What is a Computer?
Definition of Computer: Computer is an electronic
device that is designed to work with Information. The term computer is derived
from the Latin term ‘computer’, this means to calculate. Computer can not do anything
without a Program. it represents the decimal numbers through a string of binary
digits. The Word 'Computer’ usually refers to the Center Processor Unit plus
Internal memory.
Computer is an advanced electronic device that takes raw data as
input from the user and processes these data under the control of set of
instructions (called program) and gives the result (output) and saves output
for the future use. It can process both numerical and non-numerical (arithmetic
and logical) calculations. The basic components of a modern digital computer
are: Input Device, Output Device, Central Processor. A Typical modern computer
uses LSI Chips.
Charles Babbage is called the "Grand Father" of the computer. The First
mechanical computer designed by charles Babbage was called Analytical Engine. It
uses read-only memory in the form of punch cards.
Modern Computers Defined
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:
mass storage
device:
allows a computer to permanently retain large amounts of data. 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.
central processing unit
(CPU): the heart of the computer, this is the component that actually
executes instructions
Uses of
Computer
Education:
Getting the right kind of information is a major challenge as is
getting information to make sense. College students spend an average of 5-6
hours a week on the internet. Research shows that computers can significantly
enhance performance in learning. Students exposed to the internet say they
think the web has helped them improve the quality of their academic research
and of their written work. One revolution in education is the advent of
distance learning. This offers a variety of internet and video-based online
courses.
Health and Medicine:
Computer technology is radically changing the tools of medicine.
All medical information can now be digitized. Software is now able to computer
the risk of a disease. Mental health researchers are using computers to screen
troubled teenagers in need of psychotherapy. A patient paralyzed by a stroke
has received an implant that allows communication between his brain and a
computer; as a result, he can move a cursor across a screen by brainpower and
convey simple messages.
Science :
Scientists have long been users of it. A new adventure among
scientists is the idea of a “collaborator”, an internet based collaborative
laboratory, in which researchers all over the world can work easily together
even at a distance. An example is space physics where space physicists are
allowed to band together to measure the earth’s ionosphere from instruments on
four parts of the world.
Business :
Business clearly sees the interest as a way to enhance
productivity and competitiveness. Some areas of business that are undergoing
rapid changes are sales and marketing, retailing, banking, stock trading, etc.
Sales representatives not only need to be better educated and more
knowledgeable about their customer’s businesses, but also must be comfortable
with computer technology. The internet has become a popular marketing tool. The
world of cybercash has come to banking – not only smart cards but internet
banking, electronic deposit, bill paying, online stock and bond trading, etc.
Recreation and Entertainment:
Our entertainment and pleasure-time have also been affected by
computerization. For example:
i) In movies, computer generated graphics give freedom to
designers so that special effects and even imaginary characters can play a part
in making movies, videos, and commercials.
ii) In sports, computers compile statistics, sell tickets, create
training programs and diets for athletes, and suggest game plan strategies
based on the competitor’s past performance.
Government:
Various departments of the Government use computer for their
planning, control and law enforcement activities. To name a few – Traffic,
Tourism, Information & Broadcasting, Education, Aviation and many others.
Defence:
There are many uses computers in Defence such as:
1) Controlling UAV or unmanned air-crafts an example is Predator.
If you have cable I would recommend watching the shows “Future Weapons"
and “Modern Marvels". The show future weapon gives an entire hour to the
predator.
2) They are also used on Intercontinental Ballistic Missiles
(ICBMs) that uses GPS and Computers to help the missile get to the target.
3) Computers are used to track incoming missiles and help slew
weapons systems onto the incoming target to destroy them.
Sports:
In today's technologically growing society, computers are being
used in nearly every activity.
Recording Information
Official statistics keepers and some scouts use computers to
record statistics, take notes and chat online while attending and working at a
sports event.
Analyzing Movements
The best athletes pay close attention to detail. Computers can
slow recorded video and allow people to study their specific movements to try
to improve their tendencies and repair poor habits.
Writers
Many sportswriters attend several sporting events a week, and they
take their computers with them to write during the game or shortly after while
their thoughts are fresh in their mind.
Scoreboard
While some scoreboards are manually updated, most professional
sports venues have very modern scoreboards that are programmed to update
statistics and information immediately after the information is entered into
the computer.
Classification of Computers
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
What is Hardware?
Your PC (Personal Computer) is a system, consisting of many
components. Some of those components, like Windows XP, and all your other
programs, are software. The stuff you can actually see and touch, and would
likely break if you threw it out a fifth-story window, is hardware.
Not everybody has exactly the same hardware. But those of you who have a desktop system, like the example shown in Figure 1, probably have most of the components shown in that same figure. Those of you with notebook computers probably have most of the same components. Only in your case the components are all integrated into a single book-sized portable unit.
Not everybody has exactly the same hardware. But those of you who have a desktop system, like the example shown in Figure 1, probably have most of the components shown in that same figure. Those of you with notebook computers probably have most of the same components. Only in your case the components are all integrated into a single book-sized portable unit.
The system unit is the actual computer; everything else is called
a peripheral device. Your computer's system unit probably has at least one
floppy disk drive, and one CD or DVD drive, into which you can insert floppy
disks and CDs. There's another disk drive, called the hard disk inside the
system unit, as shown in Figure 2. You can't remove that disk, or even see it.
But it's there. And everything that's currently "in your computer" is
actually stored on that hard disk. (We know this because there is no place else
inside the computer where you can store information!).
The floppy drive and CD drive are often referred to as drives with
removable media or removable drives for short, because you can remove whatever
disk is currently in the drive, and replace it with another. Your computer's
hard disk can store as much information as tens of thousands of floppy disks,
so don't worry about running out of space on your hard disk any time soon. As a
rule, you want to store everything you create or download on your hard disk.
Use the floppy disks and CDs to send copies of files through the mail, or to
make backup copies of important items.
Random Access Memory (RAM)
There's too much "stuff" on your computer's hard disk to
use it all at the same time. During the average session sitting at the
computer, you'll probably use only a small amount of all that's available. The
stuff you're working with at any given moment is stored in random access memory
(often abbreviated RAM, and often called simply "memory"). The
advantage using RAM to store whatever you're working on at the moment is that
RAM is very fast. Much faster than any disk. For you, "fast"
translates to less time waiting and more time being productive.
So if RAM is so fast, why not put everything in it? Why have a hard disk at all? The answer to that lies in the fact that RAM is volatile. As soon as the computer is shut off, whether intentionally or by an accidental power outage, every thing in RAM disappears, just as quickly as a light bulb goes out when the plug is pulled. So you don't want to rely on RAM to hold everything. A disk, on the other hand, holds its information whether the power is on or off.
So if RAM is so fast, why not put everything in it? Why have a hard disk at all? The answer to that lies in the fact that RAM is volatile. As soon as the computer is shut off, whether intentionally or by an accidental power outage, every thing in RAM disappears, just as quickly as a light bulb goes out when the plug is pulled. So you don't want to rely on RAM to hold everything. A disk, on the other hand, holds its information whether the power is on or off.
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