History of Computers


Important

Computer generations are defined by major technological developments that fundamentally changed the way computers operated.

First Generation (1946–1959)

ENIAC, Electronic Numerical Integrator and Computer

  • First real computer
  • designed for military

Components

  • vacuum tubes for circuitry
  • magnetic drums for memory
  • Used machine language
    • lowest level
    • complex
  • Ran one program at a time
  • Input with punch cards

Cons

  • Often malfunctioned due to heat generated
  • Large size, because vacuum tubes were large
  • limited capacity
  • lots of maintenance

Second Generation (1959–1965)

Mainframe computers

  • used less power, and ran cooler
  • Still large as a room

Components

  • Used transistors
    • represented 2 states, on/off (0/1 binary)
  • Still used punch cards for input, printouts for output
  • Assembly language
    • COBOL - business uses
    • FORTRAN - math + science use cases

Third Generation (1965–1971)

Integrated Circuits and mini-computers

  • Beginning of modern computing

Components

  • Used integrated circuits
  • invented silicon
  • miniaturized transistors and placed on silicon chips called semiconductors
  • Used keyboard and monitors
  • Operating systems ran multiple applications simultaneously and shared memory

Fourth Generation (1971–present)

Personal computer (PC): Desktops & laptops

  • Age of microprocessors
    • thousands of integrated circuits on a single silicon chip
  • Significant reduction of processor size
    • Size of transistors reduced to 7-14 nanometers
  • Significant increase in capability

Components

  • GUIs
  • Mouse
  • Handheld devices
  • New OS: MS-DOS, Windows
  • High-level languages

Fifth Generation

  • Using AI
  • Natural language processing (NLP)
  • Quantum computing
    • the study of non-classical model of computation
    • reduce power consumption from 100-1000x
  • Nanotechnology
    • molecular-level systems
  • Overlap with Gen 4 and 5