
Recovering the Lost Apollo 10 LM Software [video] - mkarr
https://www.youtube.com/watch?v=-JTa1RQxU04
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morcheeba
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!

A fun watch.

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est31
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?

~~~
sonofgod
There's some projects. Like arctic archival of github repos:
[https://archiveprogram.github.com/](https://archiveprogram.github.com/)

Granted, this is only a snapshot, and preservation is a big problem. And you
can't easily preserve gigabytes of data in dead tree format...

Generally the best approach is "Lots of Copies Keep Stuff Safe" but moves to
streaming media and game rental services worry me.

There also needs to be a recognition that what we see is often a very small
fraction of what existed... most things won't survive, unless successive
generations of people continuously care sufficiently about them. Or they're
ubiquitous that we'll find at least one...

~~~
kevin_thibedeau
Lots of copies on flash chips are all going to be gone in 100 years.

~~~
WalterBright
I don't trust flash chips at all.

My older media is all pretty much unreadable for one reason or another. My
solution is to buy new drives every year and copy everything forward.
Fortunately, the capacity keeps rising so that works out rather well.

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douglasheriot
I think this is the GitHub repo with the code shown in the video. Very
impressive!

[https://github.com/virtualagc/virtualagc/](https://github.com/virtualagc/virtualagc/)

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fortran77
That LEM simulator they used at the end was fascinating. Is there a video that
does a deep dive of that.

Mike Stewart seems like the most charming technical guy I've ever seen.

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nessup
Incredible.

