One of the world’s first general-purpose computers just turned 80 years old
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In context: Harvard University officially introduced the Harvard Mark I computer on August 7, 1944. Also known as the Automated Sequence Controlled Calculator or ASCC, the computer was the brainchild of US physicist Howard Aiken. IBM developed the system in about four years using Aiken’s plans and military funding.
The Harvard Mark I is the first programmable computer ever built in the United States. The Register notes that Aiken developed the system’s original concept and brought it to International Business Machines (IBM) in 1937. Sitting IBM CEO Thomas Watson Sr. approved and funded the innovative project in 1939.
The ASCC was completed and built in February 1944. IBM later disassembled it and shipped it to Harvard. The university hosted the machine while US government organizations employed its remarkable computing capabilities for military-related operations. In fact, the US Navy provided IBM with the additional funding needed to complete the project.
Harvard Mark I was an electromechanical computer with 60 sets of 24 switches, used to manually enter (or “store”) up to 72 numbers containing 23 digits each. The machine could do three additions or subtractions in a second, multiplication in six seconds, and division in 15.3 seconds. Increasingly complex calculations such as logarithms or trigonometric functions could take over a minute.
Harvard University states that the military used the Harvard Mark I to calculate massive mathematical tables. The Navy utilized the machine to properly design torpedoes and underwater detection systems, while other US military branches developed camera lenses, radar systems, and more.
In 1944, while working on the Manhattan Project, John von Neumann tasked the ASCC with calculations on an implosion device for triggering the detonation of an atomic bomb. Hiroshima was razed in Little Boy’s atomic fire just one year later.
According to computer scientist Edmund Berkeley, one of the most arduous tasks involved solving a set of differential equations known as Bessel Functions, which earned the computer the nickname “Bessie.” Operators used IBM standard punch cards or highly legible typewritten numbers to encode mathematical problems into the machine.
The Harvard Mark I was removed from active service in 1959, becoming an exhibit in the Harvard Collection of Historical Scientific Instruments. In July 2021, Havard relocated it for one last time to Harvard’s new Science and Engineering Complex in Allston. Later models in the “Mark” series were conceived to mostly use electronic components such as vacuum tubes and crystal diodes (Mark III). The subsequent Harvard Mark IV was the first computer to introduce a novel architecture that stored data and instructions separately.
Image credit: Arnold Reinhold
