Introduction of computers
Introduction to computers
In this article
Are you new to computers? Do you wonder what they do and why you
would want to use one? Welcome—you're in the right place. This article gives an
overview of computers: What they are, the different types, and what you can do
with them.
What are computers?
Computers are machines that perform tasks or calculations
according to a set of instructions, or programs. The
first fully electronic computers, introduced in the 1940s, were huge machines
that required teams of people to operate. Compared to those early machines,
today's computers are amazing. Not only are they thousands of times faster, they
can fit on your desk, on your lap, or even in your pocket.
Computers work through an interaction of hardware and software.
Hardware refers to the parts of a computer that you
can see and touch, including the case and everything inside it. The most
important piece of hardware is a tiny rectangular chip inside your computer
called the central processing unit (CPU), or microprocessor. It's the "brain" of your computer—the part
that translates instructions and performs calculations. Hardware items such as
your monitor, keyboard, mouse, printer, and other components are often called
hardware devices, or devices.
Software refers to the instructions, or
programs, that tell the hardware what to do. A word-processing program that you
can use to write letters on your computer is a type of software. The operating
system (OS) is software that manages your computer and the devices connected
to it. Windows is a well-known operating
system.
ENIAC |
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Introduced in 1946, ENIAC (Electronic Numerical Integrator and
Computer) was the first general-purpose electronic computer. It was built for
the United States military to calculate the paths of artillery shells.
Physically, ENIAC was enormous, weighing more than 27,000 kilograms (60,000
pounds) and filling a large room. To process data, ENIAC used about 18,000
vacuum tubes, each the size of a small light bulb. The tubes burned out easily
and had to be constantly replaced.
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Types of computers
Computers range in size and capability. At one end of the scale
are supercomputers, very large computers with
thousands of linked microprocessors that perform extremely complex calculations.
At the other end are tiny computers embedded in cars, TVs, stereo systems,
calculators, and appliances. These computers are built to perform a limited
number of tasks.
The personal computer, or PC, is designed to be used by one person at a time. This
section describes the various kinds of personal computers: desktops, laptops,
handheld computers, and Tablet PCs.
Desktop computers
Desktop computers are designed for use
at a desk or table. They are typically larger and more powerful than other types
of personal computers. Desktop computers are made up of separate components. The
main component, called the system unit, is usually a
rectangular case that sits on or underneath a desk. Other components, such as
the monitor, mouse, and keyboard, connect to the system unit.
Laptop computers and small notebook PCs
Laptop computers are lightweight mobile
PCs with a thin screen. Laptops can operate on batteries, so you can take them
anywhere. Unlike desktops, laptops combine the CPU, screen, and keyboard in a
single case. The screen folds down onto the keyboard when not in use.
Small notebook PCs (often referred to
asmini-notebooks), are small, affordable laptops that
are designed to perform a limited number of tasks. They're usually less powerful
than a laptop, so they're used mainly to browse the web and check e‑mail.
Smartphones
Smartphones are mobile phones that have
some of the same capabilites as a computer. You can use a smartphone to make
telephone calls, access the Internet, organize contact information, send e‑mail
and text messages, play games, and take pictures. Smartphones usually have a
keyboard and a large screen.
Handheld computers
Handheld computers, also called personal digital assistants (PDAs), are battery-powered
computers small enough to carry almost anywhere. Although not as powerful as
desktops or laptops, handheld computers are useful for scheduling appointments,
storing addresses and phone numbers, and playing games. Some have more advanced
capabilities, such as making telephone calls or accessing the Internet. Instead
of keyboards, handheld computers have touch screens that you use with your
finger or a stylus (a pen-shaped pointing tool).
Tablet PCs
Tablet PCs are mobile PCs that combine
features of laptops and handheld computers. Like laptops, they're powerful and
have a built-in screen. Like handheld computers, they allow you to write notes
or draw pictures on the screen, usually with a tablet
pen instead of a stylus. They can also convert your handwriting into typed
text. Some Tablet PCs are “convertibles” with a screen that swivels and unfolds
to reveal a keyboard underneath.
What can you do with computers?
In the workplace, many people use computers to keep records,
analyze data, do research, and manage projects. At home, you can use computers
to find information, store pictures and music, track finances, play games, and
communicate with others—and those are just a few of the possibilities.
You can also use your computer to connect to the Internet, a network that links computers around the world.
Internet access is available for a monthly fee in most urban areas, and
increasingly, in less populated areas. With Internet access, you can communicate
with people all over the world and find a vast amount of information.
Here are some of the most popular things to do with
computers:
The web
The World Wide Web (usually called
the web, or web) is a
gigantic storehouse of information. The web is the most popular part of the
Internet, partly because it displays most information in a visually appealing
format. Headlines, text, and pictures can be combined on a single webpage—much like a page in a magazine—along with sounds
and animation. A website is a collection of
interconnected webpages. The web contains millions of websites and billions of
webpages.
Surfing the web means exploring it. You
can find information on the web about almost any topic imaginable. For example,
you can read news stories and movie reviews, check airline schedules, see street
maps, get the weather forecast for your city, or research a health condition.
Most companies, agencies, museums, and libraries have websites with information
about their products, services, or collections. Reference sources, such as
dictionaries and encyclopedias, are also widely available.
The web is also a shopper's delight. You can browse and purchase
products—books, music, toys, clothing, electronics, and much more—at the
websites of major retailers. You can also buy and sell used items through
websites that use auction-style bidding.
E‑mail
E‑mail (short for electronic mail) is a convenient way to communicate with
others. When you send an e‑mail message, it arrives almost instantly in the
recipient's e‑mail inbox. You can send e‑mail to many people simultaneously, and
you can save, print, and forward e‑mail to others. You can send almost any type
of file
in an e‑mail message, including documents, pictures, and music files. And with
e‑mail, you don't need a postage stamp!
For more information about using e‑mail, see Getting started
with e‑mail.
Instant messaging
Instant messaging is like having a real-time conversation with
another person or a group of people. When you type and send an instant message,
the message is immediately visible to all participants. Unlike e‑mail, all
participants have to be online (connected to the Internet) and in front of their
computers at the same time. Communicating by means of instant messaging is
called chatting.
Pictures, music, and movies
If you have a digital camera, you can move your pictures from the
camera to your computer. Then you can print them, create slide shows, or share
them with others by e‑mail or by posting them on a website. You can also listen
to music on your computer, either by importing
music from audio CDs or by purchasing songs from a music website. Or, you can
tune in to one of the thousands of radio stations that broadcast over the
Internet. If your computer comes with a DVD player, you can watch movies
too.
Gaming
Do you like to play games? Thousands of computer games in every
conceivable category are available to entertain you. Get behind the wheel of a
car, battle frightening creatures in a dungeon, or control civilizations and
empires! Many games allow you to compete with other players around the world
through the Internet. Windows includes a
variety of card games, puzzle games, and strategy games. For more information,
see Learn about
Windows games.
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