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Data Compression
Data compression is a way of coding data that uses fewer bytes than the original.

File sizes are reduced, leading to...

  • smaller storage capacity when saved on backing store Eg. hard disc
  • faster transmission down a network. Eg. downloading on the Internet.
Disadvantages:
  • compressed data needs to be de-compressed before it can be used.
  • there may be some loss of data. Eg. Loss of quality on an image, sound file or video.
Some data compression algorithms involve no loss of data, but sometimes loss of quality is acceptable (Eg for images, sound or videos).

 

Data compression programs will try to compress any file into a smaller size. (Eg. WinZip, WinRar)

 

Files may be saved in different file formats that compress the data. For example, images may be saved as a .bmp file (uncompressed) or as a .gif or .jpeg file (compressed formats).