VAXstation 3100/M76 Crashing when Warm

When I first got my VAXen the 3100/M76 was crashing on repeat. At that time it was incredibly hot in the UK. I did wonder if it was the cause at the time, but more recently have had OpenBSD running quite reliably. The past few days I have been experimenting with running NetBSD instead of OpenBSD, since it includes an Xserver (albeit unaccelerated) and isn't statically linked. It led to some posts on port-vax and here are some of the more interesting messages. I hope they are useful to someone and that Antonio doesn't mind me sharing.

From: Antonio Carlini
To: port-vax@NetBSD.org
Subject: Re: VAXstation 3100/m76 stray interrupt
Flags: replied, seen, list
Date: Tue 16 Aug 2016 22:00:50 BST
Maildir: /personal/Lists
List: port-vax.NetBSD.org

On 16/08/16 21:14, Johnny Billquist wrote:
>
>
> I would suggest running VMS on the box for a while, and try to stress
> the memory subsystem a lot. VMS have excellent error logging and
> management, so if you have any problems, you should be able to get
> more details that way. There is also built in tests in the machine,
> that could be used. But you'll need to find the manual to work out
> which tests to run. Maybe bitsavers have them, I haven't checked.
>

I had a VS3100/76 many years ago (still have it in fact!) that would
exhibit [correctable?] memory errors when things got warm (i.e. in the
summer).

This was when I was in DEC so with a bit of hunting I found the
description of the problem. IIRC there was an issue with the 74LS243 bus
transceivers.
If you had a mainboard that had a particular batch of a particular
manufacturer's variant you were likely to be susceptible to the issue.
I'm reasonably sure that I only saw correctable errors and I only saw
those because I looked in the error log. But it was a long while ago
so there may have been the odd crash too.

Anyway, it's entirely possible that NetBSD doesn't know what to do with
the interrupt reporting a memory error.

So perhaps you ran NetBSD on a warmer day?

Or perhaps it is something else entirely?

Antonio

To which I responded:

From: Aaron Jackson
To: port-vax@NetBSD.org
Subject: Re: VAXstation 3100/m76 stray interrupt
Flags: seen, list
Date: Wed 17 Aug 2016 01:48:39 BST
Maildir: /personal/Lists
List: port-vax.NetBSD.org


> I had a VS3100/76 many years ago (still have it in fact!) that would
> exhibit [correctable?] memory errors when things got warm (i.e. in the
> summer).

I was wondering if this was the problem. When I first got my VAXstation,
it was very hot and was hardly working at all, I think OpenBSD was
crashing too. It's not as hot now, OpenBSD is stable but NetBSD is
refusing to boot. I'll investigate more tomorrow.

Very interesting stuff. Thanks!

Aaron.

I haven't had a day cold enough to confirm this yet, but will be sure to update this if one comes along.

Related posts:

• OpenBSD on a VAXstation 3100 M76
• Found a HP 712/60

Tags: oldcomputers