UNIX reboots

[Rick Summerhill]

I keep seeing the undercurrent of a thread lately:  Someone
has an IBM clone PC type machine with a standard ISA bus.  DOS boots fine
and all diagnostics (which are usually, inherently DOS oriented) check out
fine.  But when UNIX tries to boot, with some combination of hardware
factors, it won't.

Here's another example, one related to my machine: I recently
purchased a huge new tower case with a 330w power supply (I want to
add new drives, etc., and I have 18 Mbytes of memory, counting video
etal.)  My old power supply is 200w.  If I sit the power supplies side
by side, and boot UNIX on either, then it boots from the old power supply,
but not from the new, larger one!  One would think the new power supply is
bad, right?  Yet when I run diagnostics, everthing checks out OK on the
new one.  Moreover, if I put it on the bench and draw lots of current
from the 5v lines - up to 25 amps - everything checks out OK!  The voltages
are clean as can be.  In addition, it boots DOS just fine.

Now, when it fails to boot UNIX, it does so in sporadic ways.  Usually, it
fails to get through checking the /usr filesystem, but sometimes it actually
completes the boot procedure and waits for a login.  Then, whenever
I start X (using a Sigma Legend video card), it always reboots.  Rebooting
here means that it goes back to the bios and does a memory check as if
it were just turned on - as if the 5 volt line dropped for an instant and
then came back.

Does anyone know what is going on here?  Are there combinations of hardware
that don't like each other?  Can oscillators in the hardware effect each
other?  Etc., etc.  Any help would be greatly appreciated.

--Rick Summerhill



--
Rick Summerhill          	Phone:  (913)532-6311
CTA, Cardwell Hall       	FAX:    (913)532-5914
Kansas State University  	Net:    rrsum at hermzel.ksu.ksu.edu
Manhattan, KS 66506