out-of-mainstream minis

Christian Gauger-Cosgrove captainkirk359 at gmail.com
Thu Jul 2 22:33:35 CDT 2015

On 2 July 2015 at 17:39, Mike Ross <tmfdmike at gmail.com> wrote:
> Take the IBM System/7. Successor to the 1800, succeeded by the
> Series/1. They were *ubiquitous* - one in every telephone exchange in
> the USA, I've heard. They even made a special ruggedised version for
Being into telephony, I can say that I've not heard anything about IBM
System/7 machines being used in exchanges. I do know that the WECo ESS
exchanges did, of course, have computers. But the ESS exchange
computers were custom systems and architectures built by Western

The 1ESS/1AESS computer architecture is however, nearly completely
extinct. There are, I believe, only two 1ESS/1AESS switches left. One
is a partial, and non-functional exchange at the museum of
communications in Seattle; the processor is complete, and it has one
of each requisite switching frame, but it can't be used as they need
to recompile the software that runs it (which isn't possible as
they're lacking the crucial internal compiler that ran on WECo's IBM
System/3x0 machines). The other 1ESS/1AESS switch is a complete and
functional unit, still in service, last I heard. But there are plans
to scrap it and put in a modern switch in its place. Saving it would
be a difficult proposition, to say the least.

Christian M. Gauger-Cosgrove
Contact information available upon request.

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