Subject: Re: [multicians] hardware maintenance panel
Date: Fri, 10 Sep 2010 15:18:50 -0400
From: Chris Jones <>
On 09/10/2010 02:11 PM, John W Gintell wrote:
It must be a Multics machine - I don't think any other architecture had
36 bit words, segment numbers, PTWs and SDWs. I don't recognize it
though. I'd guess it is an 8/70M because it looks pretty modern, but
perhaps it was something built for testing.
It sure looks to me like the Level 68 CPU maintenance panel we had at
CISL (for most of my time there we had a Level 68 CPU and a DPS-80/70M
CPU). As I recall, the DPS 8 panel was black and didn't have as many
switches or lights, depending more on a Level 6 maintenance processor
to provide many of the same functions. I always thought the Level 68
panel was the greatest computer panel I ever saw, but I'm a sucker for
switches and "blinkenlights".
Sorry I can't give many details on its operation. I do recall it was
one of a pair on the inside of the doors of the CPU (but we usually kept
the doors open to expose the full glory of the panel). I think this was
the right hand panel; the left panel might have been called the display
panel rather than the maintenance panel, but don't quote me. That one
we usually kept displaying the EAQ registers, and you could watch the
"worm" of the idle loop scroll in a circle to get an idea of how busy
the machine was or whether it was hung (REAL experts could watch the
pattern of lights as the system booted and pick out where in that
process the system was, or if it had hung).