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History of IT
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Four basic periods: Premechanical era 1. Premechanical 2. Mechanical
3. Electromechanical 4. Electronic Premechanical era around 3000 B.C. – 1450 A.D. inventions of: - writing and alphabets - pens and papers - books and libraries - numbering systems, first calculator The Abacus
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2. Mechanical age lasted from 1450 to 1850
W. Shickard invented a computing machine (+, -) B. Pascal’s Pascaline (mechanical addition, subtraction of numbers) 1673 – Leibniz’s machine ( +, -, *, / ) Ch. Babbage: - the difference engine - the analytical engine (punch cards) J. M. Jacqard invented a loom that used the punch cards The pascaline Difference and analytic engines
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3. Electromechanical age
lasted from 1840 to 1940 beginnings of telecommunication: - telegraph (early 1800s), Morse code (1835, S. Morse), telephone (1876, A. G. Bell), radio (1894, G. Marconi) Herman Hollerith: - census machine (punch cards) - established the IBM MARK 1: -completed in 1942, an automatic-sequence calculator - 3 calculations/sec, worked for 15 years - 8 feet tall, 51 feet long, 2 feet thick, weighed 5 tons
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4. Electronic age 1945 – ENIAC: - Electronic Numerical Integrator and Computer - 1st fully electronic computer, used vacuum tubes - couldn’t store its programs - developers: John Mauchly, J. Prosper Eckert - funded by U.S. Army, used for military purposes John von Neuman: binary system (0,1) stored-program computers: Manchester Mark 1, EDSAC, EDVAC the first general-purpose computer for commercial use: UNIVAC (universal automatic computer)
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Four generations of digital computing
1. - vacuum tubes=main logic elements - used punch cards and rotating magnetic drums 2. - transistors as main logic element - magnetic tape and discs instead of punched cards, magnetic cores for internal storage of data 3. - intgrated circuits - MOS memory replaced the magnetic cores - development of operating systems and programming languages 4. – large-scale and very large-scale integrated circuits - microprocessors, containing memory, logic, control circuits (CPU=central processing unit) - this allowed the home-use of PCs
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