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Super computer is one of the most powerful computers which is used to perform the complex calculations. They are the fastest computer which works in nanosecond even in a picosecond too. This computer is used for a special purpose. Usually, such computer uses parallel processors. Nowadays, the computing capability of a super computer is equal to that of 40,000 micro computers. Mostly super computers are used by government agencies. These computers are used in research and other operations where there is a huge numerical calculation. Different industries also use this huge computer for designing their products. It is also used in Hollywood movies for animation purposes. It requires large space and temperature control room. CRAY X-MP/24, NEC-500, PARAM, etc are some of the examples of a super computer. Today's super computers are designed by companies such as HP, IBM, Cray Inc.
Mainframe computers are powerful multi-user computers capable of supporting many hundreds of users simultaneously. It is also large in size. This computer has slower processing speed than a super computer but faster than a mini and micro computer. It is designed for large-scale data processing and a huge amount of data storage. They are used in a big organization such as bank, insurance companies, airlines, railway reservation system, e-mail service providers, web hosting, etc. It needed a large area approximately 1000 sq.ft. It supports a large number of I/O terminals, more than 100 terminals.
In a mainframe, each user accesses the mainframe’s resources through a device called a terminal. Their terminals are attached to the mainframes to perform the different types of task in FIFO.
Dumb terminal and intelligent terminal are the two kinds of terminals. A dumb terminal is the input/output device that functions as a window into a computer located somewhere else. An intelligent terminal can perform some processing operations, but it usually does not have any storage.
IBM 1401, ICL 2950/10,CYBER 170, etc are some of the examples of mainframe computers.
Minicomputer is also a multi-user computer capable of supporting ten to hundreds of users simultaneously. Due to the smaller size and its cost compared to mainframe and a super computer, it got its name as a minicomputer. It is also known as midrange computer. Minicomputer can handle more input and output than a micro computer. It can support about 50 terminals and requires an area around 100 sq ft. This computer is useful for medium sized business, organizations, industries, universities and banks. It is cheap and easy to operate than a mainframe computer.
Prime 9755, VAX 7500, HCL, MAGNUM, CDC-1700, etc. are some of the examples of a mini computer.
A computer which is based on a microprocessor is called microcomputer. They are small and single user computer. This computer has a keyboard for entering data, a monitor for displaying and a storage device for storing the data. It requires less area compared to other computers.
This computer consists of central processing unit and a single chip. It is mainly used in office, school, house, shop, etc.The smallest of this category are a laptop, notebook, palmtop and PDA. IBM PC, Apple/Macintosh, etc. are the examples of the microcomputer. The microcomputer is categorized as a non-portable and portable category.
Some of the examples of microcomputer are described below:
The desktop computer is the kind of personal computer (PC), which is a common type of computer used by many people today. They are a non-portable computer.
The term “desktop computer” means the concept of such a computer actually sitting on top of a desk. A computer is known as “workstation” is actually a relatively powerful kind of desktop.
This type of desktop has a faster processor, more memory and other advanced features compared to another desktop. Common desktops often have much computing capability compare to the workstation.
A ‘laptop’ computer is a light, compact and portable PC. It contains a rechargeable battery. They also contain a built-in LCD monitor. It is a portable computer.
To make them as portable as possible; most laptops try to avoid any sort of cable or wire. In laptop, instead of a mouse, a trackpad is used. Instead of wired connection to a network or printer, ‘wireless’ radio connection are used.
A laptop is also known as a notebook, which is another kind of personal computer used by many people today. It has usually a flat-screen monitor and keyboard attached to the computer.
Most of the laptop have a clam-shell case design, which means that the case opens in a way similar to a clam. Some of the laptops are in the form of a tablet.
A handheld computer is a kind of portable computer that is intended to be held and used in a hand. A handheld computer is becoming more and more common in modern society.
This computer includes various kinds of PDA (Personal Digital Assistant) computers, such as those running palm OS or windows mobile. Nowadays, mobile phones have slowly replaced by smartphones and similar handhelds with mobile phone capabilities.
Those phones which contains the running of Google Android, windows mobile and also the iPhone are the handheld computer which has the function of mobile phones.
A PDA is similar to a palmtop computer. It is more compact and typically has no keyboard, using a touch screen for all data input. The screen of PDA has a small screen. So, it has a small stylus (plastic stick) that is used to press things on a screen.
Most PDAs use some sort of handwriting recognition system to allow the user to write on the screen and have their writing converted into text. PDAs use a ‘digital diaries’ to take their e-mail, documents, appointments, etc.
Fig: Personal Digital Assistant
(Shrestha & Manandhar, 2014)
Shrestha, R. P., & Manandhar, s. (2014). Computer Essential. Kathmandu: Ashmita publication.
Gurung, Juddha bahadur et.al., Computer Science-XI,bhundipuran Prakashan, Ktm