Childrens Illustrated Encyclopedia

138

HIDDEN

Computers 138-

People usually

think of computers as

having a screen and a

keyboard, but this is not always

the case. Many devices, such as

washing machines, cars, and

cameras, contain tiny computers

that are specially programmed to

control their function.

ACCURATE WEATHER FORECASTING, safe air travel, reliable

medical technology—in today’s world we take these things for granted,

but they would be impossible without computers. Although a computer

cannot “think” for itself like a person, it works like an electronic brain,

doing tasks and interpreting data (information) very quickly. The computer

in an air-traffic control system, for instance, can keep track of hundreds of

aircraft at the same time and indicates which routes they should follow to

avoid collisions. A personal computer can be used for a variety of tasks from

word processing to searching the Internet and sending email. A computer

consists of thousands of tiny electronic circuits. Before a computer can work,

it must be given a set of instructions, called a program (or software), which

tells the mechanical and electronic components inside the computer how to

carry out a particular job. Additional components, such as a memory card or

an internal modem, can be slotted into the computer as required.

PERSONAL COMPUTERS

Many homes, schools, and offices

use personal computers—small
computers designed for use by

one person. A personal computer,
such as the laptop shown here,

consists of four basic units: a
keyboard, to type in information;

a memory, to store information
and programs; a processing unit,

to carry out the instructions
contained in the program; and

a monitor, for displaying the
results of the computer’s work.

PROCESSOR

The central processing

unit (CPU) is a

microchip that

does calculations and

other similar tasks.

DATA STORAGE

The hard disk, shown

below, is where all the

computer’s programs

and data are stored

permanently. Electronic

memory chips, however,

store data being used

by the working

computer. This data

disappears when the

power is switched off.

COMPUTERS

The monitor

displays data.

When you press the keys on a keyboard it

feeds information into the computer. Letters

or numbers appear on screen, or the

computer performs a function.

Many personal

computers today

have slots for

memory cards.

The trackpad
controls the
cursor on
the screen.

USBs, or Universal Bus

Connectors, are sockets

that provide connections

to external drives. Printers,

MP3 players, and flash

drives can be plugged

into various ports.