2.6 Data representation

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2.6.1 Units
2.6.1a bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte, petabyte
2.6.1.b how data needs to be converted into a binary format to be processed by a computer
 2.6.1
2.6.2 Numbers
2.6.2a how to convert positive denary whole numbers (0–255) into 8 bit binary numbers and vice versa
2.6.2b how to add two 8 bit binary integers and explain overflow errors which may occur
2.6.2c binary shifts
2.6.2d how to convert positive denary whole numbers (0–255) into 2 digit hexadecimal numbers and vice versa
2.6.2e how to convert from binary to hexadecimal equivalents and vice versa
2.6.2f check digits
2.6.2a
2.6.2b
2.6.2c
2.6.2d
2.6.2f
2.6.3 Characters
2.6.3a the use of binary codes to represent characters
2.6.3b the term ‘character-set’
2.6.3c the relationship between the number of bits per character in a character set and the number of characters which can be represented (for example ASCII, extended ASCII and Unicode)
 2.6.3
2.6.4 Images
2.6.4a how an image is represented as a series of pixels represented in binary
2.6.4b metadata included in the file
2.6.4c the effect of colour depth and resolution on the size of an image file
2.6.4
2.6.5 Sound
2.6.5a how sound can be sampled and stored in digital form
2.6.5b how sampling intervals and other factors affect the size of a sound file and the quality of its playback
2.6.5c sample size
2.6.5d bit rate
2.6.5e sampling frequency
 2.6.5
2.6.6 Compression
2.6.6a need for compression
2.6.6b types of compression: lossy vs lossless
 2.6.6