Computer

C-Common
O-Oriented
M-Machine
P-Particularly
U-United &
T-Technical
E-Educational
R-Research

Computer is everything whole of the parts of our body is the example of computer. our brain is processor for us.

 
But the main meaning is this :

Computer is the machine which accept the user for input and gives output as a result.
> It is that machine which makes easy our work and save cost and time.
> It helps us to communicate with other peoples.

Every Time saving machine is computer.
In this modern generation from calculator to the latest discoveries by scientists is computer.

Watch, Cell, Mobile, satellites.
Computers have so many types:

> Personal Desktops.
> Laptops.
> Super Computers.

Now the topic is about its OS Operating system:
> Windows (xp, Vista, 7, 8)
> Linux (Ubuntu, Red Hat, Mandriva)
> Mac OSx
> And E.T.C.