Physical Limits Chip Charles Babbage 1791 1871 The

Physical Limits • Chip Charles Babbage (1791– 1871) • The Difference Engine, 1823 – Special purpose device intended for the production of tables. – Made prototypes of parts of the engine – Unfinished project – London Science Museum made a working model in 1991. • The Analytical Engine, 1834 – General purpose device – Uses punched cards – Only planned • Important idea: The programmable computer

Model in London Science Museum

Augusta Ada King, Countess of Lovelace (1815 -1852) • During a nine-month period in 1842 -1843, Ada translated for Babbage Italian mathematician Luigi Menabrea's memoir on Babbage's newest proposed machine, the Analytical Engine. • With the article, she appended a set of Notes which specified in complete detail a method for calculating Bernoulli numbers with the Engine, recognized by historians as the world's first computer program. (disputed).

Willgodt T. Odhner, 1874 • Factory in St. Petersburg • Moved to Moscow after the revolution, soon discontinued • Odhner's legal successors went to Sweden, founded Aktiebolaget Original Odhner in Gothenburg • Production continued until early 1970 s • Lots of similar clones worldwide (example: 1950 s version)

Original Odhner 1874 1950 s

Herman Hollerith, 1890 • Won the contract to supply his system for the Eleventh Cencus of the United States • Developed an entire integrated system of machines, data recording devices and processes for automating the enumeration • A key element in his systems was the use of punched cards • This type of were still in use by the data processing industry into the 1970 s • Founded the company that later became IBM

John Ambrose Fleming, 1904 • Invents thermionic valve / vacuum tube • The beginning of electronics • Used for signal amplification

First vacuum tube computer • 1937 -1942 - John V. Atanasoff and Clifford Berry builds the first digital electronic computer (ABC).

ABC • Introduced the ideas of binary arithmetic, regenerative memory, and logic circuits • Special purpose computer. Used binary math to solve differential equations • Made of 300 vacuum tubes, card readers to input data, memory drums that stored information as electrical charges

Vacuum tube memory Cathode-ray tube memory, from the IBM 701 Defense Calculator, 1952

The Transistor • Invented in 1947 by John Bardeen, Walter Brattain & William Shockley at Bell Labs. • Considered by many to be one of the greatest inventions in modern history • Key active component in practically all modern electronics

The Transistor explained Idea: Use a small amount of current to control a large amout of current. collector base emitter Can be used as a switch or an amplifier.

The Integrated Circuit • 1954 - SAGE aircraft-warning system the largest vacuum tube computer system ever built. 55000 tubes, 275 tons. • 1959 - Jack Kilby of Texas Instruments patents the first integrated circuit, a small package of transistors (among other components).

The first Personal Computer? • Ambiguous question • Some digital, automatic, programmable, accessible, small, inexpensive, simple computers: – Commodore 64 (1982) – IBM PC (1981) – Apple ][ (1977)

Computers in war (handout next page)