Computer is an automatic machine which can do calculations, write and solve complex problems within seconds without making any mistake. Not only can this but it also perform many functions at a time. A signal computer can do millions of calculations within a second.
Computers are being used successfully in telecommunications, space research, engineering, science, industries, medicine, education, banks, transport, post offices, railways, sports etc.
The first electronic computer was ENIAC, which was invented in 1946 by Eckert and Mauchly of Pennysuylvania University. There were 18,000 electron tubes, 70,000 resistors and 10,000 capacitors in it. Each tube was of the size of small bottle. This computer was controlled by a team of trained operators. In 1950, the transistor replaced the vaccum tube. Nowadays integrated circuits or chips are used in computers which have reduced the size of the computer considerably. Computers are of two types-------the first type of computer is called analog computer which measures one quantity in terms of the other and the other one is digital in which various problems are solved by using digits.
A computer has three main parts------input unit, central processing unit CPU, and output unit. In the input unit, magnetic tape, punch card paper or tapes are used. There is a memory in CPU which stores the information. Its controlling system gives directions and arithmetic system performs various Operations. Printers, cathode ray tube or sound indicating units are used as output devices. In fact, the input of computer is just like our eyes and ears, CPU functions like our brain and output unit functions like our hand and mouth.
In digital computers, all information is sent through programme and these bits of information guide the functioning of computer. The data of the programme are sent to the computer through an input machine. This data is processed in the CPU. The data of programme gets stored in the memory. Calculations are done in the arithmetic and logic units. Storage and calculations are controlled by control unit and the solution of the problem is given by the output unit.
The heart of home computer is only one chip which is called a microprocessor. Different part of chip performs different functions of the computer. The chip of a home computer has two types of memory, one Central processing unit (CPU) and one clock.
Read only memory of ROM carries necessary messages for the computer. This cannot be changed. Random Access Memory or RAM is a temporary memory and it is used to give instructions and message when computer operates. The instructions given to the computer are called a programme and messages kept in it are called data. Experts wiring a computer programmes use special languages which the computer can understand. There are FORTRAN, etc. but BASIC Beginner’s all purpose symbolic instruction code is most commonly used.
The programme and data fed to the computer is called computer software. We can type words ad decimal figures with keyboard which go to Random Access Memory RAM or the computer. These do not go into the memory in the form of words and decimal figures because memory cannot store them in that form. Computer changes them into binary code. In this code, all the characters are changed into 1 and 0.
Two binary digits are called bits. Most of the computer data are controlled and stored in eight bit units, which is called a byte. The RAM of a single home computer can control about 1,28,000 bytes.
The physical parts of a computer which we can touch are called hardware. In the main processing unit of a home computer, there is a Visual Display Unit VDU resembling the TV screen, one keyboard, mouse, joystick, printer and modern.
Magnetic disks are fitted inside one or two slots of the processing unit. Programmes and data are stored on disks. These are called floppy disks.
Mouse is a device which helps you to make a design directly on the VDU. Joysticks are used in video games.
The programmes given to the computer can be received in the form of a copy printed by the printer or it can be stored on floppy disk or magnetic tapes. These can be transferred to the other computer through telephone cables. This you can do by modern, which converts computer output signals into audio signals. The modem on the other end reconverts them into original form.
Scientists have made various types of computers today but the fastest and the most powerful among them are super computers.