Charless babbage

• born: 12/26/1791

• son of a London banker

• Trinity College, Cambridge

• Lucasian Professorship

• Mathematician and Scientist

• 1822 plan for calculating and printing mathematical tables like they were used in the navy

• using the method of difference, based on polynomial functions

• 1822 design 6 decimal places with second-order difference

• 1830 engine with 20 decimal places and a sixth-order difference

• 1830 end of work on the difference engine because of a dispute with his chief engineer

• 1834 plans for an improved device, capable of calculating any mathematical function

• increase of calculating speed

• never completed

• separation of storage and calculation: • store• mill

• control of operations by microprogram:• control barrels

• user program control using punched cards• operations cards• variable cards• number cards

• more than 200 columns of gear trains and number wheels• 16 column register (store 2 numbers)• 50 register columns, with 40 decimal digits of precision• counting apparatus to keep track of repetitions • cycle time: 2.5 seconds to transfer a number from the store to a register in the

mill• addition: 3 seconds• conditional statements

• Ada Lady Lovelace, daughter of Lord Byron, was working with Babbage on the Analytical Engine• first ideas of

• algorithm representation • programming languages

• already realized:• program loops • conditional statements

• John von Neumann (1903 - 1957): universal computing machine consisting of:• memory • input / output • arithmetic/logic unit (ALU)• control unit

• based on Babbage‘s ideas• 95 % of modern computers are based on the von Neumann

architecture

• Howard Aiken (1900 – 1973) developed the ASCC computer (Automatic Sequence Controlled Calculator) • could carry out five operations, addition, subtraction, multiplication,

division and reference to previous results

• Aiken was much influenced by Babbage's writings • he saw the ASCC computer as completing the task which Babbage

had set out on but failed to complete

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