Computing from 1976

[Noel Chiappa]

    > From: Paul Koning

    > The only asynchronous computer I can think of is the Dutch ARRA 1

Isn't the KA10 basically asynchronous? (I know, it has a clock, but I'm
not sure how much it is used for.)

The thing is I recall reading (where, I don't now remember) that the CPU is
organized with 'go' pulses leading from one block of circuity to another, and
it uses delay lines to time out the passage of these pulses, so if you wanted
the CPU to be as fast as possible, you went around to each delay line and
tweaked them down until things started to fail, and then backed off a bit.


Other CPUs of that era might be the same. There's an amusing description
of the Multics CPU here:

  http://www.multicians.org/mga.html#6180

"The 6180 processor was among the last of the great non-microcoded engines.
Entirely asynchronous, its hundred-odd boards would send out requests,
earmark the results for somebody else, swipe somebody else's signals or data,
and backstab each other in all sorts of amusing ways which occasionally
failed (the 'op not complete' timer would go off and cause a fault). Unlike
the PDP-10, there was no hint of an organized synchronization strategy:
various 'it's ready now', 'ok, go', 'take a cycle' pulses merely surged
through the vast backpanel ANDed with appropriate state and goosed the next
guy down."

	Noel