Rolm Computers: 1602, 1602A, 1602B, 1666, MSExx (was Data General Nova Star Trek)

Erik Baigar erik at
Fri Apr 29 03:08:32 CDT 2016

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:

> 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

    Thanks again and have a nice weekend,


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