The first programmable desktop calculator—arguably the first personal computer. Designed by Pier Giorgio Perotto at Olivetti, Italy.
It stored programs on magnetic cards, had a built-in printer, and could execute 120 instructions. NASA bought 45 units for the Apollo program—they computed lunar module trajectories for the Moon landing.
Price: $3,200. HP later paid Olivetti $900,000 in patent royalties for their HP 9100A, which was heavily inspired by the P101.
Number keys for calculator • Use program panel to load and run the Moon trajectory demo