back2root:ibm-pc-ms-dos:interrupts:int_13:start
Int 13h - Disks - WIP
Most disk BIOS calls use the following parameter scheme:
reg | description |
AH | function request number |
AL | number of sectors (1-128 dec.) |
CH | cylinder number (0-1023 dec.) |
CL | sector number (1-17 dec.) |
DH | head number (0-15 dec.) |
DL | drive number (0=A:, 1=2nd floppy, 80h=drive 0, 81h=drive 1) |
DL | drive number (0=A:, 1=2nd floppy, 80h=C:, 81h=D:)
Note that some programming references use (0-3) as the drive number which represents diskettes only. |
ES:BX | address of user buffer |
and return with:
CF | 0 if successful
1 if error |
AH | status of operation (see INT 13,01) |
INT 13 diskette read functions should be retried at least 3 times to assure the disk motor has time to spin up to speed
physical sector numbers can be converted to and from DOS sector numbers with the following formulas:
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back2root/ibm-pc-ms-dos/interrupts/int_13/start.txt · Dernière modification : de frater