1. The History of Computers

2. People have almost always looked for tools to aid in calculation. The human hand was probably the first tool used to help people count. Devices have been invented to make the job easier and to keep people from taking off their shoes when counting to twenty.

3. The History of Computers Computers have evolved from… Computers have evolved from… Manually-Operated devices, to Mechanical devices, to Electro-Mechanical devices, and finally to Electronic computers.

4. Manually Operated Devices

5. Manually-Operated Devices The abacus may have existed as early as 5000 years ago in Asia Minor Abacus The Chinese perfected it in the 12 th century.

6. Mechanical Devices

7. In 1642, Blaise Pascal designed the first gear-driven counting machine. Pascal created the machine in an attempt to make his dad’s job, a tax collector, easier. The machine, called Pascaline, could add and subtract.

8. Mechanical Devices In the early 1670’s, Gottfried Wilhelm Leibniz invented a mechanical calculator that improved greatly on Pascal’s design. Leibniz’s calculator employed a crank on the side that simplified the repetitive operations necessary to multiply and divide. 1 st four function calculator Weighed over 20 pounds

9. Mechanical Devices In 1834, Charles Babbage proposed the construction of an “Analytical Engine”. Babbage’s design was unique and could be characterized as the first general-purpose programmable computer. If the Analytical Engine had been built, it would have included the use of punched cards to feed instructions to the machine and the capability to calculate and store numbers. instructions to the machine and the capability to calculate and store numbers.

10. Electro - Mechanical Devices

11. In 1880 the United States census took 7½ years to calculate. The U.S. Census Bureau needed a better way to calculate the census. Because of this, Herman Hollerith developed a machine using punched cards that performed a simple count of the 1890 population in only six weeks.

12. Electro-Mechanical Devices Hollerith’s invention allowed him to start a company called the Tabulating Machine Company. That company eventually became the International Business Machines Corporation (IBM)

13. Electro-Mechanical Devices Hollerith’s machine used gears, wheels, and other mechanical parts but was also powered by electricity.

14. Electro-Mechanical Devices In 1944, IBM built the Mark I which used a combination of electrical signals and mechanical gears to quickly add and subtract large numbers. The Mark I was 51 feet long and 8 feet high, and included almost 500 miles of wires. It was also the first computer to get a “bug”, which was a real insect.

15. Electro-Mechanical Devices During WW II, England built the Colossus. It was used to decode encrypted messages

16. Electronic Devices

17. Electronic Computers In 1946, The Electronic Numerical Integrator and Computer (ENIAC) was developed by John William Mauchly and John Presper Eckert. ENIAC was one of the first computers without mechanical parts. video

18. Electronic Computers Instead, ENIAC used electronic switching devices called vacuum tubes. Vacuum tubes made ENIAC about 1000 times faster than Mark I 1000 times faster than Mark I

19. Electronic Computers By the late 1950’s, the transistor began to replace the vacuum tube in computers. Transistors accomplish the same work as vacuum tubes, but are smaller, faster, and more reliable.

20. Electronic Computers In the 1960’s, the integrated circuit, commonly called a chip, was developed. An integrated circuit is a thin slice of photo-sensitive silicon, usually smaller than a dime, upon which microscopic circuits have been inscribed. The first chips usually performed only one function, such as adding.

21. Electronic Computers In the 1970’s, designers began to put multiple functions on a single chip. Soon, nearly all of the main functions of a computer were placed on a single chip. This new invention was called the microprocessor. The first microcomputers became available in the 1970’s

22. Electronic Computers Since the 1970’s, microcomputers have evolved more rapidly than ever. Each new model does more and costs less then the one before. They are cooler, faster, cheaper, more powerful, smaller, more capability