History of Computing • The synthesis of ideas underlying the general-purpose digital computer was achieved by Charles Babbage (1791-1871) • A working model of a "DIFFERENCE ENGINE” was produced in 1822. It was steam powered, and calculated mathematical tables. 2 Charles Babbage • Babbage then conceived an "analytical engine" with a storage, an arithmetic unit to perform calculations, and a punched-card input and output. • He spent most of the rest of his life (unsuccessfully) trying to build and perfect the machine, which was called by many of his contemporaries, "Babbage's folly.” Alan Turing (1912- 1954) • British Mathematician who did fundamental work on the theory of modern computer science. • Defined a simple but elegant mathematical model of a general purpose computer, now called the Turing Machine, and used it to prove what was possible or impossible for computers to do. Couldn’t get the money to build one. • Today, the ACM’s Turing Award is considered to be like the Nobel Prize of computing. 3 COMPUTER GENERATIONS •THE FIRST COMPUTERS WERE RESULTS OF WORLD WAR 2 DEVELOPMENTS, AIMED AT MILITARY USES •1944 AIKEN AT HARVARD MARK 1: FIRST ELECTROMECHANICAL DIGITAL COMPUTER (ELECTROMAGNETIC RELAYS -- MAGNETS OPEN AND CLOSES METAL SWITCHES). THE "FIRST GENERATION:” VACUMN TUBES •1946: ENIAC (Electronic Numerical Integrator and Computer) •FIRST ELECTRONIC DIGITAL COMPUTER, CONSTRUCTED WITH 17,000 VACUUM TUBES. EIGHT FEET TALL AND 80 FEET LONG. • EXTERNAL (WIRED) PROGRAM. •ENIAC could do 333 multiplications per second and cost the equivalent of $5- $10 million