Hardware Bios Commands - Adaptec AHA-1740A Technical Reference Manual

EISA-to-Fast SCSI Host Adapter
AH (Hex)
11
20
40
80
AA
BB
CC
FF

Hardware BIOS Commands

(AH) = 00h - Reset Disk System
This function does nothing to SCSI drives. Regardless of drive number, this request
is passed to the original Int 13h vector so that floppy and non-SCSI drives may be
reset.
(AH) = 01h - Read Status of Last Operation
The status of the last operation performed is returned. The status is reset to zero.
(AH) = 02h - Read Desired Sectors into Memory
The sectors requested are read from the disk to system memory. A Read (Extended)
command (SCSI Operation Code 28h) is used to execute this function.
(AH) = 03h - Write Desired Sectors from Memory
The sectors requested are written from system memory to the disk. A Write (Ex-
tended) command (SCSI Operation Code 2Ah) is used to execute this function.
(AH) = 04h - Verify Desired Sectors
The sectors requested are verified to be correctly written on the SCSI disk. A Verify
command (SCSI Operation Code 2Fh) with the byte check bit set to zero is used to
execute this function. If the verify function is not supported by the selected disk, a
Read (Extended) command is used and the data is thrown away.
(AH) = 06 - Identify SCSI Devices
This is a special call that is used to return the first supported SCSI drive. If there are
only SCSI drives, then the return value will be 80h. If there is a SCSI and a standard
controller, then the return value will be 81h.
Definition
ECC Corrected Data Error: Returned SCSI ASC:
17h - Recovered Read Error without ECC
18h - Recovered Read Error with ECC
General Controller Failure: Returned SCSI ASC:
01h 03h 05h 06h 07h 08h 09h 1Bh 1Ch 1Dh 40h 41h 42h 43h 44h 46h
47h 48h 49h
Seek Operation Failed: Returned SCSI ASC:
15h - Seek Positioning Error
02h - No Seek Complete
Time-out: Host adapter not responding to BIOS
Device Not Ready: Returned SCSI ASC:
04h - LUN not ready
28h - Unit Attention, Ready
29h - Unit Attention, Power on
2Ah - Unit Attention, Mode Select Change
Undefined error occurred: A SCSI ASC other than those listed was
returned by the target.
Write Fault: Not returned by AHA-1740A/1742A BIOS
Sense Operation Failed: An error occurred issuing the SCSI request
sense command to the target.
Onboard BIOS Interface
7-7