Compression

Files are compressed to reduce the size of them. This is done to save the amount of space they take up on a hard drive and also allow them to be downloaded over the internet quickly and without using up large amounts of 'data'.


There are two types of compression: Lossy and Lossless.


  • Lossy is where certain bits of information is removed from the file to make it smaller. Mainly used for video, images and sound.
  • Lossless is where all the data is retained but it is compressed by recording 'patterns' of the data. Used to compress files that contain computer programs (they wouldn't run if anything was missing).


Lossless leaves quite large files even after the compression whereas files compressed with lossy can be made very small.








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