Computers differ based on their data processing abilities. They
are classified according to purpose, data handling and functionality.
According to purpose, computers are either general purpose or
specific purpose. General purpose computers are designed to perform a range of
tasks.
They have the ability to store numerous programs, but lack in
speed and efficiency. Specific purpose computers are designed to handle a
specific problem or to perform a specific task. A set of instructions is built
into the machine.
According to data handling, computers are analog, digital or
hybrid. Analog computers work on the principle of measuring, in which the
measurements obtained are translated into data. Modern analog computers usually
employ electrical parameters, such as voltages, resistances or currents, to
represent the quantities being manipulated. Such computers do not deal directly
with the numbers. They measure continuous physical magnitudes. Digital
computers are those that operate with information, numerical or otherwise,
represented in a digital form. Such computers process data into a digital value
(in 0s and 1s). They give the results with more accuracy and at a faster rate.
Hybrid computers incorporate the measuring feature of an analog computer and
counting feature of a digital computer. For computational purposes, these
computers use analog components and for storage, digital memories are used.
According to functionality, computers are classified as :
Analog Computer
An analog computer (spelt analogue in British English) is a
form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic
quantities to model the problem being solved
Digital Computer
A computer that performs calculations and logical operations
with quantities represented as digits, usually in the binary number system
Hybrid Computer (Analog + Digital)
A combination of computers those are capable of inputting
and outputting in both digital and analog signals. A hybrid computer system
setup offers a cost effective method of performing complex simulations.
On the basis of Size
Super Computer
The fastest and most powerful type of computer Supercomputers are
very expensive and are employed for specialized applications that require
immense amounts of mathematical calculations. For example, weather forecasting
requires a supercomputer. Other uses of supercomputers include animated
graphics, fluid dynamic calculations, nuclear energy research, and petroleum
exploration.
The chief difference between a supercomputer and a mainframe is
that a supercomputer channels all its power into executing a few programs as
fast as possible, whereas a mainframe uses its power to execute many programs
concurrently.
Mainframe Computer
A very large and expensive computer capable of supporting
hundreds, or even thousands, of users simultaneously. In the hierarchy that
starts with a simple microprocessor (in watches, for example) at the bottom and
moves to supercomputers at the top, mainframes are just below supercomputers.
In some ways, mainframes are more powerful than supercomputers because they
support more simultaneous programs. But supercomputers can execute a single
program faster than a mainframe.
Mini Computer
A midsized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the
distinction between large minicomputers and small mainframes has blurred,
however, as has the distinction between small minicomputers and workstations.
But in general, a minicomputer is a multiprocessing system capable of
supporting from 4 to about 200 users simultaneously.
Micro Computer or Personal Computer
- Desktop Computer: a personal or micro-mini computer sufficient to fit on a desk.
- Laptop Computer: a portable computer complete with an integrated screen and keyboard. It is generally smaller in size than a desktop computer and larger than a notebook computer.
- · Palmtop Computer/Digital Diary /Notebook /PDAs: a hand-sized computer. Palmtops have no keyboard but the screen serves both as an input and output device.
Workstations
A terminal or desktop computer in a network. In this context,
workstation is just a generic term for a user's machine (client machine) in
contrast to a "server" or "mainframe."
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