GNU General Public License

The GPL license explained:

"The GPL governs the programming instructions called source code that developers write and then convert into the binary files that computers understand. At its heart, the GPL permits anyone to see, modify and redistribute that source code, as long as they make changes available publicly and license them under the GPL. That contrasts with some licenses used in open-source projects that permit source code to be made proprietary. Another requirement is that GPL software may be tightly integrated only with other software that also is governed by the GPL. That provision helps to create a growing pool of GPL software, but it's also spurred some to label the license "viral," raising the specter that the inadvertent or surreptitious inclusion of GPL code in a proprietary product would require the release of all source code under the GPL." (http://news.com.com/Sprucing+up+open+sources+GPL+foundation/2100-7344_3-5501561.html?tag=nefd.lede)

An article about the 'copyleft attitude' and the emergence of the free art license, at http://infos.samizdat.net/article301.html

Richard Stallman on the free software principles:

"My work on free software is motivated by an idealistic goal: spreading freedom and cooperation. I want to encourage free software to spread, replacing proprietary software that forbids cooperation, and thus make our society better. That's the basic reason why the GNU General Public License is written the way it is--as a copyleft. All code added to a GPL-covered program must be free software, even if it is put in a separate file. I make my code available for use in free software, and not for use in proprietary software, in order to encourage other people who write software to make it free as well. I figure that since proprietary software developers use copyright to stop us from sharing, we cooperators can use copyright to give other cooperators an advantage of their own: they can use our code.:" (http://www.gnu.org/philosophy/pragmatic.html )

French-language interview with Stallman: http://multitudes.samizdat.net/article.php3?id_article=214

Richard Stallman on why it is okay to charge for free software:

"The word ``free has two legitimate general meanings; it can refer either to freedom or to price. When we speak of ``free software, we're talking about freedom, not price. (Think of ``free speech, not ``free beer.) Specifically, it means that a user is free to run the program, change the program, and redistribute the program with or without changes. Free programs are sometimes distributed gratis, and sometimes for a substantial price. Often the same program is available in both ways from different places. The program is free regardless of the price, because users have freedom in using it." (http://www.gnu.org/philosophy/selling.html )

The Consensus of the Open Sources Initiative

Open Source projects are fundamentally similar to Free Software in that they both forbid any restriction on the free distribution of the software and on the availability of the source code. The following principles are accepted to define an Open Source project:

- no restriction on the free distribution is allowed (but payment is allowed)\ - the source must be freely available to all at no cost - changes must be accepted and distributed - the author can request a protected version number - no discrimination in usage is allowed, for every activity, including commercial usage - the rights attached to any program are for all the users all of the time - the license cannot be program specific (to avoid commercial restrictions) - the license cannot be applied to other code (such as proprietary additions) - the license must be technologically neutral (not restricted to certain devices or operating systems)

See also at http://www.opensource.org/ ; Background on the Open Source definition, by Bruce Perens, at http://www.perens.com/Articles/OSD.html