The second generation

• First generation computers


  Defined by the use of valve technology and the assumption that the main purpose of computers was to carry out calculations for code-breaking or other military purposes
• Transistor


  A tiny crystal of silicon that, when processed in various ways, can be made to conduct electrical current and act as a switch by blocking or allowing electrical current, just like a valve
• Transistors


  • Occupied less than a thousandth of the volume of a valve
  • Offered far greater reliability at a fraction of the cost
  • Power consumption was much lower than that of valves
  • Switching speed was higher
• Second-generation computers


  Used transistors
• Second-generation computers were still very expensive both to buy and to maintain
• Second-generation computer


  • IBM 608 (1955) - could be purchased for US$83,000
• Second-generation computers


  • Were far from small, the largest type was referred to as a mainframe
  • Used punched cards to program and contain data
  • As time went by, the complexity of mainframe machines grew and with it their power consumption
• Minicomputer


  A smaller type of transistor-based computer that entered the market in the early 1960s, came in a case about the size of a wardrobe, and had a number of monitors and keyboards connected to it
• Minicomputers


  • Were much cheaper to buy and to run than mainframe computers, costing about US$16,000 in 1964
  • Fell within the reach of smaller businesses
  • Expanded the number of computer users considerably and is often seen as marking the beginning of the third generation