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Benjamin Durfee

Automatic Sequence Controlled Calculator (Mark I)

Patent No. 2,616,626

IBM engineer Benjamin Durfee, along with Clair Lake and Francis Hamilton, translated Harvard physicist Howard Aiken’s concept for a large scale mechanical calculator into a working device that performed the desired mathematical operations. The Automatic Sequence Controlled Calculator (ASCC), also known as the Mark I, was designed to solve rapidly and accurately almost any mathematical problem.

Among other functional components of the Mark I, Durfee and Hamilton designed key elements of the calculator’s circuitry. This included the circuits that correlated the operations of the device’s components into a single working unit, and those required to achieve principles Aiken had established with respect to the performance of certain calculations. Durfee also was heavily involved in the testing of ASCC at IBM’s Endicott, N.Y., lab in 1943 and again at Harvard, where it was dedicated in 1944.

Earlier in his career, Durfee had assisted in the assembly and testing of the Type I printing tabulator and assisted Lake in improving the design of a nonprinting tabulator with automatic group control. In 1924, he assembled in Paris the first IBM printing tabulator sold in Europe.

Sources:

IBM. (n.d.). ASCC People and Progeny. Retrieved March 2014, from IBM: http://www-03.ibm.com/ibm/history/exhibits/markI/markI_team4.html

Benjamin M. Durfee joined IBM’s predecessor, Computing-Tabulating-Recording Company (CTR) in 1917 and attended the company’s training school in 1918. Early in his career Durfee assisted Clair Lake in the field testing of a nonprinting tabulator with automatic group control and contributed in improving the machine. Durfee eventually joined Lake at the company’s laboratory in Endicott, NY, where he assisted in the assembly and testing of the Type I printing tabulator, as well as in establishing training courses on the machine. In 1924, he assembled, in Paris, the first IBM printing tabulator sold in Europe.

Durfee became involved with the Mark I project in 1939, with Howard Aiken and fellow IBM engineers Clair Lake and Frank Hamilton, and was heavily involved with the testing of the machine.

The Mark I was electromechanical with mechanical parts that were electrically controlled and used ordinary telephone relays that enabled electrical currents to be switched on or off. Unlike modern computers, the Mark I had no keyboard, but was operated with approximately 1,400 rotary switches that had to be adjusted to set up a run. Instructions and data input were entered into the computer on continuous strips of punch-card paper.

Mark I was a powerful improvement over its predecessors in terms of the speed at which it performed a host of complex mathematical calculations. The Mark I could perform logarithmic and other functional table lookup and the four fundamental arithmetic operations, in any specified sequence, on numbers up to 23 decimal digits in length. Used by the Navy during World War II, the Mark I ran repetitive calculations for the production of mathematical tables that aided in aiming artillery bombs and shells. The computer also continued to assist in the solution of complex problems in various disciplines at Harvard for 15 years. Sections of the machine have been retained as artifacts at Harvard, IBM and the Smithsonian Institution.

Patent Number
Year
Name

2,616,626
1952
Calculator
Co-Inventors
Clair Lake
Howard Aiken
Francis Hamilton
*Listed for principal patent(s)
2,093,551
1937
Tabulating Machine
2,282,121
1942
Multiplying Machine
2,398,014
1946
Record Punching Machine
2,424,091
1947
Record Controlled Dividing Machine
2,490,362
1949
Record Controlled Calculating Machine
2,493,862
1950
Dividing Machine
2,558,941
1951
Record Controlled Machine
2,615,569
1952
Record Controlled Machine
2,616,624
1952
Calculator
2,651,460
1953
Accumulator Entry Control Means for Record Controlled Machines
2,658,682
1953
Record Controlled Machine
2,738,874
1956
Record Controlled Machine

Born: September 18, 1897 in Lakewood, OH

Died: November 20, 1980 in Pompano Beach, FL

Occupation: Engineer

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