1. Classification of Computer The digital computers that are available nowadays vary in their sizes and types. The computers are broadly classified into four categories (Figure 1.8) based on their size and type: (1) Microcomputers (2) Minicomputers (3) Mainframe computers (4) Supercomputer

2. Classification of computers based on size and type Slow Cheap Simple Small Fast Expensive Complex Large

3. Microcomputer Microcomputers are small, low cost and single-user digital computer consist of CPU,input unit, output unit, storage unit and the software. stand alone machines-can be connected together to create a network Example: IBM PC based on Pentium microprocessor and Apple Macintosh Microcomputers include desktop computers notebook computers or laptop, tablet computer handheld computer smart phones and netbook

4. PC Figure 1.9 Microcomputers Laptop Smart phone Netbook Tablet PDA

5. Mini Computer This is designed to support more than one user at a time It possesses large storage capacity and operates at a higher speed This type of computer is generally used for processing large volume of data in an organization. Eg: Servers in Local Area Networks (LAN).

6. Mini computer

7. Mainframe Computers They operate at very high speed, having very large storage capacity and can handle the work load of many users They are generally used in centralized databases. Mainframe computer

8. Supercomputers They are the fastest and most expensive machines They have high processing speed compared to other computers They have also multiprocessing technique Supercomputers are mainly being used for whether forecasting, biomedical research, Space Research and other areas of science and technology

9. Supercomputer