Components of Computer –
We will look at the different components (parts) of a computer system in this section. You can see in this article the role each part plays in a computer system.
The computer’s internal architecture varies from one computer model to another. But the basic structure remains the same for all computer systems.
This section also offers a brief overview of various types of storage systems we use to store data.
You can also read about the features of each part that plays a vital role.
Must Read :- Generation of Computers
What are the main components of the computer?
In simple words, computers are machines that perform a set of functions as directed by their users.
There are some essential elements of computer hardware, software, data, and connectivity. In the absence of these elements, no computer can operate.
These components are responsible for making computers work. Let’s take a closer look at them.
There are mainly five major components of a computer. They are as follows: –
- Input Unit
- Storage Unit
- Control Unit
- Output Unit
Let us understand each component in brief:-
Input unit
Input Unit is the link between the user and the computer. The function of an input unit is to transfer the raw data or information from the user to the computer.
The data enters the computer through various input devices such as Keyboard or pointer devices.
Data through the keyboard is provided by pressing the keys by the user whereas in pointer devices such as a mouse, joystick, etc. the data is transferred by pointing on the screen.
Irrespective of the forms in which the data have been received, the input devices must translate the information into the binary codes which the primary memory of the computer can understand.
Further, the data is used by the Central Processing Unit to process it and generate the output. .
These input devices are becoming increasingly popular nowadays from smartphones to ATM devices.
In a nutshell, the functions of an input unit are:-
- It transfers the raw data from the external world to the computer
- It converts the raw data into binary codes which are computer-readable format
- It delivers the translated data to the CPU for further processing
Also Read:- What is BIOS (Basic Input Output System)?
Storage Unit
The storage unit stores all the data or information required before, during, and after the processing.
The data that is transferred to the computer through input devices have to be first stored before processing it.
Also, the immediate results obtained in between the processes must be stored and ultimately the results achieved in the last after the processing of data have to be stored somewhere before passing to the output units.
Hence the storage unit stores all the data and provides it to the computer as and when required for its processes.
The storage in the computer is measured in Bits and Bytes.
There are two types of storage unit:-
- Primary Storage unit
- Secondary storage unit.
The primary storage unit is also known as Random Access Memory (RAM) which is the internal memory of the computer.
RAM stores data and instructions temporarily on the computer. It is volatile and loses its contents when the power is lost.
The secondary storage is non-volatile and stores all the data and information permanently.
The CPU cannot access directly the secondary storage data. For using the data it has to be first transferred from secondary storage to the primary storage unit.
In a nutshell, the functions of the storage unit are:-
- Store all the data and instructions received from the input devices
- Also, store the results obtained during ongoing processes.
- Stores the results obtained after the execution of the processes.
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Central Processing Unit
Once the data is received by input devices and stored in the primary storage unit, the computer now has to further process the data as per the instructions provided.
The unit in which the data is processed is called Central Processing Unit (CPU) or Processor or Microprocessor.
It is the main unit of the computer as all the operations are controlled by it. In other words, it works as the brain of the computer.
As a human brain controls every part of the body, similarly the CPU controls every part of the computer.
The operations performed by the CPU are called the instruction set. The instruction set is basically a machine language in the form of sequences of 0 and 1.
All the major calculations such as addition, subtraction, etc. and comparisons of data are done inside the CPU.
Internally the CPU further consists of two other units known as:-
- Arithmetic and Logical Unit and
- Control Unit.
Arithmetic and Logic Unit (ALU)
Arithmetic and Logical Unit is a digital electronic circuit present inside the CPU which carries out the arithmetic and logical operations.
The data is transferred from the primary storage unit to the arithmetic and logical unit to carry out the processes.
The intermediate results obtained during processing are also stored back in the storage unit.
Thus the exchange of data between the ALU and storage unit continues until the result is obtained, stored in the storage unit, and finally sent to the output unit.
The temporary storage area inside the CPU from which ALU takes the data is called Register which is a group of cells used for the memory addressing, data manipulation, and processing.
Some registers are used for the internal purposes and hence cannot be accessed while some registers are accessible and can be used for general purposes.
The rate at which the CPU completes its one processing cycle is known as clock speed and is measured in Megahertz or Gigahertz.
The faster the speed of the CPU, the faster the computer can operate. In a nutshell, the functions of the Central Processing Unit are:-
- It receives all the data from storage and input devices
- It controls all the operations of the computer.
- It executes the processes based on the set of instructions provided.
Related topic :- What is Processing Devices?
Control Unit –
The control unit is in charge of all the operations of a processor. It is the task of the Control Unit to communicate the processor, arithmetic & logic unit, and input/output devices on how to respond to the instructions that have been sent to the processor.
It helps the processor to select which data is to be processed, what instructions are to be interpreted, and how to complete the instructions provided.
The control unit functions by receiving input data which it converts into control signals and then they are sent to the processor.
Thus acting as a central nervous system it manages, and coordinates the entire computer system without performing on any actual ongoing processes.
In a nutshell, the functions of the control unit are: –
- To coordinate the data movement
- It helps in the interpretation of instructions
- It converts the data from input devices into control signals
Output Unit
The output unit is the final component of the computer. It works exactly opposite to the input device.
It provides the results or information from the computer to the user. As said earlier that a computer works with binary code (sequence of 0 and 1), therefore the results it gives are also in the same code.
Hence the output unit converts those binary codes into data that is easily understandable by the users.
The devices used to display the output to the users are called output devices.
Some of the examples of output devices are monitor, printer, screen, speaker, etc.
In a nutshell, the functions of an output unit are:-
- It displays or provides the final results of the process to the user
- It converts the binary coded results into the human acceptable form.

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