A computer is a pre-programmable electronic machine that accepts raw data as input, process it according to the instructions, and provide result / information to the user as output. It is not a human but it is a machine for doing some operational. Computer can store information and user can retrieve it again and again.
Although a computer can help you to perform complex jobs and solve complicated problems, therefore it is generally classified or categorized as follows.
Types of Computer Based on Power and Size:
Types of Computer Based on Function and Operation:
Types of Computer Based on Purposes and Uses:
- Special Purpose
- General Purpose
Classification / Types of Computer Based on Power and Size:
Supercomputer is most powerful multi-user and fastest computer of the world. It calculates trillion million instructions per second up to 14 accurate decimal places. Therefore, it is called “Number Cruncher”. In Supercomputer multiple CPUs are working together.
It is very expensive with normal costs of several million dollars. It is made for general purpose to solve the problems of Scientists & Engineers and is referred as “FORTRAN ENGINES” means FORmula TRANslation, because FORTRAN language is commonly used by the scientists and engineers.
Supercomputer is considered to be the main tool for reproduction of nuclear weapons denotation, aerodynamic flows and global weather patterns.
Examples: JAGUAR, NEBULAE, IBM’s ROADRUNNER, KRAKEN, JUGENE, PLEIADES, TIANHE-1, Cray-I, Cray-II, CYBER205.
Mainframe Computer is an expensive and a multi-user / multiprocessing computer capable of supporting more than hundreds or thousands of users at the same time. These computers have large size and memory and more powerful than Minicomputer. These computers have a high speed data processing power and can process over millions arithmetic expressions per second.
Mainframe computer is expensive and are used by large organizations or industries for significant jobs and data processing. For computerization of a huge business, Universities, Banks, Scientific Laboratories, National & International Markets etc. it is usually filled with large room because many peripheral, input, output devices can be attached to it.
The Mainframe Operation System can support multiprogramming, time sharing and virtual memory; therefore it is used as Server in a network with many workstations. Many of the terminals can be attached to a Mainframe computer to run different programs.
Terminal: It is a simple monitor along with input devices (keyboard and mouse) connected to the server for input data and to show results while processing occurs on the server.
Examples: IBM 709, IBM 4381, IBM zSeries, System z9 and System z10 servers, ICL 2900, NEC 610.
A Minicomputer is a multi-user / multiprocessing computer capable to handle 10 to 200 users simultaneously. These types of computers have a medium size, small memory and more powerful and expensive than Microcomputer. Minicomputer contain one or more processors, support multiprocessing and tasking. They are smaller than Supercomputer and Mainframe computer, but more powerful than personal computers and workstations. Multiple Input & Output devices can be attached to them and used in Networking.
It is used for computerized the data, scientific research, data collection, industrial process control and small business application. Time sharing, batch processing and online processing are available on it.
Example: PRIME9755, VAX8650, IBM SYSTEM36.
Personal Computer or Microcomputer:
It is a single-user computer based on microprocessor / microchip inside. It is designed for one person therefore it is called personal computer. These Computers are small in size, small in memory, and less expensive. Many input and output devices can be attached to it. Microcomputer can also attach with Mainframe Computer through a network. It is generally used in home, offices or any working place for web surfing, sending email, type documents, database, photo editing and entertainment like playing music or games. It is further classified into the following categories.
Desktop Computer: a computer that can easily be accommodated on the table.
Laptop Computer: a computer that can easily be placed in a lap.
Examples: IBM, APPLE, COMPAQ, ATARI, PENTIUM, Core series etc.
The Workstation is a terminal or a single-user computer which is connected to a network (with a mainframe or supercomputer) and more powerful as compared to microprocessors.
Classification / Types of Computer Based on Operation:
A computer which is used to measure analog / physical quantity data. Analog means variable and physical quantity may always continue their changes. Such types of computers accept input in analog form and provide results in analog form. It measures physical quantities like distance, velocity, acceleration and temperature, e.g. speedometer of a care, temperature, watch and volt meter.
Now a day analog computer is using for Engineering and Scientific works. In Oil Refinery it measures flow and temperature of oil. They are also used in Paper making and the Chemical Industry.
The output of the analog computer is generally in the form of reading. These computers are used where data can be measured directly from measuring device.
Now Analog Computer has been updated to Digital Computers. For example: Analog watch to Digital Watch, Analog weight Balance to Digital Balance and Analog Thermometer to Digital Thermometer etc.
Those Computers which accepts data in a digital form and provide us information in the same format. It measures digital quantity data and works based on binary digits i.e. 0&1.
The result of a Digital Computer is more accurate, precise and reliable than Analog Computer. It can process faster than Analog Computer. Analog Computer has a small memory while Digital Computer has high memory and storage power.
Accounting machine and Calculator are the common example of Digital Computer.
Those Computers which accepts data in digital form and provide results/ information in analog form and vice versa”.
Hybrid Computers have the characteristics of both Analog & Digital Computers and measures both analog and digital quantities. Hybrid Computer has process with the speed of analog and precision of digital computer. They are used for special purpose and are designed to perform special task e.g. ECG machine.
Hybrid Computers are also used in the Air Defense System, and in laboratories for the preparation of medicines.
Classification / Types of Computer Based on Purpose:
Special Purpose Computers:
Types of computer which has been manufactured for specific tasks are called Special Purpose Computer. These computers are also known as “Dedicated Computers” because these are designed for special jobs. In other words, they are designed to handle specific problems, e.g. control of traffic lights and in Defense System. A set of instruction or programs is fed to them. As they perform only one type of job so they are very fast.
General Purpose Computers:
Types of computers that can perform all types of jobs and can run multiply programs are called General Purpose Computers.
These computers can perform variety of jobs, e.g. documentation, accounting, playing of games, making of graphics and doing of arithmetical operations. General Purpose Computers are versatile, but they are slow in processing and less efficient as compared to Dedicated Computers.