Int 21 Fn 440C  - Greg Shenaut Aspitape.sys - Interface                    [d]

   AX = 440Ch
   BX = device handle
   CH = category code
       07h tape (ASPITAPE.SYS)
   CL = function
       01h "mtop" - perform tape operation
       02h "mtget" - get tape status
       03h ignore end-of-tape errors
       04h enable end-of-tape errors
   DS:DX -> parameter block (see #1241,#1242)

Return: CF set on error
       AX = error code (see #1366 at AH=59h/BX=0000h)
   CF clear if successful
       DS:DX -> data block

Notes: This device driver is a simple DOS interface to the Adaptec Advanced
     SCSI Programming Interface (ASPI).  It provides the following device
     names as access to the SCSI tape, 'RMTx' (rewind on close) and
     'NRMTx' (NO rewind on close) where x can go from 0 to 3.  There may
     also be the following names 'MTx' and 'NMTx' which default to 1024
     byte blocks.  The names may also have a '$' appended to try and make
     them unique from file names of 'RMT0' etc.
   once opend these devices must be put into RAW mode

See Also: AX=4402h"ASPI"

Format of ASPITAPE.SYS mtop parameter block:
Offset Size    Description (Table 1241)
 00h   WORD    operation code
       00h "MTWEOF" - write an end-of-file record
       01h "MTFSF" - forward space file
       02h "MTBSF" - backward space file
       03h "MTFSR" - forward space record
       04h "MTBSR" - backward space record
       05h "MTREW" - rewind
       06h "MTOFFL" - rewind and unload
       07h "MTNOP" - perform TEST UNIT READY
 02h   DWORD   repetition count

Format of ASPITAPE.SYS mtget parameter block:
Offset Size    Description (Table 1242)
 00h   BYTE    ASPI host ID
 01h   BYTE    SCSI target ID
 02h   BYTE    SCSI logical unit number
 03h   BYTE    device parameters
       bit 0: drive must use fixed-block read and write
       bit 7: drive is an ASPI device
 04h   BYTE    current device state (see #1243)
 05h   BYTE    unit number within driver
 06h   WORD    fixed block blocksize
 08h   BYTE    last SCSI status
 09h   BYTE    last SCSI sense key
 0Ah   WORD    last SCSI opcode (packed) (see #1244)
 0Ch   WORD    residual bytes from SCSI opcode

Bitfields for ASPITAPE.SYS current device state:
Bit(s) Description (Table 1243)
 0 device currently opened in buffered mode
 1 drive currently opened in nonbuffered mode
 2 rewind drive on last close
 3 drive has been written on
 4 drive has been read from
 5 next read will return 0 bytes
 6 EOM will resemble EOF
 7 drive may be busy rewinding

Bitfields for SCSI opcode:
Bit(s) Description (Table 1244)
 0-7   SCSI operation (SCSI packet byte 0)
 8-10  SCSI flags (SCSI packet byte 1)
 11-12 ASPI "Direction Bits" (ASPI SRB byte 3)