what is 'jump to 0' is it trouble?

[hoffman at pittvax.UUCP]

I had exactly the same problem on our 11/45 when fooling around
with 2.9.  I found that one of the interrupt vectors had not been
initialized and, when the device interrupted, it ended up calling
an interrupt service routine at location 0.  My first suggestion is
to check your l.s to make sure that all of your devices are configured.
My problem was with RP03s -- they're so old that it's no wonder that
Berkeley didn't have them configured properly.

You might also try putting a halt at instruction location 0 and
looking at the stack after it halts. It should show you where
you were before it bombed.

Good luck,
-- 
Bob Hoffman, N3CVL
Pitt Computer Science