On June 14, 1951, the U.S. Census Bureau dedicates UNIVAC, the first commercially produced electronic digital computer in the United States. UNIVAC, which stood for Universal Automatic Computer, was developed by a team of engineers led by J. Presper Eckert and John Mauchly, makers of ENIAC, the first general-purpose electronic digital computer. These giant computers, which used thousands of vacuum tubes for computation, were the forerunners of today’s digital computers.

A few months earlier, a general-purpose digital computer called the Ferranti Mark 1, had been sold and delivered to Manchester University in the UK.

The search for mechanical devices to aid computation began in ancient times. The abacus, developed in various forms by the Babylonians, Chinese, and Romans, was by definition the first digital computer because it calculated values by using digits. A mechanical digital calculating machine was built in France in 1642, but a 19th century Englishman, Charles Babbage, is credited with devising most of the principles on which modern computers are based. His “Analytical Engine,” begun in the 1830s and never completed for lack of funds, was based on a mechanical loom and would have been the first programmable computer.

By the 1920s, companies such as the International Business Machines Corporation (IBM) were supplying governments and businesses with complex punch-card tabulating systems, but these mechanical devices had only a fraction of the calculating power of the first electronic digital computer, the Atanasoff-Berry Computer (ABC). Completed by John Atanasoff of Iowa State in 1939, the ABC could by 1941 solve up to 29 simultaneous equations with 29 variables. Influenced by Atanasoff’s work, Presper Eckert and John Mauchly set about building the first general-purpose electronic digital computer in 1943. The sponsor was the U.S. Army Ordnance Department, which wanted a better way of calculating artillery firing tables, and the work was done at the University of Pennsylvania.

ENIAC, which stood for Electronic Numerical Integrator and Calculator, was completed in 1946 at a cost of nearly $500,000. It took up 15,000 feet, employed 17,000 vacuum tubes, and was programmed by plugging and replugging some 6,000 switches. It was first used in a calculation for Los Alamos Laboratories in December 1945, and in February 1946 it was formally dedicated.

Following the success of ENIAC, Eckert and Mauchly decided to go into private business and founded the Eckert-Mauchly Computer Corporation. They proved less able businessmen than they were engineers, and in 1950 their struggling company was acquired by Remington Rand, an office equipment company. On June 14, 1951, Remington Rand delivered its first computer, UNIVAC I, to the U.S. Census Bureau. It weighed 16,000 pounds, used 5,000 vacuum tubes, and could perform about 1,000 calculations per second. On November 4, 1952, the UNIVAC achieved national fame when it correctly predicted Dwight D. Eisenhower’s unexpected landslide victory in the presidential election after only a tiny percentage of the votes were in.

UNIVAC and other first-generation computers were replaced by transistor computers of the late 1950s, which were smaller, used less power, and could perform nearly a thousand times more operations per second. These were, in turn, supplanted by the integrated-circuit machines of the mid-1960s and 1970s. In the 1980s, the development of the microprocessor made possible small, powerful computers such as the personal computer, and more recently the laptop and hand-held computers.