Olivetti Programma 101

UvA Computer Museum catalogue nr 93.20

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

The Programma 101 uses an arithmetic-logic unit built from separate transistors, and a delay line memory module. There are 10 registers each holding a 22- digit decimal number (in binary-coded-decimal representation!) or a string of 24 instructions. Besides electronics, the P101 has an appreciable amount of sturdy mechanics for its keyboard, built-in printer and magnetic-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 120 instructions can be recorded on a magnetic program card. There are extensive program collections for general mathematics, electrical and civil engineering, finance, and other disciplines. The size of the machine is 19*48*61 cm, its weight is 35.5 kg. 40,000 were constructed and they were sold for US$ 3200. See the advertisement from Scientific American (1970).

Below a program (adapted from [2]) for calculating and printing n! is shown. In the left hand column the commands are shown as they are entered from the keyboard. The commands are explained by the pseudo-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.


[1a] Handleiding Programma 101 Tafelcomputer, Olivetti 19?? (Dutch version, in our library).
[1b] Programma 101 General Reference Manual, Olivetti 1965.
[2] The Olivetti Programma 101 desk calculator. In: C. Gordon Bell (ed): Computer Structures: Readings and Examples. McGrawHill 1971.
[3] Wikipedia: Programma 101.

rev February 27, 2017