
+Fh	WORD	file date in packed format (see AX=5700h)
+h	DWORD	file size
+h	DWORD	current offset in file
+	---local file---
+h	WORD	relative cluster within file of last cluster accessed
+Bh	DWORD	number of sector containing directory entry
+Fh	BYTE	number of dir entry within sector (byte offset/32)
+	---network redirector---
+h	DWORD	pointer to REDIRIFS record
+Dh  3 BYTEs	???
+	------
+h 11 BYTEs	filename in FCB format (no path/period, blank-padded)
+Bh	DWORD	(SHARE.EXE) pointer to previous SFT sharing same file
+Fh	WORD	(SHARE.EXE) network machine number which opened file
+h	WORD	PSP segment of file's owner (see AH=26h)
+h	WORD	offset within SHARE.EXE code segment of
+			sharing record (see above)  0000h = none
+h	WORD	(local) absolute cluster number of last clustr accessed
+			(redirector) ???
+h	DWORD	pointer to IFS driver for file, 0000000h if native DOS
+Format of current directory structure (CDS) (array, LASTDRIVE entries):
+Offset	Size	Description
+h 67 BYTEs	ASCIZ path in form X:\PATH (local) or \\MACH\PATH (network)
+h	WORD	drive attributes (see also note below and AX=5F07h)
+		bit 15: uses network redirector	 \ invalid if 00, installable
+: physical drive		 / file system if 11
+: JOIN'ed	  \ path above is true path that would be
+: SUBST'ed  / needed if not under SUBST or JOIN
+h	DWORD	pointer to Drive Parameter Block for drive (see AH=32h)
+---local drives---
+h	WORD	starting cluster of current directory
+h = root, FFFFh = never accessed
+Bh	WORD	??? seems to be FFFFh always
+Dh	WORD	??? seems to be FFFFh always
+---network drives---
+h	DWORD	pointer to redirector or REDIRIFS record, or FFFFh:FFFFh
+Dh	WORD	stored user data from INT 21/AX=5F03h???
+------
+Fh	WORD	offset in current directory path of backslash corresponding to
+		  root directory for drive
+		this value specifies how many characters to hide from the
+		  "CHDIR" and "GETDIR" calls; normally set to 2 to hide the
+		  drive letter and colon, SUBST, JOIN, and networks change it
+		  so that only the appropriate portion of the true path is
+		  visible to the user
+---DOS 4.x---
+h	BYTE	??? used by network
+h	DWORD	pointer to IFS driver for this drive, 00000000h if native DOS
+h	WORD	???
+Notes:	the path for invalid drives is normally set to X:\, but may be empty
+	  after JOIN x: /D in DR-DOS 5.0 or NET USE x: /D in older LAN versions
+	normally, only one of bits 13&12 may be set together with bit 14, but
+	  DR-DOS 5.0 uses other combinations for bits 15-12: 0111 JOIN,
+SUBST, 0101 ASSIGN
+Format of DR-DOS 5.0-6.0 current directory structure entry (array):
+Offset	Size	Description
+h 67 BYTEs	ASCIZ pathname of actual root directory for this logical drive
+h	WORD	drive attributes
+h SUBSTed drive
+h??? JOINed drive
+h physical drive
+h ASSIGNed drive
+h JOINed drive
+h	BYTE	physical drive number (0=A:) if this logical drive is valid
+h	BYTE	??? apparently flags for JOIN and ASSIGN
+h	WORD	cluster number of start of parent directory (0000h = root)
+h	WORD	entry number of current directory in parent directory
+Bh	WORD	cluster number of start of current directory
+Dh  2 BYTEs	??? apparently always 0001h
+Fh	WORD	cluster number of SUBST/JOIN "root" directory
+h if physical root directory
+Format of device driver header:
+Offset	Size	Description
+h	DWORD	pointer to next driver, offset=FFFFh if last driver
+h	WORD	device attributes
+		Character device:
+		   bit 15 set
+		   bit 14 IOCTL supported (see AH=44h)
+		   bit 13 (DOS 3+) output until busy supported
+		   bit 12 reserved
+		   bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported
+		   bits 10-8 reserved
+		   bit 7  (DOS 5+) Generic IOCTL check call supported (cmd 19h)
+				(see AX=4410h,AX=4411h)
+		   bit 6  (DOS 3.2+) Generic IOCTL call supported (command 13h)
+				(see AX=440Ch,AX=440Dh)
+		   bit 5  reserved
+		   bit 4  device is special (use INT 29 "fast console output")
+		   bit 3  device is CLOCK$ (all reads/writes use transfer
+				record described below)
+		   bit 2  device is NUL
+		   bit 1  device is standard output
+		   bit 0  device is standard input
+		Block device:
+		   bit 15 clear
+		   bit 14 IOCTL supported
+		   bit 13 non-IBM format
+		   bit 12 reserved
+		   bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported
+		   bit 10 reserved
+		   bit 9  direct I/O not allowed???
+			  (set by DOS 3.3 DRIVER.SYS for "new" drives)
+		   bit 8  ??? set by DOS 3.3 DRIVER.SYS for "new" drives
+		   bit 7  (DOS 5+) Generic IOCTL check call supported (cmd 19h)
+				(see AX=4410h,AX=4411h)
+		   bit 6  (DOS 3.2+) Generic IOCTL call supported (command 13h)
+				implies support for commands 17h and 18h
+				(see AX=440Ch,AX=440Dh,AX=440Eh,AX=440Fh)
+		   bits 5-2 reserved
+		   bit 1   driver supports 32-bit sector addressing
+		   bit 0   reserved
+h	WORD	device strategy entry point
+		call with ES:BX -> request header (see INT 2F/AX=0802h)
+h	WORD	device interrupt entry point
+---character device---
+Ah  8 BYTEs	blank-padded character device name
+---block device---
+Ah	BYTE	number of subunits (drives) supported by driver
+Bh  7 BYTEs	unused
+---
+h	WORD	(CD-ROM driver) reserved, must be 0000h
+h	BYTE	(CD-ROM driver) drive letter (must initially be 00h)
+h	BYTE	(CD-ROM driver) number of units
+h  6 BYTEs	(CD-ROM driver) signature 'MSCDnn' where 'nn' is version
+			(currently '00')
+Format of CLOCK$ transfer record:
+Offset	Size	Description
+h	WORD	number of days since 1-Jan-1980
+h	BYTE	minutes
+h	BYTE	hours
+h	BYTE	hundredths of second
+h	BYTE	seconds
+Format of DOS 2.x disk buffer:
+Offset	Size	Description
+h	DWORD	pointer to next disk buffer, offset = FFFFh if last
+		least-recently used buffer is first in chain
+h	BYTE	drive (0=A, 1=B, etc), FFh if not in use
+h  3 BYTEs	unused??? (seems always to be 00h 00h 01h)
+h	WORD	logical sector number
+Ah	BYTE	number of copies to write (1 for non-FAT sectors)
+Bh	BYTE	sector offset between copies if multiple copies to be written
+Ch	DWORD	pointer to DOS Drive Parameter Block (see AH=32h)
+h		buffered data
+Format of DOS 3.x disk buffer:
+Offset	Size	Description
+h	DWORD	pointer to next disk buffer, offset = FFFFh if last
+		least-recently used buffer is first in chain
+h	BYTE	drive (0=A,1=B, etc), FFh if not in use
+h	BYTE	flags
+		bit 7: ???
+		bit 6: buffer dirty
+		bit 5: buffer has been referenced
+		bit 4: ???
+		bit 3: sector in data area
+		bit 2: sector in a directory, either root or subdirectory
+		bit 1: sector in FAT
+		bit 0: boot sector??? (guess)
+h	WORD	logical sector number
+h	BYTE	number of copies to write (1 for non-FAT sectors)
+h	BYTE	sector offset between copies if multiple copies to be written
+Ah	DWORD	pointer to DOS Drive Parameter Block (see AH=32h)
+Eh	WORD	unused??? (almost always 0)
+h		buffered data
+Format of DOS 4.00 (pre UR 25066) disk buffer info:
+Offset	Size	Description
+h	DWORD	pointer to array of disk buffer hash chain heads (see below)
+h	WORD	number of disk buffer hash chains (referred to as NDBCH below)
+h	DWORD	pointer to lookahead buffer, zero if not present
+Ah	WORD	number of lookahead sectors, else zero (the y in BUFFERS=x,y)
+Ch	BYTE	00h if buffers in EMS (/X), FFh if not
+Dh	WORD	EMS handle for buffers, zero if not in EMS
+Fh	WORD	EMS physical page number used for buffers (usually 255)
+h	WORD	??? seems always to be 0001h
+h	WORD	segment of EMS physical page frame
+h	WORD	??? seems always to be zero
+h  4 WORDs	EMS partial page mapping information???
+Format of DOS 4.01 (from UR 25066 Corrctive Services Disk on) disk buffer info:
+Offset	Size	Description
+h	DWORD	pointer to array of disk buffer hash chain heads (see below)
+h	WORD	number of disk buffer hash chains (referred to as NDBCH below)
+h	DWORD	pointer to lookahead buffer, zero if not present
+Ah	WORD	number of lookahead sectors, else zero (the y in BUFFERS=x,y)
+Ch	BYTE	01h, possibly to distinguish from pre-UR 25066 format
+Dh	WORD	??? EMS segment for BUFFERS (only with /XD)
+Fh	WORD	??? EMS physical page number of EMS seg above (only with /XD)
+h	WORD	??? EMS segment for ??? (only with /XD)
+h	WORD	??? EMS physical page number of above (only with /XD)
+h	BYTE	??? number of EMS page frames present (only with /XD)
+h	WORD	segment of one-sector workspace buffer allocated in main memory
+		  if BUFFERS/XS or /XD options in effect, possibly to avoid DMA
+		  into EMS
+h	WORD	EMS handle for buffers, zero if not in EMS
+Ah	WORD	EMS physical page number used for buffers (usually 255)
+Ch	WORD	??? appears always to be 0001h
+Eh	WORD	segment of EMS physical page frame
+h	WORD	??? appears always to be zero
+h	BYTE	00h if /XS, 01h if /XD, FFh if BUFFERS not in EMS
+Format of DOS 4.x disk buffer hash chain head (array, one entry per chain):
+Offset	Size	Description
+h	WORD	EMS logical page number in which chain is resident, -1 if not
+		in EMS
+h	DWORD	pointer to least recently used buffer header.  All buffers on
+		this chain are in the same segment.
+h	BYTE	number of dirty buffers on this chain
+h	BYTE	reserved (00h)
+Notes:	buffered disk sectors are assigned to chain N where N is the sector's
+	  address modulo NDBCH,	 0 <= N <= NDBCH-1
+	each chain resides completely within one EMS page
+	this structure is in main memory even if buffers are in EMS
+Format of DOS 4.0-5.0 disk buffer:
+Offset	Size	Description
+h	WORD	forward ptr, offset only, to next least recently used buffer
+h	WORD	backward ptr, offset only
+h	BYTE	drive (0=A,1=B, etc), FFh if not in use
+h	BYTE	flags
+		bit 7: remote buffer
+		bit 6: buffer dirty
+		bit 5: buffer has been referenced
+		bit 4: search data buffer (only valid if remote buffer)
+		bit 3: sector in data area
+		bit 2: sector in a directory, either root or subdirectory
+		bit 1: sector in FAT
+		bit 0: reserved
+h	DWORD	logical sector number
+Ah	BYTE	number of copies to write
+		for FAT sectors, same as number of FATs
+		for data and directory sectors, usually 1
+Bh	WORD	offset in sectors between copies to write for FAT sectors
+Dh	DWORD	pointer to DOS Drive Parameter Block (see AH=32h)
+h	WORD	buffer use count if remote buffer (see flags above)
+h	BYTE	reserved
+h		buffered data
+Note:	for DOS 4.x, all buffered sectors which have the same hash value
+	  (computed as the sum of high and low words of the logical sector
+	  number divided by NDBCH) are on the same doubly-linked circular
+	  chain; for DOS 5.0, only a single circular chain exists.
+	the links consist of offset addresses only, the segment being the same
+	  for all buffers in the chain.
+Format of DOS 5.0 disk buffer info:
+Offset	Size	Description
+h	DWORD	pointer to least-recently-used buffer header (may be in HMA)
+		(see above)
+h	WORD	0000h (DOS 5 does not hash disk buffers, so offset 00h points
+			directly at the only buffer chain)
+h	DWORD	pointer to lookahead buffer, zero if not present
+Ah	WORD	number of lookahead sectors, else zero (the y in BUFFERS=x,y)
+Ch	BYTE	buffer location
+h base memory, no workspace buffer
+h HMA, workspace buffer in base memory
+Dh	DWORD	pointer to one-segment workspace buffer in base memory
+h  3 BYTEs	unused???
+h	WORD	???
+h	BYTE	??? apparently always 00h
+h	BYTE	??? apparently always FFh
+h	BYTE	??? apparently always 00h
+h	BYTE	??? apparently always 00h
+Ah	WORD	??? segment within HIMEM.SYS area when buffers are in HMA and
+		  UMBs are enabled???, else 0000h
+Ch	BYTE	bit 0 set iff UMB MCB chain linked to normal MCB chain
+Dh	WORD	???
+Fh	WORD	segment of first MCB in upper memory blocks or FFFFh if DOS
+		memory chain in base 640K only (first UMB MCB usually at 9FFFh,
+		locking out video memory with a DOS-owned memory block)
+h	WORD	paragraph of start of most recent MCB chain search
+Format of IFS driver list:
+Offset	Size	Description
+h	DWORD	pointer to next driver header
+h  8 BYTEs	IFS driver name (blank padded), as used by FILESYS command
+Ch  4 BYTEs	???
+h	DWORD	pointer to IFS utility function entry point (see below)
+		call with ES:BX -> IFS request (see below)
+h	WORD	offset in header's segment of driver entry point
+	???
+Call IFS utility function entry point with:
+	AH = 20h miscellaneous functions
+	    AL = 00h get date
+		Return: CX = year
+			DH = month
+			DL = day
+	    AL = 01h get process ID and computer ID
+		Return: BX = current PSP segment
+			DX = active network machine number
+	    AL = 05h get file system info
+		ES:DI -> 16-byte info buffer
+		Return: buffer filled
+			Offset	Size	Description
+h  2 BYTEs	unused
+h	WORD	number of SFTs (actually counts only
+					the first two file table arrays)
+h	WORD	number of FCB table entries
+h	WORD	number of proctected FCBs
+h  6 BYTEs	unused
+Eh	WORD	largest sector size supported
+	    AL = 06h get machine name
+		ES:DI -> 18-byte buffer for name
+		Return: buffer filled with name starting at offset 02h
+	    AL = 08h get sharing retry count
+		Return: BX = sharing retry count
+	    AL = other
+		Return: CF set
+	AH = 21h get redirection state
+		BH = type (03h disk, 04h printer)
+		Return: BH = state (00h off, 01h on)
+	AH = 22h ??? some sort of time calculation
+		AL = 00h ???
+		    nonzero ???
+	AH = 23h ??? some sort of time calculation
+	AH = 24h compare filenames
+	    DS:SI -> first ASCIZ filename
+	    ES:DI -> second ASCIZ filename
+	    Return: ZF set if files are same ignoring case and / vs \
+	AH = 25h normalize filename
+	    DS:SI -> ASCIZ filename
+	    ES:DI -> buffer for result
+	    Return: filename uppercased, forward slashes changed to backslashes
+	AH = 26h get DOS stack
+	    Return: DS:SI -> top of stack
+		    CX = size of stack in bytes
+	AH = 27h increment InDOS flag
+	AH = 28h decrement InDOS flag
+Note:	IFS drivers which do not wish to implement functions 20h or 24h-28h may
+	  pass them on to the default handler pointed at by [LoL+37h]
+Format of IFS request block:
+Offset	Size	Description
+h	WORD	total size in bytes of request
+h	BYTE	class of request
+h ???
+h redirection
+h ???
+h file access
+h convert error code to string
+h ???
+h	WORD	returned DOS error code
+h	BYTE	IFS driver exit status
+h success
+h ???
+h ???
+h ???
+h ???
+		FFh internal failure
+h 16 BYTEs	???
+---request class 02h---
+h	BYTE	function code
+h ???
+h	BYTE	unused???
+h	DWORD	pointer to ???
+Ch	DWORD	pointer to ???
+h  2 BYTEs	???
+---request class 03h---
+h	BYTE	function code
+h	BYTE	???
+h	DWORD	pointer to ???
+Ch	DWORD	pointer to ???
+h	WORD	returned ???
+h	WORD	returned ???
+h	WORD	returned ???
+h	BYTE	returned ???
+h	BYTE	unused???
+---request class 04h---
+h	DWORD	pointer to ???
+Ah	DWORD	pointer to ???
+---request class 05h---
+h	BYTE	function code
+h flush disk buffers
+h get disk space
+h MKDIR
+h RMDIR
+h CHDIR
+h delete file
+h rename file
+h search directory
+h file open/create
+Ah LSEEK
+Bh read from file
+Ch write to file
+Dh lock region of file
+Eh commit/close file
+Fh get/set file attributes
+h printer control
+h ???
+h process termination
+h ???
+	---class 05h function 01h---
+h  7	BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	BYTE	???
+h	BYTE	???
+	---class 05h function 02h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	WORD	returned total clusters
+h	WORD	returned sectors per cluster
+Ah	WORD	returned bytes per sector
+Ch	WORD	returned available clusters
+Eh	BYTE	returned ???
+Fh	BYTE	???
+	---class 05h functions 03h,04h,05h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	DWORD	pointer to directory name
+	---class 05h function 06h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	WORD	attribute mask
+h	DWORD	pointer to filename
+	---class 05h function 07h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	WORD	attribute mask
+h	DWORD	pointer to source filespec
+Ch	DWORD	pointer to destination filespec
+	---class 05h function 08h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	BYTE	00h FINDFIRST
+h FINDNEXT
+h	DWORD	pointer to FindFirst search data + 01h if FINDNEXT
+Ch	WORD	search attribute if FINDFIRST
+Eh	DWORD	pointer to filespec if FINDFIRST
+	---class 05h function 09h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	WORD	???  \ together, specify open vs. create, whether or
+h	WORD	???  / not to truncate
+Ah  4 BYTEs	???
+Eh	DWORD	pointer to filename
+h  4 BYTEs	???
+h	WORD	file attributes on call
+			returned ???
+h	WORD	returned ???
+	---class 05h function 0Ah---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	BYTE	seek type (02h = from end)
+h	DWORD	offset on call
+			returned new absolute position
+	---class 05h functions 0Bh,0Ch---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	WORD	number of bytes to transfer
+			returned bytes actually transferred
+Ah	DWORD	transfer address
+	---class 05h function 0Dh---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	BYTE	file handle???
+h	BYTE	unused???
+h	WORD	???
+Ah	WORD	???
+Ch	WORD	???
+Eh	WORD	???
+	---class 05h function 0Eh---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	BYTE	00h commit file
+h close file
+h	BYTE	unused???
+	---class 05h function 0Fh---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h  4 BYTEs	???
+h	BYTE	02h GET attributes
+h PUT attributes
+h	BYTE	unused???
+h 12 BYTEs	???
+h	WORD	search attributes???
+h	DWORD	pointer to filename
+Ah	WORD	(GET) returned ???
+Ch	WORD	(GET) returned ???
+Eh	WORD	(GET) returned ???
+h	WORD	(GET) returned ???
+h	WORD	(PUT) new attributes
+			(GET) returned attributes
+	---class 05h function 10h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	WORD	???
+h	DWORD	pointer to ???
+Ch	WORD	???
+Eh	BYTE	???
+Fh	BYTE	subfunction
+h get printer setup
+h ???
+h ???
+h ???
+h ???
+h ???
+h set printer setup
+	---class 05h function 11h---
+h  7 BYTEs	???
+Eh	DWORD	pointer to ???
+h	DWORD	pointer to IFS open file structure (see below)
+h	BYTE	subfunction
+h	BYTE	unused???
+h	WORD	???
+Ah	WORD	???
+Ch	WORD	???
+Eh	BYTE	???
+Fh	BYTE	???
+	---class 05h function 12h---
+h 15 BYTEs	unused???
+h	WORD	PSP segment
+h	BYTE	type of process termination
+h	BYTE	unused???
+	---class 05h function 13h---
+h 15 BYTEs	unused???
+h	WORD	PSP segment
+---request class 06h---
+h	DWORD	returned pointer to string corresponding to error code at 03h
+Ah	BYTE	returned ???
+Bh	BYTE	unused
+---request class 07h---
+h	DWORD	pointer to IFS open file structure (see below)
+Ah	BYTE	???
+Bh	BYTE	unused???
+Format of IFS open file structure:
+Offset	Size	Description
+h	WORD	???
+h	WORD	device info word
+h	WORD	file open mode
+h	WORD	???
+h	WORD	file attributes
+Ah	WORD	owner's network machine number
+Ch	WORD	owner's PSP segment
+Eh	DWORD	file size
+h	DWORD	current offset in file
+h	WORD	file time
+h	WORD	file date
+Ah 11 BYTEs	filename in FCB format
+h	WORD	???
+h	WORD	hash value of SFT address
+		(low word of linear address + segment&F000h)
+h  3 WORDs	network info from SFT
+Fh	WORD	???
+Format of one item in DOS 4+ list of special program names:
+Offset	Size	Description
+h	BYTE	length of name (00h = end of list)
+h  N BYTEs	name in format name.ext
+ N    2 BYTEs	DOS version to return for program (major,minor)
+		(see AH=30h,INT 2F/AX=122Fh)
+---DOS 4 only---
+ N+2	BYTE	number of times to return fake version number (FFh = always)
+Note:	if the name of the executable for the program making the DOS "get
+	  version" call matches one of the names in this list, DOS returns the
+	  specified version rather than the true version number
+----------215252-----------------------------
+INT 21 - VIRUS - "516"/"Leapfrog" - INSTALLATION CHECK
+	AX = 5252h
+Return: BX = FFEEh if resident
+SeeAlso: AX=4BFFh"Cascade",AX=58CCh
+----------2153-------------------------------
+INT 21 - DOS 2+ internal - TRANSLATE BIOS PARAMETER BLOCK TO DRIVE PARAM BLOCK
+	AH = 53h
+	DS:SI -> BIOS Parameter Block (see below)
+	ES:BP -> buffer for Drive Parameter Block (see AH=32h for format)
+Return: ES:BP buffer filled
+Note:	for DOS 3+, the cluster at which to start searching is set to 0000h
+	  and the number of free clusters is set to FFFFh (unknown)
+Format of BIOS Parameter Block:
+Offset	Size	Description
+h	WORD	number of bytes per sector
+h	BYTE	number of sectors per cluster
+h	WORD	number of reserved sectors at start of disk
+h	BYTE	number of FATs
+h	WORD	number of entries in root directory
+h	WORD	total number of sectors
+		for DOS 4+, set to zero if partition >32M, then set DWORD at
+h to actual number of sectors
+Ah	BYTE	media ID byte
+Bh	WORD	number of sectors per FAT
+---DOS 3+---
+Dh	WORD	number of sectors per track
+Fh	WORD	number of heads
+h	DWORD	number of hidden sectors
+h 11 BYTEs	reserved
+---DOS 4+ ---
+h	DWORD	total number of sectors if word at 08h contains zero
+h  6 BYTEs	???
+Fh	WORD	number of cylinders
+h	BYTE	device type
+h	WORD	device attributes (removable or not, etc)
+----------2154-------------------------------
+INT 21 - DOS 2+ - GET VERIFY FLAG
+	AH = 54h
+Return: AL = verify flag
+h off
+h on (all disk writes verified after writing)
+SeeAlso: AH=2Eh
+----------2155-------------------------------
+INT 21 - DOS 2+ internal - CREATE CHILD PSP
+	AH = 55h
+	DX = segment at which to create new PSP
+	SI = (DOS 3+) value to place in memory size field at DX:[0002h]
+Return: CF clear if successful
+Notes:	creates a "child" PSP rather than making an exact copy of the current
+	  PSP; the new PSP's parent pointer is set to the current PSP and the
+	  reference count for each inherited file is incremented
+	(DOS 2+) sets current PSP to DX
+	(DOS 3+) marks "no inherit" file handles as closed in child PSP
+SeeAlso: AH=26h,AH=50h
+----------2156-------------------------------
+INT 21 - DOS 2+ - "RENAME" - RENAME FILE
+	AH = 56h
+	DS:DX -> ASCIZ filename of existing file (no wildcards, but see below)
+	ES:DI -> ASCIZ new filename (no wildcards)
+	CL = attribute mask (server call only, see below)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (02h,03h,05h,11h) (see AH=59h)
+Notes:	allows move between directories on same logical volume
+	does not set the archive attribute (see AX=4300h), which results in
+	  incremental backups not backing up the file under its new name
+	open files should not be renamed
+	(DOS 3+) allows renaming of directories
+	(DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case
+	  error 12h (no more files) is returned on success, and both source and
+	  destination specs must be canonical (as returned by AH=60h).
+	  Wildcards in the destination are replaced by the corresponding char
+	  of each source file being renamed.  Under DOS 3.x, the call will fail
+	  if the destination wildcard is *.* or equivalent.  When invoked via
+	  AX=5D00h, only those files matching the attribute mask in CL are
+	  renamed.
+SeeAlso: AH=17h,AX=4301h,AH=60h,AX=5D00h
+----------215700-----------------------------
+INT 21 - DOS 2+ - GET FILE'S DATE AND TIME
+	AX = 5700h
+	BX = file handle
+Return: CF clear if successful
+	    CX = file's time
+		bits 15-11: hours (0-23)
+-5:  minutes
+-0:  seconds/2
+	    DX = file's date
+		bits 15-9: year - 1980
+-5: month
+-0: day
+	CF set on error
+	    AX = error code (01h,06h) (see AH=59h)
+SeeAlso: AX=5701h
+----------215701-----------------------------
+INT 21 - DOS 2+ - SET FILE'S DATE AND TIME
+	AX = 5701h
+	BX = file handle
+	CX = new time (see AX=5700h)
+	DX = new date (see AX=5700h)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h,06h) (see AH=59h)
+SeeAlso: AX=5700h
+----------215702-----------------------------
+INT 21 - DOS 4.x only - GET ???
+	AX = 5702h
+	BX = ??? (0000h through 0004h)
+	DS:SI -> ???
+	ES:DI -> result buffer
+	CX = size of result buffer
+Return: CX = size of returned data
+SeeAlso: AX=5703h,AX=5704h
+----------215703-----------------------------
+INT 21 - DOS 4.x only - GET ???
+	AX = 5703h
+	BX = file handle (only 0000h through 0004h valid)
+	DS:SI -> ??? passed through to INT 2F/AX=112Dh
+	ES:DI -> result buffer
+	CX = size of result buffer
+Return: CX = size of returned data
+	ES:DI -> zero word (DOS 4.0) if CX >= 2 on entry
+SeeAlso: AX=5702h,AX=5704h,INT 2F/AX=112Dh
+----------215704-----------------------------
+INT 21 - DOS 4.x only - TRUNCATE OPEN FILE TO ZERO LENGTH
+	AX = 5704h
+	BX = file handle (only 0000h through 0004h valid)
+	DS:SI -> ??? passed through to INT 2F/AX=112Dh
+	ES:DI -> result buffer
+	CX = size of result buffer
+Return: CX = size of returned data
+	ES:DI -> zero word (DOS 4.0) if CX >= 2 on entry
+SeeAlso: AX=5702h,AX=5703h,INT 2F/AX=112Dh
+----------2158-------------------------------
+INT 21 - DOS 3+ - GET OR SET MEMORY ALLOCATION STRATEGY
+	AH = 58h
+	AL = subfunction
+h get allocation strategy
+		Return: AX = current strategy
+h low memory first fit
+h low memory best fit
+h low memory last fit
+			 ---DOS 5.0---
+h high memory first fit
+h high memory best fit
+h high memory last fit
+h first fit, try high then low memory
+h best fit, try high then low memory
+h last fit, try high then low memory
+h set allocation strategy
+		BL = new allocation strategy (see above)
+		BH = 0 (DOS 5.0)
+h (DOS 5.0) get UMB link state
+		Return: AL = 00h UMBs not part of DOS memory chain
+			   = 01h UMBs in DOS memory chain
+h (DOS 5.0) set UMB link state
+		BX = 0000h remove UMBs from DOS memory chain
+		   = 0001h add UMBs to DOS memory chain
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h) (see AH=59h)
+Notes:	the Set subfunction accepts any value in BL for DOS 3.x and 4.x;
+or greater means last fit
+	the Get subfunction returns the last value set
+	a program which changes the allocation strategy should restore it
+	  before terminating
+	DR-DOS 3.41 reportedly reverses subfunctions 00h and 01h
+SeeAlso: AH=48h,AH=49h,AH=4Ah,INT 2F/AX=4310h,INT 67/AH=3Fh
+----------2158CC-----------------------------
+INT 21 - VIRUS - "1067"/"Headcrash" - INSTALLATION CHECK
+	AX = 58CCh
+Return: CF clear if resident
+SeeAlso: AX=5252h,AX=6969h
+===== 59h - DOS 3+ - GET EXTENDED ERROR INFORMATION =====
+<code>
+	AH = 59h
+	BX = 0000h
+</code>
+<code>
+Return: AX = extended error code (see below)
+	BH = error class (see below)
+	BL = recommended action (see below)
+	CH = error locus (see below)
+	CL, DX, SI, DI, BP, DS, and ES destroyed
+</code>
+<WRAP round box>
+functions available under DOS 2.x map the true DOS 3+ error code into one supported under DOS 2.x
+you should call this function to retrieve the true error code when an FCB or DOS 2.x call returns an error
+</WRAP>
+SeeAlso: AX=5D0Ah,INT 2F/AX=122Dh
+Values for extended error code:
+|	00h |no error                                                                         |
+|	01h |function number invalid                                                          |
+|	02h |file not found                                                                   |
+|	03h |path not found                                                                   |
+|	04h |too many open files (no handles available)                                       |
+|	05h |access denied                                                                    |
+|	06h |invalid handle                                                                   |
+|	07h |memory control block destroyed                                                   |
+|	08h |insufficient memory                                                              |
+|	09h |memory block address invalid                                                     |
+|	0Ah |environment invalid (usually >32K in length)                                     |
+|	0Bh |format invalid                                                                   |
+|	0Ch |access code invalid                                                              |
+|	0Dh |data invalid                                                                     |
+|	0Eh |reserved                                                                         |
+|	0Fh |invalid drive                                                                    |
+|	10h |attempted to remove current directory                                            |
+|	11h |not same device                                                                  |
+|	12h |no more files                                                                    |
+|---DOS 3+---  ||
+|	13h |disk write-protected                                                             |
+|	14h |unknown unit                                                                     |
+|	15h |drive not ready                                                                  |
+|	16h |unknown command                                                                  |
+|	17h |data error (CRC)                                                                 |
+|	18h |bad request structure length                                                     |
+|	19h |seek error                                                                       |
+|	1Ah |unknown media type (non-DOS disk)                                                |
+|	1Bh |sector not found                                                                 |
+|	1Ch |printer out of paper                                                             |
+|	1Dh |write fault                                                                      |
+|	1Eh |read fault                                                                       |
+|	1Fh |general failure                                                                  |
+|	20h |sharing violation                                                                |
+|	21h |lock violation                                                                   |
+|	22h |disk change invalid                                                              |
+|	::: |ES:DI -> ASCIZ volume label of required disk                                     |
+|	23h |FCB unavailable                                                                  |
+|	24h |sharing buffer overflow                                                          |
+|	25h |(DOS 4+) code page mismatch                                                      |
+|	26h |(DOS 4+) cannot complete file operation (out of input)                           |
+|	27h |(DOS 4+) insufficient disk space                                                 |
+|	28h-|31h reserved                                                                     |
+|	32h |network request not supported                                                    |
+|	33h |remote computer not listening                                                    |
+|	34h |duplicate name on network                                                        |
+|	35h |network name not found                                                           |
+|	36h |network busy                                                                     |
+|	37h |network device no longer exists                                                  |
+|	38h |network BIOS command limit exceeded                                              |
+|	39h |network adapter hardware error                                                   |
+|	3Ah |incorrect response from network                                                  |
+|	3Bh |unexpected network error                                                         |
+|	3Ch |incompatible remote adapter                                                      |
+|	3Dh |print queue full                                                                 |
+|	3Eh |queue not full                                                                   |
+|	3Fh |not enough space to print file                                                   |
+|	40h |network name was deleted                                                         |
+|	41h |network: Access denied                                                           |
+|	42h |network device type incorrect                                                    |
+|	43h |network name not found                                                           |
+|	44h |network name limit exceeded                                                      |
+|	45h |network BIOS session limit exceeded                                              |
+|	46h |temporarily paused                                                               |
+|	47h |network request not accepted                                                     |
+|	48h |network print/disk redirection paused                                            |
+|	49h |(LANtastic) invalid network version                                              |
+|	4Ah |(LANtastic) account expired                                                      |
+|	4Bh |(LANtastic) password expired                                                     |
+|	4Ch |(LANtastic) login attempt invalid at this time                                   |
+|	4Dh |(LANtastic v3+) disk limit exceeded on network node                              |
+|	4Eh |(LANtastic v3+) not logged in to network node                                    |
+|	4Fh |reserved                                                                         |
+|	50h |file exists                                                                      |
+|	51h |reserved                                                                         |
+|	52h |cannot make directory                                                            |
+|	53h |fail on INT 24h                                                                  |
+|	54h |(DOS 3.3+) too many redirections                                                 |
+|	55h |(DOS 3.3+) duplicate redirection                                                 |
+|	56h |(DOS 3.3+) invalid password                                                      |
+|	57h |(DOS 3.3+) invalid parameter                                                     |
+|	58h |(DOS 3.3+) network write fault                                                   |
+|	59h |(DOS 4+) function not supported on network                                       |
+|	5Ah |(DOS 4+) required system component not installed                                 |
+Values for Error Class:
+|	01h |out of resource (storage space or I/O channels)            |
+|	02h |temporary situation (file or record lock)                  |
+|	03h |authorization (denied access)                              |
+|	04h |internal (system software bug)                             |
+|	05h |hardware failure                                           |
+|	06h |system failure (configuration file missing or incorrect)   |
+|	07h |application program error                                  |
+|	08h |not found                                                  |
+|	09h |bad format                                                 |
+|	0Ah |locked                                                     |
+|	0Bh |media error                                                |
+|	0Ch |already exists                                             |
+|	0Dh |unknown                                                    |
+Values for Suggested Action:
+|	01h |retry                                  |
+|	02h |delayed retry                          |
+|	03h |prompt user to reenter input           |
+|	04h |abort after cleanup                    |
+|	05h |immediate abort                        |
+|	06h |ignore                                 |
+|	07h |retry after user intervention          |
+Values for Error Locus:
+|	01h |unknown or not appropriate |
+|	02h |block device (disk error)  |
+|	03h |network related            |
+|	04h |serial device (timeout)    |
+|	05h |memory related             |
+===== 5Ah - DOS 3+ - CREATE TEMPORARY FILE =====
+<code>
+	AH = 5Ah
+	CX = file attribute (see AX=4301h)
+	DS:DX -> ASCIZ path ending with a '\' + 13 zero bytes to receive the
+		generated filename
+</code>
+</code>
+Return: CF clear if successful
+	    AX = file handle opened for read/write in compatibility mode
+	    DS:DX pathname extended with generated name for temporary file
+	CF set on error
+	    AX = error code (03h,04h,05h) (see AH=59h)
+</code>
+<WRAP round box>
+creates a file with a unique name which must be explicitly deleted
+COMPAQ DOS 3.31 hangs if the pathname is at XXXXh:0000h; it apparently wraps around to the end of the segment
+</WRAP>
+SeeAlso: AH=3Ch,AH=5Bh
+===== 5Bh- DOS 3+ - CREATE NEW FILE =====
+	AH = 5Bh
+	CX = file attribute (see AX=4301h)
+	DS:DX -> ASCIZ filename
+Return: CF clear if successful
+	    AX = file handle opened for read/write in compatibility mode
+	CF set on error
+	    AX = error code (03h,04h,05h,50h) (see AH=59h)
+Notes:	unlike AH=3Ch, this function will fail if the specified file exists
+	  rather than truncating it; this permits its use in creating semaphore
+	  files because it is an atomic "test and set" operation
+SeeAlso: AH=3Ch,AH=5Ah
+----------215C-------------------------------
+INT 21 - DOS 3+ - "FLOCK" - RECORD LOCKING
+	AH = 5Ch
+	AL = subfunction
+h lock region of file
+h unlock region of file
+	BX = file handle
+	CX:DX = start offset of region within file
+	SI:DI = length of region in bytes
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h,06h,21h,24h) (see AH=59h)
+Notes:	error returned unless SHARE or network installed
+	an unlock call must specify the same region as some prior lock call
+	locked regions become entirely inaccessible to other processes
+	duplicate handles created with AH=45h or AH=46h inherit locks, but
+	  handles inherited by child processes (see AH=4Bh) do not
+SeeAlso: AX=440Bh,INT 2F/AX=110Ah,INT 2F/AX=110Bh
+----------215D00-----------------------------
+INT 21 U - DOS 3.1+ internal - SERVER FUNCTION CALL
+	AX = 5D00h
+	DS:DX -> DOS parameter list (see below)
+	DPL contains all register values for a call to INT 21h
+Return: as appropriate for function being called
+Notes:	does not check AH.  Out of range values will crash the system
+	executes using specified computer ID and process ID
+	sharing delay loops skipped
+	a special sharing mode is enabled
+	wildcards are enabled for DELETE (AH=41h) and RENAME (AH=56h)
+	an extra file attribute parameter is enabled for OPEN (AH=3Dh),
+	  DELETE (AH=41h), and RENAME (AH=56h)
+	functions which take filenames require canonical names (as returned
+	  by AH=60h); this is apparently to prevent multi-hop file forwarding
+SeeAlso: AH=3Dh,AH=41h,AH=56h,AH=60h
+Format of DOS parameter list:
+Offset	Size	Description
+h	WORD	AX
+h	WORD	BX
+h	WORD	CX
+h	WORD	DX
+h	WORD	SI
+Ah	WORD	DI
+Ch	WORD	DS
+Eh	WORD	ES
+h	WORD	reserved (0)
+h	WORD	computer ID (0 = current system)
+h	WORD	process ID (PSP segment on specified computer)
+----------215D01-----------------------------
+INT 21 U - DOS 3.1+ internal - COMMIT ALL FILES FOR SPECIFIED COMPUTER/PROCESS
+	AX = 5D01h
+	DS:DX -> DOS parameter list (see AX=5D00h), only computer ID and
+		process ID fields used
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Notes:	flushes buffers and updates directory entries for each file which has
+	  been written to; if remote file, calls INT 2F/AX=1107h
+	the computer ID and process ID are stored but ignored under DOS 3.3
+SeeAlso: AH=0Dh,AH=68h,INT 2F/AX=1107h
+----------215D02-----------------------------
+INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE FILE BY NAME
+	AX = 5D02h
+	DS:DX -> DOS parameter list (see AX=5D00h), only fields DX, DS,
+		computer ID, and process ID used
+	DPL's DS:DX -> ASCIZ name of file to close
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Notes:	error unless SHARE is loaded (calls [SysFileTable-28h]) (see AH=52h)
+	name must be canonical fully-qualified, such as returned by AH=60h
+SeeAlso: AX=5D03h,AX=5D04h,AH=3Eh,AH=60h
+----------215D03-----------------------------
+INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN COMPUTER
+	AX = 5D03h
+	DS:DX -> DOS parameter list (see AX=5D00h), only computer ID used
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	error unless SHARE is loaded (calls [SysFileTable-30h]) (see AH=52h)
+SeeAlso: AX=5D02h,AX=5D04h
+----------215D04-----------------------------
+INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN PROCESS
+	AX = 5D04h
+	DS:DX -> DOS parameter list (see AX=5D00h), only computer ID and
+		process ID fields used
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	error unless SHARE is loaded (calls [SysFileTable-2Ch]) (see AH=52h)
+SeeAlso: AX=5D02h,AX=5D03h
+----------215D05-----------------------------
+INT 21 U - DOS 3.1+ internal - SHARE.EXE - GET OPEN FILE LIST ENTRY
+	AX = 5D05h
+	DS:DX -> DOS parameter list (see AX=5D00h)
+	DPL's BX = index of sharing record (see AH=52h)
+	DPL's CX = index of SFT in sharing record's SFT list
+Return: CF clear if successful
+	    ES:DI -> ASCIZ filename
+	    BX = network machine number of SFT's owner
+	    CX = number of locks held by SFT's owner
+	CF set if either index out of range
+	    AX = 0012h (no more files)
+Notes:	error unless SHARE is loaded (calls [SysFileTable-18h]) (see AH=52h)
+	names are always canonical fully-qualified, such as returned by AH=60h
+SeeAlso: AH=5Ch,AH=60h
+----------215D06-----------------------------
+INT 21 U - DOS 3.0+ internal - GET ADDRESS OF DOS SWAPPABLE DATA AREA
+	AX = 5D06h
+Return: CF set on error
+	   AX = error code (see AH=59h)
+	CF clear if successful
+	    DS:SI -> nonreentrant data area (includes all three DOS stacks)
+		(critical error flag is first byte)
+	    CX = size in bytes of area which must be swapped while in DOS
+	    DX = size in bytes of area which must always be swapped
+Notes:	the Critical Error flag is used in conjunction with the InDOS flag
+	  (see AH=34h) to determine when it is safe to enter DOS from a TSR
+	setting CritErr flag allows use of functions 50h/51h from INT 28h under
+	  DOS 2.x by forcing use of correct stack
+	swapping the data area allows reentering DOS unless DOS is in a
+	  critical section delimited by INT 2A/AH=80h and INT 2A/AH=81h,82h
+	under DOS 4.0, AX=5D0Bh should be used instead of this function
+SeeAlso: AX=5D0Bh,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h
+Format of DOS 3.10-3.30 Swappable Data Area:
+Offset	Size	Description
+h	BYTE	critical error flag
+h	BYTE	InDOS flag (count of active INT 21 calls)
+h	BYTE	drive on which current critical error occurred, or FFh
+h	BYTE	locus of last error
+h	WORD	extended error code of last error
+h	BYTE	suggested action for last error
+h	BYTE	class of last error
+h	DWORD	ES:DI pointer for last error
+Ch	DWORD	current DTA
+h	WORD	current PSP
+h	WORD	stores SP across an INT 23
+h	WORD	return code from last process termination (zerod after reading
+		with AH=4Dh)
+h	BYTE	current drive
+h	BYTE	extended break flag
+---remainder need only be swapped if in DOS---
+h	WORD	value of AX on call to INT 21
+Ah	WORD	PSP segment for sharing/network
+Ch	WORD	network machine number for sharing/network (0000h = us)
+Eh	WORD	first usable memory block found when allocating memory
+h	WORD	best usable memory block found when allocating memory
+h	WORD	last usable memory block found when allocating memory
+h	WORD	memory size in paragraphs (used only during initialization)
+h	WORD	???
+h	BYTE	INT 24 returned Fail
+h	BYTE	bit flags for allowable actions on INT 24
+Ah	BYTE	??? flag
+Bh	BYTE	FFh if Ctrl-Break termination, 00h otherwise
+Ch	BYTE	??? flag of some kind
+Dh	BYTE	??? (doesn't seem to be referenced)
+Eh	BYTE	day of month
+Fh	BYTE	month
+h	WORD	year - 1980
+h	WORD	number of days since 1-1-1980
+h	BYTE	day of week (0 = Sunday)
+h	BYTE	working SFT pointer at SDA+2AAh is valid ???
+h	BYTE	safe to call INT 28 if nonzero
+h	BYTE	flag: if nonzero, INT 24 abort turned into INT 24 fail
+		(set only during process termination)
+h 26 BYTEs	device driver request header
+h	DWORD	pointer to device driver entry point (used in calling driver)
+h 22 BYTEs	device driver request header
+Ch 22 BYTEs	device driver request header
+h	BYTE	type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child)
+h	BYTE	??? apparently not referenced by kernel
+h  3 BYTEs	24-bit user number (see AH=30h)
+h	BYTE	OEM number (see AH=30h)
+h  2 BYTEs	???
+Ah  6 BYTEs	CLOCK$ transfer record (see AH=52h)
+h	BYTE	??? buffer for single-byte I/O functions
+h	BYTE	??? apparently not referenced by kernel
+h 128 BYTEs	buffer for filename
+h 128 BYTEs	buffer for filename
+h 21 BYTEs	findfirst/findnext search data block (see AH=4Eh)
+A7h 32 BYTEs	directory entry for found file
+C7h 81 BYTEs	copy of current directory structure for drive being accessed
+h 11 BYTEs	FCB-format filename for device name comparison
+h	BYTE	unused???
+h 11 BYTEs	wildcard destination specification for rename (FCB format)
+Fh  2 BYTEs	???
+h	WORD	???
+h  5 BYTEs	???
+h	BYTE	extended FCB file attribute
+h	BYTE	type of FCB (00h regular, FFh extended)
+Ah	BYTE	directory search attributes
+Bh	BYTE	file open mode???
+Ch	BYTE	??? flag bits 0 and 4
+Dh	BYTE	??? flag or counter
+Eh	BYTE	??? flag
+Fh	BYTE	flag indicating how DOS function was invoked
+		(00h = direct INT 20/INT 21, FFh = server call AX=5D00h)
+h	BYTE	???
+h	BYTE	??? flag
+h	BYTE	flag: 00h if read, 01h if write
+h	BYTE	drive number for ???
+h	BYTE	???
+h	BYTE	??? flag or counter
+h	BYTE	line edit (AH=0Ah) insert mode flag (nonzero = on)
+h	BYTE	canonicalized filename referred to existing file/dir if FFh
+h	BYTE	??? flag or counter
+h	BYTE	type of process termination (00h-03h) (see AH=4Dh)
+Ah	BYTE	??? flag
+Bh	BYTE	value with which to replace first byte of deleted file's name
+		(normally E5h, but 00h as described under INT 21/AH=13h)
+Ch	DWORD	pointer to Drive Parameter Block for critical error invocation
+h	DWORD	pointer to stack frame containing user registers on INT 21
+h	WORD	stores SP across INT 24
+h	DWORD	pointer to DOS Drive Parameter Block for ???
+Ah	WORD	???
+Ch	WORD	??? temp
+Eh	WORD	??? flag (only low byte referenced)
+h	WORD	??? temp
+h	BYTE	Media ID byte returned by AH=1Bh,1Ch
+h	BYTE	??? (doesn't seem to be referenced)
+h	DWORD	pointer to device header
+h	DWORD	pointer to current SFT
+Ch	DWORD	pointer to current directory structure for drive being accessed
+h	DWORD	pointer to caller's FCB
+h	WORD	number of SFT to which file being opened will refer
+h	WORD	temporary storage for file handle
+h	DWORD	pointer to a JFT entry in process handle table (see AH=26h)
+Ch	WORD	offset in DOS DS of first filename argument
+Eh	WORD	offset in DOS DS of second filename argument
+h	WORD	offset of last component in pathname or FFFFh
+h	WORD	??? offset of transfer address???
+h	WORD	??? relative cluster within file being accessed ???
+h	WORD	??? absolute cluster number being accessed ???
+h	WORD	??? current sector number
+Ah	WORD	??? current cluster number
+Ch	WORD	??? current offset in file DIV bytes per sector
+Eh  2 BYTEs	???
+h	WORD	??? current offset in file MOD bytes per sector
+h	DWORD	current offset in file
+h	WORD	???
+h	WORD	???
+Ah	WORD	???
+Ch	WORD	???
+Eh	WORD	???
+A0h	WORD	???
+A2h	DWORD	number of bytes appended to file
+A6h	DWORD	pointer to ??? disk buffer
+AAh	DWORD	pointer to working SFT
+AEh	WORD	used by INT 21 dispatcher to store caller's BX
+B0h	WORD	used by INT 21 dispatcher to store caller's DS
+B2h	WORD	temporary storage while saving/restoring caller's registers
+B4h	DWORD	pointer to prev call frame (offset 250h) if INT 21 reentered
+		also switched to for duration of INT 24
+B8h 21 BYTEs	FindFirst search data for source file(s) of a rename operation
+		(see AH=4Eh)
+CDh 32 BYTEs	directory entry for file being renamed
+EDh 331 BYTEs	critical error stack
+h	 35 BYTEs scratch SFT
+h 384 BYTEs	disk stack (functions greater than 0Ch, INT 25,INT 26)
+B8h 384 BYTEs	character I/O stack (functions 01h through 0Ch)
+---DOS 3.2,3.3 only---
+h	BYTE	device driver lookahead flag (see AH=64h)
+h	BYTE	??? looks like a drive number
+Ah	BYTE	??? flag of some kind
+Ah	BYTE	???
+----------215D07-----------------------------
+INT 21 U - DOS 3.1+ network - GET REDIRECTED PRINTER MODE
+	AX = 5D07h
+Return: DL = mode
+h redirected output is combined
+h redirected output in separate print jobs
+SeeAlso: AX=5D08h,AX=5D09h,INT 2F/AX=1125h
+----------215D08-----------------------------
+INT 21 U - DOS 3.1+ network - SET REDIRECTED PRINTER MODE
+	AX = 5D08h
+	DL = mode
+h redirected output is combined
+h redirected output placed in separate jobs, start new print job
+		now
+SeeAlso: AX=5D07h,AX=5D09h,INT 2F/AX=1125h
+----------215D09-----------------------------
+INT 21 U - DOS 3.1+ network - FLUSH REDIRECTED PRINTER OUTPUT
+	AX = 5D09h
+Note:	forces redirected printer output to be printed, and starts a new print
+	  job
+SeeAlso: AX=5D07h,AX=5D08h,INT 2F/AX=1125h
+----------215D0A-----------------------------
+INT 21 - DOS 3.1+ - SET EXTENDED ERROR INFORMATION
+	AX = 5D0Ah
+	DS:DX -> 11-word DOS parameter list (see AX=5D00h)
+Return: nothing.  next call to AH=59h will return values from fields AX,BX,CX,
+	  DX,DI, and ES in corresponding registers
+Note:	documented for DOS 5+, but undocumented in earlier versions
+SeeAlso: AH=59h
+----------215D0B-----------------------------
+INT 21 U - DOS 4.x only internal - GET DOS SWAPPABLE DATA AREAS
+	AX = 5D0Bh
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    DS:SI -> swappable data area list (see below)
+Note:	copying and restoring the swappable data areas allows DOS to be
+	  reentered unless it is in a critical section delimited by calls to
+	  INT 2A/AH=80h and INT 2A/AH=81h,82h
+SeeAlso: AX=5D06h,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h
+Format of DOS 4.x swappable data area list:
+Offset	Size	Description
+h	WORD	count of data areas
+h  N BYTEs	"count" copies of data area record
+		Offset	Size	Description
+h	DWORD	address
+h	WORD	length and type
+				bit 15 set if swap always, clear if swap in DOS
+				bits 14-0: length in bytes
+Format of DOS 4.0-5.0 swappable data area:
+Offset	Size	Description
+h	BYTE	critical error flag
+h	BYTE	InDOS flag (count of active INT 21 calls)
+h	BYTE	drive on which current critical error occurred or FFh
+h	BYTE	locus of last error
+h	WORD	extended error code of last error
+h	BYTE	suggested action for last error
+h	BYTE	class of last error
+h	DWORD	ES:DI pointer for last error
+Ch	DWORD	current DTA
+h	WORD	current PSP
+h	WORD	stores SP across an INT 23
+h	WORD	return code from last process termination (zerod after reading
+		with AH=4Dh)
+h	BYTE	current drive
+h	BYTE	extended break flag
+h  2 BYTEs	???
+---remainder need only be swapped if in DOS---
+Ah	WORD	value of AX on call to INT 21
+Ch	WORD	PSP segment for sharing/network
+Eh	WORD	network machine number for sharing/network (0000h = us)
+h	WORD	first usable memory block found when allocating memory
+h	WORD	best usable memory block found when allocating memory
+h	WORD	last usable memory block found when allocating memory
+h	WORD	memory size in paragraphs (used only during initialization)
+h	WORD	???
+Ah	BYTE	???
+Bh	BYTE	???
+Ch	BYTE	???
+Dh	BYTE	???
+Eh	BYTE	???
+Fh	BYTE	??? (doesn't seem to be referenced)
+h	BYTE	day of month
+h	BYTE	month
+h	WORD	year - 1980
+h	WORD	number of days since 1-1-1980
+h	BYTE	day of week (0 = Sunday)
+h	BYTE	???
+h	BYTE	???
+h	BYTE	???
+h 30 BYTEs	device driver request header
+h	DWORD	pointer to device driver entry point (used in calling driver)
+Ch 22 BYTEs	device driver request header
+h 30 BYTEs	device driver request header
+h  6	BYTEs	???
+h  6 BYTEs	CLOCK$ transfer record (see AH=52h)
+Ch  2 BYTEs	???
+Eh 128 BYTEs	buffer for filename
+Eh 128 BYTEs	buffer for filename
+Eh 21 BYTEs	findfirst/findnext search data block (see AH=4Eh)
+B3h 32 BYTEs	directory entry for found file
+D3h 88 BYTEs	copy of current directory structure for drive being accessed
+Bh 11 BYTEs	FCB-format filename for device name comparison
+h	BYTE	???
+h 11 BYTEs	wildcard destination specification for rename (FCB format)
+h  2 BYTEs	???
+h	WORD	???
+h  5 BYTEs	???
+Bh	BYTE	extended FCB file attributes
+Ch	BYTE	type of FCB (00h regular, FFh extended)
+Dh	BYTE	directory search attributes
+Eh	BYTE	file open mode
+Fh	BYTE	??? flag bits
+h	BYTE	??? flag or counter
+h	BYTE	??? flag
+h	BYTE	flag indicating how DOS function was invoked
+		(00h = direct INT 20/INT 21, FFh = server call AX=5D00h)
+h	BYTE	???
+h	BYTE	???
+h	BYTE	???
+h	BYTE	???
+h	BYTE	???
+h	BYTE	???
+h	BYTE	???
+Ah	BYTE	canonicalized filename referred to existing file/dir if FFh
+Bh	BYTE	???
+Ch	BYTE	type of process termination (00h-03h)
+Dh	BYTE	???
+Eh	BYTE	???
+Fh	BYTE	???
+h	DWORD	pointer to Drive Parameter Block for critical error invocation
+h	DWORD	pointer to stack frame containing user registers on INT 21
+h	WORD	stores SP???
+Ah	DWORD	pointer to DOS Drive Parameter Block for ???
+Eh	WORD	segment of disk buffer
+h	WORD	???
+h	WORD	???
+h	WORD	???
+h	WORD	???
+h	BYTE	Media ID byte returned by AH=1Bh,1Ch
+h	BYTE	??? (doesn't seem to be referenced)
+Ah	DWORD	pointer to ???
+Eh	DWORD	pointer to current SFT
+h	DWORD	pointer to current directory structure for drive being accessed
+h	DWORD	pointer to caller's FCB
+Ah	WORD	number of SFT to which file being opened will refer
+Ch	WORD	temporary storage for file handle
+Eh	DWORD	pointer to a JFT entry in process handle table (see AH=26h)
+h	WORD	offset in DOS DS of first filename argument
+h	WORD	offset in DOS DS of second filename argument
+h	WORD	???
+h	WORD	???
+Ah	WORD	???
+Ch	WORD	???
+Eh	WORD	???
+A0h	WORD	???
+A2h	WORD	??? directory cluster number???
+A4h	DWORD	???
+A8h	DWORD	???
+ACh	WORD	???
+AEh	DWORD	offset in file???
+B2h	WORD	???
+B4h	WORD	bytes in partial sector
+B6h	WORD	number of sectors
+B8h	WORD	???
+BAh	WORD	???
+BCh	WORD	???
+BEh	DWORD	number of bytes appended to file
+C2h	DWORD	pointer to ??? disk buffer
+C6h	DWORD	pointer to ??? SFT
+CAh	WORD	used by INT 21 dispatcher to store caller's BX
+CCh	WORD	used by INT 21 dispatcher to store caller's DS
+CEh	WORD	temporary storage while saving/restoring caller's registers
+D0h	DWORD	pointer to prev call frame (offset 264h) if INT 21 reentered
+		also switched to for duration of INT 24
+D4h	WORD	open mode/action for INT 21/AX=6C00h
+D6h	BYTE	??? (set to 00h by INT 21h dispatcher, 02h when a read is
+		performed, and 01h or 03h by INT 21/AX=6C00h)
+D7h	WORD	??? apparently unused
+D9h	DWORD	stored ES:DI for AX=6C00h
+DDh	WORD	extended file open action code (see AX=6C00h)
+DFh	WORD	extended file open attributes (see AX=6C00h)
+E1h	WORD	extended file open file mode (see AX=6C00h)
+E3h	DWORD	pointer to filename to open (see AX=6C00h)
+E7h	WORD	???
+E9h	WORD	???
+EBh	BYTE	???
+ECh	WORD	stores DS during call to [List-of-Lists + 37h]
+EEh	WORD	???
+F0h	BYTE	???
+F1h	WORD	??? bit flags
+F3h	DWORD	pointer to user-supplied filename
+F7h	DWORD	pointer to ???
+FBh	WORD	stores SS during call to [List-of-Lists + 37h]
+FDh	WORD	stores SP during call to [List-of-Lists + 37h]
+FFh	BYTE	flag, nonzero if stack switched in calling [List-of-Lists+37h]
+h 21 BYTEs	FindFirst search data for source file(s) of a rename operation
+		(see AH=4Eh)
+h 32 BYTEs	directory entry for file being renamed
+h 331 BYTEs	critical error stack
+h 384 BYTEs	disk stack (functions greater than 0Ch, INT 25,INT 26)
+h 384 BYTEs	character I/O stack (functions 01h through 0Ch)
+h	BYTE	device driver lookahead flag (see AH=64h)
+h	BYTE	??? looks like a drive number
+h	BYTE	??? flag of some kind
+h	BYTE	???
+h	WORD	???
+h	WORD	???
+h	WORD	???
+Ah	WORD	???
+----------215E00-----------------------------
+INT 21 - DOS 3.1+ network - GET MACHINE NAME
+	AX = 5E00h
+	DS:DX -> 16-byte buffer for ASCIZ machine name
+Return: CF clear if successful
+	    CH = validity
+h name invalid
+		nonzero valid
+		    CL = NetBIOS number for machine name
+		    DS:DX buffer filled with blank-paded name
+	CF set on error
+	    AX = error code (01h) (see AH=59h)
+Note:	supported by OS/2 v1.3+ compatibility box, PC-NFS
+SeeAlso: AX=5E01h
+----------215E01CH00-------------------------
+INT 21 - DOS 3.1+ network - SET MACHINE NAME
+	AX = 5E01h
+	CH = 00h undefine name (make it invalid)
+	   <> 0	 define name
+	CL = name number
+	DS:DX -> 15-character blank-padded ASCIZ name
+SeeAlso: AX=5E00h
+----------215E02-----------------------------
+INT 21 - DOS 3.1+ network - SET NETWORK PRINTER SETUP STRING
+	AX = 5E02h
+	BX = redirection list index (see AX=5F02h)
+	CX = length of setup string
+	DS:SI -> setup string
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h) (see AH=59h)
+SeeAlso: AX=5E03h,INT 2F/AX=111Fh
+----------215E03-----------------------------
+INT 21 - DOS 3.1+ network - GET NETWORK PRINTER SETUP STRING
+	AX = 5E03h
+	BX = redirection list index (see AX=5F02h)
+	ES:DI -> 64-byte buffer for setup string
+Return: CF clear if successful
+	    CX = length of setup string
+	    ES:DI buffer filled
+	CF set on error
+	    AX = error code (01h) (see AH=59h)
+SeeAlso: AX=5E02h,INT 2F/AX=111Fh
+----------215E04-----------------------------
+INT 21 - DOS 3.1+ network - SET PRINTER MODE
+	AX = 5E04h
+	BX = redirection list index (see AX=5F02h)
+	DX = mode
+	    bit 0: set if binary, clear if text (tabs expanded to blanks)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	calls INT 2F/AX=111Fh with 5E04h on stack
+SeeAlso: AX=5E05h,INT 2F/AX=111Fh
+----------215E05-----------------------------
+INT 21 - DOS 3.1+ network - GET PRINTER MODE
+	AX = 5E05h
+	BX = redirection list index (see AX=5F02h)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    DX = printer mode (see AX=5E04h)
+Note:	calls INT 2F/AX=111Fh with 5E05h on stack
+SeeAlso: AX=5E04h,INT 2F/AX=111Fh
+----------215F00-----------------------------
+INT 21 - DOS 3.1+ network - GET REDIRECTION MODE
+	AX = 5F00h
+	BL = redirection type
+h printer
+h disk drive
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    BH = redirection state
+h off
+h on
+SeeAlso: AX=5F01h
+----------215F01-----------------------------
+INT 21 - DOS 3.1+ network - SET REDIRECTION MODE
+	AX = 5F01h
+	BL = redirection type
+h printer
+h disk drive
+	BH = redirection state
+h off
+h on
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	when redirection is off, the local device (if any) rather than the
+	  remote device is used
+SeeAlso: AX=5F00h,INT 2F/AX=111Eh
+----------215F02-----------------------------
+INT 21 - DOS 3.1+ network, Banyan VINES, PC-NFS - GET REDIRECTION LIST ENTRY
+	AX = 5F02h
+	BX = redirection list index
+	CX = 0000h (LANtastic)
+	DS:SI -> 16-byte buffer for ASCIZ device name
+	ES:DI -> 128-byte buffer for ASCIZ network name
+Return: CF clear if successful
+	    BH = device status
+h valid
+h invalid
+	    BL = device type
+h printer
+h disk drive
+	    CX = user data previously set with AX=5F03h
+	    DS:SI and ES:DI buffers filled
+	    DX,BP destroyed
+	CF set on error
+	    AX = error code (01h,12h) (see AH=59h)
+Notes:	this function is passed through to INT 2F/AX=111Eh
+	error code 12h is returned if BX is greater than the size of the list
+	also supported by Banyan VINES, PC-NFS, and LANtastic
+SeeAlso: AX=5F03h,INT 2F/AX=111Eh
+----------215F03-----------------------------
+INT 21 - DOS 3.1+ network, Banyan VINES, LANtastic - REDIRECT DEVICE
+	AX = 5F03h
+	BL = device type
+h printer
+h disk drive
+	CX = user data to save
+h for LANtastic
+	DS:SI -> ASCIZ local device name (16 bytes max)
+	ES:DI -> ASCIZ network name + ASCIZ password (128 bytes max total)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h,03h,05h,08h,0Fh,12h) (see AH=59h)
+Note:	if device type is disk drive, DS:SI must point at either a null string
+	  or a string consisting the drive letter followed by a colon; if a
+	  null string, the network attempts to access the destination without
+	  redirecting a local drive
+SeeAlso: AX=5F02h,AX=5F04h,INT 2F/AX=111Eh
+----------215F04-----------------------------
+INT 21 - DOS 3.1+ network, Banyan VINES, LANtastic - CANCEL REDIRECTION
+	AX = 5F04h
+	DS:SI -> ASCIZ device name or path
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (01h,03h,05h,08h,0Fh,12h) (see AH=59h)
+Note:	the DS:SI string must be either a local device name, a drive letter
+	  followed by a colon, or a network directory beginning with two
+	  backslashes
+SeeAlso: AX=5F03h,INT 2F/AX=111Eh
+----------215F05-----------------------------
+INT 21 - DOS 4.x + Microsoft Networks - GET REDIRECTION LIST EXTENDED ENTRY
+	AX = 5F05h
+	BX = redirection list index
+	DS:SI -> buffer for ASCIZ source device name
+	ES:DI -> buffer for destination ASCIZ network path
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    BH = device status flag (bit 0 clear if valid)
+	    BL = device type (03h if printer, 04h if drive)
+	    CX = stored parameter value (user data)
+	    BP = NETBIOS local session number
+	    DS:SI buffer filled
+	    ES:DI buffer filled
+Notes:	the local session number allows sharing the redirector's session number
+	if an error is caused on the NETBIOS LSN, the redirector may be unable
+	  to correctly recover from errors
+SeeAlso: AX=5F06h"Network",INT 2F/AX=111Eh
+----------215F05-----------------------------
+INT 21 - STARLITE architecture - MAP LOCAL DRIVE LETTER TO REMOTE FILE SYSTEM
+	AX = 5F05h
+	DL = drive number (0=A:)
+	DS:SI -> ASCIZ name of the object to map the drive to
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+SeeAlso: AX=5F06h"STARLITE"
+----------215F06-----------------------------
+INT 21 U - Network - GET REDIRECTION LIST???
+	AX = 5F06h
+	???
+Return: ???
+Note:	appears to be similar to AX=5F02h and AX=5F05h
+SeeAlso: AX=5F05h"DOS",INT 2F/AX=111Eh
+----------215F06-----------------------------
+INT 21 - STARLITE architecture - UNMAP DRIVE LETTER
+	AX = 5F06h
+	DL = drive to be unmapped (0=A:)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+SeeAlso: AX=5F05h"STARLITE"
+----------215F07-----------------------------
+INT 21 - DOS 5.0 - ENABLE DRIVE
+	AX = 5F07h
+	DL = drive number (0=A:)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (0Fh) (see AH=59h)
+Note:	simply sets the "valid" bit in the drive's CDS
+SeeAlso: AH=52h,AX=5F08h"DOS"
+----------215F07-----------------------------
+INT 21 - STARLITE architecture - MAKE NAMED OBJECT AVAILABLE ON NETWORK
+	AX = 5F07h
+	DS:SI -> ASCIZ name of object to offer to network
+	ES:DI -> ASCIZ name under which object will be known on the network
+		MUST begin with three slashes
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+SeeAlso: AX=5F08h"STARLITE"
+----------215F08-----------------------------
+INT 21 - DOS 5.0 - DISABLE DRIVE
+	AX = 5F08h
+	DL = drive number (0=A:)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (0Fh) (see AH=59h)
+Note:	simply clears the "valid" bit in the drive's CDS
+SeeAlso: AH=52h,AX=5F07h"DOS"
+----------215F08-----------------------------
+INT 21 - STARLITE architecture - REMOVE GLOBAL NETWORK NAME OF OBJECT
+	AX = 5F08h
+	DS:SI -> ASCIZ network name (not local name) of object to unshare
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+SeeAlso: AX=5F07h"STARLITE"
+----------215F09-----------------------------
+INT 21 - STARLITE architecture - BIND TO NETWORK DEVICE
+	AX = 5F09h
+	DS:DX -> ASCIZ name of the device driver to attach to
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	the STARLITE distributed file system can attach to multiple networks
+	  simultaneously
+SeeAlso: AX=5F0Ah
+----------215F0A-----------------------------
+INT 21 - STARLITE architecture - DETACH FROM NETWORK DEVICE
+	AX = 5F0Ah
+	DS:DX -> ASCIZ name of device driver to detach from
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+SeeAlso: AX=5F09h
+----------215F32-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosQNmPipeInfo
+	AX = 5F32h
+	???
+Return: ???
+SeeAlso: AX=5F33h,AX=5F34h
+----------215F33-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosQNmPHandState
+	AX = 5F33h
+	???
+Return: ???
+SeeAlso: AX=5F32h,AX=5F34h
+----------215F34-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosSetNmPHandState
+	AX = 5F34h
+	???
+Return: ???
+SeeAlso: AX=5F32h,AX=5F33h,AX=5F36h
+----------215F35-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosPeekNmPipe
+	AX = 5F35h
+	???
+Return: ???
+SeeAlso: AX=5F38h,AX=5F39h,AX=5F51h
+----------215F36-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosTransactNmPipe
+	AX = 5F36h
+	???
+Return: ???
+SeeAlso: AX=5F34h,AX=5F37h
+----------215F37-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosCallNmPipe
+	AX = 5F37h
+	???
+Return: ???
+SeeAlso: AX=5F36h,AX=5F38h
+----------215F38-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosWaitNmPipe
+	AX = 5F38h
+	???
+Return: ???
+SeeAlso: AX=5F37h,AX=5F39h
+----------215F39-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosRawReadNmPipe
+	AX = 5F39h
+	???
+Return: ???
+SeeAlso: AX=5F35h,AX=5F3Ah,INT 2F/AX=1186h
+----------215F3A-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosRawWriteNmPipe
+	AX = 5F3Ah
+	???
+Return: ???
+SeeAlso: AX=5F3Bh,INT 2F/AX=118Fh
+----------215F3B-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetHandleSetInfo
+	AX = 5F3Bh
+	???
+Return: ???
+SeeAlso: AX=5F3Ch
+----------215F3C-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetHandleGetInfo
+	AX = 5F3Ch
+	???
+Return: ???
+SeeAlso: AX=5F3Bh
+----------215F40-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetMessageBufferSend
+	AX = 5F40h
+	???
+Return: ???
+----------215F42-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetServiceControl
+	AX = 5F42h
+	???
+Return: ???
+----------215F44-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetWkstaGetInfo
+	AX = 5F44h
+	???
+Return: ???
+SeeAlso: AX=5F45h,AX=5F49h
+----------215F45-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetWkstaSetInfo
+	AX = 5F45h
+	???
+Return: ???
+SeeAlso: AX=5F44h
+----------215F46-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetUseEnum
+	AX = 5F46h
+	???
+Return: ???
+SeeAlso: AX=5F47h,AX=5F48h,AX=5F4Ch
+----------215F47-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetUseAdd
+	AX = 5F47h
+	???
+Return: ???
+SeeAlso: AX=5F46h,AX=5F48h
+----------215F48-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetUseDel
+	AX = 5F48h
+	???
+Return: ???
+SeeAlso: AX=5F46h,AX=5F48h,AX=5F49h
+----------215F49-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetUseGetInfo
+	AX = 5F49h
+	???
+Return: ???
+SeeAlso: AX=5F44h,AX=5F47h
+----------215F4A-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetRemoteCopy
+	AX = 5F4Ah
+	???
+Return: ???
+SeeAlso: AX=5F4Bh
+----------215F4B-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetRemoteMove
+	AX = 5F4Bh
+	???
+Return: ???
+SeeAlso: AX=5F4Ah
+----------215F4C-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetServerEnum
+	AX = 5F4Ch
+	???
+Return: ???
+SeeAlso: AX=5F53h
+----------215F4D-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosMakeMailslot
+	AX = 5F4Dh
+	???
+Return: ???
+SeeAlso: AX=5F4Eh,AX=5F4Fh,AX=5F50h,AX=5F51h
+----------215F4E-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosDeleteMailslot
+	AX = 5F4Eh
+	???
+Return: ???
+SeeAlso: AX=5F4Dh,AX=5F4Fh
+----------215F4F-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosMailslotInfo
+	AX = 5F4Fh
+	???
+Return: ???
+SeeAlso: AX=5F4Dh,AX=5F4Eh,AX=5F50h
+----------215F50-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosReadMailslot
+	AX = 5F50h
+	???
+Return: ???
+SeeAlso: AX=5F4Dh,AX=5F4Fh,AX=5F51h,AX=5F52h
+----------215F51-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosPeekMailslot
+	AX = 5F51h
+	???
+Return: ???
+SeeAlso: AX=5F35h,AX=5F4Fh,AX=5F50h,AX=5F52h
+----------215F52-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - DosWriteMailslot
+	AX = 5F52h
+	???
+Return: ???
+SeeAlso: AX=5F4Fh,AX=5F50h,AX=5F51h
+----------215F53-----------------------------
+INT 21 - LAN Manager Enhanced DOS API local interface - NetServerEnum2
+	AX = 5F53h
+	???
+Return: ???
+SeeAlso: AX=5F4Ch
+----------215F80-----------------------------
+INT 21 - LANtastic - GET LOGIN ENTRY
+	AX = 5F80h
+	BX = login entry index (0-based)
+	ES:DI -> 16-byte buffer for machine name
+Return: CF clear if successful
+	    buffer filled with machine name ("\\" prefix removed)
+	    DL = adapter number (v3+)
+	CF set on error
+	    AX = error code
+Note:	the login entry index corresponds to the value BX used in AX=5F83h
+SeeAlso: AX=58F3h
+----------215F81-----------------------------
+INT 21 - LANtastic - LOGIN TO SERVER
+	AX = 5F81h
+	ES:DI -> ASCIZ login path followed immediately by ASCIZ password
+	BL = adapter number
+	    FFh try all valid adapters
+h-07h try only specified adapter
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Notes:	login path is of form "\\machine\username"
+	if no password is used, the string at ES:DI must be terminated with
+	  three NULs for compatibility with LANtastic v3.0.
+SeeAlso: AX=5F82h,AX=5F84h
+----------215F82-----------------------------
+INT 21 - LANtastic - LOGOUT FROM SERVER
+	AX = 5F82h
+	ES:DI -> ASCIZ server name (in form "\\machine")
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F81h,AX=5F88h,AX=5FCBh
+----------215F83-----------------------------
+INT 21 - LANtastic - GET USERNAME ENTRY
+	AX = 5F83h
+	BX = login entry index (0-based)
+	ES:DI -> 16-byte buffer for username currently logged into
+Return: CF clear if successful
+	    DL = adapter number (v3+)
+	CF set on error
+	    AX = error code
+Note:	the login entry index corresponds to the value BX used in AX=5F80h
+SeeAlso: AX=5F80h
+----------215F84-----------------------------
+INT 21 - LANtastic - GET INACTIVE SERVER ENTRY
+	AX = 5F84h
+	BX = server index not currently logged into
+	ES:DI -> 16-byte buffer for server name which is available for logging
+		in to ("\\" prefix omitted)
+Return: CF clear if successful
+	    DL = adapter number to non-logged in server is on
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F81h
+----------215F85-----------------------------
+INT 21 - LANtastic - CHANGE PASSWORD
+	AX = 5F85h
+	ES:DI -> buffer containing "\\machine\oldpassword" 00h "newpassword"00h
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Notes:	must be logged into the named machine
+	this function is illegal for group accounts
+----------215F86-----------------------------
+INT 21 - LANtastic - DISABLE ACCOUNT
+	AX = 5F86h
+	ES:DI -> ASCIZ machine name and password in form "\\machine\password"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	must be logged into the named machine and concurrent logins set to 1
+	  by NET_MGR.  Requires system manager to re-enable account.
+----------215F87-----------------------------
+INT 21 - LANtastic v3+ - GET ACCOUNT
+	AX = 5F87h
+	DS:SI -> 128-byte buffer for account information (see below)
+	ES:DI -> ASCIZ machine name in form "\\machine"
+Return:	CF clear if successful
+	CF set on error
+	    AX = error code
+	BX destroyed
+Note:	must be logged into the specified machine
+Format of user account structure:
+Offset	Size	Description
+h 16 BYTEs	blank-padded username (zero-padded for v4.x)
+h 16 BYTEs	reserved (00h)
+h 32 BYTEs	user description
+h	BYTE	privilege bits
+		bit 7: bypass access control lists
+: bypass queue protection
+: treat as local process
+: bypass mail protection
+: allow audit entry creation
+: system manager
+: user cannot change password
+h	BYTE	maximum concurrent users
+h 42 BYTEs	bit map for disallowed half hours, beginning on Sunday
+		(bit set if half-hour not an allowed time)
+Ch	WORD	internal (0002h)
+Eh  2 WORDs	last login time
+h  2 WORDs	account expiration date (MSDOS-format year/month:day)
+h  2 WORDs	password expiration date (0 = none)
+Ah	BYTE	number of days to extend password after change (1-31)
+h if no extension required
+---v3.x---
+Bh  5 BYTEs	reserved
+---v4.x---
+Bh	BYTE	storage for first letter of user name when deleted (first
+ 		character is changed to 00h when deleting account)
+Ch	BYTE	extended privileges
+Dh  3 BYTEs	reserved
+----------215F88-----------------------------
+INT 21 - LANtastic v4.0+ - LOGOUT FROM ALL SERVERS
+	AX = 5F88h
+Return:	CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F82h
+----------215F97-----------------------------
+INT 21 - LANtastic - COPY FILE
+	AX = 5F97h
+	CX:DX = number of bytes to copy (FFFFFFFFh = entire file)
+	SI = source file handle
+	DI = destination file handle
+Return: CF clear if successful
+	    DX:AX = number of bytes copied
+	CF set on error
+	    AX = error code
+Note:	copy is performed by server
+----------215F98-----------------------------
+INT 21 - LANtastic - SEND UNSOLICITED MESSAGE
+	AX = 5F98h
+	DS:SI -> message buffer (see below)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	v4.1- return no errors
+SeeAlso: AX=5F99h
+Format of message buffer:
+Offset	Size	Description
+h	BYTE	reserved
+h	BYTE	message type
+h general
+h server warning
+h-7Fh reserved
+h-FFh user-defined
+h 16 BYTEs	ASCIZ destination machine name
+h 16 BYTEs	ASCIZ server name which user must be logged into
+h 16 BYTEs	ASCIZ user name
+h 16 BYTEs	ASCIZ originating machine name (filled in when received)
+h 80 BYTEs	message text
+----------215F99-----------------------------
+INT 21 - LANtastic - GET LAST RECEIVED UNSOLICITED MESSAGE
+	AX = 5F99h
+	ES:DI -> messsage buffer (see AX=5F98h for format)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F98h
+----------215F9A-----------------------------
+INT 21 - LANtastic - GET MESSAGE PROCESSING FLAGS
+	AX = 5F9Ah
+Return: CF clear if successful
+	    DL = bits describing processing for received unsolicited messages
+		bit 0: beep before message is delivered
+: deliver message to message service
+: pop up message automatically (v3+)
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F9Bh,AX=5F9Ch,AX=5F9Dh
+----------215F9B-----------------------------
+INT 21 - LANtastic - SET MESSAGE PROCESSING FLAG
+	AX = 5F9Bh
+	DL = bits describing processing for received unsolicited messages
+	     (see AX=5F9Ah)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F9Ah,AX=5F9Eh
+----------215F9C-----------------------------
+INT 21 - LANtastic v3+ - POP UP LAST RECEIVED MESSAGE
+	AX = 5F9Ch
+	CX = time to leave on screen in clock ticks
+	DH = 0-based screen line on which to place message
+Return:	CF clear if successful
+	CF set on error
+	    AX = error code (0Bh)
+Notes:	the original screen contents are restored when the message is removed
+	the message will not appear, and an error will be returned, if the
+	  screen is in a graphics mode
+SeeAlso: AX=5F9Ah
+----------215F9D-----------------------------
+INT 21 - LANtastic v4.1+ - GET REDIRECTOR CONTROL BITS
+	AX = 5F9Dh
+Return:	DL = redirector control bits
+		bit 7: set to notify on print job completion
+SeeAlso: AX=5F9Ah,AX=5F9Eh
+----------215F9E-----------------------------
+INT 21 - LANtastic v4.1+ - SET REDIRECTOR CONTROL BITS
+	AX = 5F9Eh
+	DL = redirector control bits (see AH = 5F9Dh)
+Return: nothing
+SeeAlso: AX=5F9Bh,AX=5F9Dh
+----------215FA0-----------------------------
+INT 21 - LANtastic - GET QUEUE ENTRY
+	AX = 5FA0h
+	BX = queue entry index (0000h is first entry)
+	DS:SI -> buffer for queue entry (see below)
+	ES:DI -> ASCIZ server name in form "\\name"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+	BX = entry index for next queue entry (BX-1 is current index)
+SeeAlso: AX=5FA1h,AX=5FA2h
+Format of queue entry:
+Offset	Size	Description
+h	BYTE	status of entry
+h empty
+h being updated
+h being held
+h waiting for despool
+h being despooled
+h canceled
+h spooled file could not be accessed
+h destination could not be accessed
+h rush job
+h	DWORD	size of spooled file
+h	BYTE	type of entry
+h printer queue file
+h message
+h local file
+h remote file
+h to remote modem
+h batch processor file
+h	BYTE	output control
+		bit 6: don't delete (for mail)
+		bit 5: mail file contains voice mail (v3+)
+		bit 4: mail message has been read
+		bit 3: response has been requested for this mail
+h	WORD	number of copies
+h	DWORD	sequence number of queue entry
+Dh 48 BYTEs	pathname of spooled file
+Dh 16 BYTEs	user who spooled file
+Dh 16 BYTEs	name of machine from which file was spooled
+Dh	WORD	date file was spooled (see AX=5700h)
+Fh	WORD	time file was spooled (see AX=5700h)
+h 17 BYTEs	ASCIZ destination device or user name
+h 48 BYTEs	comment field
+----------215FA1-----------------------------
+INT 21 - LANtastic - SET QUEUE ENTRY
+	AX = 5FA1h
+	BX = handle of opened queue entry
+	DS:SI -> queue entry (see AX=5FA0h)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Notes:	the only queue entry fields which may be changed are output control,
+	  number of copies, destination device, and comment
+	the handle in BX is that from a create or open (INT 21/AH=3Ch,3Dh)
+	  call on the file "\\server\\@MAIL" or "\\server\@name" (for
+	  printer queue entries)
+SeeAlso: AX=5FA0h,AX=5FA2h,AX=5FA9h
+----------215FA2-----------------------------
+INT 21 - LANtastic - CONTROL QUEUE
+	AX = 5FA2h
+	BL = control command
+h start despooling (privileged)
+h halt despooling (privileged)
+h halt despooling at end of job (privileged)
+h pause despooler at end of job (privileged)
+h print single job (privileged)
+h restart current job (privileged)
+h cancel the current job
+h hold queue entry
+h release a held queue entry
+h make queue entry a rushed job (privileged)
+	CX:DX = sequence number to control (commands 06h-09h)
+	DX = physical printer number (commands 00h-05h)
+h-02h LPT1-LPT3
+h,04h COM1,COM2
+	    other	all printers
+	ES:DI -> ASCIZ server name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+----------215FA3-----------------------------
+INT 21 - LANtastic v3+ - GET PRINTER STATUS
+	AX = 5FA3h
+	BX = physical printer number (00h-02h = LPT1-LPT3, 03h-04h = COM1-COM2)
+	DS:SI -> buffer for printer status (see below)
+	ES:DI -> ASCIZ server name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+	BX = next physical printer number
+Note:	you must be logged in to the specified server
+Format of printer status:
+Offset	Size	Description
+h	BYTE	printer state
+		bit 7: printer paused
+		bits 0-6: 0 printer disabled
+will stop at end of job
+print multiple jobs
+h	WORD	queue index of print job being despooled
+		FFFFh if not despooling--ignore all following fields
+h	WORD	actual characters per second being output
+h	DWORD	number of characters actually output so far
+h	DWORD	number of bytes read from spooled file so far
+Dh	WORD	copies remaining to print
+----------215FA4-----------------------------
+INT 21 - LANtastic v3+ - GET STREAM INFO
+	AX = 5FA4h
+	BX = 0-based stream index number
+	DS:SI -> buffer for stream information (see below)
+	ES:DI -> ASCIZ machine name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+	BX = next stream number
+SeeAlso: AX=5FA5h
+Format of stream information:
+Offset	Size	Description
+h	BYTE	queueing of jobs for logical printer (0=disabled,other=enabled)
+h 11 BYTEs	logical printer resource template (may contain ? wildcards)
+----------215FA5-----------------------------
+INT 21 - LANtastic v3+ - SET STREAM INFO
+	AX = 5FA5h
+	BX = 0-based stream index number
+	DS:SI -> buffer containing stream information (see AX=5FA4h)
+	ES:DI -> ASCIZ machine name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5FA4h
+----------215FA7-----------------------------
+INT 21 - LANtastic - CREATE USER AUDIT ENTRY
+	AX = 5FA7h
+	DS:DX -> ASCIZ reason code (max 8 bytes)
+	DS:SI -> ASCIZ variable reason string (max 128 bytes)
+	ES:DI -> ASCIZ machine name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	you must be logged in to the specified server and have the "U"
+	  privilege to execute this call
+----------215FA9-----------------------------
+INT 21 - LANtastic v4.1+ - SET EXTENDED QUEUE ENTRY
+	AX = 5FA9h
+	BX = handle of opened queue entry
+	DS:SI -> queue entry (see AX=5FA0h)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	functions exactly the same as AX=5FA1h except the spooled filename is
+	  also set.  This call supports	direct despooling.
+SeeAlso: AX=5FA1h
+----------215FB0-----------------------------
+INT 21 - LANtastic - GET ACTIVE USER INFORMATION
+	AX = 5FB0h
+	BX = server login entry index
+	DS:SI -> buffer for active user entry (see below)
+	ES:DI -> ASCIZ machine name in form "\\server"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+	BX = next login index
+Format of active user entry:
+Offset	Size	Description
+h	WORD	virtual circuit number
+h	BYTE	login state
+		bit 0: fully logged in
+: remote program load login
+: user has system manager privileges
+: user can create audit entries
+: bypass mail protection
+: treat as local process
+: bypass queue protection
+: bypass access control lists
+h	BYTE	last command issued (see below)
+h  5 BYTEs	number of I/O bytes (40-bit unsigned number)
+h  3 BYTEs	number of server requests (24-bit unsigned)
+Ch 16 BYTEs	name of user who is logged in
+Ch 16 BYTEs	name of remote logged in machine
+Ch	BYTE	extended privileges (v4+???)
+ 		bit 0: user cannot change his password
+Dh	WORD	time left in minutes (0000h = unlimited) (v4+???)
+Values for last command:
+h	login
+h	process termination
+h	open file
+h	close file
+h	create file
+h	create new file
+h	create unique file
+h	commit data to disk
+h	read file
+h	write file
+Ah	delete file
+Bh	set file attributes
+Ch	lock byte range
+Dh	unlock byte range
+Eh	create subdirectory
+Fh	remove subdirectory
+h	rename file
+h	find first matching file
+h	find next matching file
+h	get disk free space
+h	get a queue entry
+h	set a queue entry
+h	control the queue
+h	return login information
+h	return link description
+h	seek on file
+Ah	get server's time
+Bh	create audit entry
+Ch	open file in multitude of modes
+Dh	change password
+Eh	disable account
+Fh	local server file copy
+---v3+---
+h	get username from account file
+h	translate server's logical path
+h	make indirect file
+h	get indirect file contents
+h	get physical printer status
+h	get logical print stream info
+h	set logical print stream info
+h	get user's account record
+---v4+---
+h	request server shutdown
+h	cancel server shutdown
+Ah	stuff server's keyboard
+Bh	write then commit data to disk
+Ch	set extended queue entry
+Dh	terminate user from server
+Eh	enable/disable logins
+Fh	flush server caches
+h	change username
+h	get extended queue entry
+	(same as get queue, but can return named fields blanked)
+----------215FB1-----------------------------
+INT 21 - LANtastic - GET SHARED DIRECTORY INFORMATION
+	AX = 5FB1h
+	DS:SI -> 64-byte buffer for link description
+	ES:DI -> ASCIZ machine and shared directory name in form
+		 "\\machine\shared-resource"
+Return: CF clear if successful
+	    CX = access control list privilege bits for requesting user
+	        bit 4: (I) allow expansion of indirect files
+: (A) allow attribute changing
+: (P) allow physical access to device
+: (E) allow program execution
+: (N) allow file renaming
+: (K) allow directory deletion
+: (D) allow file deletion
+: (L) allow file/directory lookups
+: (M) allow directory creation
+: (C) allow file creation
+: (W) allow open for write and writing
+: (R) allow open for read and reading
+	CF set on error
+	    AX = error code
+----------215FB2-----------------------------
+INT 21 - LANtastic v3+ - GET USERNAME FROM ACCOUNT FILE
+	AX = 5FB2h
+	BX = username entry index (0 for first)
+	DS:SI -> 16-byte buffer for username
+	ES:DI -> ASCIZ server name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+	BX = next queue entry index
+----------215FB3-----------------------------
+INT 21 - LANtastic v3+ - TRANSLATE PATH
+	AX = 5FB3h
+	DS:SI -> 128-byte buffer for ASCIZ result
+	ES:DI -> full ASCIZ path, including server name
+	DX = types of translation to be performed
+	    bit 0: expand last component as indirect file
+: return actual path relative to server's physical disk
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	always expands any indirect files along the path
+SeeALso: AX=5FB4h
+----------215FB4-----------------------------
+INT 21 - LANtastic v3+ - CREATE INDIRECT FILE
+	AX = 5FB4h
+	DS:SI -> 128-byte buffer containing ASCIZ contents of indirect file
+	ES:DI -> full ASCIZ path of indirect file to create, incl machine name
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	the contents of the indirect file may be any valid server-relative path
+----------215FB5-----------------------------
+INT 21 - LANtastic v3+ - GET INDIRECT FILE CONTENTS
+	AX = 5FB5h
+	DS:SI -> 128-byte buffer for ASCIZ indirect file contents
+	ES:DI -> full ASCIZ path of indirect file
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+----------215FB6-----------------------------
+INT 21 - LANtastic v4.1+ - SET AUTO-LOGIN DEFAULTS
+	AX = 5FB6h
+	ES:DI -> pointer to ASCIZ default user name, immediately followed by
+		ASCIZ password
+	BL = adapter number to use for default login attempt
+	    FFh try all valid adapters
+h-05h try adapter 0-5 explicitly
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Notes:	call with ES:DI -> two nulls to disable auto-login
+SeeAlso: AX=5FB7h
+----------215FB7-----------------------------
+INT 21 - LANtastic v4.1+ - GET AUTO-LOGIN DEFAULTS
+	AX = 5FB7h
+	ES:DI -> pointer to 16-byte buffer to store ASCIZ auto-login user name
+Return: CF clear if successful
+	    DL = adapter number used for default login attempt
+		FFh all valid adapters will be tried
+h-05h specified adapter will be tried explicitly
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5F81h,AX=5FB6h
+----------215FC0-----------------------------
+INT 21 - LANtastic - GET TIME FROM SERVER
+	AX = 5FC0h
+	DS:SI -> time block (see below)
+	ES:DI -> ASCIZ server name to get time from
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Format of time block:
+Offset	Size	Description
+h	WORD	year
+h	BYTE	day
+h	BYTE	month
+h	BYTE	minutes
+h	BYTE	hour
+h	BYTE	hundredths of second
+h	BYTE	second
+----------215FC8-----------------------------
+INT 21 - LANtastic v4.0+ - SCHEDULE SERVER SHUTDOWN
+	AX = 5FC8h
+	ES:DI -> ASCIZ server name in form "\\machine"
+	DS:SI -> ASCIZ reason string (80 characters)
+	CX = number of minutes until shutdown (0 = immediate)
+	DX = option flags (see below)
+	    bit 0: auto reboot
+: do not notify users
+: halt after shutdown
+: shutdown due to power fail (used by UPS)
+	    bits 4-7: reserved
+	    bits 8-14: user definable
+	    bit 15: reserved
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AH=5FC9h
+----------215FC9-----------------------------
+INT 21 - LANtastic v4.0+ - CANCEL SERVER SHUTDOWN
+	AX = 5FC9h
+	ES:DI -> ASCIZ server name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	you must have the "S" privilege to use this call
+SeeAlso: AH=5FC8h
+----------215FCA-----------------------------
+INT 21 - LANtastic v4.0+ - STUFF SERVER KEYBOARD BUFFER
+	AX = 5FCAh
+	ES:DI -> ASCIZ server name in form "\\machine"
+	DS:SI -> ASCIZ string to stuff (128 bytes)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	you must have the "S" privilege to use this call
+	maximum number of characters that can be stuffed is determined by the
+	  server's RUN BUFFER SIZE.
+----------215FCB-----------------------------
+INT 21 - LANtastic v4.1+ - TERMINATE USER
+	AX = 5FCBh
+	ES:DI -> ASCIZ server name in form "\\machine"
+	DS:SI -> blank-padded username.	 A null char = wildcard.
+	DS:DX -> blank-padded machine name.  A null char = wildcard.
+	CX = minutes until termination (0 = immediate)
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	you must have the "S" privilege to use this call
+	you cannot log yourself out using this call
+SeeAlso: AX=5F82h
+----------215FCC-----------------------------
+INT 21 - LANtastic v4.1+ - GET/SET SERVER CONTROL BITS
+	AX = 5FCCh
+	ES:DI -> ASCIZ server name in form "\\machine"
+	CX = bit values (value of bits you want to set)	 See below.
+	DX = bit mask (bits you are interested in, 0 = get only)  See
+below.
+Return: CF clear if successful
+	    CX = control bits after call
+		bit 0: disable logins
+	CF set on error
+	    AX = error code
+Note:	you must have the "S" privilege to SET, anyone can GET.
+----------215FCD-----------------------------
+INT 21 - LANtastic v4.1+ - FLUSH SERVER CACHES
+	AX = 5FCDh
+	ES:DI -> ASCIZ server name in form "\\machine"
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	you must have the "S" privilege to use this call.
+----------215FD0-----------------------------
+INT 21 - LANtastic - GET REDIRECTED PRINTER TIMEOUT
+	AX = 5FD0h
+Return: CF clear if successful
+	    CX = redirected printer timeout in clock ticks of 55ms
+h if timeout disabled
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5FD1h
+----------215FD1-----------------------------
+INT 21 - LANtastic - SET REDIRECTED PRINTER TIMEOUT
+	AX = 5FD1h
+	CX = printer timeout in clock ticks of 55ms, 0000h to disable timeouts
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5FD0h
+----------215FE0-----------------------------
+INT 21 - LANtastic - GET DOS SERVICE VECTOR
+	AX = 5FE0h
+Return: CF clear if successful
+	    ES:BX -> current FAR service routine
+	CF set on error
+	    AX = error code
+Note:	the service routine is called by the LANtastic redirector whenever DOS
+	  may safely be called, permitting external TSRs and drivers to hook
+	  into LANtastic's DOS busy flag checking
+SeeAlso: AX=5FE1h,INT 28,INT 2A/AH=84h
+----------215FE1-----------------------------
+INT 21 - LANtastic - SET DOS SERVICE VECTOR
+	AX = 5FE1h
+	ES:BX -> FAR routine to call when DOS services are available
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Note:	new handler must chain to previous handler as its first action
+SeeAlso: AX=5FE0h
+----------215FE2-----------------------------
+INT 21 - LANtastic - GET MESSAGE SERVICE VECTOR
+	AX = 5FE2h
+Return: CF clear if successful
+	    ES:BX -> current FAR message service routine
+	CF set on error
+	    AX = error code
+SeeAlso: AX=5FE3h
+----------215FE3-----------------------------
+INT 21 - LANtastic - SET MESSAGE SERVICE VECTOR
+	AX = 5FE3h
+	ES:BX -> FAR routine for processing network messages
+Return: CF clear if successful
+	CF set on error
+	    AX = error code
+Notes:	handler must chain to previous handler as its first action
+	on invocation, ES:BX -> just-received message
+SeeAlso: AX=5FE2h
+----------2160-------------------------------
+INT 21 - DOS 3.0+ - CANONICALIZE FILENAME OR PATH
+	AH = 60h
+	DS:SI -> ASCIZ filename or path
+	ES:DI -> 128-byte buffer for canonicalized name
+Return: CF set on error
+	    AX = error code
+h invalid component in directory path or drive letter only
+h malformed path or invalid drive letter
+	    ES:DI buffer unchanged
+	CF clear if successful
+	    AH = 00h
+	    AL = destroyed (00h or 5Ch or last char of current dir on drive)
+	    buffer filled with qualified name of form D:\PATH\FILE.EXT or
+	      \\MACHINE\PATH\FILE.EXT
+Notes:	the input path need not actually exist
+	letters are uppercased, forward slashes converted to backslashes,
+	  asterisks converted to appropriate number of question marks, and
+	  file and directory names are truncated to 8.3 if necessary.
+	'.' and '..' in the path are resolved
+	filespecs on local drives always start with "d:", those on network
+	  drives always start with "\\"
+	if path string is on a JOINed drive, the returned name is the one that
+	  would be needed if the drive were not JOINed; similarly for a
+	  SUBSTed, ASSIGNed, or network drive letter.	Because of this, it is
+	  possible to get a qualified name that is not legal under the current
+	  combination of SUBSTs, ASSIGNs, JOINs, and network redirections
+	under DOS 3.3 through 5.00, a device name is translated differently if
+	  the device name does not have an explicit directory or the directory
+	  is \DEV (relative directory DEV from the root directory works
+	  correctly).  In these cases, the returned string consists of the
+	  unchanged device name and extension appended to the string X:/
+	  (forward slash instead of backward slash as in all other cases) where
+	  X is the default or explicit drive letter.
+	functions which take pathnames require canonical paths if invoked via
+	  INT 21/AX=5D00h
+	supported by OS/2 v1.1 compatibility box
+	NetWare 2.1x does not support characters with the high bit set; early
+	  versions of NetWare 386 support such characters except in this call.
+	  In addition, NetWare returns error code 3 for the path "X:\"; one
+	  should use "X:\." instead.
+	for DOS 3.3-5.0, the input and output buffers may be the same, as the
+	  canonicalized name is built in an internal buffer and copied to the
+	  specified output buffer as the very last step
+SeeAlso: INT 2F/AX=1123h,INT 2F/AX=1221h
+----------2161-------------------------------
+INT 21 - DOS 3+ - UNUSED
+	AH = 61h
+Return: AL = 00h
+Note:	this function does nothing and returns immediately
+----------2162-------------------------------
+INT 21 - DOS 3+ - GET CURRENT PSP ADDRESS
+	AH = 62h
+Return: BX = segment of PSP for current process
+Notes:	under DOS 3+, this function does not use any of the DOS-internal stacks
+	  and may thus be called at any time, even during another INT 21h call
+	the current PSP is not necessarily the caller's PSP
+	identical to the undocumented AH=51h
+SeeAlso: AH=50h,AH=51h
+----------216300-----------------------------
+INT 21 - DOS 2.25 only - GET LEAD BYTE TABLE ADDRESS
+	AX = 6300h
+Return: CF clear if successful
+	    DS:SI -> lead byte table (see below for format)
+	CF set on error
+	    AX = error code (01h) (see AH=59h)
+Notes:	does not preserve any registers other than SS:SP
+	the US version of MSDOS 3.30 treats this as an unused function,
+	  setting AL=00h and returning immediately
+SeeAlso: AX=6301h,AH=07h,AH=08h,AH=0Bh
+Format of lead byte table entry:
+Offset	Size	Description
+h  2 BYTEs	low/high ends of a range of leading byte of double-byte chars
+h  2 BYTEs	low/high ends of a range of leading byte of double-byte chars
+	...
+  N   2 BYTEs	00h,00h end flag
+----------216300-----------------------------
+INT 21 - Asian DOS 3.2+ - GET DOUBLE BYTE CHARACTER SET LEAD TABLE
+	AX = 6300h
+Return: AL = error code
+h successful
+		DS:SI -> DBCS table (see below)
+		all other registers except CS:IP and SS:SP destroyed
+	    FFh not supported
+Notes:	probably identical to AH=63h/AL=00h for DOS 2.25
+	the US version of MSDOS 3.30 treats this as an unused function,
+	  setting AL=00h and returning immediately
+	the US version of DOS 4.0+ accepts this function, but returns an empty
+	  list
+SeeAlso: AX=6300h"DOS 2.25"
+Format of DBCS table:
+Offset	Size	Description
+h  2 BYTEs	low/high ends of a range of leading byte of double-byte chars
+h  2 BYTEs	low/high ends of a range of leading byte of double-byte chars
+	...
+  N   2 BYTEs	00h,00h end flag
+----------216301-----------------------------
+INT 21 - DOS 2.25, Asian DOS 3.2+ - SET KOREAN (HONGEUL) INPUT MODE
+	AX = 6301h
+	DL = new mode
+h return only full characters on DOS keyboard input functions
+h	return partially-formed characters also
+Return: AL = status
+h successful
+	    FFh invalid mode
+SeeAlso: AH=07h,AH=08h,AH=0Bh,AH=63h,AX=6302h
+----------216302-----------------------------
+INT 21 - DOS 2.25, Asian DOS 3.2+ - GET KOREAN (HONGEUL) INPUT MODE
+	AX = 6302h
+Return: AL = status
+h successful
+		DL = current input mode
+h return only full characters
+h return partial characters
+	    FFh not supported
+SeeAlso: AH=07h,AH=08h,AH=0Bh,AH=63h,AX=6301h
+----------2164-------------------------------
+INT 21 - DOS 3.2+ internal - SET DEVICE DRIVER LOOKAHEAD FLAG
+	AH = 64h
+	AL = flag
+h (default) call device driver function 5 (non-dest read)
+			before INT 21/AH=01h,08h,0Ah
+	    nonzero don't call driver function 5
+Return: nothing
+Notes:	called by DOS 3.3+ PRINT.COM
+	does not use any of the DOS-internal stacks and is thus fully
+	  reentrant
+SeeAlso: AH=01h,AH=08h,AH=0Ah,AX=5D06h
+----------2164--BX0000-----------------------
+INT 21 - OS/2 v2.0 Virtual DOS Machine - GET/SET TASK TITLE
+	AH = 64h
+	BX = 0000h
+	CX = 636Ch
+	DX = function
+h enable automatic title switch on INT 21/AH=4Bh
+h set session title
+	    	ES:DI -> new ASCIZ title or "" to restore original title
+h get session title
+	    	ES:DI -> buffer for current title
+	    	Return: buffer filled (single 00h if title never changed)
+SeeAlso: INT 15/AH=12h/BH=05h,INT 21/AH=4Bh
+----------2165-------------------------------
+INT 21 - DOS 3.3+ - GET EXTENDED COUNTRY INFORMATION
+	AH = 65h
+	AL = info ID
+h get general internationalization info
+h get pointer to uppercase table
+h get pointer to filename uppercase table
+h get pointer to filename terminator table
+h get pointer to collating sequence table
+h (DOS 4+) get pointer to Double-Byte Character Set table
+	BX = code page (-1=global code page)
+	DX = country ID (-1=current country)
+	ES:DI -> country information buffer (see below)
+	CX = size of buffer (>= 5)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if succesful
+	    CX = size of country information returned
+	    ES:DI -> country information
+Notes:	AL=05h appears to return same info for all countries and codepages; it
+	  has been documented for DOS 5.0, but was undocumented in ealier
+	  versions
+	NLSFUNC must be installed to get info for countries other than the
+	  default
+	subfunctions 02h and 04h are identical under OS/2
+SeeAlso: AH=38h,INT 2F/AX=1401h,INT 2F/AX=1402h
+Format of country information:
+Offset	Size	Description
+h	BYTE	info ID
+---if info ID = 01h---
+h	WORD	size
+h	WORD	country ID
+h	WORD	code page
+h 34 BYTEs	country-dependent info (see AH=38h)
+---if info ID = 02h---
+h	DWORD	pointer to uppercase table (see below)
+---if info ID = 04h---
+h	DWORD	pointer to filename uppercase table (see below)
+---if info ID = 05h---
+h	DWORD	pointer to filename character table (see below)
+---if info ID = 06h---
+h	DWORD	pointer to collating table (see below)
+---if info ID = 07h (DOS 4+)---
+h	DWORD	pointer to DBCS lead byte table (see below)
+Format of uppercase table:
+Offset	Size	Description
+h	WORD	table size
+h 128 BYTEs	uppercase equivalents (if any) of chars 80h to FFh
+Format of collating table:
+Offset	Size	Description
+h	WORD	table size
+h 256 BYTEs	values used to sort characters 00h to FFh
+Format of filename terminator table:
+Offset	Size	Description
+h	WORD	table size (not counting this word)
+h	BYTE	??? (01h for MSDOS 3.30-5.00)
+h	BYTE	lowest permissible character value for filename
+h	BYTE	highest permissible character value for filename
+h	BYTE	??? (00h for MSDOS 3.30-5.00)
+h	BYTE	first excluded character in range \ all characters in this
+h	BYTE	last excluded character in range  / range are illegal
+h	BYTE	??? (02h for MSDOS 3.30-5.00)
+h	BYTE	number of illegal (terminator) characters
+Ah  N BYTES	characters which terminate a filename:	."/\[]:|<>+=;,
+Note:	partially documented for DOS 5.0, but undocumented for earlier versions
+Format of filename uppercase table:
+Offset	Size	Description
+h	WORD	table size
+h 128 BYTEs	uppercase equivalents (if any) of chars 80h to FFh
+Format of DBCS lead byte table:
+Offset	Size	Description
+h	WORD	length
+h 2N BYTEs	start/end for N lead byte ranges
+	WORD	0000h	(end of table)
+----------2165-------------------------------
+INT 21 - DOS 4+ - COUNTRY-DEPENDENT CHARACTER CAPITALIZATION
+	AH = 65h
+	AL = function
+h capitalize character
+		DL = character to capitalize
+		Return: DL = capitalized character
+h capitalize string
+		DS:DX -> string to capitalize
+		CX = length of string
+h capitalize ASCIZ string
+		DS:DX -> ASCIZ string to capitalize
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	these calls have been documented for DOS 5+, but were undocumented in
+	  DOS 4.x.
+----------216523-----------------------------
+INT 21 U - DOS 4+ internal - DETERMINE IF CHARACTER REPRESENTS YES/NO RESPONSE
+	AX = 6523h
+	DL = character
+	DH = second character of double-byte character (if applicable)
+Return: CF set on error
+	CF clear if successful
+	    AX = type
+h no
+h yes
+h neither yes nor no
+----------2165-------------------------------
+INT 21 U - DOS 4+ internal - COUNTRY-DEPENDENT FILENAME CAPITALIZATION
+	AH = 65h
+	AL = function
+	    A0h capitalize filename character
+		DL = character to capitalize
+		Return: DL = capitalized character
+	    A1h capitalize counted filename string
+		DS:DX -> filename string to capitalize
+		CX = length of string
+	    A2h capitalize ASCIZ filename
+		DS:DX -> ASCIZ filename to capitalize
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+Note:	nonfunctional in DOS 4.00 through 5.00 due to a bug (the code sets a
+	  pointer depending on the high bit of AL, but doesn't clear the
+	  bit before branching by function number).
+----------216601-----------------------------
+INT 21 - DOS 3.3+ - GET GLOBAL CODE PAGE TABLE
+	AX = 6601h
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    BX = active code page (see AX=6602h)
+	    DX = system code page
+SeeAlso: AX=6602h
+----------216602-----------------------------
+INT 21 - DOS 3.3+ - SET GLOBAL CODE PAGE TABLE
+	AX = 6602h
+	BX = active code page
+US
+Multilingual
+Slavic/Latin II (DOS 5+)
+Turkish
+Portugal
+	Iceland
+Canada (French)
+Norway/Denmark
+	DX = system code page (active page at boot time)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+SeeAlso: AX=6601h
+----------2167-------------------------------
+INT 21 - DOS 3.3+ - SET HANDLE COUNT
+	AH = 67h
+	BX = size of new file handle table for process
+Return: CF clear if successful
+	CF set on error
+	    AX = error code (see AH=59h)
+Notes:	if BX <= 20, no action is taken if the handle limit has not yet been
+	  increased, and the table is copied back into the PSP if the limit
+	  is currently > 20 handles
+	for file handle tables of > 20 handles, DOS 3.30 never reuses the
+	  same memory block, even if the limit is being reduced; this can lead
+	  to memory fragmentation as a new block is allocated and the existing
+	  one freed
+	only the first 20 handles are copied to child processes in DOS 3.3
+BUG:	the original release of DOS 3.30 allocates a full 64K for the handle
+	  table on requests for an even number of handles
+SeeAlso: AH=26h
+----------2168-------------------------------
+INT 21 - DOS 3.3+ - "FFLUSH" - COMMIT FILE
+	AH = 68h
+	BX = file handle
+Return: CF clear if successful
+	    all data still in DOS disk buffers is written to disk immediately,
+	      and the file's directory entry is updated
+	CF set on error
+	    AX = error code (see AH=59h)
+SeeAlso: AX=5D01h,AH=6Ah,INT 2F/AX=1107h
+----------2169-------------------------------
+INT 21 U - DOS 4.0 internal - GET/SET DISK SERIAL NUMBER
+	AH = 69h
+	AL = subfunction
+h	get serial number
+h set serial number
+	BL = drive (0=default, 1=A, 2=B, etc)
+	DS:DX -> disk info (see below)
+Return: CF set on error
+	    AX = error code (see AH=59h)
+	CF clear if successful
+	    AX destroyed
+	    (AL = 00h) buffer filled with appropriate values from extended BPB
+	    (AL = 01h) extended BPB on disk set to values from buffer
+Notes:	does not generate a critical error; all errors are returned in AX
+	error 0005h given if no extended BPB on disk
+	does not work on network drives (error 0001h)
+	buffer after first two bytes is exact copy of bytes 27h thru 3Dh of
+	   extended BPB on disk
+SeeAlso: AX=440Dh
+Format of disk info:
+Offset	Size	Description
+h	WORD	info level (zero)
+h	DWORD	disk serial number (binary)
+h 11 BYTEs	volume label or "NO NAME    " if none present
+h  8 BYTEs	(AL=00h only) filesystem type--string "FAT12   " or "FAT16   "
+----------2169-------------------------------
+INT 21 - DR-DOS 5.0 - NULL FUNCTION
+	AH = 69h
+Return: AL = 00h
+SeeAlso: AH=18h
+----------216969-----------------------------
+INT 21 - VIRUS - "Rape-747" - INSTALLATION CHECK
+	AX = 6969h
+Return: AX = 0666h if resident
+SeeAlso: AX=58CCh,AH=76h"VIRUS"
+----------216A-------------------------------
+INT 21 U - DOS 4+ - COMMIT FILE
+	AH = 6Ah
+	BX = file handle
+Return: CF clear if successful
+	    AH = 68h
+	CF set on error
+	    AX = error code (06h) (see AH=59h)
+Note:	identical to AH=68h in DOS 5.0; not known whether this is the case in
+	  DOS 4.x
+SeeAlso: AH=68h
+----------216B-------------------------------
+INT 21 U - DOS 4.0 internal - ???
+	AH = 6Bh
+	AL = subfunction
+h ???
+		DS:SI -> Current Directory Structure???
+		CL = drive (1=A:)
+h ???
+		DS:SI -> ???
+		CL = file handle???
+h ???
+		DS:SI -> Current Directory Structure???
+		DI = ???
+		CX = drive (1=A:)
+Return: CF set on error
+	    AX = error code (see INT 21/AH=59h)
+	CF clear if successful
+Note:	passed through to INT 2F/AX=112Fh with AX on top of stack
+SeeAlso: AH=6Bh"DOS 5",INT 2F/AX=112Fh
+----------216B-------------------------------
+INT 21 U - DOS 5.0 - NULL FUNCTION
+	AH = 6Bh
+Return: AL = 00h
+Note:	this function does nothing and returns immediately
+SeeAlso: AH=6Bh"DOS 4"
+----------216C00-----------------------------
+INT 21 - DOS 4+ - EXTENDED OPEN/CREATE
+	AX = 6C00h
+	BL = open mode as in AL for normal open (INT 21/AH=3Dh)
+	    bit 7: inheritance
+	    bits 4-6: sharing mode
+	    bit 3 reserved
+	    bits 0-2: access mode
+	BH = flags
+	    bit 6 = auto commit on every write
+	    bit 5 = return error rather than doing INT 24h
+	CX = create attribute
+	    bits 6-15 reserved
+	    bit 5: archive
+	    bit 4: reserved
+	    bit 3: volume label
+	    bit 2: system
+	    bit 1: hidden
+	    bit 0: readonly
+	DL = action if file exists/does not exists
+	    bits 7-4 action if file does not exist
+fail
+create
+	    bits 3-0 action if file exists
+fail
+open
+replace/open
+	DH = 00h (reserved)
+	DS:SI -> ASCIZ file name
+Return: CF set on error
+	   AX = error code (see AH=59h)
+	CF clear if successful
+	   AX = file handle
+	   CX = 1 file opened
+file created
+file replaced
+Note:	the PC LAN Program only supports DL=01h, DL=10h/sharing=compatibility,
+	  and DL=12h
+SeeAlso: AH=3Ch,AH=3Dh
+----------217070BX6060-----------------------
+INT 21 - PCW Weather Card interface - GET DATA SEGMENT
+	AX = 7070h
+	BX = 6060h
+	CX = 7070h
+	DX = 7070h
+	SX = 7070h
+	DX = 7070h
+Return: AX = segment of data structure
+Notes:	the data structure is at offset 516 from this segment.
+	the update byte is at offset 514 from this segment.  Updates are
+	  once per second while this byte is nonzero and it is decremented
+	  once per second.  While this byte is 0 updates are once per minute.
+SeeAlso: AX=7070h/BX=7070h
+Format of data structure:
+Offset	Type	Description
+h	WORD	hour
+h	WORD	minute
+h	WORD	second
+h	WORD	day
+h	WORD	month
+Ah	WORD	year
+Ch	WORD	???
+Eh	WORD	relative barometric pressure (in 1/100 inches)
+h	WORD	???
+h	WORD	???
+h	WORD	temperature 1 (in 1/10 degrees F)
+h	WORD	temperature 1 lowest (in 1/10 degrees F)
+h	WORD	temperature 1 highest (in 1/10 degrees F)
+Ah	WORD	temperature 2 (in 1/10 degrees F)
+Ch	WORD	temperature 2 lowest (in 1/10 degrees F)
+Eh	WORD	temperature 2 highest (in 1/10 degrees F)
+h	WORD	wind speed (in MPH)
+h	WORD	average of 60 wind speed samples (in MPH)
+h	WORD	highest wind speed (in MPH)
+h	WORD	wind chill factor  (in 1/10 degrees F)
+h	WORD	lowest wind chill factor (in 1/10 degrees F)
+Ah	WORD	???
+Ch	WORD	wind direction (in degrees)
+Eh	WORD	accumulated daily rainfall (in 1/10 inches)
+h	WORD	accumulated annual rainfall (in 1/10 inches)
+----------217070BX7070-----------------------
+INT 21 - PCW Weather Card interface - INSTALLATION CHECK
+	AX = 7070h
+	BX = 7070h
+	CX = 7070h
+	DX = 7070h
+	SX = 7070h
+	DX = 7070h
+Return: AX = 0070h
+	BX = 0070h
+	CX = 0070h
+	DX = 0070h
+	SX = 0070h
+	DX = 0070h
+SeeAlso: AX=7070h/BX=6060h,AX=8080h
+----------2176-------------------------------
+INT 21 - VIRUS - "Klaeren"/"Hate" - INSTALLATION CHECK
+	AH = 76h
+Return: AL = 48h if resident
+SeeAlso: AX=6969h,AX=7700h"VIRUS"
+----------217761-----------------------------
+INT 21 - WATCH.COM v3.2+ - INSTALLATION CHECK
+	AX = 7761h ('wa')
+Return: AX = 6177h
+Note:	WATCH.COM is part of the "TSR" package by TurboPower Software
+SeeAlso: INT 16/AX=7761h
+----------217700-----------------------------
+INT 21 - VIRUS - "Growing Block" - INSTALLATION CHECK
+	AX = 7700h
+Return: AX = 0920h if resident
+SeeAlso: AH=76h,AH=7Fh
+----------217F-------------------------------
+INT 21 - VIRUS - "Squeaker" - INSTALLATION CHECK
+	AH = 7Fh
+Return: AH = 80h if resident
+SeeAlso: AX=7700h,AH=83h"VIRUS"
+---------------------------------------------
+Interrupt List, part 4 of 7
+This compilation is Copyright (c) 1989,1990,1991,1992 Ralf Brown
+----------2180-------------------------------
+INT 21 U - European MSDOS 4.0 - EXECUTE PROGRAM IN BACKGROUND
+	AH = 80h
+	DS:DX -> ASCIZ full program name
+	ES:BX -> parameter block (as for AX=4B00h)
+Return: CF clear if successful
+	    AX = CSID
+	CF set on error
+	    AX = error code (see AH=59h)
+Note:	this function is called by the DETACH command
+SeeAlso: AX=8700h
+----------218080-----------------------------
+INT 21 - PCW Weather Card interface - UNINSTALL PCW.COM AND FREE MEMORY
+	AX = 8080h
+Return: ???
+SeeAlso: AX=7070h/BX=7070h
+----------2181-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 81h
+	???
+Return: ???
+----------2182-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 82h
+	???
+Return: ???
+----------2183-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 83h
+	???
+Return: ???
+----------2183-------------------------------
+INT 21 - VIRUS - "SVC" - INSTALLATION CHECK
+	AH = 83h
+Return: DX = 1990h if resident
+SeeAlso: AH=76h,AH=84h"VIRUS"
+----------2184-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 84h
+	???
+Return: ???
+----------2184-------------------------------
+INT 21 - VIRUS - "SVC 5.0" or "SVC 6.0" - INSTALLATION CHECK
+	AH = 84h
+Return: DX = 1990h if resident
+	    BH = version number (major in high nybble, minor in low)
+SeeAlso: AH=83h"VIRUS",AH=89h"VIRUS"
+----------2185-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 85h
+	???
+Return: ???
+----------2186-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 86h
+	???
+Return: ???
+----------218700-----------------------------
+INT 21 U - European DOS 4.0 - GET PID???
+	AX = 8700h
+Return: AX = PID if AL nonzero
+	BX = ???
+	CX = ???
+Notes:	called by MS C v5.1 getpid() function
+	this function apparently must return AX=0001h for INT 21/AH=80h to
+	  succeed
+SeeAlso: AH=62h,AH=80h
+----------2188-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 88h
+	???
+Return: ???
+----------2189-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 89h
+	???
+Return: ???
+Note:	reportedly called by Microsoft C 4.0 startup code
+----------2189-------------------------------
+INT 21 - VIRUS - "Vriest" - INSTALLATION CHECK
+	AH = 89h
+Return: AX = 0123h if resident
+SeeAlso: AH=84h"VIRUS",AH=90h"VIRUS"
+----------218A-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 8Ah
+	???
+Return: ???
+----------218B-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 8Bh
+	???
+Return: ???
+----------218C-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 8Ch
+	???
+Return: ???
+----------218D-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 8Dh
+	???
+Return: ???
+----------218E-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 8Eh
+	???
+Return: ???
+----------218F-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 8Fh
+	???
+Return: ???
+----------2190-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 90h
+	???
+Return: ???
+----------2190-------------------------------
+INT 21 - VIRUS - "Carioca" - INSTALLATION CHECK
+	AH = 90h
+Return: AH = 01h if resident
+SeeAlso: AH=89h"VIRUS",AX=9753h"VIRUS"
+----------2191-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 91h
+	???
+Return: ???
+----------2192-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 92h
+	???
+Return: ???
+----------2193-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 93h
+	???
+Return: ???
+----------2194-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 94h
+	???
+Return: ???
+----------2195-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 95h
+	???
+Return: ???
+----------2196-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 96h
+	???
+Return: ???
+----------2197-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 97h
+	???
+Return: ???
+----------219753-----------------------------
+INT 21 - VIRUS - "Nina" - INSTALLATION CHECK
+	AX = 9753h
+Return: never (executes original program) if virus resident
+SeeAlso: AH=90h"VIRUS",AX=A1D5h"VIRUS"
+----------2198-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 98h
+	???
+Return: ???
+----------2199-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 99h
+	???
+Return: ???
+----------219A-------------------------------
+INT 21 U - European MSDOS 4.0 - ???
+	AH = 9Ah
+	???
+Return: ???
+----------21A0-------------------------------
+INT 21 - Attachmate Extra - GET 3270 DISPLAY STATE
+	AH = A0h
+Return: AL = display status
+	    bit	 7  : 0=windowed, 1=enlarged
+	    bits 6-3: current screen profile number 0-9
+	    bits 2-0: active window number
+=PC, 1-4=host B-E, 5-6=notepad F-G
+	BX = host window status
+	    bit 15:  reserved
+	    bit 14:  0=host E window installed, 1=not
+	    bit 13:  0=host E terminal on, 1=off
+	    bit 12:  0=host E window displayed, 1=not
+	    bit 11:  reserved
+	    bit 10:  0=host D window installed, 1=not
+	    bit	 9:  0=host D terminal on, 1=off
+	    bit	 8:  0=host D window displayed, 1=not
+	    bit	 7:  reserved
+	    bit	 6:  0=host C window installed, 1=not
+	    bit	 5:  0=host C terminal on, 1=off
+	    bit	 4:  0=host C window displayed, 1=not
+	    bit	 3:  reserved
+	    bit	 2:  0=host B window installed, 1=not
+	    bit	 1:  0=host B terminal on, 1=off
+	    bit	 0:  0=host B window displayed, 1=not
+Note:	Attachmate Extra is a 3270 emulator by Attachmate Corporation
+SeeAlso: AH=A1h
+----------21A1-------------------------------
+INT 21 - Attachmate Extra - SET 3270 DISPLAY STATE
+	AH = A1h
+	AL = set status byte
+	    bit	 7  : 0=windowed, 1=enlarged
+	    bits 6-3: current screen profile number 0-9
+	    bits 2-0: active window number
+=PC, 1-4=host B-E, 5-6=notepad F-G
+SeeAlso: AH=A0h,AH=A2h
+----------21A1D5-----------------------------
+INT 21 - VIRUS - "789"/"Filehider" - INSTALLATION CHECK
+	AX = A1D5h
+Return: AX = 900Dh if resident
+SeeAlso: AX=9753h,AX=A55Ah
+----------21A2-------------------------------
+INT 21 - Attachmate Extra - SET HOST WINDOW STATE
+	AH = A2h
+	AL = set status byte
+	    bit	 7  : 0=power off, 1=power on
+	    bit	 6  : 0=not installed, 1=installed
+	    bits 5-3: reserved
+	    bits 2-0: window number 1-4=host B-E
+SeeAlso: AH=A1h
+----------21A3-------------------------------
+INT 21 - Attachmate Extra - SEND KEYSTROKES TO HOST WINDOW
+	AH = A3h
+	AL = window number (1-4=host B-E)
+	CX = 0001h
+	DS:BX -> keystroke buffer
+	DL = zero if keystroke buffer contains host function code,
+	     non-zero if keystroke buffer contains ASCII character
+Return: CX = zero if character sent, non-zero if not
+	BX incremented if CX=0
+Values for host function code:
+h=reserved	10h=PF16	20h=Clear	30h=SysRq
+h=PF1		11h=PF17	21h=Print	31h=ErInp
+h=PF2		12h=PF18	22h=Left	32h=ErEof
+h=PF3		13h=PF19	23h=Right	33h=Ident
+h=PF4		14h=PF20	24h=Up		34h=Test
+h=PF5		15h=PF21	25h=Down	35h=Reset
+h=PF6		16h=PF22	26h=Home	36h=DevCncl
+h=PF7		17h=PF23	27h=Fast Left	37h=Dup
+h=PF8		18h=PF24	28h=Fast Right	38h=FldMark
+h=PF9		19h=Alt on	29h=Bksp	39h=Enter
+Ah=PF10	1Ah=Alt off	2Ah=Insert	3Ah=CrSel
+Bh=PF11	1Bh=Shift on	2Bh=Delete
+Ch=PF12	1Ch=Shift off	2Ch=Backtab
+Dh=PF13	1Dh=PA1		2Dh=Tab
+Eh=PF14	1Eh=PA2		2Eh=Newline
+Fh=PF15	1Fh=PA3		2Fh=Attn
+----------21A4-------------------------------
+INT 21 - Attachmate Extra - GET HOST WINDOW BUFFER ADDRESS
+	AH = A4h
+	AL = window number (1-4=host B-E)
+Return: DS:BX -> 3270 display buffer
+SeeAlso: AH=A5h,AH=B8h
+----------21A5-------------------------------
+INT 21 - Attachmate Extra - GET HOST WINDOW CURSOR POSITION
+	AH = A5h
+	AL = window number (1-4=host B-E)
+Return: BX = cursor position (80 * row + column, where 0:0 is upper left)
+Note:	if the host window is configured with the Extended Attribute (EAB)
+	  feature, multiply the cursor position by 2 to obtain the byte offset
+	  into the display buffer
+SeeAlso: AH=A4h
+----------21A55A-----------------------------
+INT 21 - VIRUS - "Eddie-2" - INSTALLATION CHECK
+	AX = A55Ah
+Return: AX = 5AA5h if resident
+SeeAlso: AX=A1D5h,AX=AA00h
+----------21AA00-----------------------------
+INT 21 - VIRUS - "Blinker" - INSTALLATION CHECK
+	AX = AA00h
+Return: AX = 00AAh if resident
+SeeAlso: AX=A55Ah,AX=AA03h
+----------21AA03-----------------------------
+INT 21 - VIRUS - "Backtime" - INSTALLATION CHECK
+	AX = AA03h
+Return: AX = 03AAh if resident
+SeeAlso: AX=AA00h,AH=ABh
+----------21AB-------------------------------
+INT 21 - VIRUS - "600" or "Voronezh"-family - INSTALLATION CHECK
+	AH = ABh
+Return: AX = 5555h if resident
+SeeAlso: AX=AA03h,AX=BBBBh"VIRUS"
+----------21AF-------------------------------
+INT 21 - Attachmate Extra - GET TRANSLATE TABLE ADDRESS
+	AH = AFh
+Return: DS:BX -> translate tables (see below)
+Format of translate tables:
+Offset	Size	Description
+h 256 BYTEs	ASCII to 3270 buffer code translate table
+h 256 BYTEs	3270 buffer code to ASCII translate table
+h 256 BYTEs	3270 buffer code to EBCDIC translate table
+h 256 BYTEs	EBCDIC to 3270 buffer code translate table
+----------21B5-------------------------------
+INT 21 - Novell NetWare shell 3.01 - TASK MODE CONTROL
+	AH = B5h
+	AL = subfunction
+h get task mode
+		Return: AH = 00h
+			AL = current task mode byte
+h get task mode pointer
+		Return: ES:BX -> task mode byte
+Notes:	the task mode byte specifies how task cleanup should be performed, but
+	  is declared to be version-dependent
+	allows a program to disable the automatic cleanup for programs managing
+	  task swapping, etc.
+Values for task mode byte in version 3.01:
+h-03h reserved
+h	 no task cleanup
+----------21B6-------------------------------
+INT 21 - Novell NetWare SFT Level II - EXTENDED FILE ATTRIBUTES
+	AH = B6h
+	AL = subfunction
+h get extended file attributes
+h set extended file attributes
+	CL = attributes
+	    bits 2-0: search mode (executables only)
+none (use shell's default search)
+search on all opens without path
+do not search
+search on read-only opens without path
+reserved
+search on all opens
+reserved
+search on all read-only opens
+: reserved
+: transaction tracking file
+: indexing file
+: read audit (to be implemented)
+: write audit (to be implemented)
+	DS:DX -> ASCIZ pathname
+Return: CF set on error
+	    AL = error code
+Ch caller lacks privileges
+		FFh file not found
+	CL = current extended file attributes
+SeeAlso: AX=4300h
+----------21B8-------------------------------
+INT 21 - Novell Advanced NetWare 2.0+ - PRINT JOBS
+	AH = B8h
+	AL = subfunction
+h get default print job flags
+h set default capture flags (see below)
+h get specific capture flags
+h set specific print job flags
+h get default local printer
+h set default local printer
+h set capture print queue
+h set capture print job
+h get banner user name
+h set banner user name
+	CX = buffer size
+	ES:BX -> buffer
+Return: none
+Format of capture flags table:
+Offset	Size	Description
+h	BYTE	status (used internally, should be set to 00h)
+h	BYTE	print flags
+		bit 2: print capture file if interrupted by loss of connection
+: no automatic form feed after print job
+: printing control sequences interpreted by print service
+: print banner page before capture file
+h	BYTE	printer number on server
+h	BYTE	number of copies to print
+h	BYTE	form type required in printer (default 00h)
+h 13 BYTEs	text to be placed on banner page
+h	BYTE	reserved
+h	BYTE	default local printer (00h = LPT1)
+h	BYTE	flush capture file on LPT close if nonzero
+h	WORD	timeout in clock ticks for flushing capture file on inactivity
+		(high byte first)
+h = never timeout
+h	WORD	maximum lines per page (high byte first)
+h	WORD	maximum characters per line (high byte first)
+Bh 13 BYTEs	name of form required in printer
+h	BYTE	LPT capture flag
+h inactive, FFh LPT device is being captured
+h	BYTE	file capture flag
+h if no file specified, FFh if capturing to file
+Ah	BYTE	timing out (00h if no timeout in effect, FFh if timeout counter
+		running)
+Bh	WORD	offset of printer setup string (high byte first)
+Dh	WORD	offset of printer reset string (high byte first)
+Fh	BYTE	target connection ID
+h	BYTE	capture in progress if FFh
+h	BYTE	print job number assigned to capture if FFh
+h	WORD	bindery object ID of print queue if previous byte FFh
+h	WORD	print job number (high byte first)
+----------21B8-------------------------------
+INT 21 - Attachmate Extra - DISABLE HOST BUFFER UPDATES
+	AH = B8h
+	AL = window number (1-4=host B-E)
+	DL = 01h
+Notes:	only valid in CUT mode
+	next AID keystroke (eg Enter) enables host buffer updates
+SeeAlso: AH=A4h
+----------21BB-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - SET END OF JOB STATUS
+	AH = BBh
+	AL = new EOJ flag
+h disable EOJs
+	    otherwise enable EOJs
+Return: AL = old EOJ flag
+SeeAlso: AH=D6h
+----------21BBBB-----------------------------
+INT 21 - VIRUS - "Hey You" - INSTALLATION CHECK
+	AX = BBBBh
+Return: AX = 6969h
+SeeAlso: AH=ABh"VIRUS",AH=BEh"VIRUS"
+----------21BC-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - LOG/LOCK PHYSICAL RECORD
+	AH = BCh
+	AL = flags
+	    bit 0: lock as well as log record
+: non-exclusive lock
+	BX = file handle
+	CX:DX = offset
+	BP = timeout in timer ticks (1/18 sec)
+	SI:DI = length of region to lock
+Return: AL = error code
+h successful
+h no dynamic memory for file
+	    FEh timed out
+	    FFh failed
+SeeAlso: AH=BDh,AH=BFh
+----------21BD-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - RELEASE PHYSICAL RECORD
+	AH = BDh
+	BX = file handle
+	CX:DX = offset
+Return: AL = error code (see AH=BCh)
+Note:	unlocks record but does not remove it from log table
+SeeAlso: AH=BCh,AH=BEh"Novell",AH=C0h
+----------21BE-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - CLEAR PHYSICAL RECORD
+	AH = BEh
+	BX = file handle
+	CX:DX = offset
+Return: AL = error code (see AH=BCh)
+Note:	unlocks record and removes it from log table
+SeeAlso: AH=BCh,AH=BDh,AH=C1h
+----------21BE-------------------------------
+INT 21 - VIRUS - "Datalock" - INSTALLATION CHECK
+	AH = BEh
+Return: AX = 1234h if resident
+SeeAlso: AX=BBBBh,AX=BE00h
+----------21BE00-----------------------------
+INT 21 - VIRUS - "USSR-1049" - INSTALLATION CHECK
+	AX = BE00h
+	CF set
+Return: CF clear if resident
+SeeAlso: AH=BEh"VIRUS",AH=C0h"VIRUS"
+----------21BF-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - LOG/LOCK RECORD (FCB)
+	AH = BFh
+	AL = flags
+	    bit 0: lock as well as log record
+: non-exclusive lock
+	DS:DX -> opened FCB (see AH=0Fh)
+	BX:CX = offset
+	BP = lock timeout in timer ticks (1/18 sec)
+	SI:DI = length
+Return: AL = error code (see AH=BCh)
+SeeAlso: AH=BCh,AH=C0h"Novell",AH=C2h"Novell"
+----------21C0-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - RELEASE RECORD (FCB)
+	AH = C0h
+	DS:DX -> FCB (see AH=0Fh)
+	BX:CX = offset
+Return: AL = error code (see AH=BCh)
+Note:	unlocks record but does not remove it from log table
+SeeAlso: AH=BDh,AH=BFh,AH=C1h"Novell",AH=C3h
+----------21C0-------------------------------
+INT 21 - VIRUS - "Slow"/"Zerotime", "Solano" - INSTALLATION CHECK
+	AH = C0h
+Return: AX = 0300h if "Slow"/"Zerotime" resident
+	AX = 1234h if "Solano" resident
+SeeAlso: AX=BE00h,AH=C1h"VIRUS",AX=C301h"VIRUS"
+----------21C1-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - CLEAR RECORD (FCB)
+	AH = C1h
+	DS:DX -> opened FCB (see AH=0Fh)
+	BX:CX = offset
+Return: AL = error code (see AH=BCh)
+Note:	unlocks record and removes it from log table
+SeeAlso: AH=BEh,AH=C0h"Novell",AH=C4h
+----------21C1-------------------------------
+INT 21 - VIRUS - "Solano" - ???
+	AH = C1h
+	???
+Return: ???
+SeeAlso: AH=C0h"VIRUS"
+----------21C2-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - LOCK PHYSICAL RECORD SET
+	AH = C2h
+	AL = flags
+	    bit 1: non-exclusive lock
+	BP = lock timeout in timer ticks (1/18 sec)
+Return: AL = error code
+h successful
+	    FEh timed out
+	    FFh failed
+SeeAlso: AH=BFh,AH=C3h
+----------21C2-------------------------------
+INT 21 - VIRUS - "Scott's Valley" - ???
+	AH = C2h
+	???
+Return: ???
+SeeAlso: AH=C0h"VIRUS"
+----------21C3-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - RELEASE PHYSICAL RECORD SET
+	AH = C3h
+Return: AL = error code
+Note:	unlocks but does not remove from log table
+SeeAlso: AH=C0h,AH=C2h"Novell",AH=C4h
+----------21C301DXF1F1-----------------------
+INT 21 - VIRUS - "905"/"Backfont" - INSTALLATION CHECK
+	AX = C301h
+	DX = F1F1h
+Return: DX = 0E0Eh if resident
+SeeAlso: AH=C0h"VIRUS",AX=C500h"VIRUS"
+----------21C4-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - CLEAR PHYSICAL RECORD SET
+	AH = C4h
+Return: AL = error code
+Note:	unlocks and removes from log table
+SeeAlso: AH=C1h
+----------21C5-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - SEMAPHORES
+	AH = C5h
+	AL = subfunction
+h open semaphore
+		DS:DX -> semaphore name (counted string)
+		CL = initial value
+		Return: CX:DX = semaphore handle
+			BL = open count
+h examine semaphore
+		Return: CX = semaphore value (sign extended)
+			DL = open count
+h wait on semaphore
+		BP = timeout in timer ticks (1/18 sec) (0000h = no wait)
+h signal semaphore
+h close semaphore
+	CX:DX = semaphore handle (except function 00h)
+Return: AL = error code
+h successful
+h semaphore value overflow
+h out of string space on server
+	    FEh invalid string length (AL=00h) or timeout
+	    FFh invalid initial value (AL=00h) or invalid handle
+----------21C500-----------------------------
+INT 21 - VIRUS - "Sverdlov" - INSTALLATION CHECK
+	AX = C500h
+Return: AX = 6731h if resident
+SeeAlso: AX=C301h"VIRUS",AH=C6h"VIRUS"
+----------21C6-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - GET OR SET LOCK MODE
+	AH = C6h
+	AL = subfunction
+h set old "compatibility" mode
+h set new extended locks mode
+h get lock mode
+Return: AL = current lock mode
+----------21C6-------------------------------
+INT 21 - VIRUS - "Socha" - INSTALLATION CHECK
+	AH = C6h
+Return: AL = 55h if resident
+SeeAlso: AX=C500h"VIRUS",AX=C603h
+----------21C603-----------------------------
+INT 21 - VIRUS - "Yankee" or "MLTI" - INSTALLATION CHECK
+	AX = C603h
+	CF set
+Return: CF clear if resident
+SeeAlso: AX=C500h"VIRUS",AX=C700h"VIRUS"
+----------21C7-------------------------------
+INT 21 - Novell NetWare 4.0 - TRANSACTION TRACKING SYSTEM
+	AH = C7h
+	AL = subfunction
+h begin transaction (NetWare SFT level II)
+		Return: AL = error code
+h end transaction (NetWare SFT level II)
+		Return: AL = error code
+			CX:DX = transaction reference number
+h TTS available (NetWare SFT level II)
+		Return: AL = completion code
+h TTS not available
+h TTS available
+			    FDh TTS available but disabled
+h abort transaction (NetWare SFT level II)
+		Return: AL = error code
+h transaction status
+h get application thresholds
+h set application thresholds
+h get workstation thresholds
+h set workstation thresholds
+Return: ???
+----------21C700-----------------------------
+INT 21 - VIRUS - "MH-757" - INSTALLATION CHECK
+	AX = C700h
+Return: AL = 07h if resident
+SeeAlso: AX=C603h"VIRUS",AH=CBh"VIRUS"
+----------21C8-------------------------------
+INT 21 - Novell NetWare 4.0 - BEGIN LOGICAL FILE LOCKING
+	AH = C8h
+	if function C6h lock mode 00h:
+	    DL = mode
+h no wait
+h wait
+	if function C6h lock mode 01h:
+	    BP = timeout in timer ticks (1/18 sec)
+Return: AL = error code
+SeeAlso: AH=C9h
+----------21C9-------------------------------
+INT 21 - Novell NetWare 4.0 - END LOGICAL FILE LOCKING
+	AH = C9h
+Return: AL = error code
+SeeAlso: AH=C8h
+----------21CA-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - LOG/LOCK PERSONAL FILE (FCB)
+	AH = CAh
+	DS:DX -> FCB (see AH=0Fh)
+	if function C6h lock mode 01h:
+	    AL = log and lock flag
+h log file only
+h lock as well as log file
+	    BP = lock timeout in timer ticks (1/18 sec)
+Return: AL = error code
+h successful
+h no dynamic memory for file
+	    FEh timeout
+	    FFh failed
+SeeAlso: AH=CBh
+----------21CA15-----------------------------
+INT 21 - VIRUS - "Piter" - ???
+	AX = CA15h
+	???
+Return: ???
+SeeAlso: AH=CCh"VIRUS"
+----------21CB-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - LOCK FILE SET
+	AH = CBh
+	if function C6h lock mode 00h:
+	    DL = mode
+h no wait
+h wait
+	if function C6h lock mode 01h:
+	    BP = lock timeout in timer ticks (1/18 sec)
+Return: AL = error code
+h successful
+	    FEh timed out
+	    FFh failed
+Note:	attempts to lock all logged personal files
+SeeAlso: AH=CAh
+----------21CB-------------------------------
+INT 21 - VIRUS - "Milous" - INSTALLATION CHECK
+	AH = CBh
+Return: AL = 07h if resident
+SeeAlso: AX=C700h"VIRUS",AX=CB02h
+----------21CB02-----------------------------
+INT 21 - VIRUS - "Witcode" - INSTALLATION CHECK
+	AX = CB02h
+Return: AX = 02CBh if resident
+SeeAlso: AX=CBh"VIRUS",AH=CCh"VIRUS"
+----------21CC-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - RELEASE FILE (FCB)
+	AH = CCh
+	DS:DX -> FCB (see AH=0Fh)
+Return: none
+Note:	unlocks file, but does not remove it from the log table or close it
+SeeAlso: AH=CAh,AH=CDh
+----------21CC-------------------------------
+INT 21 - VIRUS - "Westwood" - INSTALLATION CHECK
+	AH = CCh
+Return: AX = 0700h if resident
+SeeAlso: AX=CB02h,AH=CDh"VIRUS",AX=D000h"VIRUS"
+----------21CD-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - RELEASE FILE SET
+	AH = CDh
+Return: none
+Note:	unlocks all personal files, but does not remove them from log table
+SeeAlso: AH=CAh,AH=CCh
+----------21CD-------------------------------
+INT 21 - VIRUS - "Westwood" - ???
+	AH = CDh
+	???
+Return: ???
+SeeAlso: AH=CCh"VIRUS"
+----------21CE-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - CLEAR FILE (FCB)
+	AH = CEh
+	DS:DX -> FCB (see AH=0Fh)
+Return: AL = error code
+Note:	unlocks file and removes it from log table, then closes all opened and
+	  logged occurrences
+SeeAlso: AH=CAh,AH=CFh,AH=EDh"Novell"
+----------21CF-------------------------------
+INT 21 - LANstep - ???
+	AH = CFh
+	???
+Return: ???
+Note:	LANstep is a redesign of the Waterloo Microsystems PORT network
+----------21CF-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - CLEAR FILE SET
+	AH = CFh
+Return: AL = 00h
+Note:	clears all entries in personal file log table
+SeeAlso: AH=CAh,AH=CEh
+----------21D0-------------------------------
+INT 21 - Novell NetWare 4.6, Banyan VINES, Alloy NTNX - LOCK LOGICAL RECORD
+	AH = D0h
+	DS:DX -> record string (counted string, max 100 data bytes)
+	if function C6h lock mode 01h: (Novell, NTNX only)
+	    AL = flags
+		bit 0: lock as well as log the record
+		bit 1: non-exclusive lock
+	    BP = lock timeout in timer ticks (1/18 sec)
+Return: AL = error code
+h successful
+h no dynamic memory for file
+	    FEh timed out
+	    FFh unsuccessful
+SeeAlso: AH=D1h,AH=D2h
+----------21D000-----------------------------
+INT 21 - VIRUS - "Fellowship" - INSTALLATION CHECK
+	AX = D000h
+Return: BX = 1234h if resident
+SeeAlso: AH=CCh"VIRUS",AH=D5h"VIRUS",AX=D5AAh
+----------21D1-------------------------------
+INT 21 - Novell NetWare 4.6, Banyan VINES, Alloy NTNX - LOCK LOGICAL RECORD SET
+	AH = D1h
+	if function C6h lock mode 00h:
+	    DL = mode
+h no wait
+h wait
+	if function C6h lock mode 01h: (Novell only)
+	   BP = lock timeout in timer ticks (1/18 sec)
+h no wait
+Return: AL = error code (see AH=D0h)
+SeeAlso: AH=D0h,AH=D3h
+----------21D2-------------------------------
+INT 21 - Novell NetWare 4.0, Banyan VINES, Alloy NTNX - UNLOCK LOGICAL RECORD
+	AH = D2h
+	DS:DX -> semaphore identifier (counted string up to 100 chars long)
+Return: AL = error code (see AH=D0h)
+Note:	unlocks record but does not remove it from log table
+SeeAlso: AH=D0h,AH=D3h
+----------21D3-------------------------------
+INT 21 - Novell NetWare 4.0,Banyan VINES,Alloy NTNX - UNLOCK LOGICAL RECORD SET
+	AH = D3h
+Return: AL = error code (see AH=D0h)
+Note:	unlocks all semaphores logged in the semaphore set of the requesting PC
+SeeAlso: AH=D1h,AH=D2h
+----------21D4-------------------------------
+INT 21 - Novell NetWare 4.0, Banyan VINES, Alloy NTNX - CLEAR LOGICAL RECORD
+	AH = D4h
+	DS:DX -> semaphore identifier (counted string up to 100 chars long)
+Return: AL = error code
+h successful
+	    FFh not successful
+Note:	unlocks record and removes it from log table
+SeeAlso: AH=D5h
+----------21D5-------------------------------
+INT 21 - Novell NetWare 4.0,Banyan VINES,Alloy NTNX - CLEAR LOGICAL RECORD SET
+	AH = D5h
+Return: AL = error code (see AH=D4h)
+Note:	unlocks and clears all semaphores associated with the semaphore set
+	  of the requesting PC
+SeeAlso: AH=D4h
+----------21D5-------------------------------
+INT 21 - VIRUS - "Carfield" - ???
+	AH = D5h
+	???
+Return: ???
+SeeAlso: AX=D5AAh,AH=F3h"Carfield"
+----------21D5AA-----------------------------
+INT 21 - VIRUS - "Diamond-A", "Diamond-B" - INSTALLATION CHECK
+	AX = D5AAh
+Return: AX = 2A55h if "Diamond-A" resident
+	AX = 2A03h if "Diamond-B"-family virus resident
+SeeAlso: AX=D000h,AH=D5h"VIRUS",AX=D5AAh/BP=DEAAh
+----------21D5AABPDEAA-----------------------
+INT 21 - VIRUS - "Dir" - INSTALLATION CHECK
+	AX = D5AAh
+	BP = DEAAh
+Return: SI = 4321h if resident
+SeeAlso: AX=D5AAh,AX=DADAh"VIRUS"
+----------21D6-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - END OF JOB
+	AH = D6h
+Return: AL = error code
+Note:	unlocks and clears all locked or logged files and records held by
+	  process, closes all files, resets error and lock modes, and releases
+	  all network resources
+SeeAlso: AH=BBh
+----------21D7-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - SYSTEM LOGOUT
+	AH = D7h
+Return: AL = error code
+----------21D8-------------------------------
+INT 21 - Novell NetWare, Banyan VINES - ALLOCATE RESOURCE
+	AH = D8h
+	DL = resource number
+Return: AL = status
+h successful
+	    FFh unsucessful
+SeeAlso: AH=D9h
+----------21D9-------------------------------
+INT 21 - Novell NetWare, Banyan VINES - DEALLOCATE RESOURCE
+	AH = D9h
+	DL = resource number
+Return:	AL = status (see AH=D8h)
+SeeAlso: AH=D8h
+----------21DA-------------------------------
+INT 21 - Novell NetWare 4.0 - GET VOLUME STATISTICS
+	AH = DAh
+	DL = volume number
+	ES:DI -> reply buffer (see below)
+Return: AL = 00h
+SeeAlso: AH=36h
+Format of reply buffer:
+Offset	Size	Description
+h	WORD	sectors/block
+h	WORD	total blocks
+h	WORD	unused blocks
+h	WORD	total directory entries
+h	WORD	unused directory entries
+Ah 16 BYTEs	volume name, null padded
+Ah	WORD	removable flag, 0000h = not removable
+Note:	all words are big-endian (high byte first)
+----------21DADA-----------------------------
+INT 21 - VIRUS - "Gotcha" - INSTALLATION CHECK
+	AX = DADAh
+Return: AH = A5h
+SeeAlso: AX=D5AAh,AH=DAFEh"VIRUS"
+----------21DAFE-----------------------------
+INT 21 - VIRUS - "Plovdiv 1.3" - INSTALLATION CHECK
+	AX = DAFEh
+Return: AX = 1234h if resident
+SeeAlso: AX=DADAh,AH=DDh"VIRUS",AH=DEh"VIRUS"
+----------21DB-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - GET NUMBER OF LOCAL DRIVES
+	AH = DBh
+Return: AL = number of local disks as set by LASTDRIVE in CONFIG.SYS
+SeeAlso: AH=0Eh
+----------21DC-------------------------------
+INT 21 - Novell NetWare 4.0, Banyan VINES, Alloy NTNX - GET STATION NUMBER
+	AH = DCh
+Return: AL = station number
+h if NetWare not loaded or this machine is a non-dedicated server
+	CX = station number in ASCII
+Note:	station number only unique for those PCs connected to same semaphore
+	  service
+----------21DC-------------------------------
+INT 21 - PCMag PCMANAGE/DCOMPRES - TURN ON/OFF
+	AH = DCh
+	DX = state
+h turn on
+h turn off
+SeeAlso: AX=FEDCh
+----------21DD-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - SET ERROR MODE
+	AH = DDh
+	DL = error mode
+h invoke INT 24 on critical I/O errors
+h return NetWare extended error code in AL
+h return error code in AL, mapped to standard DOS error codes
+Return: AL = previous error mode
+----------21DD-------------------------------
+INT 21 - VIRUS - "Jerusalem"-family - RELOCATE VIRUS???
+	AH = DDh
+	CX = number of bytes to copy
+	DS:SI -> source of copy
+	ES:DI -> destination of copy
+Return: does not return normally; return address is caller's CS:0100h with
+	  AX = ???
+SeeAlso: AH=E0h"VIRUS",AH=EEh"VIRUS"
+----------21DE-------------------------------
+INT 21 - Novell NetWare 4.0 - SET BROADCAST MODE
+	AH = DEh
+	AL = broadcast mode
+h receive console and workstation broadcasts
+h receive console broadcasts only
+h receive no broadcasts
+h store all broadcasts for retrieval
+h get broadcast mode
+h disable shell timer interrupt checks
+h enable shell timer interrupt checks
+Return: AL = old broadcast mode
+----------21DE-------------------------------
+INT 21 - VIRUS - "Durban" - INSTALLATION CHECK
+	AH = DEh
+Return: AH = DFh if resident
+SeeAlso: AX=DAFEh,AX=DEDEh"VIRUS"
+----------21DE-------------------------------
+INT 21 - VIRUS - "April 1st EXE" - ???
+	AH = DEh
+	???
+Return: ???
+----------21DEDE-----------------------------
+INT 21 - VIRUS - "Brothers" - INSTALLATION CHECK
+	AX = DEDEh
+Return: AH = 41h if resident
+SeeAlso: AH=DEh"VIRUS",AH=E0h"VIRUS"
+----------21DF-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - CAPTURE
+	AH = DFh
+	AL = subfunction
+h start LPT capture
+h end LPT capture
+h cancel LPT capture
+h flush LPT capture
+h start specific capture
+h end specific capture
+h cancel specific capture
+h flush specific capture
+Return: AL = error code
+Note:	under NTNX, only AL=00h-03h are supported, and all four send a print
+	  break (see INT 17/AH=84h)
+----------21E0-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - PRINT SPOOLING
+	AH = E0h
+	DS:SI -> request buffer
+	ES:DI -> reply buffer
+	subfunction in third byte of request buffer
+h spool data to a capture file
+h close and queue capture file
+h set spool flags
+h spool existing file
+h get spool queue entry
+h remove entry from spool queue
+h get printer status
+h create a disk capture file
+Return: AL = error code
+----------21E0-------------------------------
+INT 21 - OS/286, OS/386 - INITIALIZE REAL PROCEDURE
+	AH = E0h
+	???
+Return: ???
+SeeAlso: AH=E1h"OS/286"
+----------21E0-------------------------------
+INT 21 - DoubleDOS - MENU CONTROL
+	AH = E0h
+	AL = subfunction
+h exchange tasks
+h resume invisible job if suspended
+h kill other job
+h suspend invisible job
+Note:	identical to AH=F0h
+SeeAlso: AH=F0h"DoubleDOS"
+----------21E0-------------------------------
+INT 21 - VIRUS - "Jerusalem", "Armagedon" - INSTALLATION CHECK
+	AH = E0h
+Return: AX = 0300h if "Jerusalem" resident
+	AX = DADAh if "Armagedon" resident
+SeeAlso: AH=DEh"VIRUS",AX=DEDEh"VIRUS",AX=E00Fh
+----------21E00F-----------------------------
+INT 21 - VIRUS - "8-tunes" - INSTALLATION CHECK
+	AX = E00Fh
+Return: AX = 4C31h if resident
+SeeAlso: AH=E0h"VIRUS",AH=E1h"VIRUS"
+----------21E1-------------------------------
+INT 21 - Novell NetWare 4.0 - BROADCAST MESSAGES
+	AH = E1h
+	DS:SI -> request buffer
+	ES:DI -> reply buffer
+	subfunction in third byte of request buffer
+h send broadcast message
+h get broadcast message
+h disable station broadcasts
+h enable station broadcasts
+h send personal message
+h get personal message
+h open message pipe
+h close message pipe
+h check pipe status
+h broadcast to console
+Return: AL = error code
+----------21E1-------------------------------
+INT 21 - OS/286, OS/386 - ISSUE REAL PROCEDURE CALL
+	AH = E1h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AH=E0h"OS/286",AH=E2h"OS/286",AH=E3h"OS/286",AX=250Eh,INT 31/AX=0301h
+----------21E1-------------------------------
+INT 21 - DoubleDOS - CLEAR KEYBOARD BUFFER FOR CURRENT JOB
+	AH = E1h
+SeeAlso: AH=E2h"DoubleDOS",AH=E3h"DoubleDOS",AH=E8h"DoubleDOS"
+SeeAlso: AH=F1h"DoubleDOS"
+----------21E1-------------------------------
+INT 21 - VIRUS - "Mendoza", "Fu Manchu" - INSTALLATION CHECK
+	AH = E1h
+Return: AX = 0300h if "Mendoza" resident
+	AX = 0400h if "Fu Manchu" resident
+SeeAlso: AX=E00Fh,AH=E4h"VIRUS"
+----------21E2-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - DIRECTORY FUNCTIONS
+	AH = E2h
+	DS:SI -> request buffer
+	ES:DI -> reply buffer
+	subfunction in third byte of request buffer
+h set directory handle
+h get directory path
+h scan directory information
+h get effective directory rights
+h modify maximum rights mask
+h get volume number
+h get volume name
+Ah create directory
+Bh delete directory
+Ch scan directory for trustees
+Dh add trustee to directory
+Eh delete trustee from directory
+Fh rename directory
+h purge erased files
+h restore erased file
+h allocate permanent directory handle
+h allocate temporary directory handle
+h deallocate directory handle
+h get volume info with handle
+h allocate special temporary directory handle
+h retrieve a short base handle (Advanced NetWare 2.0)
+h restore a short base handle (Advanced NetWare 2.0)
+h set directory information
+Return: AL = error code
+----------21E2-------------------------------
+INT 21 - OS/286, OS/386 - SET REAL PROCEDURE SIGNAL HANDLER
+	AH = E2h
+	???
+Return: ???
+SeeAlso: AH=E0h"OS/286",AH=E1h"OS/286",AH=E6h"OS/286"
+----------21E2-------------------------------
+INT 21 - DoubleDOS - SEND CHARACTER TO KEYBOARD BUFFER OF OTHER JOB
+	AH = E2h
+	AL = character
+Return: AL = 00h successful
+h buffer full (128 characters)
+SeeAlso: AH=E1h"DoubleDOS",AH=E3h"DoubleDOS",AH=E8h"DoubleDOS"
+SeeAlso: AH=F2h"DoubleDOS"
+----------21E3-------------------------------
+INT 21 - Novell NetWare 4.0, Alloy NTNX - CONNECTION CONTROL
+	AH = E3h
+	DS:SI -> request buffer
+	ES:DI -> reply buffer
+	subfunction in third byte of request buffer
+h login
+h change password
+h map user to station set
+h map object to number
+h map number to object
+h get station's logged information
+h get station's root mask (obsolete)
+h map group name to number
+h map number to group name
+h get memberset M of group G
+Ah enter login area
+Bh ???
+Ch ???
+Dh log network message
+Eh get disk utilization (Advanced NetWare 1.0)
+Fh scan file information (Advanced NetWare 1.0)
+h set file information (Advanced NetWare 1.0)
+h get file server information (Advanced NetWare 1.0)
+h ???
+h get internet address (Advanced NetWare 1.02)
+h login to file server (Advanced NetWare 2.0)
+h get object connection numbers (Advanced NetWare 2.0)
+h get connection information (Advanced NetWare 1.0)
+h create object (Advanced NetWare 1.0)
+h delete object (Advanced NetWare 1.0)
+h rename object (Advanced NetWare 1.0)
+h get object ID (Advanced NetWare 1.0)
+h get object name (Advanced NetWare 1.0)
+h scan object (Advanced NetWare 1.0)
+h change object security (Advanced NetWare 1.0)
+h create property (Advanced NetWare 1.0)
+Ah delete property (Advanced NetWare 1.0)
+Bh change property security (Advanced NetWare 1.0)
+Ch scan property (Advanced NetWare 1.0)
+Dh read property value (Advanced NetWare 1.0)
+		request buffer contains the property name in all caps
+		property "IDENTIFICATION" returns the user's name
+Eh write property value (Advanced NetWare 1.0)
+Fh verify object password (Advanced NetWare 1.0)
+h change object password (Advanced NetWare 1.0)
+h add object to set (Advanced NetWare 1.0)
+h delete object from set (Advanced NetWare 1.0)
+h is object in set? (Advanced NetWare 1.0)
+h close bindery (Advanced NetWare 1.0)
+h open bindery (Advanced NetWare 1.0)
+h get bindery access level (Advanced NetWare 1.0)
+h scan object trustee paths (Advanced NetWare 1.0)
+	    C8h check console priviledges
+	    C9h get file server description strings
+	    CAh set file server date and time
+	    CBh disable file server login
+	    CCh enable file server login
+	    CDh get file server login status
+	    CEh purge all erased files
+	    CFh disable transaction tracking
+	    D0h enable transaction tracking
+	    D1h send console broadcast
+	    D2h clear connection number
+	    D3h down file server
+	    D4h get file system statistics
+	    D5h get transaction tracking statistics
+	    D6h read disk cache statistics
+	    D7h get drive mapping table
+	    D8h read physical disk statistics
+	    D9h get disk channel statistics
+	    DAh get connection's task information
+	    DBh get list of a connection's open files
+	    DCh get list of connections using a file
+	    DDh get physical record locks by connection and file
+	    DEh get physical record locks by file
+	    DFh get logical records by connection
+	    E0h get logical record information
+	    E1h get connection's semaphores
+	    E2h get semaphore information
+	    E3h get LAN driver's configuration information
+	    E5h get connection's usage statistics
+	    E6h get object's remaining disk space
+	    E7h get server LAN I/O statistics
+	    E8h get server miscellaneous information
+	    E9h get volume information
+Return: AL = error code
+Format of object property:
+Offset	Size	Description
+h 1-16 BYTEs	property name
+  N	BYTE	flags
+		bit 0: property is dynamic
+: property belongs to set rather than item
+ N+1	BYTE	security levels (see below)
+	???
+Values for security levels:
+h	everyone may access
+h	only logged-in clients may access
+h	only clients logged-in with object's name, type, and password
+h	only clients logged-in with supervisor privileges
+h	only NetWare may access
+Note:	the above values are stored in a nybble; the high half-byte is write
+	  access and the low half-byte is read access
+Values for object type:
+h	unknown
+h	user
+h	user group
+h	print queue
+h	file server
+h	job server
+h	gateway
+h	print server
+h	archive queue
+h	archive server
+Ah	job queue
+Bh	administration
+h	remote bridge server
+h	advertising print server
+ FFh	wild (used only for finding objects)
+----------21E3-------------------------------
+INT 21 - OS/286, OS/386 - ISSUE REAL INTERRUPT
+	AH = E3h
+	AL = interrupt number
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AH=E1h"OS/286",INT 31/AX=0300h
+----------21E3-------------------------------
+INT 21 - DoubleDOS - ADD CHARACTER TO KEYBOARD BUFFER OF CURRENT JOB
+	AH = E3h
+	AL = character
+Return: AL = 00h successful
+h buffer full (128 characters)
+SeeAlso: AH=E1h"DoubleDOS",AH=E2h"DoubleDOS",AH=E8h"DoubleDOS"
+SeeAlso: AH=F3h"DoubleDOS"
+----------21E4-------------------------------
+INT 21 - Novell NetWare 4.0 - SET FILE ATTRIBUTES (FCB)
+	AH = E4h
+	CL = file attributes
+	    bit 0: read only
+: hidden
+: system
+: shareable
+	DX:DX -> FCB (see AH=0Fh)
+Return: AL = error code
+SeeAlso: AX=4301h
+----------21E4-------------------------------
+INT 21 - VIRUS - "Anarkia" - INSTALLATION CHECK
+	AH = E4h
+Return: AH = 04h if resident
+SeeAlso: AH=E1h"VIRUS",AH=E7h"VIRUS"
+----------21E400-----------------------------
+INT 21 - DoubleDOS - INSTALLATION CHECK/PROGRAM STATUS
+	AX = E400h
+Return: AL = 00h if DoubleDOS not present
+	   = 01h if running in visible DoubleDOS partition
+	   = 02h if running in the invisible DoubleDOS partition
+SeeAlso: AH=E5h"DoubleDOS",AX=F400h
+----------21E400-----------------------------
+INT 21 - OS/286, OS/386 - CHAIN TO REAL-MODE HANDLER
+	AX = E400h
+	???
+Return: ???
+Note:	protected mode only???
+----------21E402-----------------------------
+INT 21 - OS/286, OS/386 - SET PROTECTED-MODE TASK GATE
+	AX = E402h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=E403h
+----------21E403-----------------------------
+INT 21 - OS/286, OS/386 - REMOVE PROTECTED-MODE TASK GATE
+	AX = E403h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=E402h
+----------21E5-------------------------------
+INT 21 - Novell NetWare 4.0 - UPDATE FILE SIZE (FCB)
+	AH = E5h
+	DS:DX -> FCB (see AH=0Fh)
+Return: AL = error code
+----------21E5-------------------------------
+INT 21 - DoubleDOS - OTHER PROGRAM STATUS
+	AH = E5h
+Return: AL = 00h no program in other partition
+	   = 01h program in other partition is running
+	   = 02h program in other partition is suspended
+SeeAlso: AX=E400h"DoubleDOS",AH=F5h"DoubleDOS"
+----------21E500-----------------------------
+INT 21 - OS/286, OS/386 - HEAP MANAGEMENT STRATEGY
+	AX = E500h
+	???
+Return: ???
+SeeAlso: AX=E501h
+----------21E501-----------------------------
+INT 21 - OS/286, OS/386 - FORCE HEAP COMPACTION
+	AX = E501h
+	???
+Return: ???
+SeeAlso: AX=E500h
+----------21E6-------------------------------
+INT 21 - Novell NetWare 4.0 - COPY FILE TO FILE (FCB)
+	AH = E6h
+	CX:DX = number of bytes to copy
+	DS:SI -> source FCB
+	ES:DI -> destination FCB
+Return: AL = error code
+----------21E6-------------------------------
+INT 21 P - OS/286, OS/386 - ISSUE REAL PROCEDURE SIGNAL FROM PROTECTED MODE
+	AH = E6h
+	???
+Return: ???
+SeeAlso: AX=E2h"OS/286"
+----------21E7-------------------------------
+INT 21 - Novell NetWare 4.0, Banyan VINES - GET FILE SERVER DATE AND TIME
+	AH = E7h
+	DS:DX -> date/time buffer (see below)
+Return: AL = error code
+h successful
+	    FFh unsuccessful
+Note:	also supported by Alloy NTNX
+SeeAlso: AH=2Ah,AH=2Ch
+Format of date/time buffer:
+Offset	Size	Description
+h	BYTE	year - 1900
+h	BYTE	month (1=Jan)
+h	BYTE	day
+h	BYTE	hours
+h	BYTE	minutes
+h	BYTE	seconds
+h	BYTE	day of week (0 = Sunday) (Novell and NTNX only)
+----------21E7-------------------------------
+INT 21 - OS/286, OS/386 - CREATE CODE SEGMENT
+	AH = E7h
+	???
+Return: ???
+SeeAlso: AH=E8h"OS/286",AH=E9h"OS/286",AH=EAh"OS/286"
+----------21E7-------------------------------
+INT 21 - VIRUS - "Spyer"/"Kiev" - INSTALLATION CHECK
+	AH = E7h
+Return: AH = 78h if resident
+SeeAlso: AH=E4h"VIRUS",AX=EC59h
+----------21E8-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - SET FCB RE-OPEN MODE
+	AH = E8h
+	DL = mode
+h no automatic re-open
+h auto re-open
+Return: AL = error code
+----------21E8-------------------------------
+INT 21 - OS/286, OS/386 - SEGMENT CREATION
+	AH = E8h
+	AL = type
+h data segment
+h data window/alias
+h real segment
+h real window/alias
+h shareable segment
+	???
+Return: ???
+SeeAlso: AH=E7h"OS/286",AH=E9h"OS/286"
+----------21E8-------------------------------
+INT 21 - DoubleDOS - SET/RESET KEYBOARD CONTROL FLAGS
+	AH = E8h
+	AL = 00h set flags for this program
+	   = 01h set flags for other program
+	DX = keyboard control flags (bit set enables, cleared disables
+	    bit 0: menu
+	    bit 1: exchange
+	    bit 2: entire keyboard enable/disable
+	    bit 3: Ctrl-C
+	    bit 4: Ctrl-PrtSc
+	    bit 5: Alt/Erase
+	    bit 6: Ctrl-Break
+	    bit 7: Ctrl-NumLock
+	    bit 8: shift-PrtSc
+	    bit 9-13: undefined
+	    bit 14: cancel key (clear keyboard buffer)
+	    bit 15: suspend key
+Return: DX = previous flags
+Notes:	disabling Ctrl-PrtSc will allow the program to intercept the keystroke;
+	  disabling any of the other keystrokes disables them completely
+	identical to AH=F8h
+SeeAlso: AH=E1h"DoubleDOS",AH=E2h"DoubleDOS",AH=E3h"DoubleDOS"
+SeeAlso: AH=F8h"DoubleDOS"
+----------21E9-------------------------------
+INT 21 P - OS/286, OS/386 - CHANGE SEGMENTS
+	AH = E9h
+	AL = function
+h change code segment parameters
+h	change data segment parameters
+h adjust segment limit
+h change segment base address
+	???
+Return: ???
+SeeAlso: AH=E7h"OS/286",AH=E8h"OS/286",AH=EAh"OS/286",AH=EDh"OS/286"
+SeeAlso: INT 31/AX=0007h,INT 31/AX=0008h
+----------21E9-------------------------------
+INT 21 - DoubleDOS - SET TIMESHARING PRIORITY
+	AH = E9h
+	AL = 00h visible program gets 70%, invisible gets 30% (default)
+	   = 01h visible program gets 50%, invisible gets 50%
+	   = 02h visible program gets 30%, invisible gets 70%
+	   = 03h Top program gets 70%, bottom program gets 30%
+	   = 04h Top program gets 30%, bottom program gets 70%
+	   = 05h get current priority
+		Return: AL = priority setting
+Note:	identical to AH=F9h
+SeeAlso: AH=EAh"DoubleDOS",AH=EBh"DoubleDOS",AH=F9h"DoubleDOS"
+----------21E900-----------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - SHELL'S "GET BASE STATUS"
+	AX = E900h
+	DX = drive number to check (0 = A:)
+Return: AL = network pathbase
+	AH = base flags
+h drive not currently mapped to a base
+h drive is mapped to a permanent base
+h drive is mapped to a temporary base
+h drive exists locally
+----------21E905-----------------------------
+INT 21 - Novell NetWare shell 3.01 - MAP A FAKE ROOT DIRECTORY
+	AX = E905h
+	BL = drive number (0=default, 1=A:, ...)
+	DS:DX -> ASCIZ path for fake root (may include server name or be empty)
+Return: CF set on error
+	    AL = error code (03h,0Fh,11h) (see AH=59h)
+	CF clear if successful
+Note:	if drive is not currently mapped, a drive mapping will be created
+SeeAlso: AX=E906h
+----------21E906-----------------------------
+INT 21 - Novell NetWare shell 3.01 - DELETE FAKE ROOT DIRECTORY
+	AX = E906h
+	BL = drive number (0=default, 1=A:, ...)
+Note:	drive remains mapped
+SeeAlso: AX=E905h
+----------21E907-----------------------------
+INT 21 - Novell NetWare shell 3.01 - GET RELATIVE DRIVE DEPTH
+	AX = E907h
+	BL = drive number (0=default, 1=A:, ...)
+Return: AL = number of directories below the fake root
+	    FFh if no fake root assigned
+SeeAlso: AX=E905h
+----------21E908BL00-------------------------
+INT 21 - Novell NetWare shell 3.01 - SET SHOW DOTS
+	AX = E908h
+	BL = 00h	don't return '.' or '..' during directory scans
+	   = nonzero	directory scans will return '.' or '..' entries
+Return: BL = previous show-dots setting
+----------21EA-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - RETURN SHELL VERSION
+	AH = EAh
+	AL = return version environment string
+h		don't return string
+	    nonzero	return string in 40-byte buffer pointed to by ES:DI
+		Return: buffer filled with three null-terminated entries:
+			major operating system
+			version
+			hardware type
+Return: AH = operating system (00h = MSDOS)
+	AL = hardware type
+h IBM PC
+h Victor 9000
+	BH = major shell version
+	BL = minor shell version
+	CH = (v3.01+) shell type
+h conventional memory
+h expanded memory
+h extended memory
+	CL = shell revision number
+----------21EA-------------------------------
+INT 21 - DoubleDOS - TURN OFF TASK SWITCHING
+	AH = EAh
+Return: task switching turned off
+SeeAlso: AH=E9h"DoubleDOS",AH=EBh"DoubleDOS",AH=FAh"DoubleDOS"
+SeeAlso: INT FA"DoubleDOS"
+----------21EA-------------------------------
+INT 21 - OS/286, OS/386 - ALLOCATE HUGE SEGMENT
+	AH = EAh
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AH=E7h"OS/286",AH=E8h"OS/286",AH=E9h"OS/286"
+----------21EB-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - LOG FILE
+	AH = EBh
+	DS:DX -> ASCIZ filename
+	if function C6h lock mode 01h:
+	    AL = flags
+h log file only
+h lock as well as log file
+	    BP = lock timeout in timer ticks (1/18 second)
+Return: AL = error code
+h successful
+h no dynamic memory for file
+	    FEh timed out
+	    FFh failed
+SeeAlso: AH=CAh,AH=ECh"Novell"
+----------21EB-------------------------------
+INT 21 - DoubleDOS - TURN ON TASK SWITCHING
+	AH = EBh
+Return: task switching turned on
+SeeAlso: AH=E9h"DoubleDOS",AH=EAh"DoubleDOS",AH=FBh"DoubleDOS"
+SeeAlso: INT FB"DoubleDOS"
+----------21EB00-----------------------------
+INT 21 - OS/386 VMM - GET A PAGE TABLE ENTRY BY LINEAR ADDRESS
+	AX = EB00h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB02h,AX=EB04h,INT 31/AX=0506h
+----------21EB02-----------------------------
+INT 21 - OS/386 VMM - GET A PAGE TABLE ENTRY BY 16-BIT SEGMENT:OFFSET
+	AX = EB02h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB00h,AX=EB04h
+----------21EB03-----------------------------
+INT 21 - OS/386 VMM - FREE MAPPED PAGES
+	AX = EB03h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB05h,INT 31/AX=0801h
+----------21EB04-----------------------------
+INT 21 - OS/386 VMM - GET A PAGE TABLE ENTRY BY 32-BIT SEGMENT:OFFSET
+	AX = EB04h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB00h,AX=EB02h
+----------21EB05-----------------------------
+INT 21 - OS/386 VMM - MAP PAGES
+	AX = EB05h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB03h,INT 31/AX=0800h
+----------21EB06-----------------------------
+INT 21 - OS/386 VMM - LOCK PAGES IN MEMORY
+	AX = EB06h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB07h,INT 31/AX=0600h
+----------21EB07-----------------------------
+INT 21 - OS/386 VMM - UNLOCK MEMORY PAGES
+	AX = EB07h
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AX=EB06h,INT 31/AX=0601h
+----------21EC-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - RELEASE FILE
+	AH = ECh
+	DS:DX -> ASCIZ filename
+Return: none
+SeeAlso: AH=EBh"Novell"
+----------21EC-------------------------------
+INT 21 - DoubleDOS - GET VIRTUAL SCREEN ADDRESS
+	AH = ECh
+Return: ES = segment of virtual screen
+Notes:	screen address can change if task-switching is on!!
+	identical to AH=FCh
+SeeAlso: AH=FCh"DoubleDOS",INT FC"DoubleDOS"
+----------21EC-------------------------------
+INT 21 - OS/286, OS/386 - BLOCK TRANSFER
+	AH = ECh
+	???
+Return: ???
+----------21EC59-----------------------------
+INT 21 - VIRUS - "Terror" - INSTALLATION CHECK
+	AX = EC59h
+Return: BP = EC59h if resident
+SeeAlso: AH=E7h"VIRUS",AH=EEh"VIRUS"
+----------21ED-------------------------------
+INT 21 - Novell NetWare, Alloy NTNX - CLEAR FILE
+	AH = EDh
+	DS:DX -> ASCIZ filename
+Return: AL = error code
+SeeAlso: AH=CEh,AH=EBh"Novell"
+----------21ED-------------------------------
+INT 21 - OS/286, OS/386 - GET SEGMENT OR WINDOW DESCRIPTOR
+	AH = EDh
+	???
+Return: ???
+Note:	protected mode only???
+SeeAlso: AH=E9h"OS/286"
+----------21EE-------------------------------
+INT 21 - Novell NetWare 4.6, Alloy NTNX - GET PHYSICAL STATION NUMBER
+	AH = EEh
+Return: CX:BX:AX = six-byte address
+----------21EE-------------------------------
+INT 21 - DoubleDOS - GIVE AWAY TIME TO OTHER TASKS
+	AH = EEh
+	AL = number of 55ms time slices to give away
+Return: returns after giving away time slices
+SeeAlso: AH=FEh"DoubleDOS",INT FE"DoubleDOS"
+----------21EE-------------------------------
+INT 21 - VIRUS - "Jerusalem-G", "Pregnant" - INSTALLATION CHECK
+	AH = EEh
+Return: AX = 0300h if "Jerusalem-G" resident
+	AL = 05h if "Pregnant" resident
+SeeAlso: AH=DDh"VIRUS",AX=EC59h,AH=F0h"VIRUS"
+----------21EF-------------------------------
+INT 21 - Novell Advanced NetWare 1.0+ - GET DRIVE INFO
+	AH = EFh
+	AL = subfunction
+h get drive handle table
+h get drive flag table
+h get drive connection ID table
+h get connection ID table (see below)
+h get file server name table
+Return: ES:DI -> shell status table
+Note:	drive handle, flag, and connection ID tables each contain 32 entries
+Format of connection ID table:
+Offset	Size	Description
+h	BYTE	in use flag
+		E0h AES temporary
+		F8h IPX in critical section
+		FAh processing
+		FBh holding
+		FCh AES waiting
+		FDh waiting
+		FEh receiving
+		FFh sending
+h	BYTE	order number
+h	DWORD	file server's network address (high byte first)
+h  6 BYTEs	file server's node address (high byte first)
+Ch	WORD	socket number (high byte first)
+Eh	WORD	base receive timeout in clock ticks (high byte first)
+h  6 BYTEs	preferred routing node (high byte first)
+h	BYTE	packet sequence number
+h	BYTE	connection number
+h	BYTE	connection status (FFh if active)
+h	WORD	maximum receive timeout in clock ticks (high byte first)
+Bh  5 BYTEs	reserved
+Values in drive flag table:
+h	drive is not mapped
+h	permanent network drive
+h	temporary network drive
+h	mapped to local drive
+h	local drive used as permanent network drive
+h	local drive used as temporary network drive
+----------21F0-------------------------------
+INT 21 - Novell Advanced NetWare 1.0+ - CONNECTION ID
+	AH = F0h
+	AL = subfunction
+h set preferred connection ID
+h get preferred connection ID
+h get default connection ID
+h LPT capture active
+h set primary connection ID
+h get primary connection ID
+	DL = preferred file server
+Return: AL = selected file server
+----------21F0-------------------------------
+INT 21 - DoubleDOS - MENU CONTROL
+	AH = F0h
+	AL = subfunction
+h exchange tasks
+h resume invisible job if suspended
+h kill other job
+h suspend invisible job
+Note:	identical to AH=E0h
+SeeAlso: AH=E0h"DoubleDOS"
+----------21F0-------------------------------
+INT 21 - VIRUS - "Frere Jacques" - INSTALLATION CHECK
+	AH = F0h
+Return: AX = 0300h if resident
+SeeAlso: AH=EEh"VIRUS",AH=F1h"VIRUS"
+----------21F1-------------------------------
+INT 21 - Novell Advanced NetWare 1.0+ - FILE SERVER CONNECTION
+	AH = F1h
+	AL = subfunction
+h attach to file server
+		DL = preferred file server
+h detach from file server
+		DL = connection ID
+h logout from file server
+		DL = connection ID
+Return: AL = completion code
+----------21F1-------------------------------
+INT 21 - DoubleDOS - CLEAR KEYBOARD BUFFER FOR CURRENT JOB
+	AH = F1h
+SeeAlso: AH=E1h"DoubleDOS",AH=F2h"DoubleDOS",AH=F3h"DoubleDOS"
+SeeAlso: AH=F8h"DoubleDOS"
+----------21F1-------------------------------
+INT 21 - VIRUS - "F1-337" - ???
+	AH = F1h
+	???
+Return: ???
+SeeAlso: AH=F0h"VIRUS",AX=F2AAh
+----------21F2-------------------------------
+INT 21 - Novell NetWare v3.01+ shell interface - MULTIPLEXOR
+	AH = F2h
+	AL = function
+h broadcast services (see AH=E1h)
+h connection control (see AH=E3h)
+	DS:SI -> request buffer
+	ES:DI -> reply buffer
+Return: ???
+Notes:	this is a multiplexor to access other net interface functions which
+	  were accessed via a separate AH function in older versions
+	the function number in AL is added to CCh to get the old function
+	  number which is desired
+----------21F2-------------------------------
+INT 21 - DoubleDOS - SEND CHARACTER TO KEYBOARD BUFFER OF OTHER JOB
+	AH = F2h
+	AL = character
+Return: AL = 00h successful
+h buffer full (128 characters)
+SeeAlso: AH=E2h"DoubleDOS",AH=F1h"DoubleDOS",AH=F3h"DoubleDOS"
+SeeAlso: AH=F8h"DoubleDOS"
+----------21F2AA-----------------------------
+INT 21 - VIRUS - "PcVrsDs" - INSTALLATION CHECK
+	AX = F2AAh
+Return: AH = AAh if resident
+SeeAlso: AH=F1h"VIRUS",AH=F3h"VIRUS"
+----------21F3-------------------------------
+INT 21 - Novell Advanced NetWare 2.0+ - FILE SERVER FILE COPY
+	AH = F3h
+	ES:DI -> request string (see below)
+Return: AL = status/error code
+	CX:DX = number of bytes copied
+Format of request string:
+Offset	Size	Description
+h	WORD	source file handle
+h	WORD	destination file handle
+h	DWORD	starting offset in source
+h	DWORD	starting offset in destination
+Ch	DWORD	number of bytes to copy
+----------21F3-------------------------------
+INT 21 - DoubleDOS - ADD CHARACTER TO KEYBOARD BUFFER OF CURRENT JOB
+	AH = F3h
+	AL = character
+Return: AL = 00h successful
+h buffer full (128 characters)
+SeeAlso: AH=E3h"DoubleDOS",AH=F1h"DoubleDOS",AH=F2h"DoubleDOS"
+SeeAlso: AH=F8h"DoubleDOS"
+----------21F3-------------------------------
+INT 21 - VIRUS - "Carfield" - INSTALLATION CHECK
+	AH = F3h
+Return: AX = 0400h if resident
+SeeAlso: AH=D5h"Carfield",AX=F2AAh,AH=F7h"VIRUS"
+----------21F400-----------------------------
+INT 21 - DoubleDOS - INSTALLATION CHECK/PROGRAM STATUS
+	AX = F400h
+Return: AL = 00h if DoubleDOS not present
+	   = 01h if running in visible DoubleDOS partition
+	   = 02h if running in the invisible DoubleDOS partition
+SeeAlso: AX=E400h,AH=F5h"DoubleDOS"
+----------21F5-------------------------------
+INT 21 - DoubleDOS - OTHER PROGRAM STATUS
+	AH = F5h
+Return: AL = 00h no program in other partition
+	   = 01h program in other partition is running
+	   = 02h program in other partition is suspended
+SeeAlso: AH=E5h"DoubleDOS",AX=F400h"DoubleDOS"
+----------21F7-------------------------------
+INT 21 - VIRUS - "GP1" - INSTALLATION CHECK
+	AH = F7h
+Return: AX = 0300h if resident
+SeeAlso: AH=F0h"VIRUS",AH=FBh"VIRUS"
+----------21F8-------------------------------
+INT 21 - DOS v??? - SET OEM INT 21 HANDLER
+	AH = F8h
+	DS:DX -> OEM INT 21 handler for functions F9h to FFh
+		 FFFFh:FFFFh resets to original handlers
+Notes:	calls to AH=F9h through AH=FFH will return CF set and AX=1 (invalid
+	  function) if no handler set
+	handler is called with all registers exactly as set by caller, and
+	  should exit with IRET
+SeeAlso: AH=F9h"OEM"
+----------21F8-------------------------------
+INT 21 - DoubleDOS - SET/RESET KEYBOARD CONTROL FLAGS
+	AH = F8h
+	AL = 00h set flags for this program
+	   = 01h set flags for other program
+	DX = keyboard control flags (bit set enables, cleared disables)
+	    bit 0: menu
+	    bit 1: exchange
+	    bit 2: entire keyboard enable/disable
+	    bit 3: Ctrl-C
+	    bit 4: Ctrl-PrtSc
+	    bit 5: Alt/Erase
+	    bit 6: Ctrl-Break
+	    bit 7: Ctrl-NumLock
+	    bit 8: shift-PrtSc
+	    bit 9-13: undefined
+	    bit 14: cancel key (clear keyboard buffer)
+	    bit 15: suspend key
+Return: DX = previous flags
+Notes:	disabling Ctrl-PrtSc will allow the program to intercept the keystroke;
+	  disabling any of the other keystrokes disables them completely
+	identical to AH=E8h
+SeeAlso: AH=E8h"DoubleDOS",AH=F1h"DoubleDOS",AH=F2h"DoubleDOS"
+SeeAlso: AH=F3h"DoubleDOS"
+----------21F9-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = F9h
+SeeAlso: AH=F8h"OEM",AH=FAh"OEM"
+----------21F9-------------------------------
+INT 21 - DoubleDOS - SET TIMESHARING PRIORITY
+	AH = F9h
+	AL = 00h visible program gets 70%, invisible gets 30% (default)
+	   = 01h visible program gets 50%, invisible gets 50%
+	   = 02h visible program gets 30%, invisible gets 70%
+	   = 03h Top program gets 70%, bottom program gets 30%
+	   = 04h Top program gets 30%, bottom program gets 70%
+	   = 05h get current priority
+		Return: AL = priority setting
+Note:	identical to AH=E9h
+SeeAlso: AH=E9h"DoubleDOS",AH=FAh"DoubleDOS",AH=FBh"DoubleDOS"
+----------21FA-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = FAh
+SeeAlso: AH=F9h"OEM",AH=FBh"OEM"
+----------21FA-------------------------------
+INT 21 - DoubleDOS - TURN OFF TASK SWITCHING
+	AH = FAh
+Return: task switching turned off
+SeeAlso: AH=EAh"DoubleDOS",AH=F9h"DoubleDOS",AH=FBh"DoubleDOS"
+SeeAlso: INT FA"DoubleDOS"
+----------21FA--DX5945-----------------------
+INT 21 - PC Tools 7 VDEFEND - API
+	AH = FAh
+	DX = 5945h
+	AL = function
+h NOP
+h uninstall
+		Return: CF clear if successful
+			DI = 4559h
+h ???
+		BL = ???
+		Return: CF clear
+			CL = old value of ???
+SeeAlso: INT 2F/AX=6282h
+----------21FB-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = FBh
+SeeAlso: AH=FAh"OEM",AH=FCh"OEM"
+----------21FB-------------------------------
+INT 21 - DoubleDOS - TURN ON TASK SWITCHING
+	AH = FBh
+Return: task switching turned on
+SeeAlso: AH=EBh"DoubleDOS",AH=F9h"DoubleDOS",AH=FAh"DoubleDOS"
+SeeAlso: INT FB"DoubleDOS"
+----------21FB-------------------------------
+INT 21 - VIRUS - "Cinderella" - INSTALLATION CHECK
+	AH = FBh
+Return: AH = 00h if resident
+SeeAlso: AH=F7h"VIRUS",AX=FB0Ah
+----------21FB0A-----------------------------
+INT 21 - VIRUS - "dBASE" - INSTALLATION CHECK
+	AX = FB0Ah
+Return: AX = 0AFBh if resident
+SeeAlso: AH=FBh"VIRUS",AH=FCh"VIRUS"
+----------21FC-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = FCh
+SeeAlso: AH=FBh"OEM",AH=FDh"OEM"
+----------21FC-------------------------------
+INT 21 - DoubleDOS - GET VIRTUAL SCREEN ADDRESS
+	AH = FCh
+Return: ES = segment of virtual screen
+Notes:	screen address can change if task-switching is on!!
+	identical to AH=ECh
+SeeAlso: AH=ECh"DoubleDOS",INT FC"DoubleDOS"
+----------21FC-------------------------------
+INT 21 - VIRUS - "Troi" - INSTALLATION CHECK
+	AH = FCh
+Return: AL = A5h if resident
+SeeAlso: AH=FB0Ah"VIRUS",AH=FDh"VIRUS"
+----------21FD-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = FDh
+SeeAlso: AH=FCh"OEM",AH=FEh"DOS"
+----------21FD-------------------------------
+INT 21 - VIRUS - "Border" - INSTALLATION CHECK
+	AH = FDh
+Return: AH = 13h if resident
+SeeAlso: AH=FCh"VIRUS",AH=FEh"VIRUS"
+----------21FE-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = FEh
+SeeAlso: AH=FDh"OEM",AH=FFh"OEM"
+----------21FE-------------------------------
+INT 21 - DoubleDOS - GIVE AWAY TIME TO OTHER TASKS
+	AH = FEh
+	AL = number of 55ms time slices to give away
+Return: returns after giving away time slices
+SeeAlso: AH=EEh"DoubleDOS",INT FE"DoubleDOS"
+----------21FE-------------------------------
+INT 21 - VIRUS - "483" - INSTALLATION CHECK
+	AH = FEh
+Return: AH = 00h if resident
+SeeAlso: AH=FDh"VIRUS",AX=FE01h
+----------21FE01-----------------------------
+INT 21 - VIRUS - "Flip" - INSTALLATION CHECK
+	AX = FE01h
+Return: AX = 01FEh if resident
+SeeAlso: AH=FEh"VIRUS",AX=FE02h
+----------21FE02-----------------------------
+INT 21 - VIRUS - "2468"/"Tequila" - INSTALLATION CHECK
+	AX = FE02h
+Return: AX = 01FDh if resident
+SeeAlso: AX=FE01h,AX=FEDCh"VIRUS"
+----------21FEDC-----------------------------
+INT 21 - PCMag PCMANAGE/DCOMPRES - INSTALLATION CHECK
+	AX = FEDCh
+Return: AX = CDEFh if installed
+SeeAlso: AH=DCh
+----------21FEDC-----------------------------
+INT 21 - VIRUS - "Black Monday" - INSTALLATION CHECK
+	AX = FEDCh
+Return: AL = DCh if resident
+SeeAlso: AX=FE02h,AH=FFh"VIRUS"
+----------21FF-------------------------------
+INT 21 - DOS v??? - OEM FUNCTION
+	AH = FFh
+SeeAlso: AH=FEh"OEM"
+----------21FF-------------------------------
+INT 21 - CED (Command EDitor) - INSTALLABLE COMMANDS
+	AH = FFH
+	AL = subfunction
+h add installable command
+	       BL = mode - bit 0 = 1 callable from DOS prompt
+			   bit 1 = 1 callable from application
+	       DS:SI -> CR-terminated command name
+	       ES:DI -> FAR routine entry point
+h remove installable command
+	       DS:SI -> CR-terminated command name
+h reserved, may be used to test for CED installation
+Return: CF clear if successful
+	CF set on error
+	    AX = 01h invalid function
+h command not found (subfunction 01h only)
+h insufficient memory (subfunction 00h only)
+Eh bad data (subfunction 00h only)
+	AH = FFh if CED not installed
+Note:	CED is a shareware DOS command-line enhancer by Christopher J. Dunford
+SeeAlso: AX=0A00h
+----------21FF-------------------------------
+INT 21 - DJ GO32.EXE 80386+ DOS extender - DOS EXTENSIONS
+	AH = FFh
+	AL = function
+h create file
+h open file
+h get file statistics
+h get time of day
+h set time of day
+h stat
+h system
+SeeAlso: INT 10/AH=FFh"GO32"
+----------21FF-------------------------------
+INT 21 - DOSED.COM - INSTALLATION CHECK
+	AH = FFh
+	DS:SI -> "DOSED"
+	ES = 0000h
+Return: ES:DI -> "DOSED" if installed
+Note:	DOSED is a free DOS commandline editor/history buffer by Sverre H.
+	  Huseby
+----------21FF-------------------------------
+INT 21 - Topware Network Operating System - ???
+	AH = FFh
+	???
+Return: ???
+SeeAlso: INT 2F/AX=FF00h
+----------21FF-------------------------------
+INT 21 - VIRUS - "Sunday", "Tumen 0.5", "Hero" - INSTALLATION CHECK
+	AH = FFh
+Return: AH = 00h if "Tumen 0.5" or "Hero" resident
+	AX = 0400h if "Sunday" resident
+SeeAlso: AX=FEDCh"VIRUS",AX=FF0Fh
+----------21FF00DX0078-----------------------
+INT 21 - Rational Systems DOS/4G - INSTALLATION CHECK
+	AX = FF00h
+	DX = 0078h
+Return: AL <> 00h if installed
+	    GS = segment of kernel if nonzero
+SeeAlso: INT 15/AX=BF02h
+----------21FF0F-----------------------------
+INT 21 - FLU_SHOT+ v1.83 - INSTALLATION CHECK
+	AX = FF0Fh
+Return: AX = 0101h if resident
+Notes:	FLU_SHOT+ is an antivirus/antitrojan program by Ross M. Greenberg and
+	  Software Concepts Design
+	the "PSQR/1720" virus calls this function to determine whether
+	  FLU_SHOT+ is present
+SeeAlso: AH=FFh"VIRUS",AX=FF10h
+----------21FF10-----------------------------
+INT 21 - VIRUS - "Twins" - INSTALLATION CHECK
+	AX = FF10h
+Return: AL = 07h if resident
+SeeAlso: AX=FF0Fh,AX=FFFEh
+----------21FFFE-----------------------------
+INT 21 - VIRUS - "08/15"/"Many Fingers" - INSTALLATION CHECK
+	AX = FFFEh
+Return: AX = 0815h if resident
+SeeAlso: AX=FF10h,AX=FFFFh
+----------21FFFF-----------------------------
+INT 21 - VIRUS - "Ontario", "Year 1992"/"B1M92" - INSTALLATION CHECK
+	AX = FFFFh
+Return: AX = 0000h if "Ontario" resident
+	AX = 07C2h (1992) if "Year 1992"/"B1M92" resident
+SeeAlso: AX=FF0Fh,AX=FFFFh/CX=0000h,INT 6B"VIRUS"
+----------21FFFFCX0000-----------------------
+INT 21 - VIRUS - "Revenge" - INSTALLATION CHECK
+	AX = FFFFh
+	CX = 0000h
+Return: CX = 0006h if resident
+SeeAlso: AX=FFFFh,INT 6B"VIRUS"

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