1940s - Early 1950s: First Generation Computers Probably the most important contributor concerning the theoretical basis for the digital computers that were developed in the 1940s was Alan Turing, an English mathematician and logician. In 1936 he created the Turing machine, which was originally conceived as a mathematical tool that could infallibly recognize undecidable propositions. Although he instead proved that there cannot exist any universal method of determination, Turing's machine represented an idealized mathematical model that reduced the logical structure of any computing device to its essentials. His basic scheme of an input/output device, memory, and central processing unit became the basis for all subsequent digital computers. The onset of the Second World War led to an increased funding for computer projects, which hastened technical progress, as governments sought to develop computers to exploit their potential strategic importance. By 1941 the German engineer Konrad Zuse had developed a computer, the Z3, to design airplanes and missiles. Two years later the British completed a secret code-breaking computer called Colossus to decode German messages and by 1944 the Harvard engineer Howard H. Aiken had produced an all-electronic calculator, whose purpose was to create ballistic charts for the U.S. Navy. Also spurred by the war the Electronic Numerical Integrator and Computer (ENIAC), a general-purpose computer, was produced by a partnership between the U.S. government and the University of Pennsylvania (1943). Consisting of 18.000 vacuum tubes, 70.000 resistors and 5 million soldered joints, the computer was such a massive piece of machinery (floor space: 1,000 square feet) that it consumed 160 kilowatts of electrical power, enough energy to dim lights in an entire section of a bigger town. Concepts in computer design that remained central to computer engineering for the next 40 years were developed by the Hungarian-American mathematician John von Neumann in the mid-1940s. By 1945 he created the Electronic Discrete Variable Automatic Computer (EDVAC) with a memory to hold both a stored program as well as data. The key element of the Neumann architecture was the central processing unit (CPU), which allowed all computer functions to be coordinated through a single source. One of the first commercially available computers to take advantage of the development of the CPU was the UNIVAC I (1951). Both the U.S. Census bureau and General Electric owned UNIVACs (Universal Automatic Computer). Characteristic for first generation computers was the fact, that instructions were made-to-order for the specific task for which the computer was to be used. Each computer had a different binary-coded program called a machine language that told it how to operate. Therefore computers were difficult to program and limited in versatility and speed. Another feature of early computers was that they used vacuum tubes and magnetic drums for storage.

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Gerard J. Holzmann and Bjoern Pehrson, The Early History of Data Networks This book gives a fascinating glimpse of the many documented attempts throughout history to develop effective means for long distance communications. Large-scale communication networks are not a twentieth-century phenomenon. The oldest attempts date back to millennia before Christ and include ingenious uses of homing pigeons, mirrors, flags, torches, and beacons. The first true nationwide data networks, however, were being built almost two hundred years ago. At the turn of the 18th century, well before the electromagnetic telegraph was invented, many countries in Europe already had fully operational data communications systems with altogether close to one thousand network stations. The book shows how the so-called information revolution started in 1794, with the design and construction of the first true telegraph network in France, Chappe's fixed optical network. http://www.it.kth.se/docs/early_net/

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