Classification of Computers:

Digital Computer: It works upon discontinuous data. Types:

Special purpose computer: Designed to perform a specific task. The instructions are stored permanently. It is not versatile.

General purpose computer: Designed to work on different types of application. Programs are not stored permanently but are input at the time of execution.

Embedded Computer: The smallest computer embedded within the appliance. Like televisions, washing machines, watches, etc.

Microcomputer: Its CPU is microprocessor. Used in home, offices etc.

Personal Digital Assistant (PDAs): This is the smallest computer and can be held in one hand. Used as notepads, scheduling system and address book.

Laptop or PCs: These are used in businesses, home and offices.

Workstations: Similar to desktop but with greater memory and ability.

Minicomputers: This is multi-user and more powerful.

Mainframe Computers: Multi-user, multiprocessor system which is able to handle 100 users at a time.

Super Computers: These are the most powerful computers. It can perform billions of instructions per second and may have ability of 40000 microcomputers. It calculated the value of Pi to 16 million decimal places. Its cost is 15-20 million dollars. Used for weather forecasting, nuclear science research, aerodynamic modeling, metrology, seismology etc. Examples are: CRAY X-MP-14, PARAM, PACE etc.

Analog Computer: It measures continuous quantity like voltage, current, temperature etc. e.g. voltmeter, ammeter.

Hybrid Computer: It utilizes the best qualities of both the digital and analog computer. Used in weather forecasting and hospital.