My favorite part is when they needed the version of the software that was used for the moon landing but they only had the source code for a previous version (scanned from giant binder) and the hash value of the version of the landing. By a series of educated guesses, by reading memos and by analysis of the source code they modified the old code the exact way so it gave them the correct hash, confirming that they correctly and exactly recreated the original code.
https://www.youtube.com/watch?v=2KSahAoOLdU&list=PL-_93BVApb...
My favorite part is when they needed the version of the software that was used for the moon landing but they only had the source code for a previous version (scanned from giant binder) and the hash value of the version of the landing. By a series of educated guesses, by reading memos and by analysis of the source code they modified the old code the exact way so it gave them the correct hash, confirming that they correctly and exactly recreated the original code.
It's being a while and I go from memory, I might have some details wrong. See this video for this story. https://www.youtube.com/watch?v=-JTa1RQxU04