How do you make your UNIX crash ???

[der Mouse]

In article <11313 at dog.ee.lbl.gov>, torek at elf.ee.lbl.gov (Chris Torek) writes:
> [...], one should note that the more complex something is, the easier
> it is to make a mistake when implementing it.  Bugs are often found
> in complex-addressing-mode CPUs (until fixed in a later revision)
> when:

> [...]

We came across a most mysterious bug once: our MicroVAX suddenly
started coredumping in test(1), but only for this one user.  After much
disbelief and head-scratching, we eventually determined that the
coredump was due to something going wrong when the pushes involved in
taking the trap for one of the emulated instructions involved pushing
past a page boundary.  I think it might have been only when it took a
pagefault on the new page.  The user in question had just the right
size environment to tickle this.  I'm still not sure exactly *what* was
going wrong when this happened....

About then, we realized that the coredumps had started just about the
time the service guys had done some sort of maintenance operation that
involved replacing the CPU...we called them back and said "we can't
really describe how it's broken; we're not entirely certain we can
state it to ourselves.  But it's definitely broken; please replace it".
They did.  (Our sysadmin at the time was good at persuasion.)

					der Mouse

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