The Apollo On-Board Computers(web.archive.org)
web.archive.org
The Apollo On-Board Computers
https://web.archive.org/web/20120827000829/http://history.nasa.gov/afj/compessay.htm
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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.
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/
- https://github.com/chrislgarry/Apollo-11
- https://www.ibiblio.org/apollo/
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
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
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
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 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.
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.
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.
Great talk and overall super presenter IMHO.
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.
- watching https://www.youtube.com/c/CuriousMarc
- reading Ken's blog/twitter http://www.righto.com/ / https://twitter.com/kenshirriff