## History of Computer

The history of computer starts from 4000 years ago. History of computer means the gradual change in the concept over a long period of time. Around fifth century, Hindu philosophers developed a new method of counting from 0 to 9. Counting the numbers from 0 to 9 can be performed with the help of fingers. The development of counting started from the development of simple counting device called abacus.

## Abacus

It is early counting and calculating device that was developed by the Chinese people. The ABACUS was first used for computation in 3000 B.C. It was made of wooden frame on which there were strings. The frame was divided into two parts, heaven and earth, by a mid-bar. Each string in heaven had two beads each having the value of five units and each string on the earth had five beads each having the value of one unit. During the calculation, the beads were shifted to the mid-bar. It also followed the place value system. It was used to add, subtract, divide and multiply.## Napier’s Bones

In 1614 AD, a Scottish mathematician John Napier discovered the concept of Logarithms. In 1617 AD, he constructed a set of rods called Napier Bones for doing mathematical calculation easily. It consisted of eleven sets of bone rods on which the numbers were engraved. It was used for multiplication. It was based on the principle of performing multiplication by the addition of logarithms.## Slide Rule

After the invention of logarithm in 1617 AD, William Oughtred invented the slide Rule in 1620. This device was made on the principle of logarithms. This device consists of two graduated scales, one small and other larger one. One of the scales passes over the other. It was used calculation product and quotient. The calculation was done by sliding the smaller scale over the large scale and the result was obtained by viewing the scales. The slide Rule was used by the engineers till 1970s. This was replaced by pocket calculator.

## Pascal’s calculating / Adding Machine

It was developed by Blaise Pascal in 1642. It was a mechanical calculator that used toothed wheels and gears. The numbers were written on the wheels and the calculation was done by dialing the numbers. It was also called as pascaline. It was used to add, subtract, multiply and divide.

## Leibniz’s Calculator

It was made by a German philosopher Gottrified Wilhem von Leibniz in 1971 AD .It was based on Pascal’s principle.

But is used gears, toothed wheels and drums. It was able to add, subtract and even find square rooths. It worked on the principle that multiplication and division can be done by repretitive addition and subtraction of numbers. It was also called as Stepped Reckonor.

But is used gears, toothed wheels and drums. It was able to add, subtract and even find square rooths. It worked on the principle that multiplication and division can be done by repretitive addition and subtraction of numbers. It was also called as Stepped Reckonor.

## Difference Engine

In 1822 AD, an English mathematician (Professor of Mathematics at Cambridge University) Invented a machine called Difference Engine with mechanical memory to store results. It was based on the difference tables of squares of the numbers. Due to which it got its name as Difference Engine.## Analytical Engine

It was also developed by Charles Babbage in 1830s. It consisted of the input unit for taking data and instruction, mill for performing calculation, memory (punched card) with a suitable output device that was used in giving the final result. It was designed to calculate up to 20 decimals places. The same principle of Analytical Engine is used in the modern computer. So he is called as the “Father of the Modern Computer”. Using the principles of Charles Babbage, about 100 years later, Mark – I was developed by Howard Aiken in 1937.

The analytical Engine was never completed due to the lack of techniques and technology because of which he was unable to get all the parts that he wanted in his machine.

## Lady Augusta Ada Lovelace

One of the great supports of Charles Babbage was Lady Augusta Ada (the daughter of famous poet, Lord Byron). She convinced Babbage to use binary concept in his Analytical Engine. She wrote different type s of programs that were used in the Babbage machines. So she is remembered as the “First Programmer” in the history of computer science and has to her credit a computer language called ADA named after her.

## Dr. Herman Hollerith

He was the first person to use punched card practically on his Census Tabulating Machine in 1880s. The information is stored as holes in cards, which are interpreted by machines with electrical sensors. The cards were punched by a machine called Punched Card machine or Hollerith’s Tabulating Machine. Then he established Tabulating Machine Company to sell his products. Later, when other companies merged with TMC, new company were established under the name of International Business Machine Company and he became the founder of IBM. It is the world’s leading computer manufacturer.## Jacquard's Loom

In 1801, a French silk weaver Joseph Marie Jacquard invented automatic weaving machine called Jacquard's loom. At that time, loom revolutionized the weaving industry. This loom used punched cards to produce certain pattern in the woven cloth. The loom was controlled by punched holes, each row of which corresponds to one row of the design. The function of that loom depended upon the absence or presence of holes on the punched cards. This concept gave the idea of binary digits (0,1) Jacquard's Loom could be considered as the first programmable device.

## George Boole

George Boole was an English Mathematician who developed the concept of Boolean algebra or algebra of logic during 1850 - 1860 AD. Boolen logic is a principle used for binary arithmetic. This principle is used to design logic gates which is essential in modern digital computers.

## Mark-I (Howard Aiken)

In the late 1930s, next important even was added in the history of computer electro mechanical computer was born with the development of MARK-I in 1994, by Howard Aiken with the help of IBM. It also used the punched cards designed for Difference Engine. It was 51 ft long, 8 ft high and 13 fit wide. It used larger numbers of valves, switches and resistors. It was used to produce ballistics tables in 2nd world war.## John Von Neumann

John Von Neuman was a great mathematician who contributed a new understanding of how practically fast computers should be organized and built. In 1945, John Von Neumann purposed and suggested two ideas...

**They were [1] - Data and programs could be stored inside the computer. [2] - Binary number system should be used in computer processing.**

## ABC (Atanasoff Berry Computer)

Atanasoff Berry Computer (ABC) was the first electronic digital computer. This computer was designed by Dr. John Vincent Atanasoff and Cliford Berry in 1942. It used 19000 vacuum tubes as the main memory to store data. ABC was mainly used by military to compute firing and blasting data.

## Electronic Numerical Integrator and Calculator (ENIAC)

It is the first electronic computer that was developed by John Mouchaly and J. Prisper Eckert in 1947. It was based on the decimal number system. 18000 vacuums tubes were used in ENIAC. There were 70000 resistors, 10000 condensers and 6000 switches. It weighs 30 tones and occupied a space 3000 cubic feet. It could calculate 300 times faster than any calculating device at that time and it was based on decimal number.## Electronic Delay Storage Automatic Computer (EDSAC)

Electronic Delay Storage Automatic Computer was an early British computer. It was developed by Maurice V. Wilkes and his team at the University of Cambridge in England in 1949. Two groups of individuals were working at the same time to develop the first stored program computer. In the United States, at the university of Pennsylvania the EDVAC (Electronic Discrete Variable Automatic Computer) was bring worked on.

In England at Cambridge, the EDSAC (Electronic Delay Storage Automatic Computer) was also developed. The EDSAC won the race as the first stored program computer beating the United States. EDVAC by two months. EDSAC is the first computer used to store a program. It used 3000 vacuum tubes to process data. In the EDSAC, programs were input using paper tape and output result were passed to a teleprinter.

## UNIVAC – I (Universal Accounting Computer)

The Universal Automatic Computer-I was the first commercial computer produced in the United State. It was designed principally by J. Presper Eckert and John William Mauchly in 1951. The First UNIVAC was delivered to the United States Census Bureau on March 31 1951. It was the first general purpose electronic digital computer. It used magnetic tape for data input and output. This computer used 5200 vacuum tubes to process data.The machine was 25 feet by height 50 feet length, contained 5600 vacuum tubes 18000 crystical diodes and 300 relays. It utilized serial circuitry, 2.25 MHz bit rate, and had an internal storage capacity 1000 words or 12000 characters.

Power consumption was about 120 Kva. It's reported processing speed was 0.525 milliseconds for arithmetic functions 2.15 millisecond for multiplication and 3.9 milliseconds for divisions.

The UNIVAC was also the first computer to come equipped with a magnetic tape unit and was the first computer to use buffer memory.

- In 1977, Steve wozniak and Steve jobs establish the company Apple computers.
- In 1984, Apple introduces the Macintosh, the first widely available computer with a “user-friendly” graphical interface using icons, windows, and a mouse device.
- In 1989, Microsoft Corporation introduces Windows for IBM computers.

## Electronic Discrete Variable Automatic Computer (EDVAC)

In 1949, the first electronic computer was developed by John Mauchly and John Presper Eckert with the help of A. Burks, Goldstine and Numann. This machine was used to storage the data and information as well as the instruction. This computer operated electronically.Electronic Discrete Variable Automatic Computer (EDVAC) was one of the earliest electronic computers. It was the first stored program computer. Like the ENIAC, the EDVAC was built for the U.S Army's Ballistics Research Laboratory by the University of Pennsylvania's Moore School of Electrical Engineering.

This Computer Was developed by J. Presper Eckart and John William Mauchly using the concept of Hungarian mathematician, John Von Neumann. The EDVAC was completed in 1952. It was based on binary number system and used magnetic tape for storing data and instructions.

The EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory. The Computer has almost 6000 vacuum tubes and 12000 diodes, and consumed 56KW of power.

*It covered 490ft2 (45.5 Msq.) of floor space and weighed 17300 lb (7850 kg).*