Computer is an electronic machine which takes raw data as an input from the user and processes it using instructions (called program), giving output (result), and saves it for future use.In this tutorial we will explains the concepts of computer hardware, software, operating systems,memory, peripherals, etc.

In short the computer works on IPO cycle i.e. Input-Process-Output…

fig:IPO cycle

If we look closely on any digital computer,it carries out the following four functions −

Step 1 − Takes data as input(information).

Step 2 − Stores the data/instructions in its memory and uses them as required.

Step 3 − Processes the data and converts it into useful information.

Step 4 − Generates the output.




Computers are usually categories into three general categories:

1.SupercomputerThe fastest, largest, most powerful and most expensive computer.

2.Mainframe ComputerThis is a little smaller and less powerful than the supercomputer, but, like the supercomputer it is also expensive.

3.Personal Computer (PC)This is the computer that we mostly use in our daily lives. This computer is much smaller, less powerful and less expensive than the supercomputer and the mainframe computer.

There are two main types of personal computers.

  • Macintosh (Macs)
  • The PC compatibles (PC).

The main differences between the two are the operating systems and the processor they use.

This category of computer has two additional types of computers. These are mobile computer and handheld computer. The most popular type of mobile computer is the notebook or laptop computer, and the handheld computer is a very small PC that you can hold in your hand.

NOTE:regardless of computers size it has an input device, output device and a processing unit.