Components of a Computer
The computer system consists of three units-
- Input Unit
- Processing Unit
- Output Unit
Input UnitInput unit is the unit which controls the input devices used for data entry. The input devices used for entering data into the computer system are keyboard, mouse, compact discs, optical scanner, Magnetic Ink Character Recogniser (MICR), Optical Character Recogniser (OCR), barcode reader and smart card reader. Besides the above input devices there are other devices also which respond to voice or a physical touch on the screen. A menu is displayed on the screen and the data is entered by touching on the particular item displayed on the screen. Touch screen input device can normally be seen at airports and departmental stores where the user can extract information by pointing at a particular item. The device is particularly useful and also cost effective where the general information seekers are numerous.
It is also known as the Central Processing Unit (CPU). This is the main part of a computer system. It processes the given data according to the instructions and arranges the information in a manner which provides easier retrieval of the data, when required, by the user. It can be divided into three parts-
- Arithmetic and logic unit (ALU) - It is responsible for performing all the arithmetic computations, such as addition, subtraction, division and multiplication and logical operations involving comparisons among variables and data items.
- Memory Unit - This unit is used to store data before it is actually processed.
- Control Unit - This unit is responsible for controlling and coordinating the activities of all other units of the computer system.
The device which is used to get the information in a readable and understandable from after processing the given data comprises the output unit. It translates the processed data into readable and understandable information and makes it available to the users through the output device. The output devices are monitor (Visual Display Unit), Printer, LCD (Liquid Crystal Display), plotter and a recently developed device, the speech synthesizer.