| Data Compression | |||||||||||||||||
| When storing a file, a program can be run which compresses
the data so that the data takes up less storage
space.
This is useful when files are to be transmitted over a network or attached to an email as the transfer will take less time. A disadvantage is that the file will need to be decompressed before it can be used. A special program is needed for compression and for decompression although some compressed files will automatically decompress themselves.
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Some examples of Compression programs are WinZip, PKZip and WinRar Common file extensions of compressed
files are Compressed files are often referred to as Zipped files. |
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Example : Normally each
character is stored as an 8-bit binary number. One method of compressing
data is to assign the common characters a smaller number of bits and the
less commonly used characters a larger number of bits.
Graphics files take up a lot of space and usually include a number of repeated bytes.... eg The data
could be stored as
with no loss of information, ....but consists of 6 numbers instead of 10.
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| Exercise : Data Compression | |||||||||||||||||
| 'WinZip' is an example of a program which
data files.
A compressed file and . The file will need to be before it can be used.
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| (Green indicates success) | |||||||||||||||||