Help! Mysterious System Lock-Up (SCSI) Problem

[Chuck Forsberg]

In article <131 at ubbs-nh.MV.COM> noel at ubbs-nh.MV.COM (N. Del More) writes:
:The symptoms are a sudden lock-up of the system with the LED on the
:Adaptec and Drive remaining on.  I've reformatted and verified the drive
:three or four times using the Adaptec's ROM based format routine and no
:errors have been reported.  After a reboot, fsck reports no errors except
:those which would be normal after a system crash.

I've seen something vaguely similar.  I'm running 3.2, also
with an Apadtec 1540 running the secondary disk.  About twice
in the last month or so the Adaptec became wedged, with the
activity light on the Wren V on steady.  The rest of the
system appeared to run normally (activity on the main (ESDI)
disk, etc.).

I did not see this problem until I made the SCSI drive secondary.
The first 6 months I used the Wren as the only drive, and shall
revert to that configuration as soon as the 3.x dev sys can compile
all my products.

I have a suspicion the problem is related to heat buildup on the
controller board(s).  I haven't had a wedge since I stopped laying
papers/manuals on top of the i/o boards.