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Read and translate the text. "Cache" Memories



"Cache" Memories

"Cache" memories are increasingly common ("cache – a hiding place for provisions, treasures etc"). Cache memories are essentially hidden from the applications programmer; the cache belongs to the computer hardware and its controlling operating system. These work together using a cache to increase performance. Currently, a typical cache memory would be up to 256 KB in size. The cache may form a part of the circuitry of the CPU chip itself, or may be a separate chip. Either way, the system will be designed so that information in the cache can be accessed much more quickly than information in main storage.

The OS and CPU hardware arrange to copy blocks of bytes ("pages") from main memory into the cache. The selected pages could be those with the instructions currently being executed. Most programs involve loops where particular sets of instructions are executed repeatedly. If the instructions forming a loop are in the cache, the CPU's instruction-fetch operation is greatly speeded up. Sometimes it is worth copying pages with data from main memory to the cache – then subsequent data accesses are faster (though data that get changed do have to be copied back to main memory eventually). The operations shifting pages, or individual data elements, between cache and memory are entirely the concern of the CPU hardware and the operating system. The only way that a programmer should be able to detect a cache is by noticing increased system's performance.

All data manipulated by computers are represented by bit patterns. A byte, with 8 individual bits, can represent any of 256 different patterns.

Divide the text into the logical parts and give a title to each one.

Put questions to the text.

Discuss it with your groupmates.

Unit 4

Text Study: Input Devices.

Additional Text: "Seeking" for Tracks.

Grammar: Modals.

Text Study

I. Pre-reading Exercises

1. Repeat the words in chorus:

A keyboard, to coordinate, numerical, advanced, design representation, interface, to simplify, to require, double-click, to issue, application, quality.

2. While reading the text you will come across a number of international words. Try to guess what Ukrainian words they remind of you:

A manipulator, popular, indicators, graphics, representation, display, to control, the cursor, orientation, to press, commands, vertical, horizontal, manuscript, special, photos.

3. Pay attention to some grammatical points:

1) There are several devices used for inputting information into the computer. 2) It enables inputting numerical and text data. 3) Later when the more advanced graphics became to develop, user found that a keyboard did not provide the design capabilities of graphics and text representation on the display. 4) There appearedmanipulators, a mouse and a track ball. 5) The mouse provides the cursor control thus simplifying user's orientation on the display. 6) The mouse's primary functions are to help the user draw, point and select images on his computer display by moving the mouse across the screen. 6) When you move the mouse across a flat surface, the ball located on the bottom side of the mouse turns two rollers. 7) The quality of graphical plotting tables is characterizedby permitting capacity. 8) Digital video cameras have been spreadrecently.



II. Reading

Read the text and be ready to find in the text the answers to the following questions:

· What devices are there for inputting information?

  • Where do graphical plotting tables find their application?

Input Devices

There are several devices used for inputting information into the computer: a keyboard, some coordinate input devices, such as manipulators (a mouse, a track ball), touch panels and graphical plotting tables, scanners, digital cameras, TV tuners, sound cards etc.

When personal computers first became popular, the most common device used to transfer information from the user to the computer was the keyboard. It enables inputting numerical and text data. A standard keyboard has 104 keys and three more ones informing about the operating mode of light indicators in the upper right corner.

Later when the more advanced graphics became to develop, user found that a keyboard did not provide the design capabilities of graphics and text representation on the display. There appeared manipulators, a mouse and a track ball, that are usually used while operating with graphical interface. Each software program uses these buttons differently.

The mouse is an optic-mechanical input device. The mouse has three or two buttons which control the cursor movement across the screen. The mouse provides the cursor control thus simplifying user's orientation on the display . The mouse's primary functions are to help the user draw, point and select images on his computer display by moving the mouse across the screen.

In general software programs require to press one or more buttons, sometimes keeping them depressed or double-click them to issue changes in commands and to draw or to erase images. When you move the mouse across a flat surface, the ball located on the bottom side of the mouse turns two rollers. One is tracking the mouse's vertical movements; the other is tracking horizontal movements. The rotating ball glides easily, giving the user good control over the textual and graphical images.

In portable computers touch panels or touch pads are used instead of manipulators. Moving a finger along the surface of the touch pad is transformed into the cursor movement across the screen.

Graphical plotting tables (plotters) find application in drawing and inputting manuscript texts. You can draw, add notes and signs to electronic documents by means of a special pen. The quality of graphical plotting tables is characterized by permitting capacity, that is the number of lines per inch, and their capability to respond to the force of pen pressing .

Scanner is used for optical inputting of images (photographies, pictures, slides) and texts and converting them into the computer form.

Digital videocameras have been spread recently. They enable getting videoimages and photographs directly in digital computer format. Digital cameras give possibility to get high quality photos.

Sound cards produce sound conversion from analog to digital form. They are able to synthesize sounds. Special game-ports and joysticks are widely used in computer games.

Vocabulary Notes

a keyboard –клавіатура

a key – клавіша; кнопка; перемикач; ключовий, основний; головний; переключати; набирати на клавіатурі

a manipulator – маніпулятор; блок обробки

a trackball – трекбол

a touch[tAC] panel – сенсорна панель

graphic plotting tables – графічні планшети

a sound card – звукова карта (плата)

to enable – дозволяти; допускати; робити можливим

an operating mode – режим роботи

to press a button – натиснути на кнопку

to keep buttons depressed – утримувати кнопки натиснутими

double-click – подвійне натискання

to erase images –видалити, стерти зображення (об’єкт)

a roller – ролик

track – слідкувати; прослідковувати; проходити; слід; траєкторія; шлях; доріжка

by means of –за допомогою, за посередництвом

to simplify ['sImplIfaI] – спрощувати

Comprehension





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