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Question: Who invented the first computer?
Before we can answer this question, we first have to define what we mean by a "computer". Merriam Webster's Collegiate Dictionary defines a computer as "A programmable electronic device that can store, retrieve and process data". Unfortunately, this definition leaves out all the devices that led up to the "electronic" devices we are now familiar with. The on-line HyperDictionary defines a computer as "a machine for performing calculations automatically". We will use this definition to get to what we think of today as a computer. We will start by going back in time to see how the 'computer' evolved.
The first computing device, the abacus, was not electronic and did not store a program, but could be used like a pocket calculator to add, subtract and do other mathematical operations. It is thought to have been invented in ancient Babylonia (now Iraq) around 5000 years ago.
Around the same time, analog devices (machines that compute by mechanical means, such as turning wheels) computed taxes in Babylonia. Modern analog computers compute by using continuous values (changing electrical current), whereas digital computers, like the ones we see on desks today, use specific values (1 and 0).
In 1623, Wilhelm Schickard a professor in Germany, built the first mechanical calculator, but it was one of a kind and did not store a program inside it.
In 1842, Charles Babbage started working on his "Analytic Engine," an analog device to do computing with programs written on paper cards with holes punched in them. Punched cards were used as recently as the 1980's.
The first binary digital computer (the Z1) was built in 1938 by Konrad Zuse, a German engineer. Zuse also built the first general purpose programmable calculator (the Z3) in 1941. These machines used binary math (computation using only the digits 0 and 1). Neither of these machines was able to store its program internally, but relied on a long strip of paper with holes punched in it to represent the program in a coded form. They had a very limited amount of memory that could only be used for data.
In January 1943, Alan Turing, one of the founders of computer science, with some colleagues, constructed an electronic machine called COLOSSUS, to decode a secret code during World War II. COLOSSUS was one of the world's earliest working programmable electronic digital computers. But it was a special-purpose machine that couldn't even do decimal multiplication.
In 1945, the ENIAC, built by John Mauchly and J. Presper Eckert, was completed. The ENIAC was programmed by wiring cable connections and setting up to three thousand switches. Since it required switches to program it, ENIAC does not qualify as a stored-program computer, but it was the first general-purpose computer.
Also in 1945, John von Neumann wrote his "First Draft of a Report on the EDVAC," the Electronic Discrete Variable Automatic Computer. He outlined the design of a computer that could contain its own program. There are two very important features of this design. The first is that the program and data could be created somewhere else and be put into the machine later and the second is that the computer could hold both the program and its data. Unfortunately, EDVAC was not completed until 1952, thus losing the claim to be the first stored-program computer.
On May 6, 1949, Maurice Wilkes completed the EDSAC, the first practical stored-program computer, at Cambridge University, England. It was in commercial use for 7 years, but was one of a kind.
The first commercially available computer, the universal automatic computer (UNIVAC I), was also based on the EDVAC design. It was a true stored-program, general purpose electronic digital computer. The UNIVAC I was delivered to its first customer, the US Census Bureau, in 1951.
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