A computer is an electronic device that can store, retrieve, and process data. It allows users to type documents, send emails, browse the web, and create spreadsheets, presentations, and videos. Computers can be classified based on their processing power, from personal computers for single users to supercomputers that can execute hundreds of millions of instructions per second and are used by many users simultaneously.

1. What is a computer?
A computer is an electronic device that manipulates information, or data. It has the ability to store,
retrieve, and process data. You probably already know that you can use a computer to type
documents, send email, play games, and browse the Web. You can also use it to edit or create
spreadsheets, presentations, and even videos.
Type of Computers:
Computers can be broadly classified by their speed and computing power.
Sl. No. Type Specifications
1
PC (Personal
Computer)
It is a single user computer system having moderately powerful
microprocessor
2 WorkStation
It is also a single user computer system which is similar to personal
computer but have more powerful microprocessor.
3 Mini Computer
It is a multi-user computer system which is capable of supporting
hundreds of users simultaneously.
4 Main Frame
It is a multi-user computer system which is capable of supporting
hundreds of users simultaneously. Software technology is different
from minicomputer.
5 Supercomputer
It is an extremely fast computer which can execute hundreds of
millions of instructions per second.