What is a Computer? Functions, Languages and Types of computers

If you ask someone about the definition of computer, he will say that 'Computer is an electronic machine' and then he can say that it inputs data, processes it and then provides us with output. So, what does this input, process and output mean? Don't worry if you don't know about these. I will tell you in this post.

What is a Computer?

A computer can be defined as an electronic machine that stores input data and processes it. A data can be a letter, a word, a number or any information. Everything you see on a computer screen is also data. Notes written on notebook paper are also data.

A desktop computer looks like this as you can see in the image below:

desktop computer and laptop

As you can see in the photo, the parts of a desktop computer are – a monitor, a keyboard, a mouse and a CPU.

You use a keyboard to type and enter letters, numbers, symbols into a computer. Through the keyboard you also instruct the computer to perform some tasks.

Mouse is also called a pointing device and you use it to give instructions to the computer. Using the mouse, you can select photos, videos, text or any type of file that you can see on the computer screen. You can also use the mouse to use drawing tools available on software like Photoshop, Paint.

The monitor looks like a television. Whatever you type using the keyboard, you can see it on the monitor screen. If you play a video on a computer, you need a monitor to watch it. A monitor shows you the output and hence is called an output device.


Laptop is also a computer and due to its small size you can easily carry it from one place to another. When you close the lid of the laptop it looks like a small briefcase.

Every laptop has a monitor and keyboard. Instead of a mouse, laptops have a touchpad, also known as a trackpad, which looks like a small round box. You can use your fingers to touch the touchpad and use it as a pointing device.

You don't see a box like CPU in a laptop; Laptops have a built-in CPU with a keyboard mounted on top. So, with a laptop, you don't need to carry the CPU box, keyboard and mouse separately.


A smartphone is also a computer. You may ask me how? When you look at a modern smartphone, it has a touchscreen that is similar to the monitor in a desktop computer or laptop. Touchscreens also have touchpad functionality to serve as a pointing device. When you open WhatsApp or the message box, you will see a keyboard that you can use for typing. Like laptops, our smartphones also have a built-in CPU.

A smartphone today is capable of performing almost all the functions that an ordinary person needs in his daily life. You can upload your resume, application form, watch online videos, edit photos, send emails, use the Internet to search for information on Google, and much more. .

How does a computer work?

A computer requires electronic current to function which can come from a UPS, electrical power or even just batteries. Laptops and smartphones already have batteries installed in them. After power on, computer hardware requires software to run, such software is called system software (such as operating system). If you don't know what an operating system is then you can take the example of Android. Android is a popular operating system that runs on smartphones.

Therefore, a computer requires electricity, hardware, and software to start and function properly.


The full form of UPS is Uninterrupted Power Supply and it is called UPS in short. UPS is a type of battery used to provide power backup to a computer.

Main Functions of a Computer

A computer has four main functions: input, process, store, and output.

Now, you look at the picture given below.

Basic function of Computer

Input - Any data that we send to the computer through an input device is called input. If you type your name using the keyboard, your name is a data to the computer.

Process - When a computer performs arithmetic or logical operations on input data, it is called processing. For example: You type 2 and 3 and press + button, the computer will combine 2 and 3. So, when the computer is adding 2 and 3, it is processing 2 and 3.

Output - Any data or information that the computer provides to you through an output device is called output. After adding numbers 2 and 3 the computer shows you 5 on the screen. Number 5 is the output data. Also, when you see 2 and 3 on the computer screen, they are also output.

Store - If you see the above picture, a computer does the work of storing twice - after input and before output. When you input the number 2, the computer stores the number 2 in its memory. When you input 3 numbers after 2, it stores the 3 numbers in its memory. Now, it has both the numbers in its memory. If you press + button, it adds the numbers 2 and 3 and stores the result number 5 in its memory and then shows the number 5 on the screen.

Language of a Computer

Just as we humans use languages like English, Hindi, Spanish etc. to communicate with each other, similarly computers also use a language. The language of computer is called machine language. Machine language is in the form of 0's and 1's and hence it is also known as binary language. Now, you can say that you type given letters or numbers on the keyboard, you do not type 0 and 1. You are right that we type only the letters given on the keyboard.

Here, I want you to understand that a computer is an electronic device and like every electronic machine, every part of a computer contains electronic chips. Therefore, a computer actually senses electric current. And, 0 and 1 are used to identify whether we have pressed the off switch or the on switch on the computer chip. Now, you must have understood that there are switches on electronic chips. If a switch is on, the computer interprets it as 1 and when the switch is off, it interprets it as 0.

It is very difficult for humans to learn machine language, often only computer scientists use machine language. There is no need for a common man to learn machine language, hence computer language has also been developed with the help of technology. Now we can give commands to the computer using English words and sentences. Nowadays, there are many languages by learning which we can give instructions to the computer and such languages are called programming languages.

Types of Computer

Computers can be classified in various ways – by size, by processor. As most of us never look for a processor when buying a computer, I will discuss computers according to their size.

Micro Computer

Micro computers are a type of computers which we use in our home, office and you see these computers at ticket counters, retail outlets and everywhere else. They are smaller in size and cheaper than other types of computers. People can easily buy microcomputers for their personal and daily use. Today's desktop computers, laptops that we use are a type of microcomputer and are also called personal computers.

Mini Computer

Minicomputers were slightly larger in size than microcomputers, and you won't see them in use anywhere today. These are also called medium sized computers.

Mainframe Computer

A mainframe computer has the capacity to store more data than a microcomputer and is so large in size that it requires a large space like a room to be installed. Such computers are commonly used by banks, universities, small or large sized businesses. Mainframe computers are mostly used as computer servers to store and manage large amounts of data. Many microcomputers are connected to mainframe computers through computer networks.


Supercomputers are said to be the fastest computers in the world and they usually take up the space of a large room and can even take up the space of an entire building. Such computers use the largest amount of data storage capacity and multiple high-end processors for the fastest and most accurate computing. Supercomputers are widely used for scientific and research purpose and are also used by large organizations like Facebook which store large amounts of data.


Which is the first computer made in India?

Tata Institute of Fundamental Research Automatic Calculator

What is the name of India's first supercomputer?

PARAM 8000


Popular Posts

What are the Strengths and Weaknesses?

What is PowerPoint? What are its features and use?

How to create a PowerPoint Presentation?