Pre-text exercises. I. Memorize the following English words and word-combinations:

I. Memorize the following English words and word-combinations:

counting machine-машина що рахує, complicated-складний, with lightning speed- зі швидкістю світла, require- потребує, spacecraft- космічний корабель, general-purpose computers-комп’ютери загального призначення, special-purpose computer- комп’ютери спеціальногопризначення

II. Read and translate the text: “WHAT IS A COMPUTER ”

A computer is really a very specific kind of counting machine. It can do arithmetic problems faster than any person alive. By means of electric circuits it can find the answer to a very difficult and complicated problem in e few seconds.

A computer can " remember" information you give it. It stores the information in its " memory" until it is needed. When you are ready to solve a problem with lightning speed. Then it checks its work to make sure there are no mistakes.

There are different kinds of computers. Some do only one job over and over again. These are special purpose computers. Each specific application requires a specific computer. One kind of computer can help us build a spacecraft, another kind of computer can help us navigate that spacecraft. A special-purpose computer is built for this purpose alone and cannot do anything else.

But there are some computers that can do many different jobs. They are called general-purpose computers. These are the " big brains" that solve the most difficult problems of science. They answer questions about rockets and planes, bridges and ships - long before these things are even built.

We used to think of a computer as a large machine with many buttons and flashing lights that took up a whole room. But today computers are becoming smaller and are even being put inside other devices. Though these small devices are called microcomputers or minicomputers, they are still true computers.

We might list the essential constituent parts of a general-purpose computer as follows. First core store also called memory. It is best to think of computer memory simply as a place where information in stored. This information can be an instruction or an item of data. We can store many instructions or many items of data in a computer. Second an arithmetic unit a device for performing calculations. Third a control unit a device for causing the machine to perform the desired operations in the correct sequence. Fourth input devices whereby data (in the form of numbers) and operating instructions can be supplied to the machine and fifth output devices for displaying the results of calculations. The input and output devices are called peripherals.

There are several advantages in making computers as small as one can. Sometimes weight is particularly important. A modern aircraft for example carries quite a load of electronic apparatus. If it is possible to make any of these smaller and therefore lighter the aircraft can carry a bigger payload. This kind of consideration applies to space satellites and to all kinds of computers that have to be carried about. But weight is not the only factor. The smaller the computer the faster it can work.

Another advantage is that less power is required to run the computer. In space vehicles and satellites this is an important matter but even in a trial application we needed not waste power. Sometimes a computer takes so much power that cooling systems which require still more power have to be installed to keep the computer from getting too hot which would increase the risk of faults developing. So a computer which does not need to be cooled saves power on two counts.

Another advantage is reliability. Minicomputers have been made possible by the development of integrated circuits. And now that transistors and other solid state devices are used instead of valves printed circuits with their solid-state components have a very long life indeed. A computer can built up of large numbers of similar units of this kind.

Repairs of the old kind (with soldering iron and so on) are no longer needed. If one of the component circuits develops a fault all that is needed is to locate the faulty unit throw it away and plug in a new one.

Some of the first computers cost millions of dollars but people were quick to learn that it was cheaper to let a million dollar computer keep track of inventory or print payroll checks than to have a hundred clerks trying to do the same thing by hand. Scientists found that computers made fewer mistakes and could perform the tasks much faster than almost any number of people using manual methods. The demand for computers grew. As the demand grew the number of factories able to produce computers also grew.