1946

ENIAC—The First Digital Computer

John Mauchly (1907–1980), J. Presper Eckert Jr. (1919–1995)

There once was a time when computers did not exist. If the Army wanted to calculate range tables for its artillery guns, it turned to a room full of human beings who did the work by hand with paper and pen or with a mechanical adding machine. You would do the same thing to calculate the orbit of a comet or the forces on a structural beam. When you think that it might take a human being five to ten seconds to add two complex numbers together, you realize how long it took to do any sort of real computation.

And then, in 1946, with the christening of the ENIAC computer, engineers John Mauchly and J. Presper Eckert Jr., along with a team of design engineers, created the first machine that would start changing everything.

ENIAC was the first general-purpose programmable computer. By today’s standards it was incredibly primitive. It used 18,000 vacuum tubes. This meant that the computer was as big as a house, weighed 60,000 pounds (27,000 kg) and needed 150 kilowatts of electricity to operate. It could perform 5,000 additions per second.

ENIAC was nothing like the computers we use today, in the way that the Wright Brothers’ first airplane looks nothing like airplanes of today. ENIAC worked on decimal numbers rather than binary numbers and it handled 10 digits at a time. Data came in through a card reader and out through a card punch. A programmer would have to set up the computer by configuring switches and wires, and the process took multiple days.

But ENIAC could do general-purpose calculating, and this is what engineers needed. ENIAC made it possible to do calculations for the first hydrogen bomb being developed by the Manhattan Project. It took 500,000 punched cards to input the data for the problem into the machine. It is easy to imagine how difficult it would be to do those calculations with human beings and adding machines.

Computers became enablers for engineers. Problems that would have been impossible without computers suddenly became possible. Today, nearly every aspect of engineering leverages computers.

SEE ALSO Transistor (1947), Ivy Mike Hydrogen Bomb (1952), Microprocessor (1971), Watson (2011).

From left to right: Patsy Simmers, Gail Taylor, and Milly Beck holding computer boards.