what are the four main functions of a computer?

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When we start the computer and work on it. It processes different functions to start and run all the software. These are the four main functions of a computer.

In this article, you can read about these four functions. How do these functions work and how is the process going on? When you start the computer, what first thing process? Then next and a complete work of computer.

4 Main Functions of a Computer

four main function of computer

As I mentioned above, a computer has four functions. So these are the main functions of computers. Users can give input to the computer using different hardware. We can learn about all these in the next paragraphs.

The computer understands the instructions of users and processes these instructions. Process using different hardware that can already installed on the computer.

After processing the instruction, now two ways to give this information. Whether we can save this processed information in our system storage. Or we can get output in different shapes.

So, hope you can understand the basics of these functions. Now you read about each function in explaining.

User Input or Instructions

The things start here. The computer is simple a machine. It only works when we give some instructions to it.

There are many ways of giving input or instructions to computers. This means we can give input to the computer. Input using a keyboard, mouse, joystick, scanners, cameras, gamepad, microphone, etc.

Here I can give you some examples. There are many more examples that users use to give instructions to computers.

In our previous lecture on input devices, we can cover the keyboard, mouse, and other input devices. In this article, you know about the joystick, gamepad, and microphone. How these devices work and give instructions to computers.


In gaming, the joystick used to give instructions from the user. The user holds the handle of the joystick and points as he or she likes.

It works like a mouse. Means point out things you can point.

Why is it called joystick? By seeing the shape, like a handle called a stick. You grasp it in hand and use or move as you like.

The joystick has many types. Like digital, analog, paddle, etc.


A gamepad is something we can hold with both hand and control games. For control of anything, we can use something. Same in gaming, to put control on the game, you can use a gamepad.

Why is it called a gamepad? Because its controls. You also called it an input device. A gamepad is also known as a joypad. Like joystick, that used to give instructions to the computer. Gamepads use to give instructions in games.

It’s enough to understand input data or the concept of given instructions to the computer. Now let’s learn about processing.

Data Processing in Computer

Computer process the raw facts and figures. What are raw facts and figures? This unprocessed data that computers take from users as instructions or inputs.

Computer process data by the action of a series of the central processing unit. More motherboard and network cards are also involved in this data processing.

Recently I am publishing an article on the central processing unit. That article is enough to understand the total process of CPU. So, the main thing that works in data processing is the central processing unit.

Four-Step of Data Processing

There is four-step of data processing. Fetch, decode, execute and write back.

First, the computer fetches its memory. This is because to perform an action. This action performed in binary form. The whole information fetched of computer memory.

After fetching data, the computer decodes these data. Now data broken into meaning full data. After that CPU executes these instructions.

After the whole process, the data will saved in computer memory. Means data will write back.


What is the output? Output is the result of something that takes in the return of some input.

In the world of computers, when users give instructions to computers. Computer process that data and return in the form of output or some meaningful data. The output taken in return for some inputs.

Wait, I will make things easy for you.

For example, when you type computer shadows using your keyboard. Some results appear on a computer screen. The word computer shadows, we type is input and the result showing on the computer screen is output.

Hope, now things are easy. Let’s come towards.

Some about Output Devices

In our previous lecture, we discuss the output devices of computers in detail. Now I can add things more so you can understand much about that.

When we give instructions to a computer in the form of input. Some devices we need to use to show us the results or outputs.

Devices like monitors, speakers, and printers used in this context.

Types of Output of Computer

Output has four types. Sound, visual, data, and print.

Sound is using the speaker. We hear audio and songs.

Visual means using a computer screen. Data appear in the form of videos and photos or text.

Print is using the printer. We can print some soft copies in the form of hard copies.
All these outputs are in the data category.

Data Storage

Now let’s talk about the last main function of a computer. Computer store the process data in storage. Which is in the form of a hard disk.

During data processing, computers stores data in RAM. And after processing store data in ROM.

You can read explain in our previous blog post the history of storage media devices of computers.

About Data Storage Devices

Two types of storage media devices. Primary storage media devices or secondary storage media devices.

Primary like RAM. As I mentioned earlier. When the computer process the input data. Datastore in primary storage devices. And when raw facts and figures are converted into meaningful data. It will be stored in secondary storage devices or hard disks.

There are other many external or internal storage media devices. These are all used to save digital data.

Wrap up the Things

So, here is the complete detail of what are the four main functions of a computer. This means we cover four main functions of the computer.

When the computer works on some data. Then the working of computer depends on these four functions.

Means input, processing, output, and storage of data.

In our next blog post, we see the importance of computers in our life.


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