Brief History of CS

Mechanical Computers

• 1. 1791: Charles Babbage: "Difference engine" to solve math tables, "Analytical engine" for general purpose calculations

  2. Jacquard's loom: used punch cards for instructions

Electro-Mechanical Computers

• 1. 1880 Census: took 7 yrs. to tabulate results (think of Golden Gate Bridge). Herman Hollerith won contest to count 1890 census results (took only 6 weeks). 1896: founded the "Tabulating Machine Company," which merged w/2 others in 1924 to form International business Machines (IBM).

  2. Howard Aiken from Harvard got IBM's top executive (Thomas Watson) to invest $1 million (in 1936), with which he built the Harvard Mark I.

     1. 1. 8 ft. high & 55 ft. long

        2. noisy

        3. Aug. `45: Grace Murray Hopper found a 2 in. moth, thereafter calling glitches "bugs"

  3. Mauchly & Eckert (U. Penn.) built the ENIAC in 1941, modelled after Atanasoff `s (from Iowa State) ABC computer, from the 30's. [Show pictures of ABC & ENIAC. The ENIAC had 18,000 vacuum tubes, 1,500 relays, in a room 20ft. by 40ft. It sounded like a train

Computer Generations

• 1. First Generation: 1951-1958: The Vacuum Tube

     1. 1. The first commercial computer (UNIVAC) delivered to Census Bureau

        2. Problem: heat and burnout of tubes, also programming using punchboards / switches

        3. Internal components built of vacuum tubes, and computer memory built of magnetic cores [see closeup]

        4. punched cards used as supplementary storage.

        5. 1957: magnetic tape introduced [see piece of tape w/filings & magnifying glass]

  2. Second Generation: 1959-1964: The Transistor.

  3. Internal components previously built with vacuum tubes replaced by transistors [see sample].

• • • 1. Advantages of transistors: smaller, faster, more reliable, no warm-up needed

      2. Machine languages (0 & 1) -> symbolic languages (L for LOAD, rather than code)

      3. Symbolic languages -> High-level languages (FORTRAN `54, COBOL `59)

• 4. Third Generation: 1965-1970: The Integrated Circuit

  5. Many transistors combined together into a very small space, forming an integrated circuit [see wafer, various chips]

• • • 1. A Large circuit board was replaced by an integrated circuit half the size of a fingernail.

      2. IBM 360 "mainframe" computer: upward-compatible design

• 6. Fourth Generation: 1971 - present: Microprocessor (& Microcomputers)

  7. A general-purpose processor on a chip; Evolutionary, not revolutionary change

• • • 1. Widespread use: watches, calculators, irons, cars, personal computers, phones

      2. Mass production & further miniaturization meant 10's of millions of transistors (& other electrical components) on a single integrated circuit

• 8. Fifth Generation: dates?: A.I., Language understanding, handwriting recognition, parallelism (multiple CPU's in one computer)

Links, Topics

Computer History Museum online at http://www.computerhistory.org/exhibits.html (in particular the timeline and visible storage links)

Terms & a simple computer model: CPU, Memory (RAM), bit, byte, costs (see sample computer system ads)