Disabling SCSI parity checking to dump disk on ACB4000 MFM-SCSI adapter?

[Michael Engel]

On 9/23/20 8:54 PM, Grant Taylor via cctech wrote:
> On 9/23/20 12:51 PM, Michael Engel via cctech wrote:
>> Do you know if is there another OS which would make it easier to 
>> change crucial SCSI parameters in the driver (config) or maybe a 
>> specialized tool that could help me to image the disk?
>
> Try booting off of a Linux live CD / DVD and seeing if it will behave 
> any different
Not really, unfortunately. The error messages are a bit cryptic:

[ 1069.277571] (scsi8:A:0:0): Sending SDTR period 45, offset 0
[ 1069.278961] scsi 8:0:0:0: Attempting to queue a TARGET RESET message
[ 1069.278964] CDB: 0x12 0x0 0x0 0x0 0x24 0x0
[ 1069.278975] scsi 8:0:0:0: Command not found
[ 1069.278979] aic7xxx_dev_reset returns 0x2002
[ 1069.279286] (scsi8:A:0:0): Sending SDTR period 45, offset 0
[ 1069.280736] scsi8: Slave Alloc 1
[ 1069.543400] scsi target8:0:1: asynchronous
[ 1069.543416] scsi8: target 1 using asynchronous transfers
[ 1069.543420] scsi8: Selection Timeout on A:1. 0 SCBs aborted

It seems that the problem lies in the firmware of the ACB4000, which 
doesn´t seem to support some standard commands, e.g. the INQUIRY 
command. Most recent Linux SCSI drivers seem to use this command.

Some information on this problem can be found here:
https://www.zot.org/~hamish/hacks/acb-4000.html

There´s a thread (in German, sorry) in which someone tried to get a disk 
on an ACB4000 to work:
https://de.comp.os.unix.linux.misc.narkive.com/ti21cHO0/scsi-1-platte-unter-linux-ansprechen
and somebody else (also in German...) claims that he could run a disk on 
an ACB4000 (from an Atari SH204) on an Adaptec 1542:
https://forum.classic-computing.de/forum/index.php?thread/18576-wie-programme-vom-pc-auf-atari-mega-st-bringen/&pageNo=2

So maybe an Atari ST with an ACSI->SCSI adapter might help. That seems 
to be one of the machines we don´t have here...

-- Michael