cp read fault (4.2BSD on VAX 780)

[Kevin Sullivan]

we have had about 50 crashes in the last ten months.  the diagnostic
says cp read fault.  the machine finally dies with panic: mchk.  DEC
A bunch of register values get printed out.  DEC field service informs
us that the timeout address printed is the only good clue,  but that it
simply indicates the interrupt level of the problem device, not the
device itself.  since almost everything on our unibus is at priority level
5,  they are having problems isolating the malfunction.  in fact,  we have
replaced deuna, dmr, 8 dz's,  the dw780,  cables,  etc. - i.e. almost
everything,  but the problem persists.  has anyone else had this kind of
problem.  if so,  do you have any advice or info that might help us?

kevin sullivan
tufts university
kjs%tufts at csnet-relay