Types of computers

(1) Computers come in many sizes, shapes and capabilities.

Special-purpose 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 devices, including digital watches, cameras, televisions, and automobiles. Such computers are preprogrammed for a specific task, such as tuning to a particular television frequency, or keeping accurate time. They generally are “hard-wired”¹ – i.e. their programs are represented as circuits that cannot be re-programmed.

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 instructs it to scan the hard drive for viruses, and yet another transforms it into a video game.

(2) Programmable computers differ greatly in their computational power, speed, memory capacity, and physical size. Some small computers can be held in one hand and are called personal digital assistants(See Figure 1). They are used as notepads, scheduling systems², and address books; if equipped with a cellular phone, they can connect to worldwide computer networks to exchange information regardless of location. Handheld television-game devices are also examples of small computers.

Figure 1

The Palm Pilot personal digital assistant (PDA) was introduced in 1996.

(3) Desktop PCs as well as portable laptop and notebook computers refer to the class of microcomputers. They are designed for use in businesses and at home for word processing, calculating accounting information, Internet access, learning foreign languages, and for entertainment. They have large capacity internal memory to store hundreds of programs and documents. They are equipped with a keyboard; a mouse or other pointing device; and a video display monitor or liquid crystal display (LCD) to display information. Laptop and notebook computers usually have hardware and software similar to PCs, but they are more compact and have flat, lightweight LCDs rather than television-like video display monitors. Most people consider the terms “laptop” and “notebook” synonymous.

(4) Workstation is a combination of input, output, and computing hardware that can be used for work by an individual. More often, however, the term refers to a powerful, usually very expensive computer ($10,000 to $100,000). Workstations are used in computer-aided design and other applications, which require a machine with considerable calculating or graphics capability.

(5) Servers are fast, powerful computers that have greater data-processing capabilities than most PCs and workstations. They can be used simultaneously by many people. Often several PCs and workstations are connected to a server via a local area network. (LAN is a system that connects computers to each other within a building or organization so that people can use and work on the same information.) 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. Often all of the PCs at a business or university are connected to a central computer called a server.

(6) Mainframes are large, extremely fast, multi-user computers. They often contain several processors, each designed to perform a specific function. Because they can be shared by multiple users simultaneously, handle huge databases, and perform complex mathematical operations, they are used at large industrial businesses, scientific-research and university computing centers.

(7) The speed and power of supercomputers, the fastest class of computers, are almost beyond human comprehension, and their capabilities are being continually improved. They can perform many trillions of operations per second on some type of calculations and can do the work of thousands of PCs. Supercomputers achieve these speeds by means of the use of several advanced engineering techniques. For example, important circuitry is cooled to a temperature of nearly absolute zero so that electrons can move at the speed of light and many processing units are connected in such a way that they can all work on a single problem simultaneously. (See Figure 2)

Figure 2

Cray Supercomputer

The Cray-2 Supercomputer (designed by Seymour Cray of Cray Research, Eagan, MN) was first introduced in 1985, nine years after the first model, the Cray-1, was introduced. This type of supercomputer is used for mathematical studies of very complex problems, such as speech analysis, weather forecasting, and fundamental questions in physics and chemistry. It is a computer capable of many billions of arithmetic operations per second. The computer contains hundreds of processing units, similar to the central processing units in PCs. The processing units are linked together in parallel so that multiple computations can be carried out simultaneously.

Supercomputers are used to design automobiles, aircraft, and spacecraft; to predict the weather and global climate; to design new drugs and chemical compounds; and to make calculations that help scientists understand the properties of particles that make up atoms as well as the features and evolution of stars and galaxies. Supercomputers are also used widely by the military to do weapons and defense systems research, and to code or decode secret information. Because these computers can cost billions of dollars and because they can be large enough to fill in two basketball courts, they are used primarily by government agencies and large research centers.

Notes:¹hardwired– постоянно [жёстко] замонтированный, постоянно запаянный;

²schedulingsystem– система календарного планирования

EXERCISES

Ex. 30. Search TEXT B for the equivalents of the following phrases:

1. программа, встроенная в микрочип;

2. предварительно запрограммированные на выполнение определённой задачи;

3. настраивать на определённую частоту телевизионного канала;

4. схема, которую невозможно перепрограммировать;

5. значительно отличаться по;

6. вычислительная мощность, вычислительные возможности;

7. использовать в качестве блокнотов, адресных книг или для календарного планирования;

8. сотовый телефон;

9. глобальная компьютерная сеть;

10. обмениваться информацией независимо от того, где находишься;

11. игровая ТВ приставка;

12. учетная [бухгалтерская] информация;

13. изучение иностранных языков;

14. видеомонитор, похожий на телевизор;

15. большие возможности обработки данных;

16. подсоединиться к серверу через локальную вычислительную сеть;

17. информационный фонд, называемый базой данных;

18. передовые технологии приборостроения;

19. охлаждать до практически абсолютного нуля;

20. разрабатывать новые лекарства и химические соединения;

21. соединены таким образом, что …;

22. свойства частиц, входящих в состав атома;

23. исследования в области систем вооружения;

24. правительственные учреждения.

Ex. 31. Give short answers to the general questions and add something to develop the idea.

1. Are general-purpose computers designed to perform specific tasks?

2. Do personal computers and business computers refer to special-purpose machines?

3. Can electronic calculators accept new programs?

4. Is a special-purpose computer more versatile than a general-purpose one?

5. Are PDAs smaller and less powerful than PCs?

6. Does a desktop PC refer to the class of portable computers?

7. Do microcomputers have large capacity internal memory?

8. Do you consider the terms “laptop” and “notebook” synonymous?

9. Are workstations powerful but cheap computers?

10. Can mainframes be shared by multiple users simultaneously?

11. Is LAN a system that connects computers to each other within a city?

12. Are supercomputers used only by the military?

Ex. 32. Complete the sentences. Try to do the task without consulting the text.

1. Computers come in many ___, ___ and ___.

2. Special-purpose computers can be found in various electronic devices such as ___, ___, ___, ___, ___.

3. General-purpose computers differ greatly in their ___, ___, ___, and ___.

4. Such electronic devices as ___ and ___ refer to the class of the smallest programmable computers.

5. Personal digital assistants are used as ___, ___, and ___.

6. Such computers as ___, ___, and ___ are called microcomputers.

7. Microcomputers are used for ___, ___, ___, ___, and for ___.

8. Microcomputers are equipped with a ___, a ___, and a ___ or ___.

9. Laptops and notebooks usually have ___ and ___ similar to PCs.

10. Workstations are machines with great ___ and ___ capability.

11. Mainframes are ___, ___, ___ computers.

12. Several ___ and ___ are often connected to a server via a local area network.

Now go back to the text to check up your answers.

Ex. 33. TEST. Choose the required variant to complete each sentence.

1. A ___ can be equipped with a cellular phone.

A. general-purpose computer C. supercomputer

B. PDA D. game console

2. Such pointing device as a ___ is most commonly used to input information into a microcomputer.

A. joystick C. compact disc

B. keyboard D. mouse

3. Workstations are similar to PCs but they ___.

A. are less expensive C. have greater computational power

B. are more compact D. have flat, lightweight LCDs

4. Mainframes are used at large industrial businesses, scientific-research and university computing centers because they ___.

A. often contain several processors

C. can perform simple mathematical operations

B. handle huge databases

D. are used by multiple users simultaneously for playing games

5. Often all of the PCs at a business or university are connected to a main computer, which is called a ___.

A. workstation C. PDA

B. server D. supercomputer

6. Supercomputers are used only by government agencies and large research centers because they can ___.

A. cost billions of dollars C. be large enough to fill in two tennis courts

B. decode secret information D. perform trillions of operations per second

Ex. 34. Render the texts into English (do it in writing).