Computer

The word "computer" comes from the word "compute", which means, "to calculate". Hence, people usually a computer to be a calculating device that can perform arithmetic operations at high speed. In fact the original objective for inventing a computer was to create a fast calculating machine. However, more than 80% of work done by computers today is of non-mathematical or non-numerical nature. Hence, to define computer merely as a calculating device is to ignore over 80% of its functions.

How computer works?

Any computer—regardless of its type—is controlled by programmed instructions, which give the machine a purpose and tell it what to do. The computers discussed here and which are everywhere around you— are digital computers. Digital computers are so called because they work “ by the numbers." That is, they break all types of information into tiny units, and use numbers to represent those pieces of information. Digital computers also work in very strict sequences of steps, processing each unit of information individually, according to the highly organized instructions they must follow. A lesser-known type of computer is the analog computer; which works in a very different way from digital computers. The earliest computers were analog systems, and today's digital systems owe a great deal to their analog ancestors. Analog and digital computers differ in many respects, but the most important distinction is the way they represent data. Digital systems represent data as having one distinct value or another; with no other possibilities. Analog systems, however represent data as variable points along a continuous spectrum of values. This makes analog computers somewhat more flexible than digital ones, but not necessarily more precise or reliable. Early analog computers were mechanical devices, weighing several tons and using motors and gears to perform calculations.