classification of Computers and their types ( based on size, based on work, based on purpose -are mainly classified based on their different size and shapes.
1. Based on Size
Microcomputers – are the least powerful, yet the most widely used and fastest growing type of computers and are also called portable computers, Microcomputer consists of three basic categories of physical equipment, i.e. system unit, input/output unit and memory unit.
Some Types Of Microcomputer Are As follows-:
(a) Desktop Computer- or Personal Computer (PCs) These are small, relatively inexpensive computers. These are based on the microprocessor technology (Integrated Circuit IC). In 1958, Jack Kelby and Robert Noyce invented the first IC.
(b) Laptop- These computers are also known as ultra book or notebook. These are portable, Lightweight and fit into most briefcases. They include rechargeable battery, so these can work anywhere. First laptop was developed by Alan Key. Laptop consume less power than desktops.
(c) Handheld Computer or Palmtops- These are the smallest and are designed to fit into the palm. So, these are also known as Palmtop. They are practical for certain functions such as phone books and calendars. They use the pen for input instead of keyboard.
(d) Tablet Computer They have key features of the notebook computer, but these can accept input from a pen instead of the keyboard or mouse.
(e) Personal Digital Assistant (PDA) It is also known as a handheld PC, or personal data assistant, is a mobile device that functions as a personal information manager.
b). Mini computer
Minicomputer – are smaller in size, faster, cost lower than mainframe computers. Initially, the minicomputer Was designed to carry out some specific tasks, like engineering and Computer Aided design (cad) calculation. they are used as central computer, which is called as server.
NOTE- In 1965, DEC (Digital Equipment Corporation) build the first mini computer the PDP-8 which was similar in size to a simple refrigerator and caused about $18,000.
Mainframe computer – These are the computers having large internal memory storage and comprehensive range of software. These computers are bigger in size comparatively to mini computers but smaller than supercomputers. Mainframe computer serves as a backbone for the entire business world. Mainframe computers are IBM-370, IBM-S/390, UNIVAC-1110
NOTE- A main frame computer can connect to more then a thousand remote work stations. The speed of these computers is measured in MIPS.
d). Super computer
Supercomputers– are the fastest and most expensive machines. They have high processing speed compared to other computers. The speed of supercomputers are measured in FLOPS (Floating Point Operations Per Second) Supercomputers are used for highly calculation intensive tasks, such as weather forecasting, nuclear research, military agencies and scientific research laboratories. Supercomputers are most powerful, large in size and memory, compared to all other computers.
NOTE- 1. The first super computer was build by Burroughs. The name of the super computer made in India is Param, which has been made by an organization named C-DAC based in Pune (1990).
2. Cray-1 was the world’s first super computer introduced by Seymour R CRAY in 1976.
3. PARAM Kanchenjunga is the latest machine in the series of PARAM made by NIT (National Institute of Technology) Sikkim 17th April 2016.
4. Tianhe-2 is the world fastest super computer launched by China at NUDT university in 2013. It is based on Rylin Linux operating system with 33.86 petaflops.
2. Based on work
Analog computers– are the job-oriented computers. They carry out arithmetic and logical operations by manipulating and processing of data. e.g. speedometers, seismograph, etc. Analog computer can perform several mathematical operation simultaneously. It uses continuous variable for mathematical operation and utilises mechanical or electrical energy.
Digital computer- These computers work by calculating the binary digits. A digital computer not only performs mathematical problems, but also combines the bytes to produce desired graphics, sounds, e.g. desktop (PC).
c). Hybrid computer
Hybrid computer- computers are the combination of analog and digital computers. Machines used in hospitals like ECG and DIALYSIS are the commonly used hybrid computer. These computers contain special equipment to convert analog voltage to digital voltage and vice-versa.
3).Based on purpose
a).General purpose computer
General Purpose Computer- are those computers. Which are used to solve variety of problems by changing purpose computers by changing the program or instructions. e.g. to make small database, calculations, accounting, etc
special purpose computers- are those computers which are used to solve a single and dedicated type of problem. e.g. automatic aircraft landing, multimedia computer etc.