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Who Invented the Computer?

March 21, 2011

Unlike today's children, children of my generation didn't have many possessions. This was not merely because money was in short supply. Before the electronic age, there just weren't that many unique items to buy. Today, if you take an inventory of a child's possessions, you'll find that nearly everything is electronic, and quite expensive. There are cellphones, music players, video players and televisions, video games, computers, talking dolls and talking action figures.

One of my prized possessions as a child was a pencil box. This wasn't an ordinary pencil box. Built into its sliding door was a mechanical calculator consisting of a row of gear-like wheels. By using a pencil point to rotate these wheels, you could add and subtract very large numbers. Large number arithmetic was still a difficult process for a young child to do. It was magic. As Arthur C. Clarke famously said, "Any sufficiently advanced technology is indistinguishable from magic." As a child, I didn't realize that this "advanced technology" was actually 300 years old.

The polymath, Blaise Pascal, whose name is immortalized as a computer language, invented this mechanical calculator in 1642. This calculator, now called Pascal's calculator, or the Pascaline, allowed the mechanical addition and subtraction of numbers. Of course, it could also multiply numbers by repeated additions. It actually did the calculation, unlike the millennia old abacus, which acts more as a memory aid. Was the Pascaline the first computer? Maybe.

Dictionary entry for abacus.

Dictionary entry for abacus.
Via Wikimedia Commons

As an extension of the Pascaline, Gottfried Leibniz produced the Leibniz wheels that added multiplication and division operations. Mechanical calculators that allowed all four of the basic mathematical functions had continued improvements that continued to the introduction of the Comptometer in 1887 and its improvements through most of the twentieth century. Are any of these the first computer? Maybe.

The Jacquard loom was a process controller used for the manufacture of complex textile weaves. It used punched cards as a memory element, but it didn't manipulate the data on the cards. It just passed the data through to the weaving elements. Was this the first computer? Probably not.

The mathematician, William Oughtred, invented the slide rule in 1622. As its history reveals, this analogue computer helped to put men on the Moon. I've called the slide rule an analogue computer, and it predates Pascal's calculator. Was the slide rule the first analog computer; and, perhaps, the first computer? Well...?

In 1927, Vannevar Bush built a mechanical analogue computer called the Differential Analyzer at MIT. This machine could solve differential equations with eighteen independent variables. If you argue that the slide rule is not really a computer, your arguments are fairly limp when weighed against the Differential Analyzer. Was this, then, the first computer? Well...?

The German engineer, Konrad Zuse, built a "Turing-complete" programmable computer, the Z3, in 1941. Zuse also created the first high-level programming language, Plankalkül, in 1946. Zuse had purposely discounted the use of vacuum tubes as switches, probably because of cost and reliability issues. The Z3 was electromechanical, using telephone relays, but it could do 22-bit floating-point arithmetic, could loop (although not conditionally), it had memory, and it used what's now called the "von Neumann architecture" that stores both programs and data in memory. Now, that's a computer! Was it the first...?

How could we have a discussion like this without mentioning Charles Babbage, who designed, but did not build, a decimal, programmable, mechanical computer in the mid-nineteenth century? Or the vacuum tube Colossus computer built by Alan Turing and his colleagues with the sole purpose of code-breaking during World War II? The first wasn't built, but quite a few Nobel Prizes have been awarded for theory, not experiment. The second used vacuum tubes, so it was electronic as well as digital, but it wasn't general-purpose.

The ENIAC was a vacuum tube computer considered to be the first general-purpose electronic computer. It was programmable, Turing-complete, and a thousand times faster than electromechanical computers. It was designed and patented (US Patent No. 3,120,606, 1964) by John Mauchly and J. Presper Eckert of the University of Pennsylvania. So, in ENIAC we have the "first computer." Not really. The ENIAC patent was declared invalid in 1973, and its subject matter entered the public domain. The reason for this, as decided in court, was that John Vincent Atanasoff, a professor at Iowa State University, had actually invented "the automatic electronic computer."

Atanasoff and a graduate student, Clifford Berry, built what's now called the Atanasoff-Berry_Computer (ABC) from 1937-1942. The machine contained 280 dual-triode vacuum tubes, but it was not programmable. Its only function was to solve systems of linear equations. The ABC was not a Turing complete computer, and it was not a stored program computer. It did use binary digits. A recent biography of Atanasoff supports the claim that he's the inventor of the electronic digital computer.[1-2]

The answer to the question, "Who Invented the Computer?" depends on what you define as a "computer." As you can see, there are many different types of computers. There are analogue, digital, mechanical, electromechanical, electronic and combinations thereof. As if this question doesn't generate enough controversy, what was the first personal computer? The TX-0, perhaps?


  1. John Gilbey, "Biography: The ABC of computing," Nature, vol. 468, no. 7325 (December 9, 2010), pp. 760-761.
  2. Jane Smiley, "The Man Who Invented the Computer: The Biography of John Atanasoff, Digital Pioneer," Doubleday (October 19, 2010), 256 Pages (via Amazon).
  3. George Dyson, "The Birth of the Computer," TED 2003 Conference Video (March, 2003).

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