Ознакомьтесь с терминами текста 3.

human-readable form — удобная для чтения форма

performance — (рабочая) характеристика; производительность; быстродействие; скорость ра­боты; пропускная способность

character printer — принтер с посимвольной печатью; символьный принтер

line printer — принтер с построчной печатью

page printer — принтер с постраничной печатью

(non) impact printer — (бес)контактный принтер

letter-quality printer — принтер с типографским каче­ством печати

dot-matrix printer — точечно-матричный принтер

ink-jet printer — струйный принтер

laser-beam printer — лазерный принтер

to identify— идентифицировать; распознать; обозначить

approach — подход; метод; принцип; прибли­жение

at a time — за один раз; одновременно

to cause — вызывать; приводить к (ч.-л.); застав­лять; вынуждать

to strike against a ribbon — ударять по ленте

typewriter— печатное устройство

to spray drops of ink — распылять капли чернил

to affect— влиять; воздействовать; сказываться на (ч.-л.)

technique— метод; способ; техника; методика; технология

printer output — вывод на печать; распечатываемые дан­ные

15. Прочтите текст и назовите типы принтеров и их назна­чение.

OUTPUT DEVICES. PRINTERS

Printers provide information in a permanent, human-read­able form. They are the most commonly used output devices and are components of almost all computer systems. Printers vary greatly in performance and design. We will classify printers as character printers, line printers and page printers in order to identify three different approaches to printing, each with a dif­ferent speed range. In addition, printers can be described as ei­ther impact or nonimpact. Printers that use electromechanical mechanisms that cause hammers to strike against a ribbon and the paper are called impact printers. Nonimpact printers do not hit or impact a ribbon to print.

Character printers print only one character at a time. A type­writer is an example of a character printer. Character printers are the type used with literally all microcomputers as well as on computers of all sizes whenever the printing requirements are not large. Character printers may be of several types. A letter-quality printer is a character printer which produces output of typewriter quality. Letter-quality printers typically have speeds ranging from 10 to 50 characters per second. Dot-matrix print­ers form each character as a pattern of dots. These printers have a lower quality of type but are generally faster printers than the letter-quality printers — in the range of 50 to 200 characters per second. One of the newest types of character printer is the ink-jet printer. It sprays small drops of ink onto paper to form print­ed characters. The ink has a high iron content, which is affect­ed by magnetic fields of the printer. These magnetic fields cause the ink to take the shape of a character as the ink approaches the paper.

Line printers are electromechanical machines used for high-volume paper output on most computer systems. Their print­ing speeds are such that to an observer they appear to be print­ing a line at a time. They are impact printers. Tire speeds of line printers vary from 100 to 2500 lines per minute. Line printers have been designed to use many different the drum and the chain. Drum printers use a solid, cylindrical drum, rotating at a rapid speed. Speeds of dram printers vary from 200 to over 2000 lines per minute. Chain printers have their character set on a rapidly rotating chain called a print chain. Speeds of chain printers range from 400 to 2400 lines per minute.

Page printers are high-speed nonimpact printers. Their print­ing rates are so high that output appears to emerge from the printer a page at a time. A variety of techniques are used in the design of page printers. These techniques, called electrophoto­graphic techniques, have developed from the paper copier tech­nology. Laser-beam printers use a combination of laser beam and electrophotographic techniques to create printer output at a rate equal to 18000 lines per minute.

Ответьте на вопросы, используя информацию текста.

1. What are the three types of printers? 2. What is a letter-quality printer? 3. What is a dot-matrix printer? 4. What type of printer is the most common with microcomputer systems? 5. What is the most common printer type used on large com­puter systems? 6. What is an impact printer? Give an example. 7. What is a nonimpact printer? Give examples. 8. What are the most widely used printers? 9. How do you distinguish between a letter-quality printer and a dot-matrix printer? 10. Which of these printers is slower? 11. What types of character printers do you know? 12. How are printed characters formed by means of an ink-jet printer? 13. What are the main types of a line print­er? Which of them is faster? 14. What techniques are used in the operation of page printers?

17. Найдите в тексте английские эквиваленты следующих
словосочетаний:

Удобная для восприятия человека форма; наиболее ча­сто употребляемые устройства вывода информации; раз­личаться по рабочим характеристикам и внешнему виду; принтеры с посимвольной печатью; принтеры с построч­ной печатью; принтеры с постраничной печатью; различ­ные методы печати; диапазон скорости; принтеры контак­тные и бесконтактные; ударять по ленте; печатать по одному символу; буквально все компьютеры; а также; тре­бования печати; принтер с типографским качеством печа-ти; точечно-матричные принтеры; струйные принтеры; разбрызгивать капли чернил; высокое содержание железа; магнитные поля; принимать форму символа; кажется, что печатают по строчке; барабанный принтер; цепочечные принтеры; лазерный принтер.

18. Вспомните значение новых слов и попытайтесь пере­
вести словосочетания с этими словами.

Approach: comprehensive approach; database approach; ed­ucational (training) approach; general approach; graphic ap­proach; self-study approach; step-by-step approach; trial-and-error approach.

Performance: application performance; computer perfor­mance; device performance; disk performance; display perfor­mance; error performance; execution performance; memory performance; network performance; processor performance.

Printer: black-and-white printer; color printer; character (at-a-time) printer; dot-matrix printer; graphical (image) printer; impact printer; ink^:jet printer; laser printer; letter-quality print­er; matrix printer; network printer; page (at-a-time) printer.

Technique: advanced technique; analog technique; comput­ing technique; display (video) technique; formatting technique; hardware technique; measuring technique; modeling (simula­tion) technique; multimedia technique; numerical technique; programming technique; scanning technique; software tech­nique; testing technique.

20. Прочтите текст и составьте письменно реферат на ан­глийском языке.

MAGNETIC MEDIA DEVICES

Some of the devices mentioned above can perform both the input and output functions. Magnetic disc, magnetic diskette, and magnetic tape are examples of such devices. Magnetic discs, diskettes, and tapes can record data as output from primary stor­age and can also serve as input devices returning the data to primary storage.

Data are recorded on magnetic discs and magnetic tapes ei­ther by outputting the data from primary storage or by using a data recorder. Data recorders are not input devices, and they are not connected to the computer system. Instead they are offline recorders. The magnetic media recording devices are key-to-disk, key-to-diskette, and key-to-tape machines.

Key-to-disk devices are used as data recording stations in multistation shared-processor systems. They are able to correct data before storing it on a magnetic disk and before its entry into the main computer system.

Key-to-diskette systems store data on flexible discs, called diskettes. Diskettes are inexpensive and reusable.

Key-to-tape devices can record data on reels, on cassettes, and on tape cartridges. The magnetic tape reels produced by key-to-tape systems are in a computer-compatible format for subsequent direct data input into a computer. However, data on cartridges and cassettes often are transferred to higher-speed media, such as a full-sized reel of magnetic tape or magnetic disc, for data transfer to the computer.

21. Выполните перевод следующего текста письменно по
вариантам.

KEYBOARD DEVICES

1. There is a wide variety of keyboard devices, or terminals, available for use in entering data directly into a computer. The visual display terminal (VDT) is the most popular type of I/O device in use today. It consists of a type writerlike key­board for inputting and a cathode ray tube (CRT) for display­ing output data. Each character entered through the keyboard is also displayed on the CRT. When keyed the data are held in a small memory, called a buffer, within the terminal itself. The data are not sent on to the computer until the operator presses an enter key on the keyboard. This allows the operator the op­portunity to proofread or verify the data being entered by read­ing the data displayed on the screen. There are three major uses of VDT's: alphanumeric displays, graphic displays, and input through a light pen.

Alphanumeric displays. The most common use of the visual display terminal is to display alphanumeric data, that is, char­acter data. Because of their relatively fast output rates and their ability to provide a viewer with an "instant" output, video dis­plays have replaced printers for many applications.

Graphic displays. Visual display terminals with a graphic dis­play capability provide a very powerful and versatile tool for many users. Graphic-display devices provide not only a means of displaying high-resolution drawings but also the capability of manipulating and modifying the graphic display. The businessperson can use the graphic display to present data in the form of line charts, bar charts, or pie charts. Graphic displays can be very effective in information systems for business man­ager.

2. Different types of keyboard devices, such as visual display terminals, teleprinter terminals, and point-of-sale devices are among the keyboard devices.

A light pen is a photosensitive pen like instrument which can sense a position on the cathode ray tube (CRT) when the end of the pen is held against the screen. The light pen is an input device. By sensing the position on the screen when you touch it by the light pen, you are inputting data to the main storage. The light pen is commonly used by engineers to modify designs.

Teleprinter terminals. There are situations where it is desir­able to have a printed copy of data outputted to a terminal. If a user finds a printed copy to be required, the solution could be a teleprinter terminal. A teleprinter terminal has a keyboard for input and a typewriterlike printer for output. These printers are character printers and are therefore slower output devices than CRT displays.

A point-of-sale (POS) device is the electronic equivalent of a cash register, however it is capable of capturing more data than a cash register. Most point-of-sale devices are online terminals attached to a computer for processing the transaction while the customer is making the purchase. The significant features of most of the current electronic POS devices include: the capa­bility of entering extensive information about the sale, the guid­ing of the operator through the possible transactions by a series of lighted indicators or messages, a provision for transmission of the data to a central computer, and the provision for a local computational capability such as price extensions and tax cal­culations.

3. Прочтите внимательно текст. Заполните пропуски подхо­
дящими словами в предложениях, данных после текста.

SCANNERS

Scanners provide a capability for direct data entry into the computer system. The major advantage of this direct data entry is that humans do not have to key the data. This leads to faster and more accurate data entry. The two major types of scanners are optical scanners and magnetic-ink character recognition devices.

Optical scanners are input devices that can "read" data re­corded on paper. The scanning techniques used involve a light source and light sensors; thus, they are called optical devices. The data to be scanned may be typed or handwritten charac­ters, data-coded as pencil marks, or data-coded as bars. The common optical scanner devices are called optical character readers, optical mark readers, and bar-code readers.

An optical character reader (OCR) inputs data by using opti­cal scanning mechanisms that can detect or scan alphabetic and numeric characters printed on paper. If the data are typewrit­ten, they must be typed using a special type font, called an OCR font. Examples of the use of OCR devices include the scanners used by the Postal Service to aid in sorting bulk mail, and as first-draft input for word processing system.

Optical mark readers (OMR) are able to detect pencil marks, made on special paper forms. The actual inputting of data through an OMR device involves shining a light on the page being scanned and detecting the reflections from the pencil marks. Pencil marks made with a soft lead pencil (high graph­ite content) will reflect the light. It is this reflection that the OMR device detects.

Optical bar-code readers detect combinations of marks or printed bars that represent the data. Bar codes have been used for a number of years for some types of credit card processing and by the post office for mail sorting. It is very common to use bar-code readers in conjunction with point-of-sale devices. The most widely known bar code is the universal product code (UPC), which now appears on almost all retail packages.

Magnetic-ink character recognition (MICR) devices were de­veloped to assist the banking industry. MICR devices speed up data input for the banking industry by reading characters im­printed on paper documents using a magnetic ink (an ink that contains iron oxide particles). Check and deposit form process­ing is the largest application of MICR.

Notes _____________

bar-coded reader — устройство считывания штрих-кода type font — печатный шрифт point-of-sale device — кассовый терминал

1. The scanning techniques of optical scanners use .

a) mechanical mechanisms; b) electronic processor c) a light source

2. Optical bar-code readers have been used by the .

a) radioengineering; b) banking industry; c) post-office

3. The largest application of is processing of various documentation in bank industry, a) OMR; b) OCR; c)MICR

PERSONAL COMPUTERS