Most software you buy or get off the Internet is Compressed. Computers store information in bytes which are made up of on or off signals. The software applications that use these files need to have all the on and off signals (bytes) in place but when the file is stored they can be modified to take up less space on the storage disk or tape.
There are commercial and shareware programs that will compress and decompress files for you. Some popular form of data compression are zip, tar or stuffit but there are others available as well.
Programs are also available to compress and decompress your files as you or the application you are using requires them. This can be a way of making more space available on a hard drive. Windows comes with a program that will compress part of your hard disk. Be sure to read the documentation before embarking on a project like compressing a hard drive.
Last update: August 7, 2013