The 1983 version of the “IBM XT BIOS Technical Reference” shows these functions are available for the XT but many other programming references say they aren't available until the AT.
This is probably due to misunderstanding the design of the disk BIOS. Upon bootup the hard disk BIOS replaces the default INT 13h diskette handler with the hard disk INT 13h handler.
reg | value | descr |
---|---|---|
AH | 0x09 | |
DL | var | Drive number (0x80=drive 0, 0x81=drive 1) |
reg | descr |
---|---|
CF | 0 (clear) if successful 1 (set) if error |
AH | status (see INT 13,01) |