Лекция: Computers

Generally, a computer is any device that can perform numerical calculations—even an adding machine or a slide rule. Currently, however, the term usually refers to an electronic device that can perform automatically a series of tasks according to a precise set of instructions. The set of instructions is called a program, and the tasks may include making arithmetic calculations, storing, retrieving, and processing data, controlling another device, or interacting with a person to perform a business function or to play a video game.

The “brains” of today's computers are integrated circuits (ICs), sometimes called microchips, or simply chips. Some chips make up a computer's central processing unit (CPU), which controls the computer's overall operation; some are math coprocessors that can perform millions of mathematical operations per second; and others are memory chips that can each store billions of characters of information at one time.

Computers come in many sizes and shapes. Special-purpose, or dedicated, computers are designed to perform specific tasks. Their operations are limited to the programs built into their microchips. These computers are the basis for electronic calculators and can be found in thousands of other electronic products, including digital watches, cameras and automobiles.

General-purpose computers, such as personal computers and business computers, are much more versatile because they can accept new programs. Each new program enables the same computer to perform a different set of tasks. For example, one program instructs the computer to be a word processor, another transforms it into a video game.

Although some general-purpose computers are as small as pocket radios, the smallest computers generally recognized are called subnotebooks. These usually consist of a CPU, electromechanical or solid-state storage and memory, a liquid-crystal display (LCD), and a keyboard—all housed in a single unit about the size of an encyclopedia volume.

Modern desktop personal computers (PCs) are many times more powerful than the huge, million-dollar business computers of the 1960s and 1970s. Today's PCs can perform several billion operations per second. These computers are used not only for household management and personal entertainment, but also for most of the automated tasks required by small businesses, including word processing, generating mailing lists and calculating accounting information. The fastest desktop computers are called workstations, and they are generally used for scientific, engineering, or advanced business applications.

Servers are fast computers that have greater data-processing capabilities than most PCs and workstations and can be used simultaneously by many people. Often several PCs and workstations are connected to a server via a local area network (LAN). The server controls resources that are shared by the people working at the PCs and workstations. An example of a shared resource is a large collection of information called a database.

Mainframes are large, extremely fast, multiuser computers that often contain complex arrays of processors, each designed to perform a specific function. Because they can handle huge databases, simultaneously accommodate scores of users, and perform complex mathematical operations, they have been the mainstay of industry, research, and university computing centers.

The speed and power of supercomputers, the fastest class of computer, are almost beyond human comprehension, and their capabilities are continually being improved. The fastest of these machines can perform many trillions of operations per second on some type of calculations and can do the work of thousands of PCs. Supercomputers attain these speeds through the use of several advanced engineering techniques. For example, critical circuitry is supercooled to a temperature of nearly absolute zero so that electrons can move at the speed of light, and many processing units are linked in such a way that they can all work on a single problem simultaneously. Because these computers can cost billions of dollars—and because they can be large enough to cover the size of two basketball courts—they are used primarily by government agencies and large research centers.

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According to the text which computers

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4. Выберите слова из списка и заполните таблицу, чтобы получились словосочетания. Переведите словосочетания на русский язык.

slide, electronic, integrated, central, memory, word, liquid-crystal, personal, data-processing, engineering, government, large research.

5. Вставьте предлоги и переведите словосочетания..

according___a set of instructions; millions___operations___second; to be limited___the programs; to transform something___something else; to be connected___a local area network; to be shared___people; ___human comprehension; a temperature___nearly absolute zero; move___the speed___light; work___a problem; to cost billions___dollars;

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