http://www.youtube.com/watch?v=3r2xWVCn97A
Thursday 3 April 2014
what is Laptop computer ?
A small, portable computer -- small enough that
it can sit on your lap. Nowadays, laptop computers are more frequently called
notebook computers.
what is Workstation?
It is a type of computer used for engineering applications
(CAD/CAM), desktop publishing, software development, and other types of
applications that require a moderate amount of computing power and relatively
high quality graphics capabilities. Workstations generally come with a large,
high-resolution graphics screen, at large amount of RAM, built-in network
support, and a graphical user interface. Most workstations also have a mass
storage device such as a disk drive, but a special type of workstation, called
a diskless workstation, comes without a disk drive. The most common operating
systems for workstations are UNIX and Windows NT. Like personal computers, most
workstations are single-user computers. However, workstations are typically
linked together to form a local-area network, although they can also be used as
stand-alone systems.
what is Minicomputer?
It is a midsize computer. 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 up to 200 users simultaneously
Wednesday 2 April 2014
Personal computer
It can be defined as a small, relatively
inexpensive computer designed for an individual user. In price, personal
computers range anywhere from a few hundred pounds to over five thousand
pounds. All are based on the microprocessor technology that enables
manufacturers to put an entire CPU on one chip. Businesses use personal
computers for word processing, accounting, desktop publishing, and for running
spreadsheet and database management applications. At home, the most popular use
for personal computers is for playing games and recently for surfing the
Internet.
Personal computers first appeared in the late
1970s. One of the first and most popular personal computers was the Apple II,
introduced in 1977 by Apple Computer. During the late 1970s and early 1980s,
new models and competing operating systems seemed to appear daily. Then, in
1981, IBM entered the fray with its first personal computer, known as the IBM
PC. The IBM PC quickly became the personal computer of choice, and most other
personal computer manufacturers fell by the wayside. P.C. is short for personal
computer or IBM PC. One of the few companies to survive IBM's onslaught was
Apple Computer, which remains a major player in the personal computer
marketplace. Other companies adjusted to IBM's dominance by building IBM
clones, computers that were internally almost the same as the IBM PC, but that
cost less. Because IBM clones used the same microprocessors as IBM PCs, they
were capable of running the same software. Over the years, IBM has lost much of
its influence in directing the evolution of PCs. Therefore after the release of
the first PC by IBM the term PC increasingly came to mean IBM or IBM-compatible
personal computers, to the exclusion of other types of personal computers, such
as Macintoshes. In recent years, the term PC has become more and more difficult
to pin down. In general, though, it applies to any personal computer based on
an Intel microprocessor, or on an Intel-compatible microprocessor. For nearly
every other component, including the operating system, there are several
options, all of which fall under the rubric of PC
Monday 31 March 2014
what is Supercomputer and Mainframe computer?
Supercomputer is a broad term for one of the
fastest computers currently available. Supercomputers are very expensive and
are employed for specialized applications that require immense amounts of
mathematical calculations (number crunching). For example, weather forecasting
requires a supercomputer. Other uses of supercomputers scientific simulations,
(animated) graphics, fluid dynamic calculations, nuclear energy research,
electronic design, and analysis of geological data (e.g. in petrochemical
prospecting). Perhaps the best known supercomputer manufacturer is Cray
Research.
Mainframe was a term originally referring to the cabinet containing the central processor unit or "main frame" of a room-filling Stone Age batch machine. After the emergence of smaller "minicomputer" designs in the early 1970s, the traditional big iron machines were described as "mainframe computers" and eventually just as mainframes. Nowadays a Mainframe is a very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. 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. 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. The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.
Sunday 30 March 2014
computer definition
A computer is a machine that can be programmed
to manipulate symbols. Its principal characteristics are:
§ It responds to a specific set of instructions
in a well-defined manner.
§ It can execute a prerecorded list of
instructions (a program).
§ It can quickly store and retrieve large amounts
of data.
Therefore computers can perform complex and
repetitive procedures quickly, precisely and reliably. Modern computers are
electronic and digital. The actual machinery (wires, transistors, and circuits)
is called hardware; the instructions and data are called software. All
general-purpose computers require the following hardware components:
§ Central processing unit (CPU): The heart of the
computer, this is the component that actually executes instructions organized
in programs ("software") which tell the computer what to do.
§ Memory (fast, expensive, short-term memory):
Enables a computer to store, at least temporarily, data, programs, and
intermediate results.
§ Mass storage device (slower, cheaper, long-term
memory): Allows a computer to permanently retain large amounts of data and
programs between jobs. Common mass storage devices include disk drives and tape
drives.
§ Input device: Usually a keyboard and mouse, the
input device is the conduit through which data and instructions enter a
computer.
§ Output device: A display screen, printer, or
other device that lets you see what the computer has accomplished.
In addition to these components, many others
make it possible for the basic components to work together efficiently. For
example, every computer requires a bus that transmits data from one part of the
computer to another.
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