On Thu, 28 Apr 2016, Christian Kennedy wrote:
I was a staff engineer at ROLM MSC between '82 - '86. By that time by any reasonable measure MSC and telecomm were two utterly different companies that happened to have common parentage; technology cross-over
[Another snip] OK, so you are an insider to the Rolm MSC (=Mil-Spec-Computers?) division and in "your" years there, the design of the MSE series and probably beginning Hawk must have been accomplished?
certainly seems that experience building stuff on the MSC side informed *some* of the early design decisions on the telcom side.
OK, this makes sense to me as you in MSC certainly knew how to design sequencers and things like the connection tables from designing the processors and the MMUs. A very nice example from my point of view is the 3761 card for the Rolms Computers, which is a MIL1553 bus interface: This one essentially is a dedicated sequencer capable of autonomously routing data (and doing simple processing of it on the fly) by a command queue which resides in the hosts memory and is accessed in the background via DMA cycles. This obviously delivers outstanding realtime performance which is not only important in controlling aircraft but the same know how may have inspired the CBX.
TDM of the 12-bit bus through the "connection table", which was a 384 slot recirculating
As mentioned in another posting, there is a nice video from the old days giving a description on the CBX's internals: https://www.youtube.com/watch?v=A8J6CGI6HA0
One of the more interesting was when the switch refused to honor extension status changes and instead entertained itself by ringing each extension *once* in ascending order, then repeating.
Very funny - but those days a reboot of the whole system takes just a fraction of a second - nowadays restarting a complex telephone system containing several servers may take several minutes which is even a bigger nuisance than the lost connection... Thanks again and have a nice weekend, Erik.