The first generation

• First generation computers


  Computing has its origins in mechanical devices designed to help solve arithmetical problems, dating back hundreds or even thousands of years
• Examples of early mechanical devices

  • Greek Antikythera clockwork mechanism
  • Abacus
• Programmable computers


  Computers that can have their instructions changed to produce different results
• Programmable computers


  • Instructions can be stored and recalled, rather than wired in
  • Represent numbers using on/off electronic switches (binary)
• Early programmable electronic computers

  • Colossus (used for code-breaking in WWII)
  • ENIAC (first general-purpose computer)
• Early programmable electronic computers

  • Used bulky, expensive vacuum valves as electronic switches
  • Large, heavy, and unreliable compared to modern computers
• ENIAC weighed 27 tons and occupied 63 square metres
• Power consumption


  • Affects environmental impact and running costs
  • Heat generated by computers is an important consideration
• Colossus used 8 kW, ENIAC used 170 kW
• Power consumption of some home devices

  • Electric fire (2 kW)
  • Electric iron (1 kW)
  • 46-inch TV (120 W)
  • Desktop computer (300 W)
  • Energy-saving light bulb (10 W)
  • Electric kettle (2 kW)
• To compare power consumption, figures in kilowatts need to be converted to watts by multiplying by 1000
• Heating devices


  Generally use a lot of power
• Heat from computers was used to dry clothes at Bletchley Park
• Thomas Watson, Chairman of IBM, 1943: '"I think there is a world market for maybe five computers"'
• Popular Mechanics, March 1949: '"Where a calculator on the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and perhaps weigh 1.5 tons."'
• Throughout much of the first generation, computers were seen as mysterious entities
• Alan Turing proposed the Turing test in 1950 to determine if a computer can think like a human