GNU/Linux has taken the world of computers by storm. At one time, personal computer users were forced to choose among proprietary operating environments and applications. Users had no way of fixing or improving these programs, could not look "under the hood" and were often forced to accept restrictive licenses. GNU/Linux and other open source systems have changed that -- now PC users, administrators, and developers can choose a free operating environment complete with tools, applications, and full source code.
A great deal of the success of GNU/Linux is owed to its open source nature. Because the source code for programs is publicly available, everyone can take part in development, whether by fixing a small bug or by developing and distributing a complete major application. This opportunity has enticed thousands of capable developers worldwide to contribute new components and improvements to GNU/Linux, to the point that modern GNU/Linux systems rival the features of any proprietary system and distributions include thousands of programs and applications spanning many CD-ROMs or DVDs.