BSD Unix machines hanging

[Root Boy Jim]

In <23407 at gwen.cs.purdue.edu>, you write:

>We have been experiencing a rather odd and intermittant problem with
>our Unix machines. It is not confined to a particular machine or Unix;
>it has happened with 4.2, 4.2 NFS, and 4.3 BSD on VAX 780, 785 and
>uVAX II machines.
>
>Symptoms: The machines appear to lock up, users cannot get characters
>echoed, console is hung. In short, the machine seems dead. The only
>way to recover is a reboot. 
>
>However, the machine is still running in a sense. One can ping the
>machine in question, and it responds. One can open a TCP connection to
>the machine, and the connection succeeds, but hangs at that point.

You didn't say what kind(s) of disks/controller(s) you have. We have
an SI 9900 controller connected to a CDC 9766 (rm05) and an eagle.
Every so often the controller goes out to lunch, but is fortunately
awakened by flipping the controller reset switch. Anyone doing I/O
thru this beast will hang until the remedy is applied. Anyone doing
I/O only to our DEC Massbus rm03's will be unaffected. This is annoying,
but not disasterous except when dialing in from home.

	(Root Boy) Jim Cottrell		<rbj at icst-cmr.arpa>