About computers
Man has been defined by someone as a tool making animal. At first, he made tools to help him in his physical work. Simple levers that help a farmer to produce better crops, bicycles that help him reduce distances, and killing-machines like rifles and missiles that makes killing his fellow man easier are all tools he made to help in his physical work. Most of man's work is mental and he made machines to ease his mental work and we call them computers.
We are all familiar with what a computer is in a specific, contemporary sense. Personal computers are found in most aspects of daily life, and for some it is hard to even imagine a world without them. But the term computer means more than simply the Macs and PCs we are familiar with. A computer is, at its most basic, a machine which can take instructions stored inside them, and perform computations based on those instructions.
It is the ability to be controlled by instructions stored inside them, known as programs in the parlance of computers, that distinguishes a computer from a mechanical calculator. While both are able to make computations, a calculator responds simply to immediate input. In fact, most modern calculators are actually computers, with a number of pre-installed programs to help aid in complex tasks.
Computers range from the very small to the very large. Some are capable of doing billions of calculations in a single second, while others may take longer periods of time to do even the most simple calculations. But theoretically, anything one computer is capable of doing, another computer will also be able to do. Given the right instructions, and sufficient memory, a computer found in a wristwatch should be able to accomplish anything a supercomputer can
