Summary: they found a document with checksums for each of the 36 banks of the missing software. This let them know that two banks had changed. Working from an earlier and later source listing versions, they had to recreate only some of the changes. Luckily, they found memos describing the changes - mostly in a newer gravity model. All that was left was to put the code in the proper places, and some obvious guesses (e.g. new constants at the end of existing constants) -- and it worked!<p>A fun watch.
We aren't printing out our source code any more. Which means that such recovery methods won't work in the future. Has archival of such historic stuff improved since?
I think this is the GitHub repo with the code shown in the video. Very impressive!<p><a href="https://github.com/virtualagc/virtualagc/" rel="nofollow">https://github.com/virtualagc/virtualagc/</a>
That LEM simulator they used at the end was fascinating. Is there a video that does a deep dive of that.<p>Mike Stewart seems like the most charming technical guy I've ever seen.