Technology History | Cruft Laboratory, Harvard — The Machine Had Been Working Since May

The ceremony was in August. The machine had been running Navy calculations since May.

On 7 August 1944 IBM formally presented the Automatic Sequence Controlled Calculator to Harvard University, in the basement of Cruft Laboratory on Oxford Street, where it had stood since February.

Harvard's staff called it the Mark I, and that is the name that stuck.

Fifty-one feet long and eight feet high, it was about five tons of shafts, rotating counters and electromechanical relays turned by a single motor.

It was not electronic and it did not hold its program in memory; instructions arrived on punched paper tape, which makes it a programmable calculator rather than a computer in the sense the word took on a few years later.

Howard Aiken proposed the design to IBM in November 1937, and Thomas Watson Sr. personally approved the funding and the engineers in February 1939.

IBM built the machine at its Endicott plant in New York and shipped it to Cambridge in February 1944.

What people remember about the dedication is the argument that preceded it.

Aiken's press release presented him as the inventor and named only IBM's James Bryce from the company side, leaving out Clair Lake, Frank Hamilton and Benjamin Durfee, the engineers who had built it.

Watson was furious and attended the ceremony only briefly.

He wrote to Aiken afterwards that acknowledging the erroneous publicity would have been a gracious gesture toward those three men.

The two never worked together again.

Aiken built the Mark II, III and IV without IBM, and IBM built the Selective Sequence Electronic Calculator partly to make its own case in public.

The machine itself just worked.

John von Neumann used it in 1944 for calculations connected to the atomic bomb project, and the Navy crew who ran it around the clock included Lieutenant Grace Hopper, one of its programmers.

The Mark I was dismantled in 1959.

A preserved section, with its rows of dial switches and one of the output typewriters, moved around Harvard several times before being installed in 2021 in the Science and Engineering Complex at 150 Western Avenue in Allston, where it stands in the East Atrium beside an IEEE milestone plaque.

Cruft Laboratory is still at 19A Oxford Street and still in use by engineering and physics.

The photograph shows the surviving section in its earlier display at the Harvard Science Center, before the move across the river.

Sources: Harvard Collection of Historical Scientific Instruments; Harvard Gazette; IEEE ETHW milestone record; Computer History Museum; Bernard Cohen's account of the Watson-Aiken correspondence.

Photo: Waldir Pimenta, public domain, via Wikimedia Commons.