Sleepycat License is an OSI

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...

-approved open source license used by Oracle Corporation

Oracle Corporation

Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

 for the Berkeley DB

Berkeley DB

Berkeley DB is a computer software library that provides a high-performance embedded database for key/value data. Berkeley DB is a programmatic software library written in C with API bindings for C++, PHP, Java, Perl, Python, Ruby, Tcl, Smalltalk, and most other programming languages...

, Berkeley DB Java Edition and Berkeley DB XML embedded database products. The name of this license is derived from the name of the company which commercially sold the Berkeley DB products, Sleepycat Software

Sleepycat Software

Sleepycat Software, Inc. was the company primarily responsible for maintaining the Berkeley DB packages from 1996 to 2006.Berkeley DB is a widely used and freely-licensed database software originally developed at the University of California, Berkeley for 4.4BSD Unix, and developers from that...

, which was acquired by Oracle in 2006. Oracle continues to use the name "Sleepycat License" despite not using the term "Sleepycat" in any other documentation.

According to 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...

, it qualifies as a free software license, and is compatible with the 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 license is a strong form of 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...

 because it mandates that redistributions in any form not only include the source code of Berkeley DB

Berkeley DB

Berkeley DB is a computer software library that provides a high-performance embedded database for key/value data. Berkeley DB is a programmatic software library written in C with API bindings for C++, PHP, Java, Perl, Python, Ruby, Tcl, Smalltalk, and most other programming languages...

, but also "any accompanying software that uses the DB software". It is possible to circumvent this strict licensing policy through the purchase of a commercial software license from Oracle Corporation

Oracle Corporation

Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

 consisting of terms and conditions which are negotiated at the time of sale. This is an example of dual licensing

Dual license

Multi-licensing is the practice of distributing software under two or more different sets of terms and conditions. This may mean multiple different licenses or sets of licenses. Prefixes may be used to indicate the number of licenses used, e.g...

.

External links

• Oracle Berkeley DB Licensing Information
• Text of the Sleepycat License (old)