OT: how big would it be?

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Wed Oct 20 08:36:59 1999

> Say someone were to home-build a CPU from scratch using only individual
> components, no ICs only modern descrete(?) components. How big would the
> CPU be? For comparison lets say it would be an 8080 clone. Any guesses?

ok, By discrete you meand transistors and diodes.

An 8080 cpu would likely fill a rack 20-25" high with boards.
The memory would have to be core for practicality as a static FF cell
uses lots of transistors and would be huge. using core 64k would likely
fill one or more 6" racks (using 1967ish technology). A uart would fill
a 9x11 board with TTL and that would expand to maybe 4-5 boards as
transistors/diodes.

A pdp-8 (early) had a pannel roughly 24"x50" with flip chip modules mostly
transistors and the 4k core was a 10" tall rack section. for rough
comparison. In many respects the 8080 is a far more complex CPU and would
be significantly bigger. It would also be slow compared to the NMOS part.

Doing it in ttl or bit slices would still be big, I've done that. using
2900 parts(ca mid to late '70s) the CPU equivelent was over 100 chips and
filled 4 10x8" cards.

Allison
Received on Wed Oct 20 1999 - 08:36:59 BST