BSD licenses

BSD licenses are a family of permissive free software licenses. The original license was used for the Berkeley Software Distribution (BSD), a Unix-like operating system after which it is named.

The original owners of BSD were the Regents of the University of California because BSD was first written at the University of California, Berkeley. The first version of the license was revised, and the resulting licenses are more properly called modified BSD licenses.

Two variants of the license, the New BSD License/Modified BSD License,[1] and the Simplified BSD License/FreeBSD License[2] have been verified as GPL-compatible free software licenses by the Free Software Foundation, and have been vetted as open source licenses by the Open Source Initiative,[3] while the original, 4-clause license has not been accepted as an open source license and, although the original is considered to be a free software license by the FSF, the FSF does not consider it to be compatible with the GPL due to the advertising clause.[4]

Being a permissive free software license, the licenses places minimal restrictions on how the software can be redistributed. This is in contrast to copyleft licenses, which have reciprocity / share-alike requirements.

Contents

Terms

Besides the original license used in BSD, there are several derivative licenses that are commonly referred to as a "BSD license". Today, the typical BSD license is the 3-clause version, which is revised from the original 4-clause version.

Note that: In all BSD licences as following, <organization> is the organization of the <copyright holder> or just the <copyright holder>, and <year> is the year of the copyright. As published in BSD, <copyright holder> is "Regents of the University of California", and <organization> is "University of California, Berkeley".

Previous license

Prior BSD License
Author Regents of the University of California
Publisher Public Domain
Published 1988[5]
DFSG compatible Yes
Free software Yes
OSI approved No
GPL compatible No
Copyleft No
Copyfree No
Linking from code with a different license Yes

Some releases of BSD prior to the adoption of the 4-clause BSD license used a license that is clearly ancestral to the 4-clause BSD license. These releases include 4.3BSD-Tahoe (1988) and Net/1 (1989). Though largely replaced by the 4-clause license, this license can be found in 4.3BSD-Reno, Net/2, and 4.4BSD-Alpha.

Copyright (c) <year> <copyright holder>.
All rights reserved.

Redistribution and use in source and binary forms are permitted
provided that the above copyright notice and this paragraph are
duplicated in all such forms and that any documentation,
advertising materials, and other materials related to such
distribution and use acknowledge that the software was developed
by the <organization>.  The name of the
University may not be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

4-clause license (original "BSD License")

BSD License
Author Regents of the University of California
Publisher Public Domain
Published 1990[6]
DFSG compatible Yes[7]
Free software Yes[4]
OSI approved No[3]
GPL compatible No[4]
Copyleft No[4]
Copyfree No
Linking from code with a different license Yes

The original BSD license contained a clause not found in later licenses, known as the "advertising clause". This clause eventually became controversial, as it required authors of all works deriving from a BSD-licensed work to include an acknowledgment of the original source in all advertising material. This was clause number 3 in the original license text:[8]

Copyright (c) <year>, <copyright holder>
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
   This product includes software developed by the <organization>.
4. Neither the name of the <organization> nor the
   names of its contributors may be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

This clause was objected to on the grounds that as people changed the license to reflect their name or organization it led to escalating advertising requirements when programs were combined together in a software distribution—every occurrence of the license with a different name required a separate acknowledgment. In arguing against it, Richard Stallman has stated that he counted 75 such acknowledgments in a 1997 version of NetBSD.[9] In addition, the clause presented a legal problem for those wishing to publish BSD-licensed software which relies upon separate programs using the more-restrictive GNU GPL: the advertising clause is incompatible with the GPL, which does not allow the addition of restrictions beyond those it already imposes.

Today, this original license is now sometimes called "BSD-old" or "4-clause BSD".

3-clause license ("New BSD License" or "Modified BSD License")

New BSD License
Author Regents of the University of California
Publisher Public Domain
Published 01999-07-22July 22, 1999[8]
DFSG compatible Yes[7]
Free software Yes[1]
OSI approved Yes[3]
GPL compatible Yes[1]
Copyleft No[1]
Copyfree Yes
Linking from code with a different license Yes

The advertising clause was removed from the license text in the official BSD on 01999-07-22July 22, 1999 by William Hoskins, Director of the Office of Technology Licensing for UC Berkeley.[8] Other BSD distributions removed the clause, but many similar clauses remain in BSD-derived code from other sources, and unrelated code using a derived license.

While the original license is sometimes referred to as "BSD-old", the resulting 3-clause version is sometimes referred to by "BSD-new." Other names include "New BSD", "revised BSD", "BSD-3", or "3-clause BSD." This version has been vetted as an Open source license by the OSI as the "The BSD License".[3] The Free Software Foundation, which refers to the license as the "Modified BSD License", states that it is compatible with the GNU GPL. The FSF encourages users to be specific when referring to the license by name (i.e. not simply referring to it as "a BSD license" or "BSD-style") to avoid confusion with the original BSD license.[1]

This version allows unlimited redistribution for any purpose as long as its copyright notices and the license's disclaimers of warranty are maintained. The license also contains a clause restricting use of the names of contributors for endorsement of a derived work without specific permission.

Copyright (c) <year>, <copyright holder>
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the <organization> nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

2-clause license ("Simplified BSD License" or "FreeBSD License")

Simplified BSD License
Author The FreeBSD Project
Publisher Public Domain
Published ?
DFSG compatible Yes
Free software Yes[2]
OSI approved Yes[3]
GPL compatible Yes[2]
Copyleft No[2]
Copyfree Yes
Linking from code with a different license Yes

An even more simplified version has come into use, primarily known for its usage in FreeBSD.[10] The primary difference between it and the New BSD (3-clause) License is that it omits the non-endorsement clause. It also adds a further disclaimer about views and opinions expressed in the software. The Free Software Foundation, which refers to the license as the FreeBSD License, states that it is compatible with the GNU GPL. In addition, the FSF encourages users to be specific when referring to the license by name (i.e. not simply referring to it as "a BSD license" or "BSD-style"), as it does with the modified/new BSD license, to avoid confusion with the original BSD license.[2]

Copyright <year> <copyright holder>. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are
permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice, this list of
      conditions and the following disclaimer.

   2. Redistributions in binary form must reproduce the above copyright notice, this list
      of conditions and the following disclaimer in the documentation and/or other materials
      provided with the distribution.

THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

The views and conclusions contained in the software and documentation are those of the
authors and should not be interpreted as representing official policies, either expressed
or implied, of <copyright holder>.

Other projects, such as NetBSD, use a similar 2-clause license, but without the additional disclaimer.[11] This version has been vetted as an Open source license by the OSI as the "Simplified BSD License."[3]

Proprietary software licenses compatibility

The BSD License allows proprietary use, and for the software released under the license to be incorporated into proprietary products. Works based on the material may be released under a proprietary license or as closed source software.

It is possible for something to be distributed with the BSD License and some other license to apply as well.

See also

References

  1. ^ a b c d e "Various Licenses and Comments about Them - GNU Project - Free Software Foundation (FSF): Modified BSD license". Free Software Foundation. http://www.gnu.org/licenses/license-list.html#ModifiedBSD. Retrieved 02 October 2010. 
  2. ^ a b c d e "Various Licenses and Comments about Them - GNU Project - Free Software Foundation (FSF): FreeBSD license". Free Software Foundation. http://www.gnu.org/licenses/license-list.html#FreeBSD. Retrieved 02 October 2010. 
  3. ^ a b c d e f "Open Source Initiative OSI - The BSD License:Licensing". Open Source Initiative. http://www.opensource.org/licenses/bsd-license.php. Retrieved 06 December 2009. 
  4. ^ a b c d "Various Licenses and Comments about Them - GNU Project - Free Software Foundation (FSF): Original BSD license". Free Software Foundation. http://www.gnu.org/licenses/license-list.html#OriginalBSD. Retrieved 02 October 2010. 
  5. ^ The year given is the year 4.3BSD-Tahoe was released. Whether this is the first use of the license is not known.
  6. ^ The year given is the year 4.3BSD-Reno was released. Whether this is the first use of the license is not known.
  7. ^ a b "Debian -- License information". Debian. http://www.debian.org/legal/licenses/. Retrieved 18 February 2010. 
  8. ^ a b c "To All Licensees, Distributors of Any Version of BSD". University of California, Berkeley. 1999-07-22. ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change. Retrieved 2006-11-15. 
  9. ^ Richard Stallman. "The BSD License Problem". Free Software Foundation. http://www.gnu.org/philosophy/bsd.html. Retrieved 2006-11-15. 
  10. ^ "The FreeBSD Copyright". The FreeBSD Project. http://www.freebsd.org/copyright/freebsd-license.html. Retrieved 6 December 2009. 
  11. ^ "NetBSD Licensing and Redistribution". The NetBSD Foundation. http://www.netbsd.org/about/redistribution.html. Retrieved 06 December 2009. 

External links