FYI -- 50 years of Moore's Law at (proof of) work: Mining Bitcoins on the Apollo Guidance Computer (see below). --- I've recently been learning about the detailed calculations of satellite GPS computations, so I'm much more interested in how quickly the AGC could do today's GPS calculations. BTW, Einstein's special relativity (satellite speed adjustment to the clock) and Einstein's general relativity (satellite altitude from the Earth's center) are both important: higher altitude clocks tick faster by ~45usecs/day, while fast orbiting satellites tick slower by ~7usecs/day, resulting in a ~38usec/day (11.4km/day=7.1miles/day) difference. Q: Did the Apollo Guidance Computer have to deal with corrections for relativity? --- http://www.righto.com/2019/07/bitcoin-mining-on-apollo-guidance.html Ken Shirriff's blog Bitcoin mining on an Apollo Guidance Computer: 10.3 seconds per hash 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 million times the age of the universe to successfully mine a Bitcoin block. ... https://arstechnica.com/tech-policy/2019/07/computer-from-nasas-apollo-progr... Computer from NASA's Apollo program reprogrammed to mine bitcoin It takes the Apollo Guidance Computer 10 seconds to compute a single hash value. Timothy B. Lee - Jul 9, 2019 10:15 pm UTC