Table of Contents
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Types of computers
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Microcomputers, also known as personal computers, are the computers you typically find in homes and small businesses. A microcomputer usually costs between $1000 and $2000. It might be a stand-alone unit or be connected to a network that can share hardware and software resources. Even when a PC is connected to a network it will generally carryout processing tasks for only one user. Microcomputers come in many shapes and sizes. Microsoft DOS and MS Windows 9x, ME & XP are popular operating systems for microcomputers. IMB’s OS/2 and Linux can also be found on them.
Microcomputers which are network servers use such network operating systems as MS Windows 2000 Server, Novell NetWare, and Redhat Linux.
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A minicomputer is somewhat larger than a microcomputer and can carryout the processing for many users. If you are using a minicomputer system, you use a terminal to input your processing requests and view the results. A terminal is a device with a keyboard and screen used for input and output, but not for processing. Although a terminal resembles a microcomputer because it has a keyboard and screen, a terminal does not have any processing power of its own. For this reason they are often called dumb-terminals. Microcomputers use a program called telnet, (terminal emulation) to emulate a dumb-terminal and provide input and output to a minicomputer.
When you input a processing request, your terminal transmits it to the minicomputer. Then minicomputer sends back results to your terminal when the processing is complete. Minicomputers cost from $20,000 to $500,000. High-end workstations which are more powerful than microcomputers but are single user computers are sometimes referred to a minicomputers.
Linux and verious UNIXs are the operating systems for minicomputers.
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Mainframes are large, fast and very expensive computers, generally used by business or governments to provide centralized storage, processing, and management of large amounts of data. As with a minicomputer, one mainframe computer carries out processing tasks for multiple users who input processing requests using a terminal. However, a mainframe generally services more users than a minicomputer. To process large amounts of data, mainframes often include more than one processing unit. One of these processing units directs overall operations. A second processing unit handles communication with all the users requesting data. A third processing unit finds the data requested by users. Some microcomputers that used for network servers now have multiple CPUs.
Mainframes remain the computer of choice in situations where reliability, data security, and centralized control are necessary. The price of a mainframe computer system is typically several hundred thousand dollars. A mainframe computer is housed in a closet-size cabinet and its peripheral devices are contained in separate cabinets.
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Supercomputers are the fastest and most expensive type of computer. The cost of a supercomputer ranges from $500,000 to $35 million or even more.
Originally designed for “computer-intensive” task such as weather prediction, molecular modeling, and code-breaking, supercomputers today have also expanded into business markets where the sheer volume of data would cause lengthy processing delays in a traditional mainframe environment. For example, MCI uses supercomputer technology to manage a huge pool of customer data. Queries that once took over two hours, now take about a minute of supercomputer time.
The speed of a supercomputer can reach one trillion instructions per second, making it possible to perform complex tasks such as modeling the movement of thousands of particles in a tornado or creating realistic animations.
updated 4 Jan. 2002 Copyright 1999 - 2002 by John R. Taylor
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