History of Computers

1. History of Computers Computer Science AMSACS

2. Historical Developments • The history of computers goes back longer than you think. • Computers did not always look like, nor behave like, computers that we have today. • We are going to proceed in “generations” • Note that nobody is in perfect agreement about these generations • However, they are a convenient way to organize the history of computers

3. History of “Computers” • Abacus---Approximately 3000 BC • Calculators---1600s • Punched Card Devices---1800s • First Electronic Computers---1940s • Mainframes---1950s • Minicomputers---1960s • Microcomputers and Internet ---1970s • Microcomputer Systems---1980s • World Wide Web --1990s

4. Generation 0: Mechanical Calculators • The Abacus • Before the 1500s calculations were made with an Abacus. It is a mechanical aid used for counting and making quick calculations. • It was available in many cultures: China, Mesopotamia, Japan, Greece, and Rome. Still in use around the world.

5. Generation 0: Mechanical Calculators Blaise Pascal • Blaise Pascal was a French mathematician, physicist, philosopher. In 1642 he invented the first mechanical calculator called the Pascaline. • It could perform additions, subtractions and carries. It was initially used to help Pascal’s father with tax computations. • The Pascalineused cogs and gears to solve math equations. These early calculators did not have memory and required human intervention at each step.

6. Charles Babbage • In 1822 Charles Babbage (English mathematician), sometimes called the “father of computing” built the Difference Engine. • The machine designed to automate the computation of polynomial functions – not simply simple addition and subtraction. • Babbage’s “computer” improved upon previous machines by implementing some storage of calculations – that is, “memory”. However it still required human intervention.

7. Charles Babbage • In 1833 Babbage designed the Analytical Engine, but he died before he could build it • It was built after his death, powered by steam! • This is really the first machine that somewhat resembles our computers. It had: • An arithmetic processing unit (the mill) • A memory (the store) • Input/output devices (punched metal cards) • In 1842,Ada Lovelace (English mathematician) wrote instructions for the Analytical Engine to compute the Bernoulli numbers: the first computer program! Created by Ms. Jain CS AMSACS

8. Generation 1: Vacuum Tubes • The vacuum tube is the first known device to amplify, switch, or modify a signal (by controlling the movements of electrons) • In the 1930s, Konrad Zuse (German) designed a machine akin to the Analytical Engine of Babbage that was supposed to use vacuum tubes

9. ENIAC Electronic Numerical Integrator And Calculator It was the first electronic digital computer that could be programmed for more than one purpose. Remember the Colossus was only programmed to decode the German “Enigma” code. The ENIAC was built during World War II. In twenty seconds, ENIAC could do a math problem that would have taken 40 hours for one person to finish.  The ENIAC was 100 feet long and 10 feet tall and weighed 30 tons. It contained over 18,000 vacuum tubes.

10. New Computer Concepts • The use of binary • In the 1930s Claude Shannon (the father of “information theory”) had proposed that the use of binary arithmetic and boolean logic should be used with electronic circuits. • The Von-Neumann architecture • In 1944, John von Neumann (Hungarian) learned about ENIAC and joined the group. • He wrote an article about computer architecture that formalized the ideas that came out of the ENIAC project and made them available to a wider audience.

11. CPU Memory I/O System The Von-Neumann Architecture • Three hardware systems • A Central Processing Unit (CPU) • A memory, which stores both programs and data • An input/output system • Computers today are still very close to this basic architecture.

12. Computer Bugs • In 1947, Grace Hopper was working on the Harvard University Computer based on vacuum tubes. • When the machine was experiencing problems, an investigation showed that there was a moth trapped. • The operators removed the moth and affixed it to the log. The entry reads: "First actual case of bug being found.“ • Thus the following terms were born: • “computer bugs” =mistakes in a computer program. • “debugging a computer program” =fixing mistakes in a program. Created by Ms. Jain CS AMSACS

13. Generation 2: Transistors • Vacuum tubes, on top of being large, were not reliable. • In 1948, Bardeen, Brattain, and Shockley invented the transistor at Bell Labs. It wasmuch smaller than a vacuum tube, reliable,and could perform the same work. • This was the beginning of a new era for electronics and for the computer market.

14. Generation 3: Integrated Circuits • In the late 1950s, Kilby and Noyce came up with the idea of an Integrated Circuit • The Integrated Circuit allowed dozens of transistors to exist on a single “silicon chip”. • Modern Integrated Circuits can hold thousands or millions of transistors. • This invention led computers to become smaller, faster, and cheaper

15. Programming Languages • In the 1950s Grace Hopper was programming computers for the Navy. She believed that programming languages should be closer to English. • She designed a programming language that became COBOL – the first widely used computer programming language that is still in use today. Created by Ms. Jain CS AMSACS

16. Generation 4: Microprocessors • Improvements to Integrated Circuit technology made it possible to integrate more and more transistors in a single chip. • It now became possible to have a full CPU on a single chip, also called a microprocessor. • A microprocessor is a computer processor on a microchip (small chip). It is the "engine" that goes into motion when you turn your computer on. A microprocessor is designed to perform arithmetic and logic operations. • The first microprocessor was created by Intel in 1971.

17. Generation 4: Microprocessors The Microcomputer Revolution Begins • 1971, Intel develops the first microprocessor chip. • 1975 the Altair known as the first personal computer is sold. It is a kit that must be assembled. • 1975 Microsoft is started by Bill Gates and Paul Allen. Their first product is PC-DOS (Disk Operating System). • 1976 Apple Computer is formed by Steven Jobs and Steve Wozniak. • Further advances rapidly increase memory size, storage space, and processing speeds.

18. Generation 4: Microprocessors Microcomputers • The advent of microprocessors made it possible to build Personal Computers (PCs). Prior to microprocessors, computers were only used by companies and government agencies. • Computers could now be made whose price, size, and capabilities make it useful for individuals. TEA

19. ENIAC on a chip In 1997, students at U. Penn built a single chip (microprocessor) equivalent to the ENIAC ENIAC: 1,800 sq. ft., 30-ton, 174 kilowatts Microprocessor with 174,569 transistors M I C R O P R O C E S S O R = Created by Ms. Jain CS AMSACS

20. Internet In the early 1970s • The US Government-sponsored Arpanet computer network is converted to new technology. The new network is called the “Internet.” • In the 1970’s the Internet is used mainly by scientists, universities and large businesses. Created by Ms. Jain CS AMSACS

21. 1990s Connecting the World • Tim Berners-Lee • Developed HTML and the World Wide Web (WWW) was born. This made the Internet more accessible to the public. Created by Ms. Jain CS AMSACS Internet

22. Generation 5– Future Technology • The term “Generation 5” is used sometimes to refer to “scifi” future developments: • Voice recognition • Artificial intelligence • Advanced robotics • Smart houses • Wearable computers • Truly individualized education

23. Summary • Generation 0: Mechanical Calculators • Generation 1: Vacuum Tubes • Generation 2: Transistors • Generation 3: Integrated Circuits • Generation 4: Microprocessors • Generation 5: Future Technology