On Jan 29, 9:57 am, dr pepper <[email protected]> wrote:
> Fascinating.
>
> Reminded me of colosus, maybe thats where some of the ideas are from,
> must cost a mint to make one of those, interesting looking at the vid
> that the time counters at the bottom of the machine are counting in
> binary, maybe bcd, the tubes higher up must be bcd to decimal
> translater matrixes.
>
> I really like the planar dekatron, if someone finds a load of those
> stockpiled it'll make a few quid, but thats not gonna happen.
>

Believe it or not, digital logic predates ICs. The British Colosus to
ENIAC, UNIVAC, and all the computers built to the late 50s used vacuum
tubes. To bad there's no technical documents on Colosus. They probably
built more than one, but it was a very classified project, and they
destroyed all documentation on it. The British have recently
resurrected the Harwell WITCH dekatron computer:

http://en.wikipedia.org/wiki/Harwell_computer

Computer manufacturers were early adopters of transistors, so by about
1958, a tube computer was considered an old design. Of course, at that
time there were less than 100 computers in the world (?).

But with discrete components, you have a lot of options for your
logic. Yes, you can build binary counters, and decode the binary or
BCD results, or you can use ring counters which needs no further
decoding.

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