Function 440Dh (68-13) IOCTL: Generic IOCTL Request ≥ DOS 3.2
This subfuntion provides low-level control over a block device.
On entry: AH 44h
AL 0Dh
BL Drive number (0=default, 1=A, etc.)
CH 08h (Major code)
CL Minor code:
40h = Set device parameters
60h = Get device parameters
41h = Write track on logical device
61h = Read track on logical device
42h = Format and verify track on logical
device
62h = Verify track on logical device
DS:DX Pointer to parameter block