If every computer and microprocessor suddenly stopped working, our modern world would grind to a halt. All digital watches and clocks would go blank, pocket calculators would be useless, making a phone call would be impossible, aircraft would be grounded, banks and most other companies would be unable to do business, and since computers control the distribution of electricity from power stations, everything that used electricity from such stations would stop working.

 

A World Without Computers

A washing machine that is controlled by a microprocessor can rinse and spin-dry clothes in a number of ways. The chip holds a range of programs from which we can select the washing cycle that best suits the particular load of laundry we have put in. A washing machine designed without a microprocessor would still get clothes clean. It would just not be able to offer as many options for automatically controlling the way the laundry is washed.

 

In the same way, ovens, television sets, cars, and dozens of other machines and gadgets have gained extra capabilities because of the information-processing technology that is now built into them. But they would still work and do perfectly good jobs if they were designed without chips. After all, most of the machines that have an important effect on our lives today were invented long before there were any microchips or before computers had become practical enough for widespread use.

 

Likewise, phone networks and electric power networks don't have to be controlled by computers. Banks, factories, offices, libraries, transport systems, and emergency services could all be redesigned to carry on their work if computers were no longer available.

 

So if computers are not strictly necessary for most of the jobs they do, why do we bother to use them? The answer is that they make our lives easier. They increase speed, efficiency, and choice in all sorts of human activities, and they put us in control of vast amounts of new information.

 

There are also some present-day activities that would not be possible if computers didn't exist. Among these are space exploration, satellite communications, and many of the important new scanning procedures carried out in hospitals to detect early signs of life-threatening diseases.

 

Revolution in the Home

Nowhere is the spectacular progress of computer technology more obvious than in the home. In the mid-1970s, home or personal computers were available only as kits for hobbyists. These computers were slow, and their memories were so limited that they could not have stored more than a few pages of text from this book. Yet, despite their limitations, the first home computers did have one very important effect. They attracted the attention of thousands of enthusiasts, some of whom became experts in producing imaginative software – especially games software – for these new, miniature machines. From these early beginnings stemmed the huge market for video games and computer entertainment that exists today.

 

In comparison with the first kit computers, today's personal computers (PCs), for use by individuals at home or at work, possess awesome power. In fact, today's PCs are as fast, and have as much storage capacity, as the largest computers of twenty years ago.

 

People now use PCs for countless applications in business, entertainment, and education. Modern PCs can display information in fine detail on color screens, presenting text, still images, animated cartoons, or video clips. They can play spoken words, music, or any other sounds over loudspeakers.

 

The amount of information that PCs can handle has increased dramatically through the development of CD-ROMs. These are compact disks, like music CDs, that have been adapted to store information for use by computers. A single CD-ROM can hold tends of millions of words, thousands of still pictures and sound clips, and dozens of short sections of film. Today's PCs that are equipped to handle sophisticated pictures and sounds stored on CD-ROMs are known as multimedia computers.

 

In addition to having more powerful hardware, modern PCs are much more user-friendly than computers were in the past. This means they can be used by almost anyone, without the need to understand how a computer works. A person can choose what to do next simply by pointing to an ICON or a small picture on the screen with the help of a moveable device called a MOUSE.

 

Today, PCs are used in the home for everything from playing sophisticated games to composing music. They are used to help people write letters, keep accounts, guide amateur telescopes, learn foreign languages, and create new kinds of art. This enormous number of potential computer applications has produced demands for ever more powerful PCs. This, in turn, has spurred further computer developments, since any company that comes up with a new, faster processing chip or an improved package of software stands to earn considerable profit. In the years ahead, PCs seem destined to progress to the stage where they will play a central role in both our domestic and working lives.

 

School's Out – Forever?

Imagine that instead of going to school you could have your favorite teachers come to give you private lessons in the comfort of your own home. You could ask them whatever questions you liked, work at the speed that suited you best, and concentrate on the subjects that interested you most. To a limited extent, future computers will be able to take on the role of expert tutors, when and where the are needed.

 

In the early 1990s it became possible to quickly find information on almost any topic by using an interactive encyclopedia on CD-ROM. And whereas an ordinary encyclopedia offered just words and still pictures, a CD-ROM could give you the option of watching a short video or listening to a sound clip about your chosen topic. It also let you search quickly for details on a particular subject or print out text or pictures for use in a project.

 

Now the Internet is used by many hundreds of millions of people everyday for finding out whatever they want to know. PCs, laptop computers, and even smart phones place much of the world's information at your fingertips, so that you can hold in your hand the equivalent of great libraries on any subject imaginable.

 

Electronic books have become available allowing you to read a novel, for instance, from a screen. Soon computers will be able to understand human speech so well that keyboards are no longer needed. Eventually, personal computers will be able to hold a conversation with you, so people may come to think of them more as companions of friends than as mere machines.

 

To be able to study when and where you like by using a clever pocket tutor sounds wonderful. But it is very unlikely that such a machine, by itself, would be able to take the place of a schoolroom. Many of us already spend a lot of time watching television and working or playing with computers. Would it be good to encourage people to spend even longer periods staring at a computer screen, without the human contact and discussions with friends and teachers that a school environment allows? And is it really likely that, given the opportunity, most children would choose to do schoolwork on their computers rather than play games with them or go out with friends?

 

As time goes on, computers seem certain to play a more and more important part in education. But instead of replacing human teachers, computers are much more likely to provide extensions to traditional ways of learning and new opportunities for students to express themselves.

 

Storing Computer Data

The amount of information a computer can hold is measured in units called BYTES – one byte being equivalent to a single character, such as a letter or a digit. A computer's internal memory may have a capacity of several billion bytes (gigabytes). Most of this is in the form of hard disks which store data magnetically, in the same way audio tapes store sounds (see Figure 2). A hard disk uses a coating that contains particles of iron oxide. These particles line up like compass needles when a magnetic field is applied to them. The pattern of these particles corresponds to the data stored on the disk.   CD-ROMs store information in the form of tiny pits and blanks on the shiny surface of 5-inch metal disks. By scanning the mirror-like surface, a laser beam reads the data that is coded in the pattern of the pits and blanks. CD-ROMs used to have the drawback that, once written on, they could not be erased or overwritten. In other words, they could not be used repeatedly for different purposes. A new kind of optical disk was developed, however, that is erasable and can be written over again and again.

 

The Everywhere Machines

The computer is an invention that, like the wheel, can be used in countless ways. Computers help analyze pictures sent back by orbiting satellites so that scientists can monitor Earth's natural resources and environment. They allow researchers to make forecasts about possible changes in the world's climate caused by human activities.

 

Computers are used by the police to store information about convicted criminals; to reconstruct the appearance of suspects, based on the evidence of witnesses; and to identify patterns in the criminal activities of lawbreakers, especially those who strike repeatedly within certain areas (see Figure 3).

 

Computers that are designed to process images collected by small video cameras are providing another tool in the fight against crime. When installed in public places, such miniature video cameras are unnoticed, but they can record everything that goes on in an area. If a crime is committed within the camera's range, pictures of suspects are recorded. Using a computer, these pictures can be compared with images in an electronic library of known criminals, just as fingerprints are now compared. The computers can also be used by police to track down new offenders. The same kind of surveillance system can be used to identify employees entering a workplace and to monitor the movements of confused or dangerous people in hospitals and prisons. Soon, fraud involving credit cards and bank cards will shrink when people's faces can be scanned and checked at the till or cash dispenser. And wanted criminals will be intercepted at airports before they have the chance to flee.

 

Computers are used by engineers to test the strength of new designs for buildings and bridges. They let scientists analyze the results of experiments or test theories about the nature of matter, about the properties of new drugs, or about events at the beginning of the universe. Just as other machines allow us to overcome the limitations of our bodies and muscles, so computers act as powerful extensions of our brains.

 

However, many dangers arise as well as well from the expanding use of computers in society. There is a fear that, because so much information on people is now held on computers, it is becoming too easy for organizations to invade our privacy. And, although computerized surveillance systems may help in the fight against crime, in the wrong hands they could also be used to spy on people.

 

Other problems might arise if the computer systems at the heart of major public or military organizations were to develop flaws that went undetected. Such systems may also be vulnerable to attack by people, known as "hackers," who crack the security codes of computers and then, in some cases, destroy or steal important information stored on the computers' disks. In short, our increasing reliance on computers brings many potential problems in addition to great benefits.

 

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