[ILUG] SCSI woes

[Kenn Humborg]

I was hoping to do a bit more experimenting before posting
here, but it's getting late, all this plugging/unplugging,
powering up/powering down and dismantling of boxes is
keeping people awake...

Mixed success with my latest retro-computing foray.  The
TK50Z tape drive seems to work fine.  For some reason, 
the SCSI driver doesn't find it on boot, but a quick
echo add-single-device 0 0 1 0 > /proc/scsi/scsi soon
brings it to its senses.  Then various mt commands
seem to work fine.  Must try reading/writing data 
tomorrow...  Anyway, this suggests that the host 
adapter is pretty much OK (except for not spotting 
stuff on boot).

But the disks are giving me grief.  The disks live in 
a 2-disk cabinet (a BA42, if it means anything to you).
If I disconnect both disks from the internal ribbon
cable and connect one external connector to the PC and
put a terminator on the other, Linux boots fine.
So it doesn't look like a cabling problem.

If I connect one (or both) of the disks and leave them
powered off, the SCSI driver stalls during boot and
after a few seconds throws up a load of diagnostics
and repeats this every few seconds.  There's no obvious
'timeout' or other error reason given.  (I know...
I should have written it down.  THWACK!)

If I power up the disk, the driver stalls completely 
on boot.  No messages at all.

The host adapter is an Adaptec ADP1505, the driver is
the aha152x.  I see that the driver hasn't been updated 
since 1996.  The disks are RZ55s.

Any words of wisdom from the SCSI veterans out there?
Is this more or less likely to be a driver problem,
a disk problem, or some wierd cabling problem?

Thanks all,

Kenn