23 Jan
2010
23 Jan
'10
6:13 p.m.
Randy Dawson wrote:
A relay computer is something I too would like to build if ever I were to come
across enough suitable relays.
A couple of years ago I fleshed out the Simon design and wrote it up, as well
as breadboarding a small portion of it.
(http://people.cs.ubc.ca/~hilpert/e/simon/index.html)
Ultimately, I felt it would be unsatisfying to implement it fully, due to it's
limitations.
Funny how the adder circuit keeps coming up, one of those perennial topics in
computing. I too worked on optimising it.
(http://people.cs.ubc.ca/~hilpert/e/simon/imp.html#ALU). Later I saw Zuse's
design and noted that I had -almost- arrived at the same design. The number of
contacts and basic circuit were identical, but I missed one final optimisation
of flipping some contacts in the sum circuit so the relays required would be
4-pole & 4-pole rather than 5 & 3 (the former tending to be a little more
practical in the real world, of course).
Date: Sat, 23 Jan 2010 10:45:57 +0000
From: philip at axeside.co.uk
To:
Subject: Re: starting my relay computer project
Have you read "The Computer - My Life" by Konrad Zuse (New York:
Springer Verlag, 1993. ISBN 0-387-56453-5)? Mostly historical /
autobiographical, but some good technical bits on the evolution of relay
logic as Zuse's designs got more mature. Interesting how the number of
relays per bit he needed in his adder circuit got less and less...
Phillip,
Thanks for the lead on the book, and no I have not seen it.
The Harry Porter relay computer and others seem to all use Zuse 4PDT relay design for the
alu.
If you have not been to his web site, take a look at the youtube, It appears that there
are a lot of us relay computer guys out there (when the you tube finishes there are
related links presented).
Somewhat related, and also my interest, are the marble machines that do logic. Of course
there is the Edmund Scientific NIM plastic 3 bit machine, analog computers and dont forget
Martin Gardner and the deck of cards paper computers.
There is more to classic computing than collecting microprocessor based machines.