Int 21/AX=440Ch

Greg Shenaut ASPITAPE.SYS - INTERFACE

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 #01554,#01555)

Return:
CF set on error
AX = error code (see #01680 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 01554) 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 01555) 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 #01556) 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 #01557) 0Ch WORD residual bytes from SCSI opcode

Bitfields for ASPITAPE.SYS current device state: Bit(s) Description (Table 01556) 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 01557) 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)

Category: Disk I/O Enhancements - Int 21h - G

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