History of Computers

  1. 1623: Mechanical calculator
    • Wilhelm Schickard invented first known mechanical calculator, capable of simple arithmetic.
    • Similar mechanical adding machine made in 1640’s by Blaise Pascal. Still on display in Paris.
    The "Pascaline," from The History of Computing Project

  2. 1673: More advanced mechanical calculator
    • 1673 by German mathematician Gottfried Leibniz
    • Capable of multiplication and division
    • Purely mechanical with no source of power.
    Leibniz's Step Reckoner
    The "Step Reckoner," from maxmon.com

  3. 1823: Charles Babbage begins work on Difference Engine
    Difference Engine
    • He designed, but it was completed by a Swedish inventor in 1854.
    • Image of the Difference Engine from Niagara College
  4. 1833: Charles Babbage begins Analytical Engine
    • Never completed.
    • Important concept: a general-purpose machine capable of performing difference functions based on programming.

  5. 1834: Ada Byron, Lady Lovelace impressed with the concept of the Analytical Engine at a dinner party.
    • Daughter of poet Lord Byran
    • Created plans for how the machine could calculate Bernoulli numbers. This is regarded as the first “computer program," and she is the first "programmer."
    • The Department of Defense named a language “Ada” in her honor in 1979.

  6. 1890: punched cards used by Herman Hollerith to automate Census
    • Concept of programming the machine to perform different tasks with punched cards was from Babbage.
    • Punch cards based on Josph Marie Jacquard’s device to automate weaving looms.
    • Hollerith founded a company that became International Business Machines (IBM) to market the technology.
    Sample Punch Card
    Sample Punch Card, from About.com

  7. 1939: prototype of the first electronic computer
    Atansoff Barry Computer
    • Assembled by John Atansoff and Cliford Barry.
    • John Atansoff came up with the concept of using binary numbers.
    • Completed in 1942 using 300 vacuum tubes.
    • Could solve small systems of linear equations
    • Image from The History of Computing Project

  8. 1946: ENIAC completed
    • Electronic Numerical Integrator and Computer
    • By Presper Eckert and John Mauchly
    • 18,000 vacuum tubes.
    • Occupied a 30 by 50 foot room
    • Programming by plugging wires into a patch panel. Very difficult to do, because this style programming requires intimate knowlege of the computer.
    ENIAC, from ftp.arl.mil

  9. 1946: John van Neumann Architecture stored-programming concept
    • He suggested that programs and data could be represented in a similar way and stored in the same internal memory.
    • All modern computers store programs in internal memory.

Four generations of computers

  1. Vacuum tube (1939)
  2. Transistor (invented in 1947, used in IBM 7090 in 1958)
  3. Integrated circuit or chip (invented in 1959, used in IBM 360 in 1964)
    • A small wafer of silicon that has been photographically imprinted to contain a large number of transistors together.
  4. Large-scale integration: microprocessor (1975)
    • Entire processing unit on a single chip of silicon
Vacuum tube
Vacuum tube, from computermuseum.li

Transistors, from Texas Instruments
Integrated Circuit
Circuit, from IEEE Virtual Museum
Old CPU's, from Wikipedia

Robert Noyce, one of the inventors of the integrated circuit and founder of Intel speaking of a modern computer chip compared to the Eniac: "It is 20 times faster, has a larger memory, is thousands of times more reliable, consumes the power of a light bulb rather than that of a locomotive, occupies 1/30,000 the volume and costs 1/10,000 as much."

Source: Robers, Eric S. The Art and Science of C. Addison-Wesley Publishing Company. Reading: 1995.