Introduction to computers
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, in 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 items
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. Two well-known operating systems are Windows and Macintoshoperating
system. Your computer uses the Windows operating system.
ENIAC
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.
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.
Desktop computer
Laptop computers
Laptop
computers are
lightweight mobile PCs with a thin screen. They are often callednotebook
computers because of their small size. 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.
Laptop computer
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, handhelds 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, handhelds have touch screens that you use with your finger or a stylus (a
pen-shaped pointing tool).
Handheld computer
Tablet PCs
Tablet
PCs are
mobile PCs that combine features of laptops and handhelds. Like laptops,
they're powerful and have a built-in screen. Like handhelds, 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.
Tablet PC
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.
Example
of a webpage (Microsoft Game Studios)
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, government 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.
For
information about how to explore the Internet and the web, see Exploring the Internet.
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 stamp! SeeGetting 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. (To learn more about what you
can do with photos, see Working with digital pictures .)
You can also listen to music on your computer, either by importing
(transferring to your computer) music from audio CDs or by purchasing songs
from a music website. Or, 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.
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 race 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 (see Learn about games inWindows Vista).
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