Olivetti Programma 101

Introduced in 1965, the Programma 101 [1], made by Olivetti(Italia), was one of the first successful programmable electroniccalculators. Today it can be seen not only in our Computer Museum,but also in the reknown Stedelijk Museum of Amsterdam, where it iskept for its outstanding exterior design by the architect MarioBellini.

The Programma 101 uses an arithmetic-logic unit built fromseparate transistors, and a delay line memory module. There are 10registers each holding a 22- digit decimal number (inbinary-coded-decimal representation!) or a string of 24instructions. Besides electronics, the P101 has an appreciableamount of sturdy mechanics for its keyboard, built-in printer andmagnetic- card reader/recorder. The output was printed on a fast,30 column drum printer.

The machine's arithmetic operations are -, +, *, /, sqrt, abs.Other operators include data transfer between registers,conditional and unconditional jump. Programs containing up to 120instructions can be recorded on a magnetic program card. There areextensive program collections for general mathematics, electricaland civil engineering, finance, and other disciplines. The size ofthe machine is 19*48*61 cm, its weight is 35.5 kg. 40,000 wereconstructed and they were sold for US$3200. See the advertisement from Scientific American(1970).

Below a program (adapted from [2]) for calculating and printingn! is shown. In the left hand column the commands are shown as theyare entered from the keyboard. The commands are explained by thepseudo-code at the right. Three registers are used: A, M and D.

This or any other P101 program can be executed on our emulator, running on a PC.

[1] Handleiding Programma 101 Tafelcomputer, Olivetti 19?? (inDutch).
[2] The Olivetti Programma 101 desk calculator. In: C. Gordon Bell(ed): Computer Structures: Readings and Examples. McGrawHill1971.
[3] P.G. Perotto: Olivetti, dalla P101 in avanti. In: Atti delConvegno Internazionale sulla Storia e Preistoria del CalcoloAutomatico e dell'Informazione, AICA 1991 pp 218-221 (inItalian).