First Generation of Modern Computers

1945-1956

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Konrad Zuse

John von Neumann

 

UNIVAC at CBS News Center

    With the beginning of the Second World War, governments sought to develop computers to exploit their potential strategic importance.  This increased funding for computer development projects hastened technical progress.  By 1941 German engineer Konrad Zuse had developed a computer, the Z3, to design airplanes and missiles.  The Allied forces, however, made greater strides in developing powerful computers.  In 1943, the British completed a secret code-breaking computer called Colossus to decode German messages.  The Colossus's impact on the development of the computer industry was rather limited for two important reasons.  First, Colossus was not a general-purpose computer; it was only designed to decode secret messages.  Second, the existence of the machine was kept secret until decades after the war (Goldstine 250).

    American efforts produced a broader achievement.  Howard H. Aiken, a Harvard engineer working with IBM, succeeded in producing an all-electronic calculator by 1944.  The purpose of the computer was to create ballistic charts for the U.S. Navy. It was about half as long as a football field and contained about 500 miles of wiring.  The Harvard-IBM Automatic Sequence Controlled Calculator, or Mark I for short, was an electronic relay computer.  It used electromagnetic signals to move mechanical parts. The machine was slow (taking 3-5 seconds per calculation) and inflexible (in that sequences of calculations could not change); but it could perform basic arithmetic as well as more complex equations (Stern 47).

    Another computer development spurred by the war was the Electronic Numerical Integrator and Computer (ENIAC), produced by a partnership between the U.S. government and the University of Pennsylvania.  Consisting of 18,000 vacuum tubes, 70,000 resistors and 5 million soldered joints, the computer was such a massive piece of machinery that it consumed 160 kilowatts of electrical power, enough energy to dim the lights in an entire section of Philadelphia.  Developed by John Presper Eckert and John W. Mauchly, ENIAC, unlike the Colossus and Mark I, was a general-purpose computer that computed at speeds 1,000 times faster than Mark I.  After completion in 1945, the ENIAC was used extensively for calculations during the design of the hydrogen bomb.  By the time it was decommissioned in 1955 it had been used for research on the design of wind tunnels, random number generators, and weather prediction (Stern 2).  

    In the mid-1940's John von Neumann joined the University of Pennsylvania team, initiating concepts in computer design that remained central to computer engineering for the next 40 years.  Von Neumann designed the Electronic Discrete Variable Automatic Computer (EDVAC) in 1945 with a memory to hold both a stored program as well as data.  This stored memory technique as well as the conditional control transfer, that allowed the computer to be stopped at any point and then resumed, allowed for greater versatility in computer programming.  Through the use of a memory that was large enough to hold both instructions and data, and using the program stored in memory to control the order of arithmetic operations, EDVAC was able to run orders of magnitude faster than ENIAC.  By storing instructions in the same medium as data, designers could concentrate on improving the internal structure of the machine without worrying about matching it to the speed of an external control.  The key element to the von Neumann architecture was the central processing unit, which allowed all computer functions to be coordinated through a single source (Goldstine 171, 181 -183).  

    Eckert and Mauchly later developed what was arguably the first commercially successful computer in the UNIVAC I (Universal Automatic Computer).  In 1951, the UNIVAC I became one of the first commercially available computers to take advantage of these advances.  Both the U.S. Census Bureau and General Electric owned UNIVACs.  One of UNIVAC's impressive early achievements was predicting the winner of the 1952 presidential election, Dwight D. Eisenhower.  The UNIVAC,  45 minutes after the polls closed and with 7% of the vote counted, predicted Eisenhower would defeat Stevenson with 438 electoral votes (Stern 149).