Relay computers

From: John Lawson <>
Date: Fri Sep 24 13:39:36 2004

On Fri, 24 Sep 2004, Dwight K. Elvey wrote:

>> From: "Ade Vickers" <>
>> At 22:50 23/09/2004, you wrote:
>> Cheers,
>> Ade.
> Hi Ade
> I think your counts are way off. As I recall, I did a schematic
> a while back for a single bit of an alu and it only took about
> 4 or 5 relays. I did use DC and diodes for steering.

   I also think that these relay counts are a bit excessive. We are
forgetting the huge amount of wisdom available on relay logic design,
starting mainly with AT&T and the Bell System, and many other authors who
wrote on this subect from the 20s thru the 60s. There are several
branches of mathematics and combinatorial logic devoted to the analysis
and optimization of relay logic systems - which of course is being rapidly
forgotten today for obvious reasons.

   That makes these books cheap / free :

Engineer's Relay Handbook, various authors (Hayden)

Switching Circuits and Logical Design, Caldwell (Wiley)

Design of Switching Systems, Ritchie* (Bell System)

and those are just the three cluttering up my desk - there are probably 10
more on the shelves.

   Point being - the design of a modern Relay Computer must start with the
Boolean design and equations, to which are then applied the well-known and
well-documented principles of Optimization as they concern
electro-mechanical logic. Then the practical (also well-documented)
aspects of: speed, timing, current draw, contact protection, etc. Layout
and wiring optimization come next... not the least being: when it breaks,
can you find it and fix it?



Note: This book is by the "C" language author's Father....
Received on Fri Sep 24 2004 - 13:39:36 BST

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