What is Computer? Some essential Components information

What is Computer Some essential Components information

A computer is an electronic device that can accept input data & instructions, process them & give an output. The computer can also store the data, instruction & the output if required. For example, a user can give input data 1, 2 & an instruction Add to the computer. The computer process the data & instruction & the result=3 is displayed in the screen. The data, instruction & the result may be stored in the memory of the computing device. The input devices gives the input data / instruction, CPU (Central Processing Unit) process them, output devices (RAM, Hard disk etc.) is used to store them.

The essential components of a typical computer include the following:

Input Devices:

Input devices are those devices that give input data & instruction to the computer. Some example of input devices include keyboard, mouse, joystick, mic webcams, scanner etc.


Keyboard is the most common type of input devices using which a user can give data & instruction to the computer. There are 4 types of keyboards depending on the type of connections used. They are

AT keyboard:

AT (Advanced Technology)

Consists of 5 pin connector, most found in Pentium 3d & early Pentium 4 computers. Now a days this technology is almost outdated.

PS/2 Keyboard:

PS (Personal System)

Consists of 6 pin connector

Found in new generation computers.

USB – Keyboard:

USB (Universal Serial Bus)

Wireless Keyboard:

Keyboard without wires

Consists of a wireless connected from USB.


Mouse is another input device that is used to point & select objects in the 2 or 3 dimensions of our computer. Basically there are two types of mouse, the Wheel mouse & the optical mouse. The wheel mouse is a mechanical mouse which works by the mechanical movement of a ball. The optical mouse works with the reflection of the light. Again depending on the type of connection there are 4 types of mouse.

Serial Mouse:

Consists of 9 pin connector.

Connected in COM (Communication or Serial port).

Now this technology is almost outdated.

PS/2 Mouse

PS (Personal System)

Consists of 6 pin connector.

Found in new generation computers

USB Mouse:

USB (Universal Serial Bus)

Wireless Mouse:

Mouse without wires

Consists of a wireless connected from USB.


The Central Processing Unit (CPU) or simply a processor interprets the computer program instructions & process data. CPU has two components, the Arithmetic & Logic Unit (ALU) and the Control Unit (CU). The ALU is responsible for caring out all the arithmetic calculations like additions, subtraction, division, multiplication etc. And all the logical computations. The CU controls & monitors all the operations of a typical computer. Examples of CPU are Intel Pentium 1, 2, 3, 4, Intel Dual Core, Intel Celeron etc.

Output Devices:

The output device displays the result of the processing of the input data and the processed instructions. Example of output devices are Printer, Monitor, Speaker, Headphones etc.


Memory is the most essential component of a computing system. It is used to hold the data and instruction during the processing by the CPU. Memory is also used to run any program. Basically there are two types of memory; Primary & Secondary.

Primary Memory:

The primary memory is the main memory of a computer that is used to run a program and to hold all the data & instructions for a short period of time (Temporary). The primary memory is of volatile type, which means it loses all information if the computer loses power. Usually, primary memory is of lower capacity (MBs to few GBs) RAM (Random Access Memory) is an example of Primary Memory.


Read Only Memory (ROM): We can only read information from a ROM, We cannot write new information, edit/modify existing information & delete information from a ROM, CD-ROM.

Random Access Memory (RAM): We can read, write edit/modify & delete any information from RAM.

Secondary Memory: The secondary memory is of PERMANENT type and it is used to store information for a period of time. Usually, secondary memory is of higher capacity (in Terabytes) Example of secondary memory include Hard disk Drives.

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Sabith Al Safa