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History of Computers

History of Computers. Computer Programming I. Mechanical Devices. Pascaline (1642) Set of gears, similar to clock Only performed addition Stepped Reckoner Gottfried Leibniz Cylindrical wheel with movable carriage Add, subtract, multiply, divide, square roots Jammed/malfunctioned.

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History of Computers

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  1. History of Computers Computer Programming I

  2. Mechanical Devices • Pascaline (1642) • Set of gears, similar to clock • Only performed addition • Stepped Reckoner • Gottfried Leibniz • Cylindrical wheel with movablecarriage • Add, subtract, multiply, divide, square roots • Jammed/malfunctioned

  3. Mechanical Devices • Difference Machine (1822) • Charles Babbage • Produce table of numbers used by ships’ navigators. • Never built • Analytical Machine (1833) • Perform variety of calculations by following a set of instructions (or program) on punched cards • Never built • Used as a model for modern computer

  4. Mechanical Devices • Babbage’s chief collaborator on the Analytical Machine was Ada Byron. • Ada Byron • Sponsor of Analytical Machine • One of first people to realize its power and significance • Often called the first programmer because she wrote a program based on the design of the Analytical Machine.

  5. Electro-Mechanical Devices • Hollerith’s Tabulating Machine • Herman Hollerith – used electricity • For US Census • Holes representing information to be tabulated were punched in cards • Successful • Mark I (1944) • IBM & Harvard • Mechanical telephone replay switches to store information and accepted data on punch cards. • Highly sophisticated calculator - unreliable

  6. The Mark 1

  7. Electro-Mechanical Devices • These devices were not mass produced. • Not Reliable • Still took time • Hollerith’s machine took 6 years for a general account. • Mark 1 – 51 ft. long, weighed 5 tons

  8. First Generation Computers • Atanasoff-Berry Computer (ABC) • Built b/w 1939-1942 • Used binary number system • Vacuum tubes • Stored info by electronically burning holes in sheets of paper. • ENIAC • Electronic Numerical Integration and Calculator • 1943, 30 tons, 1500 sq ft., 17,000+ vacuum tubes • Secret military project during WWII to calculate trajectory of artillery shells. • Solve a problem in 20 min that would have take a team of mathematicians three days to solve.

  9. What is a Computer? An electronic machine that accepts data, processes it according to instructions, and provides the results as new data.

  10. The Stored Program Computer • Alan Turing & John von Neumann • Mathematicians with the idea of stored programs • Turing • Developed idea of “universal machine” • Perform many different tasks by changing a program (list of instructions) • Von Neumann • Presented idea of stored program concept • The stored program computer would store computer instructions in a CPU.

  11. The Stored Program Computer • Von Neumann, Mauchly and Eckert designed & built the EDVAC (Electronic Discrete Variable Automatic Computer) and the EDSAC (Electronic Delay Storage Automatic Computer) • Designed to solve many problems by simply entering new instructions stored on paper tape. • Machine language (1’s & 0’s)

  12. The Stored Program Computer • Mauchly & Eckert built 3rd computer (UNIVAC - UNIVersal Automatic Computer) • 1st computer language – C-10 (developed by Betty Holberton) • Holberton also developed first keyboard and numeric keypad • First UNIVAC sold to US Census Bureau in 1951

  13. Second Generation Computers • 1947, Bell Lab (Shockley, Bardeen, Brittain) • Invented the transistor • Replaced many vacuum tubes • Less expensive, increased calculating speeds • Model 650 (early 1960s) • IBM introduced first medium-sizedcomputer (Model 650) • Still expensive

  14. Second Generation Computers • Change in way data was stored • Magnetic tape and high speed reel-to-reel tape machines replaced punched cards • Magnetic tape gave computers ability to read (access) and write (store) data quickly and reliably

  15. Third Generation Computers • Integrated circuits (ICs) – replaced transistors • Kilby and Noyce – working independently developed the IC (chip) • ICs • Silicon wafers with intricate circuits etched in their surfaces and then coated with a metallic oxide that fills in the etched circuit patterns • IBM System 360 (1964) • One of first computers to use IC

  16. Mainframes A large computer that is usually used for multi-user applications IBM System 360 one of first mainframes Used terminals to communicate with mainframe

  17. Fourth Generation Computer • Microprocessor (1970) • Hoff at Intel Corp, invented microprocessor • Entire CPU on a chip • Makes possible to build the microcomputer (or PC) • Altair – one of first PCs 1975 • Wozniak and Jobs designed and build first Apple Computer in 1976 • IBM introduced IBM-PC in 1981

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