What is a computer?

A computer is an electronic machine which performs calculations, solves problems and stores information. Its hallmark is its blinding speed and almost unfailing accuracy. Today, computers are used in almost all fields - be it education, research, business, journalism or even art.

But even before the computer machine was invented, there already existed another kind of computer in the world - the human brain. The human brain computer is smarter than any kind of computer. The reason - it can think. Machine computers cannot think. They only do what people tell them to do.

There are two basic types of computers - analog and digital. The analog computer operates on data based on various physical quantities, such as voltage. The digital computer, on the other hand, works with numbers, words and digits. The computer which combines the functions of these two, and utilises both analog and digital data, is called a hybrid computer.

Today, most of the computers that you see around you in offices, schools and libraries are digital.

More than two thousand years ago, the abacus-was invented. It is a simple frame with rods which have beads. These beads denote numbers. To solve mathematical problems with the abacus is not just interesting, but is also very graphic.

Then in 1642, a French scientist, Blaise Pascal, invented a machine which used wheels, instead of beads, for adding and subtracting. Counting with wheels is used even today in electric metre boxes, and in mileage metres in automobiles. Then, a German mathematician, Gottfried W.Leibniz, developed a more advanced version of Pascal's machine which could divide, multiply and extract square roots. This is the machine which we know as the calculator.

Towards the end of the 18th century, Joseph Jacquard, a Frenchman, used punched cards to control the pattern on a loom. Though this was no computer, it sowed the seeds for the development of computer technology. It helped to count and keep records. Later, computers received "input" from holes punched onto cards or paper tape, and a little later from computer keyboards.

Based on these machines, an English inventor, Charles Babbage developed the first automatic digital computer in the 1830s, and called it the analytical engine. This computer was designed to do arithmetical operations, as well as suggest the best option based on its computations. However, the analytical engine was never completed, because techniques for fabricating metal parts had not yet been developed.

The next step in the evolution of the modern computer can be attributed to the English mathematician and logician, George Boole. Boole's system of binary logic operators (e.g. AND, OR and NOT) became the basis of computer theory and procedures. Even today it is referred to as Boolean algebra.

Any major invention is the result of the combined efforts of several geniuses, who pick up from where some other scientist or inventor left off. In this chain of events, the next major contributor was Herman Hollerith, a statistician from the United States. Somewhere in the latter part of the 19th century, he introduced punched cards in data processing. Punched cards are based on the principle that a pattern of holes in perforated cards can be read electrically, by a machine designed for this purpose.

The first fully electronic digital computer was built by J.Presper Eckert and John W.Mauchly of the University of Pennsylvania, in the 1940s. It was called ENIAC (Electronic Numerical Integrator And Calculator) and it became operational in 1946. It was the first digital computer. Since then, computers started being applied in almost every area of operation which required precision, speed, calculation and quick results. The first machine, built by Charles Babbage was quite bulky and the ENIAC was also quite big. Efforts were directed towards reducing the size of the machine, while still retaining its basic operational ability.

The first major- breakthrough came in the 1980s with the fabrication of the IC (Integrated Circuit), a device which consisted of hundreds of transistors, diodes and resistors on a tiny silicon chip, the size of a finger nail. This not only permitted a smaller size, but also higher speed at a lower cost.

The next major development was the LSI (Large-scale Integration) by which thousands of transistors, and related devices, could be packed on to a single integrated circuit.

In the same sequence, the next step was the use of the VLSI (Very Large Scale Integration) which has increased the functions of computers, and also its memory and storage capacity. Whereas the LSI circuits could contain thousands of components on a silicon chip less than 0.-2 inch square, the VLSI circuits could hold hundreds of thousands of parts within the same amount of space. These developments led to cost reduction, which is probably one of the main reasons why we get to see computers in schools, offices and even homes.

Computer hardware refers to the physical equipment that makes up a computer system.

The keyboard of a computer is very much like a typewriter keyboard. It has 3 sets of keys:

Alphabet keys

Numeric keys

Function and Cursor keys

The keyboard is used to send information to other parts of the computer. The instructions typed out on the keyboard are called programs. What you type is displayed on the computer screen which is like a T.V. screen.

When the program is completely typed, and then you type RUN, the computer shows the results on the screen. Lists of information, pictures, maps and video games are typed in the same way.

A computer displays the program or information on the screen. If you want this information on paper, a machine called a printer prints it out for you. There are different kinds of printers. The simple ones print only letters and numbers and a few other symbols. The better ones can print almost anything - even pictures in bright colours.