Intermittant lockup of VAX

[Wayne Steinmetz]

Here's the problem.  On a very intermittant occasion, our 785 will hang
anywhere from 5 to 15 minutes.  During this time, nothing entered at
either a terminal or the console will be processed even though characters
are echoed back showing what you typed.  After the elapsed time has passed,
all processing continues as if nothing had ever happened (including a
flood of responses to the commands you typed in while the system was hung).

We are running 4.1BSD on a VAX 11/780 converted to a 785.  Our root drive
is an RM03.  Both the root drive and the tape drive (a TU16 - ugh) share MBA0.
We are using SI 9751's on a SI 9900 controller as our peripheral drives.
We are also running with 12M of memory.

This problem started when we were just a 780 with 3 RM03's and the tape drive
on its own buss, so I don't think the hardware configuration is the problem.

If this type of problem has ever been experienced by anyone out there, we
sure would like to hear about.  Since it's so intermittant, it's very
difficult to get our local FE's in on the problem.


						STUMPED!