Categories of Computers.

Computers are  classified on the basis of  size  speed , processing power  and Price. However the classification of computers are not very straight forward .The distinction between theses  categories is sometimes not very clear. Some categories overlap different categories.

Computers can be divided into the following categories:-

1. Microcomputer or personal Computer.

2.Mini Computer

3.Main-frame Computer

4.Super Computer

5.Embedded Computer 

Storage and Communication Devices.

Storage Devices:-

The hardware component used to store Data,Instructions and Information permanently are Normally Called as Storage Devices.

It is also called Non-Volatile because its contents remain safe when computer is turned off.
Some Important Storage Devices are Floppy disk, Zip drive, Hard disk, Usb drive, Memory cards, CD-Rom, CD+RW, and DVD+RW drives.

Communication Devices:-

The Hardware component used to communicate and exchange Data,Instructions, and information with other computer are called Communications Devices.

An important communication Device is called Modem.

It Enables the computer to communicate with other computers through Telephone line or cable.

CPU and Memory

CPU:-

CPU stands for Central Processing Unit.It is also called Processor.It is the Brain of the Computer.
It is the most important component of the Computer.It interprets and executes the instructions in the computer.A Computer can not work with-out CPU. All Computers must have Central Processing Unit.


Memory:-

The hardware component that stores data and instructions temporarily is called Memory.It is also called  Primary memory or Main memory.It consists of electronic chips connected to Mother-board.It is used to store the Input data before processing.It also stores processed data after processing until the data is sent to output devices.The main memory is also called Volatile because its contents are lost when the computer is turned off.

Output Devices

The data processed into useful information is called Output.
A Hardware component used to display information to the user is called Output Devices.Most commonly used Output Devices are Monitor,Printer and Speaker.

Monitor:-

Monitor is used to Display text,graphics and video Output.

Printer:-

Printer is used to Display Printed Output on paper.

Speakers:-

Speaker is used to hear Sound,Music and Video Outputs.