About the GNU GPL

The GNU General Public License (GNU GPL) is a free software license, 'GNU' is a recursive acronym for GNU's Not Unix, but the license can be used for any type of code for any platform. The latest version of the license, version 2, was released in 1991.

The GPL grants the recipients of GPL'd software a number of freedoms not normally associated with proprietry licenses;

The freedom to use the program, for any purpose (commercial or otherwise).
The freedom to reverse engineer the software and examine how it works, and to modify it.
The freedom to redistribute copies.
The freedom to modify or improve the program, and release the modified version to the public. (Note that access to the source code is a pre-condition for this).

In contrast proprietary software licenses rarely allow the end-user to do more than run a compiled version of a given peice of software. Access to source code is very rare, and the license could be worded to restrict activities such as reverse engineering, or allowing the public access to the services the software provides (think database servers or websevers).

However the GPL is not the most 'free' (as in redistribution) software license, others such as BSD-style licenses allow for derivative works to be redistributed as proprietary software. The GPL however, ensures that the license terms and freedoms are preserved in all future copies and derivative works. It does this using a legal mechanism known as copyleft, which requires all derivative works of GPL'd code also to be licensed under the GPL.

Richard M. Stallman is the author of the GNU GPL (and founder of the free software movement ).

GNU GPL Version 1 was in use from 1985 (depreciated)

GNU GPL Version 2 was released in 1991

GNU GPL Version 3 is currently being written by Richard Stallman and the FSF's general counsel Eben Moglen and is rumoured to address issues such as patent and copyright information and globalisation. It is widely expected to be released in early 2007.

For more information see www.gnu.org, additional information is available at www.fsf.org.

For comments or suggestions please use the contact us link and refer to the GPL article. For a copy of the GNU GPL (Version 2) click here and save the text file to disk.