back to the AGC, was Re: TTL 7400's Available

[Brent Hilpert]

Chuck Guzis wrote:
> 
> I stumbled on this document:
> 
> http://klabs.org/mapld04/papers/g/g233_alonso_p.doc
> 
> while wondering about AC transformer-coupled logic and discovered
> that the original idea for the Apollo guidance computer was to use AC-
> coupled (core-transistor) logic.
> 
> How's that for tying two threads together? :)

Now that was a fun read. I'm still trying to understand his description of
the core rope ROM though. I'm familiar with core-rope ROM (or at least one
version of it) from attempting to make a reader to dump the contents of a Wang
calc microcode ROM, but the AGC version sounds like the
address-decoding/word-selection is done differently (..need a diagram).

And whats up with this mention of LCD displays? I didn't think there was
anything practical available that early, or that was going to stand up to the
rigours of space-flight - I have a calc with one of the first commercial LCDs
(1972) and it's still kind of rudimentary - slow, poor contrast, temperature sensitive...

(And it confirmed that the AGC was constructed from a single gate/IC type.)