What is a Computer?


A Computer is an electronic machine which is the combination of many Peripheral devices. It is compact in size and is specially designed for personal use like Home and Office works. This contains a minimal number of Peripherals and also the inner parts are not much expensive because of personal use. The PC is cost-efficient and based on the price the quality and features get increased. Based on their functions PCs are classified into different types. These are the things will be explained in this tutorial.

Humans cannot work for a long time without taking rest but, the computers can do until the system gets failure. Anyone can program a computer for specific works. The computers are called Humanoids.


Nowadays, the world is running with a Computer alone because of the Evolution of Computers. In other words, we said the world does not run without a computer. Olden Computers are in tons of weight, only a trained person will able to operates a computer. The First Electronic Computer is ENIAC and the total weight of the machine is 30 tons. But today we carry a computer in hand, Pocket and bags, these are due to the evolution of computers.

Types of Computers

Based on the needs, the computers are classified into two types.

1. Stationary


The name Stationary denotes ‘Stable’ or Non- Portable. Because of larger size and weight, it is difficult to carry from one place to another. They contains a larger body and more cables. Example: Workstations and Desktops.

Workstations are a huge size computers which are used for high-end applications like Space applications, Graphical editing, Software developing, Gamming, etc. It contains High-end Processors, Graphics, RAM, Larger Displays and many other external Peripherals.

Desktops are smaller because they have minimum features compare to the Workstations. It is for personal use in home and offices. It contains a minimum size RAM, Hard Drive, Processor.

A Desktop Computer
Figure1: A Desktop Computer


Nowadays, peoples need to carry their computers on their own for work and everywhere. For these kinds of needs, the Desktop computers are further developed as Laptops, Mobile phones, Tablets, etc. It is smaller than a Workstation and a Desktop. In this type, the displays and the other hardware are attached together.

Laptop computers are small, lightweight, and also made as Clamshell design for the portability. Based on the performance laptops are classified as Gaming Laptops, Office Laptops, Personal laptops, etc.

Mobile Phones are also called as pocket PCs. It is very smaller in size and can carry anywhere in a pocket. Nowadays, everyone have this mobile phones with them. Mobile Phones also perform many functions like Desktops and Laptops. We can play games, Type a document, Accessing the internet, etc.

Layers of a Computer

Mainly the computers are built with four layers namely,

  1. Hardware
  2. Operating System
  3. Software
  4. Users


Hardware is a physical component which made a physical connection with each other. There are many physical components present in a computer and some of them are listed below.

A computer is a combination of many Input units, Output units, Processing unit and also external peripherals. Every computer like Mobile phone, Desktop, Laptops, Workstation all have these Input and Output units.

Input Units

  1. Keyboard
  2. Mouse
  3. Scanner
  4. Camera
  5. Microphone

Output Units

  1. Monitor
  2. Printer
  3. Projector
  4. Speaker

Processing Units

  1. GPU
  2. CPU
  3. RAM
  4. Hard disk
  5. CD Drive

The above-listed units are the general input, output and processing units in a computer. Now we can see, how the above units are connected with each other and form a Personal Computer.

Figure 2: General computer connection

Operating System

An operating system is a program which controls the whole computer hardware and software. It is the main program in any computer device. For example, in a desktop, laptop, mobile phone are the computer devices which runs with operating systems like Windows, Linux, Android, iOS, etc. An OS gives the proper user interface to the user.


Software is also a program which is used for a specific function. Now you are reading this website using a software called a browser. Like the browser, there are many application available for a specific function. In your mobile phone, you are using the Phone app or Contacts app to view your contacts and to call a specific person. This is done with the help of the specific apps or software.


A user is a person who uses the computer. You are now using either a mobile, laptop, tablet, desktop or some other computer device to read this webpage. Here you are the user of that device. In any device, User plays a major role because the user controls the whole computer.

Working of a computer

Let see Figure 2, it is the basic parts of the computer. When Power On, the SMPS starts and splits the 230V and sent to each component of the computer. Each components need the power to run. Then the internal Motherboard contains a BIOS Chip which starts the Software part. After the starting Bios, the main process called Booting occurs. It is one the main part in a computer. Then, the BIOS chip starts the booting process. The Operating System(OS) will Launch after the Booting process. In case of dual boot, the BIOS asks for the selection of OS. This process is common for all kinds of PCs, Laptops, Mobile phones, Workstations, etc.