Purpose

The purpose of compression is to:

• reduce the size of files
• reduce download times
• reduce storage requirements
• make best use of bandwidth (in relation to prior point)
  • given the fact that vast amounts of data are transmitted over the internet daily, efficient use of bandwidth can be critical

Methods

There are two methods of compression.

• lossy - results in a loss of some data when compressed
  • reduces quality and file size
  • suitable for images, video and audio
• lossless - results in no loss of data
  • reduces file size
  • suitable for executables and documents

Some files are not suitable for lossy compression, i.e., text files. They must instead be compressed using lossless.