The Olivetti Programma 101 | 1965

The Olivetti Programma 101

 The Olivetti Programma 101 (P101), also known as Perottina, is one of the early commercial desktop programmable calculators. Although it was not the first all-in-one calculator, it played a significant role in the commercial market. This calculator was produced by the Italian manufacturer Olivetti, and its inventor was Italian engineer Pier Giorgio Perotto. The P101 featured many of the capabilities found in large computers of the time and was first unveiled at the 1964 New York World's Fair, with mass production beginning in 1965. Its futuristic design made a lasting impression, and it was priced at $3,200 (equivalent to about $30,900 in 2023). Around 44,000 units were sold, with the majority of them being used in the United States.

The P101 was commonly referred to as a "printing programmable calculator" or "desktop calculator," and its instruction set allowed for basic arithmetic operations as well as conditional jumps, classifying it as a "stored-program computer."

The design of the Programma 101 was conceived by Olivetti engineer Pier Giorgio Perotto in Ivrea, Italy. While the style was credited to Marco Zanuso, the actual design work was carried out by Mario Bellini. The P101's design was innovative and ergonomic for its time. It was partially based on a 1961 joint project with Olivetti to develop a computer.

The hardware of the Programma 101 consisted of circuit board assemblies using transistors, diodes, resistors, capacitors, and other components, typical of the distributed devices of the time. The design predated the advent of microprocessors, and integrated circuits were scarcely used.

The P101 operated by storing information on a 240-byte magnetic delay line memory, with a cycle time of 2.2 milliseconds.

The development team for the Programma 101 aimed to create a simple product that anyone could use. Unlike the large and complex computers of the era, they envisioned a design that would be suitable for personal desks. Roberto Olivetti contacted Mario Bellini to discuss the complex project, and Bellini later recalled, "It wasn't just about designing a box with machines and circuits inside. It was about designing a personal object that could sit on someone's desk and interact with people." His design made the machine more human-centered, and as a result, the Programma 101 became more than just a calculator.

One of the most innovative aspects of the Programma 101 was its use of detachable magnetic cards to store and retrieve programs. This was a groundbreaking technology at the time, allowing users to store a program on a card and quickly load and execute it. This practical and unique approach set the P101 apart in the computer industry and later earned Mario Bellini the Compasso d'Oro industrial design award.

The calculator's dimensions were 275mm x 465mm x 610mm, and it weighed 35.5 kg. While large and heavy by today's standards, it was a powerful machine for its size. Its power consumption was 0.35 kW, and its output device was a 30-column printer that printed results on 9 cm-wide paper. The P101 was capable of handling numbers up to 22 digits in total, with up to 15 digits after the decimal point.

The Programma 101 provided arithmetic operations, square roots, absolute value calculations, and the ability to retrieve and store data from memory. Users could set up calculations using memory registers and execute various operations. Programming was done using a simple assembly language, mainly consisting of commands for data transfers and calculations between registers.

The Programma 101 functioned by allowing programs to be stored on magnetic cards, each holding up to 120 instructions. The instructions were in binary code, with each command designed to perform a specific operation on a register. This enabled users to automate complex calculations.

As a result, the Programma 101 was a significant step forward in the development of personal computers and programmable calculators at the time.

The Programma 101 was unveiled at the 1964 New York World's Fair, where it attracted significant attention. A total of 40,000 units were sold, with 90% of them being purchased in the United States. The retail price was $3,200, which increased to approximately $3,500 by 1968.

Around ten units of the Programma 101 were sold to NASA and used in the Apollo 11 lunar landing mission.

"When Apollo 11 landed on the Moon, we had a desktop computer of sorts. It was the Olivetti Programma 101, a super calculator. It was about a foot and a half square and around 8 inches tall. It could do addition, subtraction, multiplication, and division, but it could also remember the sequence of these calculations and record it on a magnetic card. The magnetic cards were about 30 cm long and 5 cm wide. So, we could write the program sequence and store it there, and for example, when the Lunar Module’s high-frequency antenna was not very smart and didn’t know where Earth was, we had to run four separate programs using the Programma 101." — David W. Whittle, 2006

The Programma 101 was also reportedly used by the U.S. Air Force during the Vietnam War for calculating coordinates for bombing targets for B-52 Stratofortresses.

Over the years, several programs have been developed to simulate the functionality of the Programma 101:

• 1976 – Steven DeRose developed a translator at Prairie School that converted Programma 101 code into BASIC, used by students before they learned BASIC programming.
• 1995 – E.H. Dooijes at the University of Amsterdam created a Programma 101 simulator in Turbo Pascal, which operated in batch mode only.
• 2005 – Engineer Claudio Larini created a Programma 101 simulator, with the collaboration of Gastone Garziera, one of the engineers behind the original P101.
• 2016 – The Department of Information Engineering and Electrical Engineering at the University of Cassino developed a Programma 101 simulator, under the supervision of Giovanni De Sandre.
• Tecnologicamente Museum – Located in Ivrea, the museum houses a Java-based simulator of the Programma 101 developed by Giuliano Gaiti, a collaborator of Programma 101 inventor Pier Giorgio Perotto.
• Marco Galeotti developed a complete integrated development environment (IDE) for the Programma 101, offering enhanced programming and debugging features.