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| ] which are examples of copyleft licenses include the ], the ], the ], and the ]. Copyleft licenses for materials other than software include the ], and the ]. The latter is being used for the contents of this ]. | ] which are examples of copyleft licenses include the ], the ], the ], and the ]. Copyleft licenses for materials other than software include the ], and the ]. The latter is being used for the contents of this ]. | ||
| The copyleft concept has been suggested as a solution to other problems. For instance, some who opposed ] suggest that if some entity (], its ], or "]") or a foundation representing same, were recognizing as holding a copyright in the genome of each naturally-evolved species, then all minor genetic modifications of same would be 'derivative works'. The foundation representing the rights of the natural entity, perhaps as small as a single ] where the species evolved, would offer copyleft-style licenses only to those 'improvers' who paid royalties to preserve the natural ecology where the original species was from. Also, the foundation might be able to restrict certain modifications. | |||
| For this to work, copyright rather than ] would have to be held to apply to genomes - presently considered ]. There are also efforts to build ] portfolios, clearly inspired by the copyleft principle, which might also be a way to accomplish these purposes. | |||
| See also: ], ] | |||
Revision as of 22:30, 23 January 2003
Copyleft refers to a concept invented by Richard Stallman of the Free Software Foundation in 1984: the application of copyright laws to ensure uncompromised public freedom to manipulate, improve, and redistribute specific information and all its derivative works. Initially only designed for software distribution, the concept is now also being used for other types of material.
In copyleft, the copyright holder grants an irrevocable license to the recipient of a copy, permitting the redistribution (including sale) of possibly modified further copies, under the condition that all those copies carry the same license and are made available in a form which facilitates modification.
Some other free software licenses as well as so-called open source licenses, such as those used by BSD and the X Window System, are not copyleft licenses because they do not extend to derivative works and include no requirement to make source code available. It is a matter of debate whether these licenses provide a larger or smaller degree of freedom than copyleft licenses. While the former licenses attempt to maximize the freedom of the initial recipient, the latter licenses try to maximize the freedom of all potential recipients in the future.
Copyleft licenses are sometimes referred to as viral copyright licenses, because any works derived from a copylefted work must themselves be copylefted. This term is considered derogatory, as it compares copylefted works to harmful computer viruses. However, the analogy between copyleft and computer viruses is not close; as advocates of copyleft point out, computer viruses infects computers without the awareness of the user, whereas the copyleft actually grants the user certain permissions to distribute modified programs, which is otherwise not allowed under copyright law, and under most proprietary licenses.
The concept of copyleft arose when Stallman was working on a LISP interpreter. Symbolics asked to use the LISP interpreter, and Stallman agreed to supply them with a public domain version of his work. Symbolics extended and improved the LISP interpreter, but when Stallman wanted access to the improvements that Symbolics had made to his interpreter, Symbolics refused. Stallman then proceeded to create a software license that would prevent this behavior.
The term "Copyleft" comes from the phrase "Copyleft--all rights reversed", which Don Hopkins wrote in a message to Stallman in 1984 and which is intended as a double pun on the phrase "Copyright--all rights reserved".
Free software licenses which are examples of copyleft licenses include the GNU General Public License, the GNU Lesser General Public License, the Mozilla Public License, and the Q Public License. Copyleft licenses for materials other than software include the Open Content License, and the GNU Free Documentation License. The latter is being used for the contents of this encyclopedia.
The copyleft concept has been suggested as a solution to other problems. For instance, some who opposed genetically modified food suggest that if some entity (Earth, its biosphere, or "Mother Nature") or a foundation representing same, were recognizing as holding a copyright in the genome of each naturally-evolved species, then all minor genetic modifications of same would be 'derivative works'. The foundation representing the rights of the natural entity, perhaps as small as a single ecoregion where the species evolved, would offer copyleft-style licenses only to those 'improvers' who paid royalties to preserve the natural ecology where the original species was from. Also, the foundation might be able to restrict certain modifications.
For this to work, copyright rather than patent law would have to be held to apply to genomes - presently considered public domain. There are also efforts to build open patent portfolios, clearly inspired by the copyleft principle, which might also be a way to accomplish these purposes.
See also: counter-copyright, open patent