In computing

Computing

Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...

, software that is copyright

Copyright

Copyright is a legal concept, enacted by most governments, giving the creator of an original work exclusive rights to it, usually for a limited time...

ed and licensed under a software license is done under a variety of licensing schemes. For end-users there are various licenses ranging from very restrictive proprietary

Proprietary software

Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...

 licenses to open-source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 licenses.

There are also different licensing schemes for access to and use of source code

Source code

In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...

. To address special intellectual property issues regarding source code, open-source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 licenses, and special licenses, such as copyleft

Copyleft

Copyleft is a play on the word copyright to describe the practice of using copyright law to offer the right to distribute copies and modified versions of a work and requiring that the same rights be preserved in modified versions of the work...

, have been created.

Not all software is licensed, or even copyrighted, and this article is thus not an exhaustive list of the terms under which software is available in the market. Software may be published without an accompanying license, as License-Free Software, in which case it remains copyrighted, its distribution is subject to ordinary copyright law, and its sale is subject to ordinary sales law. In some countries, software may also be released to the public domain

Public domain

Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...

, in which case it is not copyrighted and the notion of a copyright license

License

The verb license or grant licence means to give permission. The noun license or licence refers to that permission as well as to the document recording that permission.A license may be granted by a party to another party as an element of an agreement...

 simply does not apply at all (although the other parts of a software licence, including warranty provisions, will still apply to the sale of such software).

Open-source/free software licenses

The terms "Open-source

Alternative terms for free software

Alternative terms for free software have been a controversial issue among free software users from the late 1990s onwards. Coined in 1983 by Richard Stallman, "free software" is used to describe software which can be used, modified, and redistributed with little or no restriction...

 licenses" and "free software licenses" are usually interchangeable. While there is no one universally agreed-upon definition of free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

, various groups that maintain approved lists of licenses. The Open Source Initiative

Open Source Initiative

The Open Source Initiative is an organization dedicated to promoting open source software.The organization was founded in February 1998, by Bruce Perens and Eric S. Raymond, prompted by Netscape Communications Corporation publishing the source code for its flagship Netscape Communicator product...

 is one such organization keeping a list of "open source" licenses. The Free Software Foundation

Free Software Foundation

The Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...

 maintains a list of what it considers free.

GPL 2-compatible

The GNU General Public License

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

 is a popular license, with offerings including Linux

Linux kernel

The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....

, such that it is useful to know if the license chosen is compatible

License compatibility

License compatibility refers to the problem with licenses applied to works subject to copyright, particularly licenses of software packages, which can contain contradictory requirements, rendering it impossible to combine source code from such packages or content from such works in order to create...

 with it. Knowing compatibility is important if a developer wants to avail him- or herself of the wide GPL software 'commons'.

• Artistic License
  Artistic License
  The Artistic License refers most commonly to the original Artistic License , a software license used for certain free and open source software packages, most notably the standard Perl implementation and most CPAN modules, which are dual-licensed under the Artistic License and the GNU General Public...
  
   2.0
• Berkeley Database License (aka the Sleepycat License
  Sleepycat License
  Sleepycat License is an OSI-approved open source license used by Oracle Corporation for the Berkeley DB, Berkeley DB Java Edition and Berkeley DB XML embedded database products...
  
   or Sleepycat Software Product License)
• Boost Software License
• BSD license (modified version)
• BDL / BSD Documentation License
• CeCILL
  CeCILL
  CeCILL is a free software license adapted to both international and French legal matters, in the spirit of and retaining compatibility with the GNU General Public License....
  
   (CEA CNRS INRIA Logiciel Libre)
• Cryptix General License
  Cryptix General License
  The Cryptix General License is in use by the Cryptix project, well known for their Java Cryptography Extension. It is a modified version of the BSD license, with similarly liberal terms. The Free Software Foundation states that it is a permissive free software license compatible with the GNU...
  
  
• EUPL - European Union Public License
  European Union Public Licence
  The European Union Public Licence is a software licence that has been created and approved by the European Commission. It is a free software licence.Its first version 1.0 was approved on 9 January 2007....
  
  
• GPL / GNU General Public License
  GNU General Public License
  The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....
  
  
• Intel Open Source License
  Intel Open Source License
  The Intel Open Source license is identical to the BSD license with the following section addedThe extra section does not add to the terms of the license, rather it reminds users of U.S. export laws...
  
  
• ISC license

• LGPL / GNU Lesser General Public License
  GNU Lesser General Public License
  The GNU Lesser General Public License or LGPL is a free software license published by the Free Software Foundation . It was designed as a compromise between the strong-copyleft GNU General Public License or GPL and permissive licenses such as the BSD licenses and the MIT License...
  
  
• License of Python
• MIT license
  MIT License
  The MIT License is a free software license originating at the Massachusetts Institute of Technology . It is a permissive license, meaning that it permits reuse within proprietary software provided all copies of the licensed software include a copy of the MIT License terms...
  
  
• Public Domain
  Public domain
  Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...
  
  
• W3C Software Notice and License
  W3C Software Notice and License
  The W3C Software Notice and License is a permissive free software licence used by software released by the World Wide Web Consortium, like Amaya. The license is a permissive license, compatible with the GNU General Public License.-Software using the License:...
  
  
• WTFPL
  WTFPL
  The WTFPL is an infrequently used, extremely permissive free software license. The original Version 1.0 license, released March 2000, was written by Banlu Kemiyatorn who used it for Window Maker artwork. Samuel “Sam” Hocevar, a French programmer who was the Debian project leader from 17 April...
  
  
• X11 license
• zlib/libpng license
• Zope Public License
  Zope Public License
  Zope Public License is a free software license, used primarily for the Zope application server software. The license is similar to the well-known BSD license, however the ZPL also adds clauses prohibiting trademark use and requiring documentation of all changes.-External links:* v2.0 at the Open...
  
  

GPL 2-incompatible

The GPL has certain special requirements that make code under licenses incompatible

License compatibility

License compatibility refers to the problem with licenses applied to works subject to copyright, particularly licenses of software packages, which can contain contradictory requirements, rendering it impossible to combine source code from such packages or content from such works in order to create...

 (that is, cannot be licensed) under the GPL.

• Academic Free License (AFL)
  Academic Free License
  The Academic Free License is a permissive free software license written in 2002 by Lawrence E. Rosen, the general counsel of the Open Source Initiative ....
  
  
• Affero General Public License
  Affero General Public License
  The Affero General Public License, often abbreviated as Affero GPL and AGPL , refers to two distinct, though historically related, free software licenses:...
  
   (version 1)
• Apache License
  Apache License
  The Apache License is a copyfree free software license authored by the Apache Software Foundation . The Apache License requires preservation of the copyright notice and disclaimer....
  
  
• Apple Public Source License (APSL)
  Apple Public Source License
  The Apple Public Source License is the open source and free software license under which Apple's Darwin operating system was released. A free software and open source license was voluntarily adopted to further involve the community from which much of Darwin originated.The first version of the Apple...
  
  
• BSD license (original version)
• Common Public License
  Common Public License
  In computing, the CPL is a free software / open-source software license published by IBM. The Free Software Foundation and Open Source Initiative have approved the license terms of the CPL....
  
  
• Common Development and Distribution License (CDDL)
  Common Development and Distribution License
  Common Development and Distribution License is a free software license, produced by Sun Microsystems, based on the Mozilla Public License , version 1.1....
  
  
• Eclipse Public License (EPL)
  Eclipse Public License
  The Eclipse Public License is an open source software license used by the Eclipse Foundation for its software. It replaces the Common Public License and removes certain terms relating to litigations related to patents....
  
  
• IBM Public License
  IBM Public License
  The IBM Public License is a free software / open-source software license written and sometimes used by IBM.It is approved by the Open Source Initiative and is described as a "free software license" by the Free Software Foundation ....
  
  
• LaTeX Project Public License (LPPL)
  LaTeX Project Public License
  The LaTeX Project Public License is a software license originally written for the LaTeX system. Software distributed under the terms of the LPPL can be regarded as free software, however it is not copylefted....
  
  

• Microsoft Public License
• Microsoft Reciprocal License
• Mozilla Public License (MPL)
  Mozilla Public License
  The Mozilla Public License is a free and open source software license. Version 1.0 was developed by Mitchell Baker when she worked as a lawyer at Netscape Communications Corporation and version 1.1 at the Mozilla Foundation...
  
  
• Netscape Public License (NPL)
  Netscape Public License
  The Netscape Public License is a free software license, the license under which Netscape Communications Corporation originally released Mozilla....
  
  
• Open Software License
  Open Software License
  The Open Software License is a software license created by Lawrence Rosen. The Open Source Initiative has certified it as an open source license, but the Debian project judged version 1.1 to be incompatible with the DFSG...
  
  
• OpenSSL license
• PHP License
  PHP License
  The PHP License is the software license under which the PHP scripting language is released. The PHP License is a non-copyleft free software license according to the Free Software Foundation and an open source license according to the Open Source Initiative...
  
  
• Q Public License (QPL)
  Q Public License
  The Q Public License is a non-copyleft license, created by Trolltech for its free edition of the Qt. It was used until Qt 3.0, as Trolltech toolkit version 4.0 was released under GPL version 2...
  
  
• Sun Industry Standards Source License (SISSL)
  Sun Industry Standards Source License
  The Sun Industry Standards Source License is now a retired free and open source license, recognized as such by the Free Software Foundation and the Open Source Initiative . Under SISSL, developers could modify and distribute source code and derived binaries freely. Furthermore, developers could...
  
  
• Sun Public License
  Sun Public License
  The Sun Public License is a software license that applies to some open-source software released by Sun Microsystems . It has been approved by the Free Software Foundation as a free software license, and by the Open Source Initiative as an open source license...
  
  
• XFree86 1.1 License

Non-free software license

• Microsoft Reference License

License given to the users of software marketed by software companies for a price and for a specified period(in some cases).

Commercial Royalty-Free

A form of licensing where typically a development version of the product is for a fee but the deployment of applications built or assembled with or using the product do not incur an additional fee.

Free Licensed Closed-Source

• Free Solaris Binary License
• Free For non commercial Use
  • Can be used for free by a party if the goal does not involve commercial gain. If it is used for commercial gain, payment is required. If it is used for charity/personal objectives, payment is not required.