© Prentice-Hall, Inc Definition  Computer - An electronic device that has the ability to store, retrieve, and process data and can be programmed with instructions that it remembers.

Gross Anatomy  Hardware Equipment associated with the computer Equipment associated with the computer Input devices, processor, output devices, storageInput devices, processor, output devices, storage  Software Instructions that tell the hardware what to do Instructions that tell the hardware what to do Two categories of software: Two categories of software: System softwareSystem software Application softwareApplication software

© Prentice-Hall, Inc History of Computers Modern computers result from 2 streams of evolution  Mechanization of arithmetic calculating machines (hardware) calculating machines (hardware)  Concept of stored programs process control (software) process control (software)

© Prentice-Hall, Inc A Brief History of the Computer  First “computer”? The first actual calculating mechanism known to us is the abacus, which was invented about 2000 years ago The first actual calculating mechanism known to us is the abacus, which was invented about 2000 years agoabacus Abacus: The art of calculating with beads Abacus: The art of calculating with beadsAbacus: The art of calculating with beadsAbacus: The art of calculating with beads Adapted From:

© Prentice-Hall, Inc A Brief History of the Computer  Many references cite the French mathematician, physicist, and theologian Blaise Pascal as being the inventor of the first mechanical calculator in 1642, the Arithmetic Machine Blaise Pascal Arithmetic MachineBlaise Pascal Arithmetic Machine Adapted From: Liebniz calculator

© Prentice-Hall, Inc A Brief History of the Computer  However, it now appears that the first mechanical calculator may have been conceived by someone else almost 150 years earlier than Pascal's machine. Can you guess who? Leonardo Da Vinci Adapted From:

© Prentice-Hall, Inc A Brief History of the Computer  In the early 1800s, a French silk weaver called Joseph-Marie Jacquard invented a way of automatically controlling the warp and weft threads on a silk loom by recording patterns of holes in a string of cards Adapted From:

© Prentice-Hall, Inc A Brief History of the Computer  The first device that might be considered to be a computer in the modern sense of the word was the Difference Engine to automatically calculate mathematical tables conceived in 1822 by the British mathematician and inventor Charles Babbage Difference Engine Difference Engine Adapted From:

© Prentice-Hall, Inc A Brief History of the Computer  The Difference Engine was only partially completed when Babbage conceived the idea of another, more sophisticated machine called the Analytical Engine Analytical EngineAnalytical Engine  The Analytical Engine was intended to use loops of Jacquard's punched cards to control an automatic calculator, which could make decisions based on the results of previous computations Analytical Engine Analytical Engine Adapted From:

© Prentice-Hall, Inc A Brief History of the Computer  Working with Babbage was Augusta Ada Lovelace, the daughter of the English poet Lord Byron. Ada, who was a splendid mathematician and one of the few people who fully understood Babbage's vision, created a program for the Analytical Engine  Ada is now credited as being the first computer programmer and, in 1979, a modern programming language was named ADA in her honour Adapted From:

© Prentice-Hall, Inc A Brief History of the Computer   In 1939, a German engineer, Konrad Zuse built the first programmable, general- purpose digital computer. His computer was built from electric relays to automate engineering calculations   “I was too lazy to calculate and so I invented the computer.”

© Prentice-Hall, Inc A Brief History of the Computer   John Atanasoff invented the Atanasoff-Berry Computer (ABC) —the first electronic digital computer. Built in 1939, this computer used vacuum tubes and was based on binary arithmetic. It was never a fully operational product.

© Prentice-Hall, Inc A Brief History of the Computer  In 1944, Howard Aiken completed the Mark I, the largest electromechanical calculator ever built. It was built with electromechanical relays and followed instructions punched in paper tape

© Prentice-Hall, Inc A Brief History of the Computer  The first computer “bug”

© Prentice-Hall, Inc A Brief History of the Computer   In 1945, Mauchly and Eckert built the ENIAC (Electronic Numerical Integrator and Computer). The ENIAC was built with 18,000 vacuum tubes that failed on an average of once every seven minutes   After the war, they created the UNIVAC I - the first general- purpose commercial computer

© Prentice-Hall, Inc First-Generation Computers  1930s – 1940s  Vacuum tubes used as switches  Large computers  Extremely slow by today’s standards  Prone to frequent failure  Includes the ABC, Mark I, ENIAC, UNIVAC, and others of similar design

© Prentice-Hall, Inc Second-Generation Computers  1950s – mid-1960s  Transistors used as switches  Smaller than vacuum-tube-built computers  As much as a thousand times faster than first-generation computers  More reliable and less expensive

© Prentice-Hall, Inc Third-Generation Computers  Late 1960s  Hundreds of transistors packed into a single integrated circuit on a silicon chip  Dramatic reduction in size and cost  Significant increases in reliability, speed, and efficiency  Mass production techniques to manufacture chips inexpensively

© Prentice-Hall, Inc Fourth-Generation Computers  1970s to present  Complete computer on a chip  Radical change in the appearance, capability and availability of computers

Some Links  Computer History  Computer History   Charles Babbage and His Difference Engine  w w w  ENIAC   Computer History Museum Overview  dD5dI dD5dI dD5dI © Prentice-Hall, Inc