Howard Aiken and the Harvard Mark I
Written by Historian   
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Howard Aiken and the Harvard Mark I
The War Years
Mark II and beyond


Aiken on active service

Most of Aiken's war years were spent with the Mark I but one early incident gives some insight into his personality. Working first as an instructor he eventually found himself at the Navy mines school. He was sent out on a mission to deal with a torpedo that a German submarine had launched and which had run aground on a beach. When the torpedo was located Aiken, as the ranking officer, felt obliged to disarm it.

As the first torpedo of its kind to be found on a US beach he had no idea how to go about it but this increased the value of the knowledge to the war effort. He unscrewed a metal plate using some radio tools and it shot out across the beach as the firing spring was released. When asked why he didn't simply blow the device up with rife fire Aiken commented "Lieutenant Commanders were a dime a dozen. Torpedoes were one of the most valuable things you can capture." Clearly this sentiment doesn't square with his reputation for a high self regard!


The Mark I Takes Shape

Meanwhile back at IBM's North Street Laboratory in Endicott, N.Y the Mark I, or rather the ASCC, was  being constructed. Its team consisted of Clair D. Lake, a prolific IBM inventor, as chief engineer and Aiken's chief contact, assisted by Benjamin M. Durfee and Frank E. Hamilton.



Harvard Mark I under construction


Progress was slow due to other wartime demands but by February 1944, it was completed. After being switched on briefly to be tested it was then was disassembled and shipped off to Harvard where it was formally presented on August 7, 1944.


ibmmarkiteamFrom left to right: Frank E. Hamilton, Clair D. Lake, Howard H. Aiken and Benjamin M. Durfee.

A source of conflict

Aiken and Watson disagreed about how the machine should look - a small detail but it gives you some idea of the differences between the two. Aiken wanted everything to be on view so that scientists could see how it worked. Watson on the other hand wanted it encased in stainless steel shaped and curved into a modernistic symbol of the new age. Watson won but lost the next round. At the dedication of the machine Aiken did not mention Watson and arranged a press conference that gave the impression that he, Aiken, was the brains behind the mechanical brain. Watson was furious. Later Tom Watson recalled that if the two men had had guns there would have been a shoot out. Watson resented Aiken for 20 years and IBM top management remembered the insult for a lot longer.

The Finished Mark I

The Harvard Mark I was an impressive beast. Wrapped in steel and glass it looked the part of the new mechanical brain. Inside though it was an electro-mechanical snail. It was fifty one feet long, eight feet high and weighed five tons. At least 530 miles of cable were used together with 175,000 plug connections, 3500 relays and, more unusual for a computer, 1200 ball bearings! The panels at the left-hand end allowed 60 constants to be set using 1400 dial switches. Next came 72 storage counters each holding 23 digits plus sign. These were used in addition, subtractions and as accumulators and took up one third of the machine. These were standard IBM mechanical registers and they were the heart of the machine. Results from one register were passed to another by electrical contacts.

A bank of multipliers and dividers came next followed by functional units which could calculate logs, anti logs and trigonometric functions. Three paper tape feed interpolators allowed tabulated functions to be fed into the calculation. The operation of all of the computational units was controlled by an electro mechanical sequencer and finally a bank of electric typewriters , card feeds and card punch completed the machine. The instructions, i.e. the program, for the Mark I was fed in via a fourth paper tape reader.


The finished Mark I






Last Updated ( Saturday, 19 January 2013 )
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