Ken Shirriff implemented the SHA-256 hash algorithm and ran it on the vintage Apollo Guidance Computer (AGC) that they’re restoring:
We’ve been restoring an Apollo Guidance Computer. Now that we have the world’s only working AGC, I decided to write some code for it. Trying to mine Bitcoin on this 1960s computer seemed both pointless and anachronistic, so I had to give it a shot. Implementing the Bitcoin hash algorithm in assembly code on this 15-bit computer was challenging, but I got it to work. Unfortunately, the computer is so slow that it would take about a billion times the age of the universe to successfully mine a Bitcoin block.
See the full post on Ken Shirriff’s blog.