Gcse Data Representation

Front 1

Bit

Back 1

A single binary digit: 1 or 0

Front 2

Byte

Back 2

8 bits

Front 3

Nibble

Back 3

4 bits

Front 4

Kilobyte

Back 4

1024 bytes / 210 bytes

Front 5

Megabyte

Back 5

1024 kilobytes / 220 bytes

Front 6

Gigabyte

Back 6

1024 megabytes / 230 bytes

Front 7

Terabyte

Back 7

1024 gigabytes / 240 bytes

Front 8

Binary Base

Back 8

2 number system, used by computers, uses the digits 1 & 0 only.

Front 9

Denary Base

Back 9

10 number system, how we normally count, uses digits 0 to 9.

Front 10

Hexadecimal (hex)

Back 10

Base 16 number system used by humans to represent groups of four bits at a time. Uses digits 0 to F.

Front 11

Character set

Back 11

The set of symbols that can be represented by a computer. The symbols are called characters and can be letters, digits, space, punctuation marks and some control characters such as “escape”. Each character is represented by a numerical code that is stored as a binary integer.

Front 12

ASCII

Back 12

American Standard Code for Information Interchange: a 7-bit character set used by PCs. (There is also an extended ASCII character set that uses 8 bits.)

Front 13

Bitmap image

Back 13

An image that has been stored as a series of values per pixel. The colour of each individual pixel is stored in a file.

Front 14

Pixel

Back 14

Short for picture element. It is the smallest component of a bit-mapped image.

Front 15

Colour depth

Back 15

The number of bits used to represent the colour of a single pixel in a bitmapped image. Higher colour depth gives a broader range of distinct colours. For example, an image stored as a .gif file uses 8 bits per pixel so the image could use 256 different colours.

Front 16

Resolution

Back 16

The number of pixels in an image expressed as: the-number-of-pixels-across x the-number-of-pixels-down eg: 400 x 600.

Front 17

Metadata

Back 17

Data about data. In the case of image files metadata is the data the computer needs to interpret the image data in the file, for example: resolution, colour depth and image dimensions.

Front 18

Analogue

Back 18

A continuously changing wave such as natural sound.

Front 19

Digital

Back 19

Data that is made up of separate values. How data is stored on a computer.

Front 20

Sample rate

Back 20

The number of times per second that the sound wave is measured. The higher the rate the more accurately the sound wave is represented.

Front 21

Sample interval

Back 21

The time gap between measurements of the sound wave being taken.

Front 22

Sample resolution

Back 22

The number of bits used to store the value of each sample. The higher the number of bits the more accurately the value is stored.

Front 23

ADC

Back 23

Analogue to Digital converter: takes real-world analogue data and converts it to a binary representation that can be stored on a computer.

Front 24

Data

Back 24

Facts and figures with no context or format to give them meaning.

Front 25

Information

Back 25

Processed data that has context and format so that it conveys meaning.