Replicas - was Re: *** Ideas needed for developing interactive

From: Ethan Dicks <>
Date: Sun Sep 12 23:40:48 2004

On Sun, Sep 12, 2004 at 09:28:25PM -0700, vrs wrote:
> > An SMT transistorized machine would be an interesting project, but hell to
> > debug I would imagine.
> One could perhaps build it out of modules -- make SMT versions of Rxxx
> modules, etc., then use those to build up the CPU. Then one could debug at
> the module level before tackling the whole thing.

One could, but the interconnection thing would be a killer - I suppose the
cheapest way to do it might be a "fatherboard" arrangement with a nest of
pins for the backplane, and pin receptacles on the modules (though the
more traditional pins-on-the-module-and-sockets-on-the-motherboard would
be about the same cost, probably). In the case of a PDP-8 design, there
are several busses that might have to be run, but you could sort-of cheat
and aggregate the registers (like is done with the 6 x M220 cards in an
-8/i or -8/L) to group things together. I would expect that in addition
to the registers themselves (AC, MD, MA...) whatever memory there was would
fit nicely in the same area.


Ethan Dicks, A-130-S      Current South Pole Weather at 13-Sep-2004 04:30 Z
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Received on Sun Sep 12 2004 - 23:40:48 BST

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