[HECnet] old problem with 11/34 solved

[Dave McGuire]

  Hey folks.  Remember when I was losing my mind trying to get my
PDP-11/34 up and running RSX-11M just before VCF-East in April, and it
kept crashing during sysgen?

  Well...it turns out that my FP11-A board was flaky.  It failed some of
its tests in XXDP.  Then I ran some XXDP tests on the processor itself,
and it failed in a couple of places in the MMU tests.  That explains why
it ran RT11 just fine, but not a more demanding-on-the-MMU OS like RSX.

  So I replaced the FP11-A with one that passes its tests (no time to
troubleshoot it right now, and I have a few spares) and was about to
start working on the CPU, when I decided to re-run the MMU tests.  Now
the MMU checks out fine.  I put the originally flaky FP11-A board back,
and the MMU tests fail again...so somehow this FP11-A is wreaking havoc
with the MMU.

  So now the machine is about midway through phase II of sysgen, running
great, and seems to be rock solid.

               -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA