1. CLASSIFICATION OF COMPUTERS

2. Types of Computers

3. Supercomputer

4. Mainframe Computer

5. Micro Computer / Personal Computer

6. Handheld PC (PDA)

7. Classification of Computers :
According to Size
According to Technology
According to Purpose

8. Classification of Computers According to size
Supercomputers
Mainframe Computers
Minicomputers
Workstations
Microcomputers, or Personal Computers

9. Supercomputers Supercomputers are the most powerful computers.
Supercomputers are widely used in scientific applications such as aerodynamic design simulation, processing of geological data. 
They are used for problems requiring complex calculations.
Because of their size and expense, supercomputers are relatively rare.  Supercomputers are used by universities, government agencies, and large businesses.

10. Mainframe Computers
Mainframe Computers are usually slower, less powerful and less expensive than supercomputers.
A technique that allows many people at terminals, to access the same computer at one time is called time sharing.
Mainframes are used by banks and many business to update inventory etc.
Mainframe computers can support hundreds or thousands of users, handling massive amounts of input, output, and storage.

11. Mainframe Computers
Mainframe computers are used in large organizations where many users need access to shared data and programs.
Mainframes are also used as e-commerce servers, handling transactions over the Internet.

12. Minicomputers
Minicomputers are much smaller than mainframe computers and they are also much less expensive.
They possess most of the features found on mainframe computers, but on a more limited scale.
They can still have many terminals, but not as many as the mainframes.
Minicomputers may be used as network servers and Internet servers.

13. Workstations Workstations are powerful single-user computers.
Workstations are also desktop machines. They are, however, more powerful providing processor speeds about 10 times that of PCs.
Workstations are used for tasks that require a great deal of number-crunching power, such as product design and computer animation.
Workstations are often used as network and Internet servers.

14. Microcomputers
Microcomputers is the smallest, least expensive of all the computers. Micro computers have smallest memory and less power, are physically smaller and permit fewer peripherals to be attached.

15. Microcomputers
Microcomputers are more commonly known as personal computers. The term “PC” is applied to IBM-PCs or compatible computers.
Desktop computers are the most common type  of PC. Notebook (laptop) computers are used by people who need the power of a desktop system, but also portability. Handheld PCs (such as PDAs) lack the power of a desktop or notebook PC, but offer features for users who need limited functions and small size.

16. Classification of Computers According to Technology :
Analog Computers
Digital Computers
Hydrid Computers

17. Analog Computers
Analog computers always take input in form of signals.
The input data is not a number infact a physical quantity like temp., pressure, speed, velocity.
Signals are continuous

18. Analog Computers:-
These computers recognize data as a continuous measurement of a physical property ( voltage, pressure, speed and temperature).
Example: Automobile speedometer, Thermometer.

19. Analog Computer

20. Digital Computers
These computers take the input in the form of digits & alphabets & converted it into binary format.
Digital computers are high speed, programmable electronic devices.
Signals are two level of (0 for low/off , 1 for high/on).
High Accuracy
Examples: Computer used for the purpose of business and education are also example of digital computers.

21. Hybrid Computers
The combination of features of analog and digital computer is called Hybrid computer.
Hybrid computer is a digital computer that accepts analog signals, converts them to digital and processes them in digital form. 

22. Hybrid Computers:
Eg:-computer used in hospitals to measure the heartbeat of the patient.

23. Classification of Computers According to Purpose :
General purpose Computers
Special Computers

24. General purpose Computers :
A ‘General Purpose Computer’ is a machine that is capable of carrying out some general data processing under program control.
Refers to computers that follow instructions, thus virtually all computers from micro to mainframe are general purpose.
Even computers in toys, games and single- function devices follow instructions in their built-in program.

25. Special purpose Computers :
A computer that is designed to operate on a restricted class of problems.
Use special purpose computer equipment to obtain patient diagnostic information.
ECG machines