Penn Library

John W. Mauchly and the Development of the ENIAC Computer

The UNIVAC and the Legacy of the ENIAC

The ENIAC's legacy was larger than just the UNIVAC computer built by the Eckert- Mauchly Computer Corporation. The SEAC, ILLIAC, Whirlwind and MANIAC--as well as von Neumann's computer built at the Institute for Advanced Studies in Princeton, New Jersey--were among the one-of-a-kind computers that succeeded the ENIAC. Seeing the potential in electronic digital computation, other private firms, including Engineering Research Associates and IBM, soon entered into the business of digital electronic computers. The backdrop of this panel recapitulates the technical lineage that led into the ENIAC and lists the series of computer systems that emerged in its wake.

Photograph of UNIVAC, n.d. (click to expand to 83k)

Merger agreement with Remington Rand, 15 February 1950. (click to expand to 165k)
The development of a commercial computer proved too difficult for a start-up company. Although Mauchly and Eckert could produce an experimental machine in the confines of a laboratory, a standard commercial system run by trained operators rather than research engineers required further improvements in design and reliability. Problems concerning military security and the hostile attitude of certain influential academic advisors to the military made Eckert and Mauchly's job more difficult. Ultimately it was the cost of developing a commercial computer that led Eckert and Mauchly sold their company to Remington Rand in February of 1950.
The first UNIVAC computer was delivered to the Census Bureau in June 1951. Unlike the ENIAC, the UNIVAC processed each digit serially. But its much higher design speed permitted it to add two ten-digit numbers at a rate of almost 100,000 additions per second. Internally, the UNIVAC operated at a clock frequency of 2.25 MHz, which was no mean feat for vacuum tube circuits. The UNIVAC also employed mercury delay-line memories. Delay lines did not allow the computer to access immediately any item data held in its memory, but given the reliability problems of the alternative Cathode Ray Tube (CRT) technology, this was a good technical choice.


Photograph of J. W. Mauchly
leaning over UNIVAC console.
(click to expand to 83k)


Article on use of UNIVAC to forecast 1952 presidential election results for CBS, from Philadelphia Evening Bulletin, 15 October 1952. Pres Eckert at center, Walte r Cronkite at right. (click to expand to 358k)
Finally, the UNIVAC had placed strong emphasis on its input/output capabilities, being designed specifically for data processing applications such as that of the Census Bureau. In this connection, EMCC had developed a digital magnetic tape recording unit that could deliver data to the UNIVAC at a rate of 40,000 binary digits (bits) per second. For a brief period, Univac had captured a majority of the market for digital electronic computer systems.

Illustration from cover of Remington Rand brochure on UNIVAC, n.d.. (click to expand to 110k)

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