BSD licenses
Encyclopedia
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, and
the Simplified BSD License/FreeBSD License 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
,
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.
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.
Note that: In all BSD licences as following,, and
is "Regents of the University of California", and is "University of California, Berkeley".
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
.
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".
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". 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.
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.
. 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.
Other projects, such as NetBSD
, use a similar 2-clause license, but without the additional disclaimer. This version has been vetted
as an Open source license by the OSI as the "Simplified BSD License."
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 early versions of BSD itself, which included proprietary material from AT&T
.
Berkeley Software Distribution
Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...
(BSD), a Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating system after which it is named.
The original owners of BSD were the Regents of the University of California
Regents of the University of California
The Regents of the University of California make up the governing board of the University of California. The Board has 26 full members:* The majority are appointed by the Governor of California for 12-year terms....
because BSD was first written at the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
. 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, and
the Simplified BSD License/FreeBSD License have been verified as GPL
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....
-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...
free software licenses by 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...
, and have been vetted
Vetting
Vetting is a process of examination and evaluation, generally referring to performing a background check on someone before offering him or her employment, conferring an award, etc...
as open source licenses by 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...
,
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.
Being a permissive free software license, the licenses places minimal restrictions on how the software can be redistributed. This is in contrast to 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...
licenses, which have reciprocity / share-alike requirements.
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,
Previous license
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.4-clause license (original "BSD License")
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: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
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...
.
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
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....
: the advertising clause is 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...
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")
The advertising clause was removed from the license text in the official BSD on by William Hoskins, Director of the Office of Technology Licensing for UC Berkeley. 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
Vetting
Vetting is a process of examination and evaluation, generally referring to performing a background check on someone before offering him or her employment, conferring an award, etc...
as an Open source license by the OSI as the "The BSD License". 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.
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.
2-clause license ("Simplified BSD License" or "FreeBSD License")
An even more simplified version has come into use, primarily known for its usage in FreeBSDFreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
. 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.
Other projects, such as NetBSD
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...
, use a similar 2-clause license, but without the additional disclaimer. This version has been vetted
Vetting
Vetting is a process of examination and evaluation, generally referring to performing a background check on someone before offering him or her employment, conferring an award, etc...
as an Open source license by the OSI as the "Simplified BSD License."
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. This was in fact the case with early versions of BSD itself, which included proprietary material from AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
.
See also
- Permissive and copyleft licensesFree software licenceA free software licence is a software licence which grants recipients rights to modify and redistribute the software, which would otherwise be prohibited by copyright law. A free software licence grants, to the recipients, freedoms in the form of permissions to modify or distribute copyrighted work...
- ISC license