Someone mined Bitcoin with a computer that NASA used to land on the moon

The AGC was a remarkable piece of technology used during the Apollo program for space exploration. Developed in the 1960s, it played a crucial role in guiding astronauts to the moon and back. Despite its limitations, the AGC was revolutionary for its time, being one of the first computers to use integrated circuits.
 

Ken Shirriff, a software engineer and tinkerer, has a passion for restoring and reverse engineering ancient systems. From old IBM mainframes to the Xerox Alto, Shirriff breathes life into archaic hardware and software. His latest project involved restoring a 52-year-old AGC, a rare feat considering that only one operational AGC exists today.

 

After successfully getting the AGC up and running, Shirriff decided to give it a more modern task: mining Bitcoin. Implementing the Bitcoin hash algorithm in assembly code on a 15-bit computer from the '60s was no small feat. The AGC lacked a microprocessor, as it predates the era of microprocessors. Despite its limitations, Shirriff persisted.

 

The AGC, weighing 70 pounds and fitting under a cubic foot, was a marvel of miniaturization for its time. It could perform around 40,000 additions per second, sluggish by today’s standards but sufficient for guidance, navigation, and engine control. In contrast, modern USB stick miners churn out 130 billion hashes per second. Shirriff’s Bitcoin program ran on the AGC, displaying results on a custom-made DSKY (Display/Keyboard).

 

The AGC took 5.15 seconds for one SHA-256 hash, resulting in a hash rate of 10.3 seconds per Bitcoin hash. To put this in perspective, the current Bitcoin network performs about 65 quintillion hashes per second. Mining a single block with the AGC would take a mind-boggling billion times the age of the universe.
 

In summary, Ken Shirriff’s experiment bridged the gap between space exploration history and Bitcoin, showcasing the AGC’s enduring legacy and the incredible progress in computing power since the Apollo era.