History of Computers Abacus An early device to

History of Computers Abacus An early device to record numeric values 1 6

John Napier • In 1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. • Ex: log 2 x = 5 2 6

Blaise Pascal Mechanical device to add, subtract, divide & multiply 8 -digit Pascaline 3 6 -digit Pascaline 6

Pascaline Insides 4

Slide Rule • Napier's invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960's by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon. 5

Joseph Jacquard’s Loom, the punched card 6 Examples of Punch Cards

Charles Babbage Analytical Engine 7 • By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. Babbage was not deterred, and by then was on to his next brainstorm, which he called the Analytic Engine. This device, large as a house and powered by 6 steam engines, It was programmable, thanks to the punched card technology of Jacquard.

Mark I • The machine weighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long, and had a 50 ft rotating shaft running its length, turned by a 5 horsepower electric motor. • The Mark I ran non-stop for 15 years, sounding.

Mark I

Generations of Computer First Generation (1940 -1956) Vacuum Tubes Large, not very reliable, generated a lot of heat Magnetic Drum Memory device that rotated under a read/write head Card Readers Magnetic Tape Drives Sequential auxiliary storage devices 10 8

Characteristics of First Generation § The operating system of the first generation computers were very slow § They are very large in size § Production of the heat was in large amount § Machine language was used for programming § They were difficult to program and use. 11

Second Generation (1956 -1963) Transistor Replaced vacuum tube, fast, small, durable, cheap Magnetic Cores Replaced magnetic drums, information available instantly Magnetic Disks Replaced magnetic tape, data can be accessed directly 12 9

Characteristics of Second Generation § Second generation computers were smaller in comparison with the first generation computers. §They are faster in comparison with first generation computers. §They generated less heat and less prone to failure. §They took comparatively less computational time. § Assembly language was used for programming and it has faster input/output devices. 13

Third Generation (1964 -1971) Integrated Circuits Replaced circuit boards, smaller, cheaper, faster, more reliable Transistors Now used for memory construction Terminal An input/output device with a keyboard and screen 14 10

Characteristics of third Generation § IC was used in this generation. §It was smaller in size and cheaper as compare to the second generation. § They were fast and more reliable. §High level language was developed. § Input/output devices became more sophisticated. 15

Fourth Generation(After 1971) Very Large-scale Integration(LSI & VLSI) Great advances in chip technology PCs, the Commercial Market, Workstations Personal Computers and Workstations emerge New companies emerge: Apple, Sun, Dell … Laptops Everyone has his/her own portable computer 16 11

Characteristics of Fourth Generation § Fourth generation have microprocessor based systems. §They are the cheapest among all the computer generation. § Many high level languages were developed such as COBOL, FORTRAN, BASIC, PASCAL and C language. § Networking between the systems was developed. 17

Fifth Generation (1980 onwards) ULSI(Ultra Large Scale Integration) It is more powerful as well as faster than the microprocessors used by the computers of fourth generation. 18 18

Characteristics of Fifth Generation § Fifth generation computers will use super or ultra scale integration chips. § They will have artificial intelligence. § They will be able to recognize image and graphs. §It will be able solve highly complex problem including decision making, logical reasoning. § They will be able to use more than one CPU for faster processing speed. 19