|
The GNU General Public License (GNU GPL or GPL) is a widely used〔 free software license, which guarantees end users (individuals, organizations, companies) the freedoms to run, study, share (copy), and modify the software. Software that allows these rights is called free software and, if the software is copylefted, requires those rights to be retained. The GPL demands both. The license was originally written by Richard Stallman of the Free Software Foundation (FSF) for the GNU project. In other words, the GPL grants the recipients of a computer program the rights of the Free Software Definition〔GPL FAQ: (Does using the GPL for a program make it GNU Software? )〕 and uses copyleft to ensure the freedoms are preserved whenever the work is distributed, even when the work is changed or added to. The GPL is a copyleft license, which means that derived works can only be distributed under the same license terms. This is in distinction to permissive free software licenses, of which the BSD licenses and the MIT License are the standard examples. GPL was the first copyleft license for general use. Prominent free software programs licensed under the GPL include the Linux kernel and the GNU Compiler Collection (GCC). Some other free software programs (MySQL is a prominent example) are dual-licensed under multiple licenses, often with one of the licenses being the GPL. Historically, the GPL license family has been one of the most popular software licenses in the FOSS domain.〔〔〔〔〔〔〔 David A. Wheeler argues that the copyleft provided by the GPL was crucial to the success of Linux-based systems, giving the programmers who contributed to the kernel the assurance that their work would benefit the whole world and remain free, rather than being exploited by software companies that would not have to give anything back to the community.〔(【引用サイトリンク】title=Why the GPL rocketed Linux to success )〕 On 29 June 2007, the third version of the license (GNU GPLv3) was released to address some perceived problems with the second version (GNU GPLv2) that were discovered during its long-time usage. To keep the license up-to-date, the GPL license includes an optional "any later version" clause, allowing users to choose between the original terms or the terms in new versions as updated by the FSF. Developers can omit it when licensing their software; for instance the Linux kernel is licensed under GPLv2 without the "any later version" clause. == History == The GPL was written by Richard Stallman in 1989, for use with programs released as part of the GNU project. The original GPL was based on a unification of similar licenses used for early versions of GNU Emacs, the GNU Debugger and the GNU C Compiler.〔(【引用サイトリンク】 title=The History of the GPL )〕 These licenses contained similar provisions to the modern GPL, but were specific to each program, rendering them incompatible, despite being the same license. Stallman's goal was to produce one license that could be used for any project, thus making it possible for many projects to share code. The second version of the license, version 2, was released in 1991. Over the following 15 years, members of the free software community became concerned over problems in the GPLv2 license that could let someone exploit GPL-licensed software in ways contrary to the license's intent.〔(【引用サイトリンク】 title=Why Upgrade to GPL Version 3 --GPLv3 )〕 These problems included tivoization (the inclusion of GPL-licensed software in hardware that refuses to run modified versions of its software), compatibility issues similar to those of the Affero General Public License—and patent deals between Microsoft and distributors of free and open source software, which some viewed as an attempt to use patents as a weapon against the free software community. Version 3 was developed to attempt to address these concerns and was officially released on 29 June 2007.〔(【引用サイトリンク】 title=FSF releases the GNU General Public License, version 3 – Free Software Foundation – working together for free software )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「GNU General Public License」の詳細全文を読む スポンサード リンク
|