A Computer is an advanced electronic device that takes raw data as input from the user and processes it under the control of a set of instructions , also known as program, gives the result (output), and stores the information for future use.
The main functions of a computer can, thus, be simplified as follows:
- Take input data and instructions from a user (Input)
- Process the data as per instructions or programs and convert it to a form understandable by the computer (Processing)
- Display or generate the processed data (Output)
- Store the data or instructions for future use (Storage)
Basic Components of a Computer
Input Unit
The input unit is comprised of devices which act as a link between the user and the computer by enabling the user to enter or send data, or control signals to the computer. These devices translate the information entered by the user into a form which is understandable by the computer.
The Central Processing Unit (CPU) of a computer receives the input and processes it to produce the output. Examples of input devices include keyboard, mouse, joystick, scanner, microphone, web scanner, etc.
Central Processing Unit (CPU)
The Central Processing Unit (CPU), also known as the processor, or microprocessor is considered to be the brain of the computer. It is rightly considered so as it carries out all the important functions such as receiving the instructions from both the hardware and software and producing the output accordingly. It is also responsible for storing data, intermediate results and all sorts of important programs.
The CPU is made up of the following three components given below:
• Arithmetic Logic Unit (ALU): As the name suggests, the ALU performs two main functions- (i)arithmetic functions such as addition, subtraction, multiplication division, and comparisons; and
(ii) logical functions such as selecting, comparing, and merging the data.
• Memory Unit: The memory unit is also known as the main memory or Random Access Memory (RAM). Its function is to temporarily store data, programs, and intermediate and final results of processing. It also supplies these information to the other units when necessary.
• Control Unit: The control unit takes the input signals or instructions from the user and converts them into control signals for execution in the CPU. It fetches the instructions from the main memory and then decodes and executes these instructions. It is, therefore, responsible for controlling and coordinating the functioning of all parts of the computer.
Output Unit
The output unit is comprised of devices that provides the final result or information obtained after processing from the computer. Like the input unit, these devices also act as a link between the user and the computer. Output devices translate the information from the computer into human readable format. Examples of output devices are monitor, printer, speaker, etc.
Types of Computers
Computers, on the basis of size and power, can be classified in the following ways (although the distinction between them may be blurred):
Supercomputer: This is the fastest type of computer, which is usually employed for specialised applications that require immense amounts of mathematical calculations.
Mainframe: It is also a powerful computer, however, the main difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe executes hundreds or thousands of programs simultaneously.
Minicomputer: It is a mid-sized multi-user computer capable of supporting from 4 to about 200 users simultaneously.
Microcomputer or Personal computer: It is a small, single-user computer based on a microprocessor, consisting of a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.
Workstation : It is also a single-user computer but it has a more powerful microprocessor and a higher-quality monitor than a personal computer.
Characteristics of a Computer
Speed: A computer is capable of performing millions of calculations in a few seconds as compared to man who will spend many months for doing the same task.
Storage: A computer is capable of storing huge amount of information.
Accuracy: It also has a high accuracy rate, to the extent of an error free result, provided the correct input is entered.
Diligence: A computer is free form boredom or tiredness, unlike humans and can perform the same work continuously with the same speed and accuracy.
Versatility: A computer is a versatile device, which can be used to perform
various types of tasks.
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