Failing PowerPC system...

[Jarod Wilson]

On Thursday 13 March 2008 05:44:30 pm Jarod Wilson wrote:
> On Thursday 13 March 2008 10:46:49 am Jarod Wilson wrote:
> > On Thursday 13 March 2008 12:23:18 am Dan Williams wrote:
> > > On Thu, 2008-03-13 at 00:01 -0400, Jarod Wilson wrote:
> >
> > [OS X lockups and sha1sum failures under linux on ppc mac]
> >
> > > > So anyone have suggestions for diagnosing exactly what component is
> > > > starting to fail? My first thought was cpu, then motherboard, and now
> > > > memory... I figure memory is probably the easiest place to start
> > > > poking, but is there a memtest86 equivalent for PowerPC? If not, I
> > > > guess its memory stick roulette, and on to other hardware from there.
> > > > Open to any and all suggestions...
> > >
> > > RAM is definitely the first place to look.  You also might just want to
> > > take the RAM out and firmly reseat it.  That's fixed these sorts of
> > > things for me a few times before.
>
> [...]
>
> > Just found http://pyropus.ca/software/memtester/ and will see if that
> > builds/runs/does something useful under ppc32 linux or os x... There's
> > also a non-free (but fairly cheap at $1.39) memtest os x at
> > http://memtestosx.org/.
>
> Never mind. Memory stick roulette suggests either all the sticks are bad,
> or something else is failing. Backed off to running my sha1sum test with
> only 1 stick at a time, and could reproduce the sha1sum failures on each of
> them. Failures seem to happen more frequently after a number of iterations,
> like after the system heats up a bit. On with the show...

So I finally yanked the mammoth heatsink and processor module, and noticed 
that what I presume was once thermal paste between the cpus and the heat sink 
looks a lot more like a thin layer of dirt than thermal paste. I cleaned off 
both the cpus and heatsink, laid down some new thermal paste, buttoned 
everything back up, and now 1000 consecutive sha1sums all return the same 
result. Woo! Back in business...

-- 
Jarod Wilson
jwilson at redhat.com