Прочтите текст и скажите, какие устройства относятся к сфере ввода-вывода информации.

Text 1. INPUT-OUTPUT ENVIRONMENT

Data and instructions must enter the data processing system, and information must leave it. These operations are performed by input and output (I/O) units that link the computer to its external environment.

The I/O environment may be human-related or human-in­dependent. A remote banking terminal is an example of a hu­man-related input environment, and a printer is an example of a device that produces output in a human-readable format. An example of a human-independent input environment is a de­vice that measures traffic flow. A reel of magnetic tape upon which the collected data are stored in binary format is an ex­ample of a human-independent output.

Input-Output Interfaces. Data enter input units in forms that depend upon the particular device used. For example, da,ta are entered from a keyboard in a manner similar to typing, and this differs from the way that data are entered by a bar-code scan­ner. However, regardless of the forms in which they receive their inputs, all input devices must provide a computer with data that are transformed into the binary codes that the primary memo­ry of the computer is designed to accept. This transformation is accomplished by units called I/O interfaces. Input interfaces are designed to match the unique physical or electrical character­istics of input devices to the requirements of the computer sys­tem. Similarly, when output is available, output interfaces must be designed to reverse the process and to adapt the output to the external environment. These I/O interfaces are also called channels or input-output processors (IOP).

The major differences between devices are the media that they use and the speed with which they are able to transfer data to or from primary storage.

Input-Output Device Speed. Input-output devices can be clas­sified as high-speed, medium-speed, and low-speed. The devic­es are grouped according to their speed. It should be noted that the high-speed devices are entirely electronic in their operation or magnetic media that can be moved at high speed. Those high­speed devices are both input and output devices and are used as secondary storage. The low-speed devices are those with com­plex mechanical motion or operate at the speed of a human operator. The medium-speed devices are those that fall be­tween — they tend to have mechanical moving parts which are more complex than the high-speed devices but not as complex as the low-speed.

High-speed devices: magnetic disk; magnetic tape. Medium-speed devices: card readers; line printers; page print­ers; computer output microfilms; magnetic diskette; optical character readers; optical mark readers; visual displays.

Low-speed devices: bar-code readers; character printers; dig­itizers; keyboard input devices; plotters; voice recognition and response units.

3. Дайте ответы на следующие вопросы.

1. What is the purpose of input and output devices? 2. What types of input-output devices do you know? 3. Why are data transformed into a binary code while entering the input device?

4. Give an example of a human independent output. 5. What isan I/O interface? 6. What are the major differences between the various I/O devices? 7. What types of I/O devices tend to behigh-speed devices? 8. What types of devices tend to be lowspeed devices?

4. Найдите в тексте английские эквиваленты следующих словосочетаний:

Среда устройств ввода-вывода; система обработки ин­формации; внешняя среда; связан с человеком; независим от человека; удаленный банковский терминал; измерять поток данных; бобина с магнитной лентой; хранить со­бранную информацию; двоичный формат; интерфейс вво­да-вывода; вводить с клавиатуры; устройство считывания штрих-кода; не смотря на; преобразовать в двоичный код; сопоставлять параметры; подобным образом; интерфейс вывода; изменить процесс в обратном направлении; на­строить устройство ввода-вывода к внешней среде; глав­ное отличие; основная память; вторичная память; низко­скоростные устройства; в соответствии.

5. Вспомните значение новых слов и попытайтесь переве­сти словосочетания, употребляемые с этими словами.

Environment: application environment; communication en­vironment; execution environment; external environment; hard­ware environment; interface invironment; management envi­ronment; multimedia environment; network environment; processing environment; security environment; software envi­ronment; user environment.

Interface: channel interface; common interface; data inter­face; database interface; display interface; external interface; flexible interface; floppy-disk interface; general-purpose inter­face; hardware interface; low-level interface.

Scanner: bar code scanner; black-and-white scanner; color scanner; desktop scanner; hand scanner; laser scanner; manual scanner; optical scanner; visual scanner.

Terminal: batch terminal; desktop terminal; display terminal; printer terminal; remote terminal; security terminal; logical terminal; text terminal. •

6. Вспомните формы инфинитива, проанализируйте и пе­реведите следующие предложения.

Infinitive Active Passive
Indefinite to ask to be asked
Continuous to be asked  
Perfect to have asked to have been asked
Perfect Continuous to have been asking  

1. A printer is an example of a device to produce output in a human-readable format. 2. The high-speed devices to be used as secondary storage are both input and output devices. 3. The progress of electronics to have resulted in the invention of elec­tronic computers was a breakthrough (прорыв) of the second part of the 20th century. 4. Mendeleyev's periodic law to have been accepted as a universal law of nature is of great importance nowadays. 5. When output is available, output interfaces must be designed to reverse the process and to adopt the output to the external environment. 6. The memory stores the instructions and the data to be quickly retrieved on demand by the CPU. 7. Computers to have been designed originaly for arithmetic pur­poses are applicable for great variety of tasks at present. 8. The film to have been running for over a month this year attracts at­tention of many spectators. 9. The CPU of a computer to be arranged in a single or very small number of integrated circuits is called a microprocessor. 10. Russia was the first country to start the cosmic era.

7. Прочтите внимательно текст, составьте аннотацию на английском языке, озаглавьте текст. /Для составления аннотации используйте следующие клише:

The text / article under review ...(gives us a sort of infor­mation about...)

The article deals with the problem ...

At the beginning (of the text) the author describes... (dwells on explainstouches upon analyses...; comments ... ; characterizes ... ; underlines ... ; reveals ... ; gives ac­count of...)

The article begins with the description oja review of...,

the analysis of...

The article opens with ...

Then (after that, further on, next) the author passes on to gives a detailed (thorough) analysis (description), goes on to say that...

To finish with, the author describes ...

At the end of the article the author draws the conclusion that...; the author sums it all up (by saying ...)

In conclusion the author...

As it is well known, a computer cannot perform or complete any useful work unless it is able to communicate with its exter­nal environment. All data and instructions enter and leave the central processing unit through primary storage. Input-output devices are needed to link primary storage to the environment, which is external to the computer system. So input devices are used to enter data into primary storage. Output units accept data from primary storage to provide users with information or to record the data on a secondary storage device. Some devices are used for both the input and output functions.

The data with which these devices work may or may not be in a form that humans can understand. For example the data that a data entry operator keys into the memory of a computer by typing on a keyboard are readable by humans. However, the data that tell a computer about the performance of an automo­bile engine are not in a form that humans can read. They are electrical signals from an analog sensor. Similarly, output may be on a printed page, which humans can read easily, or upon some other medium where the data are not visible, such as on magnetic tape or disk.

As we know, all of the data flow from input to final output is managed by the control unit in the CPU. Regardless of the na­ture of the I/O devices, special processors called I/O interfaces

are required to convert the input data to the internal codes used by the computer and to convert internal codes to a format which is usable by the output device.

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