Free-software license
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A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder (usually the author) of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software (or free and open-source software) as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.[2]
Comparison
[edit]| Public domain & equivalents | Permissive license | Copyleft (protective license) | Noncommercial license | Proprietary license | Trade secret | |
|---|---|---|---|---|---|---|
| Description | Grants all rights | Grants use rights, including right to relicense (allows proprietization, license compatibility) | Grants use rights, forbids proprietization | Grants rights for noncommercial use only. May be combined with copyleft. | Traditional use of copyright; no rights need to be granted | No information is made public |
| Software | Unlicense | MIT, Apache | GPL, AGPL, LGPL,[3] MPL[3] | JRL, AFPL | proprietary software, no public license | private, internal software |
| Other creative works | PD, CC0 | CC BY | CC BY-SA | CC BY-NC | All-reserved copyright, no public license | unpublished |
Free-software licenses provide risk mitigation against different legal threats or behaviors that are seen as potentially harmful by developers:
| AGPLv3 | GPLv3 | GPLv2 | LGPLv3 | LGPLv2.1 | MPLv2 | Apache-2.0 | BSD | |
|---|---|---|---|---|---|---|---|---|
| SaaS/cloud | Yes | No | No | No | No | No | No | No |
| Tivoization | Yes | Yes | No | Yes | No | No | No | No |
| Patent trolling | Yes | Yes | No | Yes | No | Yes | Yes | No |
| Proprietization | Yes | Yes | Yes | Partial | Partial | Partial | No | No |
| Granularity | Project | Project | Project | Library | Library | File | N/a | N/a |
| Trademark grant | ? | ? | ? | ? | ? | No | No | No |
History
[edit]Pre-1980s
[edit]In the early times of software, sharing of software and source code was common in certain communities, for instance academic institutions. Before the US Commission on New Technological Uses of Copyrighted Works (CONTU) decided in 1974 that "computer programs, to the extent that they embody an author's original creation, are proper subject matter of copyright",[4][5] software was not considered copyrightable. Therefore, software had no licenses attached and was shared as public-domain software. The CONTU decision plus court decisions such as Apple v. Franklin in 1983 for object code, clarified that the Copyright Act gave computer programs the copyright status of literary works and started the licensing of software.
Free-software licenses before the late 1980s were generally informal notices written by the developers themselves. These early licenses were of the "permissive" kind.
1980s
[edit]In the mid-1980s, the GNU project produced copyleft free-software licenses for each of its software packages. An early such license (the "GNU Emacs Copying Permission Notice") was used for GNU Emacs in 1985,[6] which was revised into the "GNU Emacs General Public License" in late 1985, and clarified in March 1987 and February 1988.[7][8][9] Likewise, the similar GCC General Public License was applied to the GNU Compiler Collection, which was initially published in 1987.[10][11] The original BSD license is also one of the first free-software licenses, dating to 1988. In 1989, version 1 of the GNU General Public License (GPL) was published. Version 2 of the GPL, released in 1991, went on to become the most widely used free-software license.[12][13][14]
1990s to 2000s
[edit]Starting in the mid-1990s and until the mid-2000s, the open-source movement pushed and focused the free-software idea forward in the wider public and business perception.[15] In the Dot-com bubble time, Netscape Communications' step to release its webbrowser under a FOSS license in 1998,[16][17] inspired many other companies to adapt to the FOSS ecosystem.[18] In this trend companies and new projects (Mozilla, Apache foundation, and Sun, see also this list) wrote their own FOSS licenses, or adapted existing licenses. This License proliferation was later recognized as problem for the Free and open-source ecosystem due to the increased complexity of license compatibility considerations.[19] While the creation of new licenses slowed down later, license proliferation and its impact are considered an ongoing serious challenge for the free and open-source ecosystem.
From the free-software licenses, the GNU GPL version 2 has been tested in to court, first in Germany in 2004 and later in the US. In the German case the judge did not explicitly discuss the validity of the GPL's clauses but accepted that the GPL had to be adhered to: "If the GPL were not agreed upon by the parties, defendant would notwithstanding lack the necessary rights to copy, distribute, and make the software 'netfilter/iptables' publicly available." Because the defendant did not comply with the GPL, it had to cease use of the software.[20] The US case (MySQL vs Progress) was settled before a verdict was arrived at, but at an initial hearing, Judge Saris "saw no reason" that the GPL would not be enforceable.[21]
Around 2004, lawyer Lawrence Rosen argued in the essay Why the public domain isn't a license that software could not truly be waived into public domain and can't be interpreted as very permissive FOSS license,[22] a position which faced opposition by Daniel J. Bernstein and others.[23] In 2012, Rosen accepted the CC0 as open source license and conceded that copyright can be waived away, backed by Ninth circuit decisions.[24]
In 2007, after years of draft discussion, the GPLv3 as major update of the GPLv2 was released. The release was controversial[25] due to the significant extended scope of the license, which made it incompatible with the GPLv2.[26] Several major FOSS projects (Linux kernel,[27][28] MySQL,[29] BusyBox,[30][31] Blender,[32] VLC media player[33]) decided against adopting the GPLv3. On the other hand, in 2009, two years after the release of the GPLv3, Google open-source programs office manager Chris DiBona reported that the number of open-source projects licensed software that had moved to GPLv3 from GPLv2 was 50%, counting the projects hosted at Google Code.[34]
2010s
[edit]In 2011, four years after the release of the GPLv3, 6.5% of all open-source licensed projects were GPLv3 while 42.5% were still GPLv2 according to Black Duck Software data.[28][35] Following in 2011 451 Group analyst Matthew Aslett argued in a blog post that copyleft licenses went into decline and permissive licenses increased, based on statistics from Black Duck Software.[36][37]
In 2015 according to Black Duck Software[38] and GitHub statistics,[39] the permissive MIT license dethroned the GPLv2 as most popular free-software license to the second place while the permissive Apache license follows already at third place. In June 2016 an analysis of Fedora Project's packages revealed as most used licenses the GPL, MIT, BSD, and the LGPL.[40]
Definitions
[edit]OSI-approved open-source licenses
[edit]The group Open Source Initiative (OSI) defines and maintains a list of approved open-source licenses. OSI agrees with FSF on all widely used free-software licenses, but differ from FSF's list, as it approves against the Open Source Definition rather than the Free Software Definition. It considers Free Software Permissive license group to be a reference implementation of a Free Software license.[citation needed][clarification needed] Thus its requirements for approving licenses are different.
FSF-approved free-software licenses
[edit]The Free Software Foundation, the group that maintains the Free Software Definition, maintains a non-exhaustive list of free-software licenses.[41]
The Free Software Foundation prefers copyleft (share-alike) free-software licensing rather than permissive free-software licensing for most purposes. Its list distinguishes between free-software licenses that are compatible or incompatible with the FSF's copyleft GNU General Public License.
Conditions in free-software licenses
[edit]There exists an ongoing debate within the free-software community regarding the fine line between what restrictions can be applied and still be called "free".[citation needed]
Only "