🚀 go-pugleaf

I just bought  and installed a Toshiba 12X CD-ROM drive on my Mac. The 
installation appeared to work just fine until I booted up the MacIvory. I
logged in and my lispm-init file was in the process of loading when the mouse 
pointer froze and the Mac was crashed. I tried again and it crashed again 
although not at the same point in loading the lispm-init file. After much 
troubleshooting and gnashing of teeth, here are some of the things I've
learned:

Sometimes the Mac will crash after I launch Genera but before the initial
Lisp Listener window is even displayed. But I've never made it all the way
through loading my lispm-init file.

The crash is typically (always?) preceded by the tape drive erroneously
being accessed (it has a characteristic "chattering" sound).

Since it looks like some kind of problem on the SCSI chain, I've tried
numerous permutations of both the order in which devices are physically
chained to together as well as what SCSI ID they are set to. I've swapped
SCSI cables for spares. Nothing helps. (Although I do manage to pick 
setups where the Mac can't see one or both disk drives when it boots up
--what a black art!) I'm sure all SCSI devices are set to different IDs.
The only thing I know of that is at all potentially funny about about my SCSI
chain is that the Mac's internal disk died a while ago (doesn't mount when
the Mac comes up). It's SCSI ID 0 and terminates one end of the SCSI chain.
Since it wasn't immediately obvious how to terminate the SCSI chain at that
end if I unplug the ribbon cable from the drive, I just left it alone. I hasn't
seemed to cause any problems. The other end of the chain has an active
terminator (I also swapped in a passive terminator just for fun).

If I remove the CD-ROM from the SCSI chain, the MacIvory works again.

Can anyone shed light on this problem?


Here's Genera's "Show Machine Configuration" output in case it's useful:

Macintosh IIci: 68030 CPU, FPA, Apple Extended Keyboard II.
Motherboard: Apple Computer, Inc Macintosh II Built-In Video p/n 
342-0733/342-0734/342-0735/342-0736
             (id #x1F) rev Macintosh II Family 1.0 18-Jul-89.
NuBus slot C: Symbolics Inc. MacIvory Processor p/n MacIvory-3 (id #x14F) s/n 
030412 rev 20.0, 2.0MW,
 Ivory rev4A.
NuBus slot E: A-Series Ethernet A-Series p/n SS DEV (id #x8) rev 001.
SCSI address 0: QUANTUM P40S 940-40-94XX A.2, direct access.
SCSI address 2: QUANTUM FIREBALL1080S 1Q09, direct access, 2134305 blocks of 512
bytes (1042M bytes
                total).
SCSI address 3: QUANTUM LPS525S 3110, direct access, 1027548 blocks of 512 bytes
(502M bytes total).
SCSI address 5: TEAC MT-2ST/N50 RV E, removable sequential access.