A developer mined bitcoin on an Apple II, a home computer built in 1983 with an eight-bit processor. Bitcoin’s hashing algorithm uses thirty-two-bit operations, so the program had to construct those operations from smaller pieces. Programmer Peter Ferrie helped optimize the code until it reached approximately 3.8 hashes per second. A modern Mac obtained mining work and passed it to the Apple II through a virtual floppy disk over a serial connection. A low-resolution Bitcoin symbol rotated when new work arrived. The developer estimated an average of 256 trillion years to find a block at the difficulty then prevailing.