The license-specific tag for the BSD family of permissive open-source licenses. Use on questions about them; their origins, use, and design.
The original license used on BSD Unix had four clauses, and has been officially rescinded by UC Berkeley. The advertising clause (the third of four clauses) required you to acknowledge use of the copyright owner's code in your advertising of any product using that code.
The BSD "New" 3-clause license omits that third clause.
An even newer BSD license omits the third clause of the New" license and is the "2-clause" license.
The OpenBSD license exists as the 3-clause BSD license and as a 1-clause BSD license with a shortened disclaimer, that is also known as the ISC license.
- Original 4-clause BSD license (rescinded)
- BSD 3-Clause "New" or "Revised" license
- BSD 2-Clause "Simplified" license
- FreeBSD license
- OpenBSD license (also called the ISC license)
The Original BSD license is incompatible with GPL, but the two- and three-clause licenses have been declared to be compatible with GPL.
Gnu.org declares that the FreeBSD license is the same as the BSD 2-Clause licence, but the text of the FreeBSD license actually contains an additional disclaimer about "views and conclusions".