3 ms·

54 years ago - wow - was the Apollo 11 Moon Landing Guidance Computer (AGC) chip the best tech had to offer back then?

GlenTheMachine 3y ago
Yes, given the size, power, and reliability constraints. There were, of course, far more powerful computers around… but not ones you could fit in a spacecraft the size of a Volkswagen Beetle. The Apollo program consumed something like half of the United States’ entire IC fabrication capacity for a few years. https://www.bbc.com/future/article/20230516-apollo-how-moon-missions-changed-the-modern-world# https://www.bbc.com/future/article/20230516-apollo-how-moon-...
- db48x 3y ago
  The AGC was 2 ft³. I believe the volume was written into the contract for development of the computer, and was simply a verbal guess by the owner of the company during negotiations. On the other hand, they had been designing control systems for aircraft and missiles for over a decade at that point so it was not an entirely uninformed guess. The amazing thing is that they did manage to make it fit into 2 ft³, even though the integrated circuits it used had not yet been invented when the contract was written.
dgacmu 3y ago
Yes when accounting for size. If you wanted something that was the size of a refrigerator, you could buy a data general Nova in 1969: https://en.m.wikipedia.org/wiki/Data_General_Nova https://en.m.wikipedia.org/wiki/Data_General_Nova 8KB of RAM! But hundreds of pounds vs 70lb for the AGC with fairly comparable capability (richer instructions/registers, lower initial clock rate). The AGC was quite impressive in terms of perf/weight
kens 3y ago
The Apollo Guidance Computer was the best technology when it was designed, but it was pretty much obsolete by the time of the Moon landing in 1969. Even by 1967, IBM's 4 Pi aerospace computer was roughly twice as fast and half the size, using TTL integrated circuits rather than the AGC's RTL NOR gates.

Yes, given the size, power, and reliability constraints. There were, of course, far more powerful computers around… but not ones you could fit in a spacecraft the size of a Volkswagen Beetle. The Apollo program consumed something like half of the United States’ entire IC fabrication capacity for a few years. https://www.bbc.com/future/article/20230516-apollo-how-moon-missions-changed-the-modern-world# https://www.bbc.com/future/article/20230516-apollo-how-moon-...

db48x 3y ago
The AGC was 2 ft³. I believe the volume was written into the contract for development of the computer, and was simply a verbal guess by the owner of the company during negotiations. On the other hand, they had been designing control systems for aircraft and missiles for over a decade at that point so it was not an entirely uninformed guess. The amazing thing is that they did manage to make it fit into 2 ft³, even though the integrated circuits it used had not yet been invented when the contract was written.

dgacmu 3y ago

Yes when accounting for size. If you wanted something that was the size of a refrigerator, you could buy a data general Nova in 1969: https://en.m.wikipedia.org/wiki/Data_General_Nova https://en.m.wikipedia.org/wiki/Data_General_Nova 8KB of RAM! But hundreds of pounds vs 70lb for the AGC with fairly comparable capability (richer instructions/registers, lower initial clock rate). The AGC was quite impressive in terms of perf/weight

kens 3y ago

The Apollo Guidance Computer was the best technology when it was designed, but it was pretty much obsolete by the time of the Moon landing in 1969. Even by 1967, IBM's 4 Pi aerospace computer was roughly twice as fast and half the size, using TTL integrated circuits rather than the AGC's RTL NOR gates.