BSD licenses

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"New" BSD License
Author	Regents of the University of California
Version	N/A
Copyright	Public Domain
Published	1990^[1]
DFSG compatible	Yes
Free software	Yes
OSI approved	Yes
GPL compatible	Yes
Copyleft	No
Linking from code with a different license	Yes

BSD licenses represent a family of permissive free software licences. The original was used for the Berkeley Software Distribution (BSD), a Unix-like operating system for which the license 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. Permissive licenses, sometimes with important differences pertaining to license compatibility, are referred to as "BSD-style licenses". Several BSD-like licenses, including the New BSD license, have been vetted by the Open Source Initiative as meeting their definition of open source.

The licenses have few restrictions compared to other free software licenses such as the GNU General Public License or even the default restrictions provided by copyright, putting it relatively closer to the public domain.

1 Terms
2 Proprietary software licenses compatibility
3 UC Berkeley advertising clause
4 BSD-style licenses
5 See also
6 References
7 External links

[edit] Terms

The text of the license is considered to be in the public domain and thus may be modified without restriction.

* 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 <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.

[edit] Proprietary software licenses compatibility

The BSD License allows proprietary commercial use, and for the software released under the license to be incorporated into proprietary commercial products. Works based on the material may even be released under a proprietary license (but still must maintain the license requirements). Some notable examples of this are the use of BSD networking code in Microsoft products,^[2] and the use of numerous FreeBSD components in Mac OS X.^[3]

It is possible for something to be distributed with the BSD License and some other license to apply as well. This was in fact the case with very early versions of BSD itself, which included proprietary material from AT&T.

[edit] UC Berkeley advertising clause

As originally distributed, the BSD license had an extra clause, requiring authors of all works deriving from a BSD-licensed work to include an acknowledgment of the original source. This is numbered as clause 3 in the original license text:

* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*    This product includes software developed by the University of
*    California, Berkeley and its contributors.

This clause has been objected to on the grounds that as people changed the license to reflect their name or organisation it led to escalating advertising requirements when programs were combined together in a software distribution—every occurrence of the license with a different name requires a separate acknowledgement— the Free Software Foundation has cited the requirement for 75 such acknowledgments when advertising a 1997 version of NetBSD.^[4] In addition, it presents a legal problem for those wishing to publish BSD-licensed software which relies upon separate programs using the more-restrictive GPL: the advertising clause is incompatible with the GPL, which does not allow the addition of restrictions beyond those it already imposes.

The advertising clause was removed from the official BSD license text on July 22, 1999 by William Hoskins, the director of the office of technology licensing for Berkeley.^[5] Other BSD distributions removed the clause, but many similar clauses remain in BSD-derived code from other sources.

The original license is now sometimes called "BSD-old" or "4-clause BSD", while the current revision of the BSD license is sometimes referred to by names including "BSD-new", "revised BSD", or "3-clause BSD".

[edit] BSD-style licenses

Main article: Permissive free software licences

Several free or open source licenses that derive from or are similar to the BSD license are widely used:

NetBSD switched to a 2-clause BSD-like license on 2008-04-30.
A 2-clause BSD-like license also exists which deletes the third clause, prohibiting use of the copyright holder's name for endorsement purposes. Removal of that clause makes the license functionally equivalent to the MIT License. This is the only BSD-style license permitted for certain libraries included in KDE.
FreeBSD also uses a 2-clause license with an additional statement at the end that the views of contributors are not the official views of the FreeBSD Project.
FreeBSD also provides the FreeBSD Documentation License, a license similar to the subsequent BSD Documentation License that contains terms specific to documentation.
The Massachusetts Institute of Technology (MIT)'s own MIT license is based on the BSD license, with most clauses removed and explicit permission for sublicensing and selling.
OpenBSD uses a license modeled after the ISC license, "equivalent to a two-term BSD copyright with language removed that is made unnecessary by the Berne convention."^[6]
The University of Illinois/NCSA Open Source License combines text from both the MIT and BSD licenses, and is equivalent to the 3-clause BSD license.
The Xiph.Org Foundation uses the 3-clause license for the binary libraries of their different projects without significant differences from the New BSD license.
Microsoft's Public License^[7] is "much like a BSD-style license, except that it prohibits re-licensing if the code is distributed in source code form."^[8]