INTRODUCTION Term “Computer” Computer definition Data Information Basic operations- input - process - output - storing - control

Applications Office Automation Database Accounting Budgeting Reservation Internet Digital Audio/video.

Characteristics Speed Accuracy Automatic Endurance Versatility Storage Reduction in cost.

Evolution of computers The computers have gone through the different stages of evolution which began with the development and use of technology.

Abacus Chinese invented calculating device. Also called as “Soroban” Performs simple addition & subtraction.

Abacus.. The beads of computer represents digits. The value of digit in each position is determined by adding the value of the beads . The beads on the rightmost represents ones, on next adjacent represents tens and next represents hundreds and so on. For addition and subtraction, the beads can be moved side ways. Multiplication and division operations are done using repeated additions and subtractions.

Napier’s device John Napier a Scottish mathematician invented logarithms. It contains 11 animal bones which were replaced by rods. These rods carried numbers marked on them. It simplifies the multiplication and division processes. Here all numbers could be expressed in exponential form. Multiplication and Division could be accomplished by adding or subtracting the exponents.

Napier’s device

Ex:359*7=2513. 2/1 3/5 6/3 2 5 1 3

Pascal Calculating Machine Pascaline. In 16422, a French mathematician, Blaise Pascal invented the first functional automatic calculator that could add and subtract.

PCM.. He develops a mechanism to calculate with 8 figures and carrying of 10's , 100's, and 1000's etc. It consists of a set of toothed wheels or gears with each wheel or gear having digits 0 to 9 engraved on it. When a gear with ten teeth made one rotation (tens) a second gear shift one tooth until that gear rotated ten times (hundreds) that shifts another gear (thousands) etc. This principle was still used in pumps of petrol stations, and your electricity meters at home.

Punched Card Machine

Punched Card Machine In 1801, French weaver Joseph Marie Jacquard invented this. Punched card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions. The lower ten positions represented (from top to bottom) the digits 0 through 9. The top two positions of a column were called zone punches, 12 (top) and 11. 12 for plus and 11 for minus. Originally only numeric information was punched, with 1 punch per column indicating the digit.

Charles Babbage’s Engine A) Difference Engine - 1822 In 1822, Charles Babbage proposed a mechanical computer to perform differential equations called a Difference Engine. In general, calculating the value of a polynomial can require any or all of addition, subtraction, multiplication and division. An advantage of the method of finite differences is that it eliminates the need for multiplication and division, and allows the values of a polynomial to be calculated using simple addition only.

B) Analytical Engine - 1833 It was the first mechanical calculator incorporate with five units- input, output, store, mill, and control. The input devices are included in the form of punched cards. Store was used for storing numbers and Mill was used to do the calculations by rotation of gears and wheels. Control unit did the job of supervision of all other units and output devices to produce printed results. So it is a complete design for general general-purpose computer.

ABC In 1937, Dr. John Atanstoff with the help of his assistant Berry designed the Atanasoff Berry Computer (ABC). It was the first electronic digital computer, solves the system of linear equations. It featured several innovations in computing such as: a binary system of arithmetic parallel processing regenerative memory separation of memory & computing functions

ENIAC Electronic Numerical Integrator and Calculator In 1946, John Eckert and John Mauchly introduced this first electronic general purpose computer.

ENIAC.. It used electronic vacuum tubes, resistors, capacitors& switches to make the internal parts of the computer. It was considered as significant development because of its speed. Drawbacks: ENIAC's memory was composed of vacuum tubes; was rather limited, besides being expensive to construct and maintain. Reprogramming ENIAC presented another serious drawback: physical switches and plugs had to be reconfigured over a period of hours or days in order to solve a new type of problem.

EDVAC Electronic Discrete Variable Automatic Computer  It was the successor of ENIAC, uses the stored program concept introduced by John Von Neumann in 1949.

EDVAC.. It differs from ENIAC in two ways, - use of binary numbers for electronic arithmetic operations. - Internal storage of instructions were written in digital forms.

EDSAC Electronic Delay Storage Automatic Calculator. In 1949, at the Cambridge university, Maurice Wilkes developed EDSAC.

EDSAC.. It was the first full-scale electronic computer to implement the stored-program principle. This machine used mercury delay lines for memory storage. It accomplish its addition in 1500 sec whereas multiplication in 4000 sec’s.

UNIVAC The Eckert and Mauchly Corporation manufactured UNIVAC in 1951 Universal Automatic Computer was the first commercial computer. It marked as the real beginning of the computer era.

The UNIVAC had an add time of 120 microseconds, multiply time of 1,800 microseconds and a divide time of 3,600 microseconds. Input consisted of magnetic tape with a speed of 12,800 characters per second . Output media/speed was magnetic tape/12,800 characters per second,

VLSI Very Large Scale Integration Here hundreds of thousands of transistors were placed on a single chip. ROM, Read Only Memory By the late 1980’s some personal computers were run by microprocessor Handling of 32 bits of data at a time, could process about 4,000,000 instructions per second. By now, personal computers become part of everyday life. This transformation was the result of the invention of the Microprocessor, a processor on a single integrated circuit chip.

VLSI