The Apollo On-Board Computers

https://web.archive.org/web/20120827000829/http://history.nasa.gov/afj/compessay.htm

by rayascott • 4 years ago

47 9 4 years ago

web.archive.org

mshook• 4 years ago

If you're into that kind of stuff I recommend:

- watching https://www.youtube.com/c/CuriousMarc

- reading Ken's blog/twitter http://www.righto.com/ / https://twitter.com/kenshirriff

CamperBob2• 4 years ago

Also:

https://www.amazon.com/Sunburst-Luminary-Apollo-Don-Eyles/dp...

Bayart• 4 years ago

I was about to recommend CuriousMarc. I don't know where I found out about him, perhaps on HN, but watching someone knowledgeable geek out in depth about ancient computing (beyond the Apollo stuff) really does scratch an itch.

itsjustjordan• 4 years ago

The source code is available on GitHub along with a virtual version you can play with.

- https://github.com/chrislgarry/Apollo-11

- https://www.ibiblio.org/apollo/

bmitc• 4 years ago

The main person behind that effort, as far as I know, is Mike Stewart, and there is an excellent video of him working on restoring original AGC hardware.

https://www.youtube.com/watch?v=2KSahAoOLdU

https://www.capellaspace.com/meet-mike-stewart-a-capella-fli...

https://thenewstack.io/how-a-programmer-recreated-apollo-10s...

https://github.com/virtualagc

shadowofneptune• 4 years ago

The best presentation I have seen on the AGC architecture: https://youtu.be/xx7Lfh5SKUQ

It does present addresses in hexadecimal, oddly. The computer was 15-bit and used octal in its display panel. I suppose the presenters thought the audience would understand hex better.

tatoalo• 4 years ago

In addition to the fantastic ccc.de talk, I suggest this one related to the 1202 alarm: https://youtu.be/B1J2RMorJXM

Great talk and overall super presenter IMHO.

james-redwood• 4 years ago

I once met a first year engineering student who was the daughter of a friend of mine. When she complained that you can do nothing cool with small computers, I pointed her to an article about this.

compumike• 4 years ago

You may also enjoy some of the historical photos here: https://wehackthemoon.com/tech/apollo-guidance-computer-agc-...

A few highlights:

- photo #2 shows the construction of literally hand-weaved read-only memory for the 36,864 words of fixed program memory. Literally weaving wires through (or bypassing around) tiny magnetic cores for each bit of storage. Must be re-weaved for a new "build"

- photo #10 shows the prototype, occupying many many racks (not yet miniaturized!)

- photo #20 shows characteristics of the machine (2048 words of writable memory; 575us for a double-precision multiplication)

- photo #24 https://www.youtube.com/watch?v=_gIrELUMtp0 (32 seconds) shows large-scale breadboarding before the computer logic design was miniaturized

- https://www.youtube.com/watch?v=F1-KBKaCiMM (4 minutes 28 seconds) gives a nice overview of the AGC challenges

The Apollo On-Board Computers

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