On 2 July 2015 at 17:39, Mike Ross <tmfdm...@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 Electric.
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. Regards, Christian -- Christian M. Gauger-Cosgrove STCKON08DS0 Contact information available upon request.