OT: how big would it be?

From: Philip.Belben_at_pgen.com <(Philip.Belben_at_pgen.com)>
Date: Thu Oct 21 09:52:53 1999

> IIRC, the 8080 was about 4000 MOSFET transistors. If you implemented it
> with individual FETs, and packed it densely, I think you could fit it in
> a 10.5" high rack space easily, and a 5.25" high rack space with difficulty.
> Of course, you'll need plenty of forced air cooling. From a serviceability
> point of view, building it less densely is clearly better.

True.

> If you implemented it with bipolar transistors configured as saturating
> logic, it would require perhaps twice as many transistors and a lot more
> resistors for TTL logic, or 50% more transistors, a lot of diodes, and a
> lot of resistors for DTL logic.

Also true. A lot of the power estimates have been based on the assumption that
we have bipolar transistors. What about discrete mosfets? We could do NMOS or
even CMOS designs directly that way...

I liked Hans's suggestion (which I have now deleted, alas) of a museum exhibit
with three identical computers, but with processor as single chip, board of
gates, and rack of trannies for comparison. It does provide a service that you
couldn't get another way...

... or could you? Didn't PDP8 come in all three versions?

I've often wondered if you could build a transistorised computer without pcbs at
all. You know, trannies on tag board, little plugs bolted onto the ends (or on
flying leads) and so on... I was assuming ECL for two reasons - if you use
early transistors (Ge), ECL would probably be the only way to go at all fast;
and ECL gives the advantage of easy differential line drivers and receivers for
long interconnects.

Philip.






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Received on Thu Oct 21 1999 - 09:52:53 BST