)
Values for device driver command code:
 00h (0)  INIT
 01h (1)  MEDIA CHECK (block devices)
 02h (2)  BUILD BPB (block devices)
 03h (3)  IOCTL INPUT
 04h (4)  INPUT
 05h (5)  NONDESTRUCTIVE INPUT, NO WAIT (character devices)
 06h (6)  INPUT STATUS (character devices)
 07h (7)  INPUT FLUSH (character devices)
 08h (8)  OUTPUT
 09h (9)  OUTPUT WITH VERIFY
 0Ah (10) OUTPUT STATUS (character devices)
 0Bh (11) OUTPUT FLUSH (character devices)
 0Ch (12) IOCTL OUTPUT
 0Dh (13) (DOS 3.0+) DEVICE OPEN
 0Eh (14) (DOS 3.0+) DEVICE CLOSE
 0Fh (15) (DOS 3.0+) REMOVABLE MEDIA (block devices)
 10h (16) (DOS 3.0+) OUTPUT UNTIL BUSY (character devices)
 11h (17) (European MS-DOS 4.0) STOP OUTPUT (console screen drivers only)
 12h (18) (European MS-DOS 4.0) RESTART OUTPUT (console screen drivers only)
 13h (19) (DOS 3.2+) GENERIC IOCTL
 14h (20) (DOS 4.0, KKCFUNC) DEVICE RESTORE (character device)
 15h (21) (European MS-DOS 4.0) RESET UNCERTAIN MEDIA FLAG
 16h (22) (DOS 4.0) unknown???
 17h (23) (DOS 3.2+) GET LOGICAL DEVICE
 18h (24) (DOS 3.2+) SET LOGICAL DEVICE
 19h (25) (DOS 5.0+) CHECK GENERIC IOCTL SUPPORT
 80h (128)(CD-ROM,DRFAT32) READ LONG
 81h (129)(CD-ROM) reserved
 82h (130)(CD-ROM,DRFAT32) READ LONG PREFETCH
 83h (131)(CD-ROM,DRFAT32) SEEK
 84h (132)(CD-ROM) PLAY AUDIO
 85h (133)(CD-ROM) STOP AUDIO
 86h (134)(CD-ROM,DRFAT32) WRITE LONG
 87h (135)(CD-ROM,DRFAT32) WRITE LONG VERIFY
 88h (136)(CD-ROM) RESUME AUDIO