About Computers
You've probably known about computers your whole life. But computers have not
really been around for very long. Computers started to be come popular with
big companies in the 1960s. Computers didn't become widespread in homes and
schools until the 1980s.
I.How Do people Use Computers
People use computers in many ways. Stores use computers to keep track of
products and check you out at the cash register. Banks use computers to send
money all over the world.
Computers help teachers keep track of lessons and grades. They help students
to research and learn. Computers let you hook up to networks network called
the Internet.
Scientists use computers are not just desktops and laptops. Computers are
everywhere around your home. There are tiny computers inside microwave ovens,
television sets, and videocassette recorders (VCRs) or digital video
disc(DVD)players. There are even tiny computers in cars to help them run
better.
II.Hardware and Software
Computers need hardware and software in order to work. Your desktop of
laptop and all the parts inside are called hardware. The central processing
unit(CPU) makes the computer work. The keyboard, mouse, printer, and monitor
are also pieces of computer hardware.
Memory chips are hardware that stores information and instructions.
Information also gets stored on the hard disk drive.
The programs that run the computer are called software. The computer
operating system is software that tells the computer how to run. Applications
of programs are software that does certain tasks. Word-processing programs,
for example, let you write school reports and letters.
III.How Can Computers Do So Much
One reason that computers can do so much is that they have a special
language that tells them what to do. Computer language has only two letters:
zeros and ones. computers can read these ones and zeros extremely quickly.
Each zero or one is called a bit. Eight zeros and ones together are called a
byte. Bits and bytes get stored in computer memory chips. Every year,
computer engineers make chips that can hold more bytes. The chips can hold
more information. Programmers can write applications that can do more things.
IV.Who Invented the Computer
Many inventions have contributed to the development of modern computers.
French mathematician Blaise Pascal and other inventors in 1600s began making
machines that could add and subtract numbers. Wheels, levers, and other moving
parts made these machines work. In the 1800s, British mathematicians Charles
Babbage and Augusta Ada Byron worked on plans for machines that could store
information on cards with holes punched in them.
American inventor Herman Hollerith made a machine that automatically totaled
population figures for the 1890 United States census. His company joined with
other companies to become International Business Machines(IBM) in 1924. Other
inventors built better computers. But none of these early computers were
digital-that is,none used the digits zero and one.
The first digital computer, called ENIAC (see Figure 1A-1), was built in the
1940s. It was huge. It was as big as a house. it had more than 18000 glass
tubes inside and weighed more than five elephants.
The first computer used by business was called UNIVAC. Big computers like
ENIAC and UNIVAC were called mainframes. The desktop or laptop computer that
you use today is much more powerful than those big machines.
In the 1940s, scientists at Bell Telephone Laboratories invented a tiny
electric switch called the transistor. In the 1960s, scientists and engineers
invented integrated circuits or computer chips. Computer chips cram millions
of transistors into a space the size of your little fingernail. Computer chips
allowed computer to be smaller.
Personal computers (PCs) were invented in the 1970s. Most PCs are meant to
be used by only one person at a time. They are small enough to fit on a desk.
The Altair 8800 was the first PC. Apple Computer made its first PC in 1977.
IBM made its first PC in 1981.
V. Who Invented Computer Programs
Computer programs are sets of instructions that tell a computer what to do.
Many people worked on early computer programs. The first programs were very
hard to write and understand. They were extremely long strings of zeros and
ones.
American naval officer and mathematician Grace Murray Hopper in 1952 wrote
the first program that turned English computer instructions into the strings
of ones and zeros that make computer work. These programs are called
compilers. In 1957, she helped develop the first programming language that
companies could by and use. It was called FLOW-MATIC. Hopper was also first to
use the word bug to mean a problem with a computer. She found a moth trapped
in one of the computers she worked with. She taped the moth into her notebook
and wrote. "First actual case of a bug being found."
VI. Later Developments
AS computers have become more powerful and widespread, operating systems
have become extremely complex. Few people can use a computer without one.
Scientists as AT&T developed an operating systems such as Linux are popular at
universities and among computer professionals. In 1975, Bill Gates and his
friend Paul Allen wrote a program for the Altair 8800 and founded the
Microsoft Corporation. Microsoft later developed the DOS and Windows operating
system used on many home and offices PCs.
Computers keep getting smaller and more powerful. Personal computers that
fit on a desktop today are more powerful than early "supercomputer" that
filled entire rooms. Cell phones and watches contain tiny computer that can
store information such as telephone numbers, addresses, and appointments.
These devices allow you to surf the Web and play games. Many computer experts
think that computers have only begun to make their mark on history.