INT 21,44,D / IOCTL,D - Generic I/O for Block Devices

AH = 44h

AL = 0D

BL = drive number (0=default, 1=A:, 2=B:, 3=C:, ...)

CH = device type

= 08 for disk drive (block device)

CL = minor function code

= 40 set device parameters

= 41 write track on logical device

= 42 format/verify track on logical drive

= 47 set access flag (DOS 4.x)

= 60 get device parameters

= 61 read track on logical device

= 62 verify track on logical drive

= 67 get access flag (DOS 4.x)

DS:DX = pointer to parameter block

on return

AX = error code if CF set (see ~DOS ERROR CODES~)

- provides device independent primitive control operations

- implemented from DOS 3.2

- see IBM DOS Technical Reference Manual for more details