## WHAT IS COMPUTER

In simple words, a computer is an electronic device, which processes information based on the instructions provided, and generates the desired output. Like any other system, a computer system also requires an input, which is processed to get the desired output. In the case of computers, two kinds of inputs are required. One, the basic or raw data, and 2^{nd} is a set of instructions containing the methodology to process this data. This set of instructions is called a program or software in computer jargon.

## EVOLUTION

In order to understand today’s computers; it might be worthwhile to take a quick look at the evolution of computers. Historians trace back the history of calculation with the **Abacus (a wooden frame with balls or beads strung on parallel wires)** and to its origin to around 5000 B.C. It was used for performing simple calculations. In the seventeenth century, John Napier, a Scottish mathematician, did considerable work on the aids for calculation. The most notable one was the invention of logarithms in 1614.

In 1620, just six years after the invention of logarithms, *William Oughtred*, an English mathematician, invented the **slide rule**. This is a calculating device based on the principles of logarithms. A slide rule consists of two graduated scales, one of which slides over the other. The scales are devised in such a manner that suitable alignment of one scale against the other makes it possible to compute products, additions, etc., just by inspection.

**In l642, Blaise pascal, a French mathematician, invented the first mechanical calculating machine**

*. In this machine, numbers were entered by dialing a series of numbered wheels. Another series of toothed wheels transferred the movements to a dial, which showed the results*.

**. This was able to perform multiplications and divisions. Between 1802 and 1804. Joseph Marie Jacquard, a French textile manufacturer, invented a mechanical system for use in the textile industry. This machine was used to automatically control weaving looms to facilitate the production of woven cloth with complex patterns.**

*Gottfried von Leibnitz*, a German mathematician, in 1671 invented a calculating machine## THE FIRST COMPUTER

In 1822, Charles Babbage, a professor of mathematics at Cambridge University, devised a machine called “Difference Engine” for the Royal Society. This difference engine was used to perform simple computations needed for setting up trigonometric and logarithmic tables. In short, Babbage had developed a prototype computer, which was 100 years ahead of its time. He is, therefore, widely considered as the *father of modern day computers*.

After World War **II**, there was a need for advanced calculations. By that time, many mechanical desk calculators with high degree of reliability had been developed. Howard H. Aiken of Harvard University, while working on his doctorate in physics, in the year 1937, designed a machine that could automatically perform a sequence of arithmetic operations. Completed in 1944, it was named Mark I. The time taken for average multiplication and division was about four and eleven seconds, respectively. The results were printed at the rate of one result per five seconds.

## NEXT GENERATIONS

** ENIAC **Electronic Numerical Integrator and Calculator, which was completed in 1946 was the first electronic calculator. The ENIAC performed 5000 additions per second, consumed 150 kilowatts of power, and needed to be water cooled.

** EDVAC** Between 1947 and 1950, the More School personnel and the Ballistics Research Laboratory of the U.S. Army built a computer named EDVAC (Electronic Discrete Variable Automatic Computer), which was based on John von Neumann’s ideas. Neumann (frequently referred to as the father of modern computers) was the first to introduce the stored program concept in a computer.

As you go through the history of evolution of computers, you would ﬁnd that the earliest computers were very big and therefore consumed a lot of power. This resulted in their heating Very quickly and they had to be frequently shut down and cooled. This made them very expensive to build and maintain. As the technology improved, computers became smaller in size, the season for the much faster and more powerful. But most importantly, from users’ point of view, they became more affordable and user-friendly. This is success of computers and why they have been able to transform from ‘huge monoliths’ to ‘personal assistants’.