What Was the First Commercially Available Digital Computer?

The first commercially available digital computer was the Ferranti Mark I, an English computer first released in February 1951. Americans followed with the more famous and commercially successful Universal Automatic Computer (UNIVAC) in March 1951.

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Ferranti Mark I

Freddie Williams and Tom Kilburn invented the predecessor of the Mark I, "Baby," at the University of Manchester in England in the late 1940s. In collaboration with Ferranti Limited, they developed the Mark I for commercial purposes.


The Ferranti Mark I had 4,000 vacuum tubes, 2,500 capacitors and 12,000 resistors. Input and output to the computer was via paper tape.


American scientists J. Presper Eckert and John W. Mauchly developed the UNIVAC, which the Bureau of Census commissioned. It took up 352 square feet of space and required 5,400 vacuum tubes.


Nine Ferranti Mark I computers were sold to universities and corporations, including the University of Manchester and the University of Toronto. The UNIVAC achieved greater prominence after an American broadcaster announced that a UNIVAC had predicted the outcome of the 1952 U.S. presidential election.


After they became commercially available, computers entered the public consciousness, especially after the UNIVAC successfully predicted the 1952 election.

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