Data Representation

Flashcards by , created over 6 years ago

GCSE Computing (Data representation in computers) Flashcards on Data Representation, created by Kjaer on 06/13/2013.

Created by Kjaer over 6 years ago
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Question Answer
Bit A single binary digit: 1 or 0
Byte 8 bits
Nibble 4 bits
Kilobyte 1024 bytes / 2
Megabyte 1024 kilobyte / 22⃣0⃣ bytes
Gigabyte 1024 megabytes / 23⃣0⃣ bytes
Terabyte 1024 gigabytes / 2 4⃣0⃣ bytes
Binary Base 2 number system, used by computers, uses the digits 1 & 0 only
Deanery Base 10 number system, how we normally count, uses digits 0 to 9
Hexadecimal ( hex) Base 16 number systemised by humans to represent groups of four bits at a time. Uses digits 0 to F
Overflow When the result of a numeric calculation is too large to be stored in the space reserved for that type of data.
Character set The set of symbols that can be represented by a computer. The symbols are called characters and can be letters, digits l, 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.
ASCII American standard code for information interchange: a 7- bit character set used by PC's.(there is also an extended ASII character set that uses 8 bits.)
EBCDIC (or. Eb-Sid- ic) Extended binary coded decimal interchange code: an 8 bit character set used by old mainframes.
Unicode A 16- bit character set that allows many more characters to be coded.
Bitmap image An image that had been stored as a series of values per pixel. The colour of each individual pixel is stored in a file.
Pixel Short for picture element. It is the smallest component of a bit- mapped image.
Colour depth The number of bits used to represent the colour of a single pixel in a bit mapped image. Higher colour depth gives a broader range of distinct colours. For example, an image stored as a .gif file used 8 bits per pixel so the image could use 256 different colours.
Resolution The number of pixels in a image expressed as: the-number-of-pixels-down eg: 400 * 600.
Metadata 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.
Analogue A continuously changing wave such as natural sound.
Digital Data that is made up of separate values. How data is stored on a computer.
Sample rate The number of times per second that the sound wave is measured. The higher the rate the more accurately the sound wave is represented.
Sample interval The time gap between measurements of the sound wave being taken. Another way of expressing the sampling rate.
Sample resolution 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.
ADC Analogue to digital converter: takes real- world analogue data and converts it to a binary representation that can be stored on a computer.
Data Facts and figures with no context or formation to give them meaning.
Information Processed data that has context and format so that it conveys meaning.
Instruction set The group of instructions available for that specific processor to use. The number of instructions available will depend on the number of bits used. For example, with 4 bits there could potentially be 15 different instructions.
Op code The group of bits in an instruction that represents the operation such as EAT, MOVE or TURN.
Compiler A piece of system software that converts a program written in a high level programming language into machine code (binary).
Machine code A binary representation of a program.
High level programming language A programming language written in constructs using language we can can understand. Language include Delphi, Visual Basic, Java and C++.