Feature Eighty years ago, IBM presented Harvard University with one of the world's earliest computers: the Automated Sequence Controlled Calculator (ASCC), later known as the Harvard Mark I.

The computer was the brainchild of Howard Aiken, who convinced IBM Corp that the project was a good idea at the end of the 1930s. IBM president at the time, Thomas Watson, reckoned the machine would be a good showcase for Big Blue's abilities, and with additional funding from the US Navy, IBM began building the machine in 1939.

Construction took almost four years and was completed in 1943. The computer was dismantled and shipped to Harvard in 1944. It was declared operational in May that year and officially presented at a dedication ceremony on August 7, 1944. Just over 80 years ago.

The machine was in operation until 1959 when it was dismantled again. The Print and Punch unit of the machine is currently on loan to the Smithsonian Institution. Other components can be found in Harvard's Science and Engineering Complex in Allston, US.

Having become operational during World War II, the military pressed the computer into service. According to Harvard, the US Navy put it to work for calculations as part of the design for torpedoes and underwater detection systems, and other branches of the military used it in the design of surveillance camera lenses. The computer, nicknamed "Bessie" as one of its projects involved solving Bessel Functions, was also used for calculations as part of the Manhattan Project.

Weighing in at approximately five tons, the electromechanical calculating machine could solve addition problems in less than a second, multiplication in six seconds, and division in 12 seconds. One of its first programmers was Grace Hopper, who would go on to be a member of the team that found the first-reported computer bug when working on the Mark I's follow-up, the Mark II.

The computer read its instructions from punched paper and used physical switches to enter program data constants. Its successors would eventually ditch the electromechanical relays in favor of electronic components.

The Harvard Mark I was very much a one-of-a-kind machine, although interested readers based in the UK or visiting it should pay a visit to The National Museum of Computing for more electromechanical calculating goodness in the form of a working reconstruction of the Turing-Welchman Bombe, and Colossus, the world's first electronic computer.

Harvard University is a great place to start for learning more about the Harvard Mark I, the role it played, and how it worked. We'd also recommend Howard Aiken - Portrait of a Computer Pioneer for an insight into the man who conceived the computer as well the various books documenting the life and work of Grace Hopper. Grace Hopper and the Invention of the Information Age by Kurt Beyer is a particular favorite of this writer. ®

https://www.theregister.com//2024/08/08/harvard_mark_1/