Word building

Ex. 1. The table gives some prefixes commonly used in computer science. Knowing the meaning of these prefixes will help you understand new words.

Prefix	Meaning	Examples
deci- hexadeci- kilo- mega- giga- mini- micro- bi- tri- multi- mono-	Ten sixteen one thousand (1,000) (1,024 in binary: 210) large; one million very large; one thousand million small very small two three many one	decimal, decimalize, decibel hexadecimal kilocycle, kilogram(me), kilowatt megahertz, megalith, megaton gigantic, gigabyte, gigahertz minibus, minimum, minimize microfilm, microphone, microwave bidirectional, bidimensional, binary tripartite, tricycle, trilingual multi-racial, multi-user, multitasking monologue, monosyllable, monolingual

Ex. 2. Explain these expressions, taking into account the prefixes and root word.

Example the binary system

The binary system is a notation which uses two digits, 0 and 1.

1. a minicomputer

2. a microcomputer

3. the decimal system

4. the hexadecimal system

5. a multi-user configuration

6. a bidimensional chessboard

7. a tricycle

8. a monochrome computer

9. a CPU with 256 MB of RAM

10. a document of 3 kilobytes

T E X T B

Task

a) Did you know that...

1. bits can also be used to code pictures?

2. the information displayed on the computer screen corresponds, dot by dot, with bits held in the main memory?

3. on colour systems, if you have 8 bits per primary colour, the palette of your computer can obtain 16.7 million colours?

b) Read the text and study the diagram.

Bits for pictures

Each tiny dot on the screen of a computer is called a picture element or pixel. Images and text are formed by combining a large number of pixels.

In a bit-mapped display, the dots displayed on the screen correspond, pixel by pixel, with bits in the main memory of the computer. The bits are held in an area of the memory called the 'refresh buffer' and are stored in groups that represent the horizontal and vertical position of the pixels on the screen and whether the pixels are on or off.

On monochrome systems, one bit in this 'map' represents one pixel on the screen and can be either 'on' or 'off (black or white).

On colour systems, each pixel is a certain combination of the three primary colours: red, green and blue. The total number of colours which can be shown on the screen is called the colour palette. The size of this palette depends on the graphics adaptor, a separate video card that converts the bits into visual signals. A graphics adaptor with 1 bit per primary colour can generate up to 8, or 2³, colours, as you can see from the table on page 19. A graphics adaptor with 8 bits per primary colour can generate 16.7 million or (2³)⁸ colours.

Colour	Red	Green	Blue
Black	0	0	0
Blue	0	0	1
Green	0	1	0
Cyan	0	1	1
Red	1	0	0
Magenta	1	0	1
Yellow	1	1	0
White	1	1	1

( One bit per primary colour)

Ex. 1. Using the information in the passage and the illustrations, match the terms in the box with the appropriate explanation or definition.

a) pixel; b) bit; с) bit-mapped display; d) primary colours; e) palette.

1. The menu of colours available on a graphics system; its size depends on the hardware.

2. Red, green and blue (RGB) in computers.

3. The smallest element of a display surface.

4. A display on the screen which corresponds, pixel by pixel, with bits stored in memory cells.

5. The acronym for 'binary digit'; one of the digits (0 and 1) used in binary notation.

Ex. 2. a) Translate the last paragraph (starting from 'On colour systems, ...') into your language.

b) Do you understand the calculations made to obtain a palette of 16.7 million colours? (If you don't, ask a partner to explain them to you.)

Ex. 3. Translate these sentences into Russian.

1. Computer images can be black and white (monochrome), grayscale (полутоновый), or full-coloured pictures, depending on your equipment and software used.

2. The resolution and the number of colours in the file greatly affect file size; the quality and size of the image therefore depend on the computer's memory and disk space.

3. Data-generated graphics are bit-mapped images produced by a program using numeric information.

4. The data usually comes from spreadsheets but can also come from databases, text files, and direct input. The graphs and charts produced by data-generated software include maps, flowcharts (блок-схемы), and weather-forecasting graphics.

Ex. 4. Translate these sentences into English.

1. Все числа внутри компьютера представляются с помощью нулей и единиц.

2. Иными словами, компьютеры обычно работают в двоичной системе.

3. Единицей информации в компьютере является один бит, т.е. двоичный разряд, который может принимать значение 0 и 1.

4. Восемь последовательных битов составляют байт.

5. В одном байте можно закодировать значение одного символа из 256 возможных.

6. Более крупными единицами информации являются килобайт, мегабайт, гигабайт.

7. Для примера скажем, что если на странице текста помещается 2500 знаков, то 1 Мбайт- это примерно 400 страниц, а 1 Гбайт -400 000 страниц.

8. В компьютерной литературе, при описании обрабатываемых компьютером данных часто используют шестнадцатеричную систему счисления.

9. Она удобна тем, что очень просто соотносится с двоичной системой.

10. Одна шестнадцатеричная цифра соответствует четырём двоичным разрядам.