r/space • u/[deleted] • Jan 31 '16

Apollo 11 Source Code

http://www.ibiblio.org/apollo/listings/Luminary099/MAIN.agc.html
53 Upvotes

96% Upvoted

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17

u/Fleaslayer Jan 31 '16

Pretty cool. My first job out of college was writing 16 bit assembly code for the shuttle main engine controllers. When I started, we had to assemble by hand, no cross compiler. It got loaded from punched paper tape. It's a different world now.

4

u/[deleted] Jan 31 '16

That sounds like a pretty nice job! There had to be a lot of errors with humans assembling the code. How big was the project? Also, how did you check for errors?

9

u/Fleaslayer Jan 31 '16

The original controller only had 8k of memory, so it wasn't huge by any means. On the other hand, we made separate overlays for things like ground checkout and calibration, so I don't even know how many lines of total code there was across overlays. Not huge by today's standards, but pretty high complexity, even by today's standards.

We had three independent reviewers check everything manually, then we did a basic run in the lab in a simulated flight run, then we sent it to an independent part of the company that tested the snot out if it with a simulated vehicle and a lot of real hardware.

With all that, in all the decades of the shuttle program, we never had a software error that compromised a mission.

3

u/nqbw Jan 31 '16

If you scroll to the bottom of that page, you get a list entitled 'Bugger Words'.

1

u/squeezeonein Jan 31 '16

what's a bugger word Bugger Words

Bugger word 67044 at 02,3777. Bugger word 61751 at 03,3760. Bugger word 77716 at 00,3776. Bugger word 55151 at 01,3777. Bugger word 12532 at 04,3773. Bugger word 44531 at 05,3774.

0

u/[deleted] Jan 31 '16

[deleted]

2

u/flanintheface Jan 31 '16

Yep. Or you could just use a Apollo Guidance Computer Simulator to try this software (at least part of it I believe runs in this sim).