Compression decreases the size of data.

Compression decreases the size of data, normally done to preserve space, archive old files or to reduce network bandwidth required while transmitting file. Compression can be applied to files, folders, disks and even whole disk arrays. A myriad of compression programs exist, each with their own advantages and disadvantages such as: compression ratio, speed of compression, and program comparability. Questions relating to specific programs that perform compression can be found under tags such as and even and