INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS
AX = 4403h
BX = handle for device "SCSITAPE"
CX = number of bytes to write
DS:DX -> SCSITAPE control block (see below)
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: INT 78/AH=10h

Format of SCSITAPE control block:
Offset  Size    Description
00h    WORD    command type
'F' Format (argument 1 = interleave, argument 2 = format type)
'E' Erase
'R' Rewind
'L' Load
'N' No Load
'S' Space (argument 1 = count, argument 2 = type)
'M' File Mark (argument 1 = count)
'A' Reassign
02h    WORD    argument 1
04h    WORD    argument 2
06h    WORD    segment of command buffer
08h    WORD    offset of command buffer
0Ah    WORD    length of command buffer

See also: 214405

214403 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS