non-IBM drives in PS/2 Model 80

[reed at m.cs.uiuc.edu]

In preparation to running AIX on my PS/2 Model 80, I've been trying
(unsuccessfully) to install an internal CDC Wren V.  At present, I have
a 70 MB IBM drive in the system enclosure.  The Wren V is model 94186-383H
(383.3 MB unformatted) and ESDI compatible.  After trying a seemingly
endless series of cabling and jumper setting variations, I'm stuck.  As
best I understand it, in the Model 80, drives are radially connected, rather
than daisy chained.  I've jumpered the new drive as drive  under the
assumption that drive 1 is the current IBM drive.  From the IBM and
CDC documentation, it's not clear which drive should be terminated; I
tried both combinations with no luck.

When I boot with the IBM diagnostics diskette, the system reports
a 10491 error then finds two drives.  However, as the diagnostics continue,
it reports that the new drive is 316 MB and then fails the seek test.
This happens as soon as the disk controller sends the first command to
the drive.  Attempting to boot DOS just hangs the system.

Anyway, I'm out of ideas.  Does anyone have suggestions on what I
might try?

Dan Reed
Department of Computer Science
University of Illinois at Urbana-Champaign
reed at a.cs.uiuc.edu