Programma 101

The Olivetti Programma 101, also known as Perottina or P101, is one of the first "all in one" commercial desktop programmable calculators, although not the first. Produced by Italian manufacturer Olivetti, based in Ivrea, Piedmont, and invented by the Italian engineer Pier Giorgio Perotto, the P101 used many features of large computers of that period. It was launched at the 1964 New York World's Fair; volume production started in 1965. A futuristic design for its time, the Programma 101 was priced at $3,200 (equivalent to $29,700 in 2022). About 44,000 units were sold, primarily in the US.

It is usually called a printing programmable calculator or desktop calculator because its arithmetic instructions correspond to calculator operations, while its instruction set (which allows for conditional jump) and structure qualifies it as a stored-program computer.