History of Computer abacus invented in ancient China Blaise Pascal (1623-1662) ! Blaise Pascal was a French mathematician Pascal’s calculators ran with gears and wheels Pascal Calculator Charles Babbage (1791-1871) Charles Babbage was an English mathematician. Considered a “father of the computer” He invented computers but failed to build them. The first complete Babbage Engine was completed in London in 2002, 153 years after it was designed. Babbage Engine Alan Turing (1912-1954) Alan Turing was a British computer scientist. ! He proposed the concepts of "algorithm" and "computation" with the Turing machine in 1936 , which can be considered a model of a general purpose computer. Alan Turing (1912-1954) During the second World War, Turing worked for Britain’s code breaking centre. He devised a number of techniques for breaking German ciphers. Turing was prosecuted in 1952 for homosexual acts. He accepted treatment with estrogen injections (chemical castration) as an alternative to prison. Grace Hopper (1906–1992) Grace Hopper was an American computer scientist and United ! States Navy rear admiral. She created a compiler system that translated mathematical code into machine language. Later, the compiler became the forerunner to modern programming languages Grace Hopper (1906–1992) In 1947, Hopper and her assistants were working on the "granddaddy" of modern computers, the Harvard Mark II. "Things were going badly; there was something wrong in one of the circuits of the long glass- enclosed computer," she said. Finally, someone located the trouble spot and, using ordinary The bug is so famous, tweezers, removed the problem, a you can actually see two- inch moth. From then on, him/her in the when anything went wrong with a Smithsonian computer, we said it had bugs in it.” Museum. Harvard Mark II Grace Hopper Nanosecond ! A Grace Hopper nanosecond is a visual aid that represents how fast electricity can travel in one billionth of a second. The name comes from the foot-long lengths of telephone wire that Admiral Grace Hopper used to give out at lectures. Admiral Hopper used the wires to illustrate how in one billionth of second (a nanosecond ) an electronic signal can travel almost twelve inches. .