BSD Licensing

BSD licensing means free, permissive licenses for open-source software, with low restrictions regarding the use and distribution of the licensed software. The first BSD license was used for Berkeley Software Distribution (thus the name of BSD), a Unix-like operating system. All further revisions are called modified BSD licenses.

BSD licenses, widely used nowadays, resemble a lot the original BSD Unix license, first written in 1969. The BSD license simple requires retaining the BSD license notice for all code, if it’s redistributed in source code format, or reproducing the notice, if it’s redistributed in binary format. It doesn’t require the distribution of the source code at all.

There are 4 main clauses to the classic BSD license:

1. As specified in the BSD Unix license, the code can be copied, modified and redistributed as long as a copy of the original copyright notice is retained.
2. Any documentation or material accompanying the distribution must reproduce the copyright notice, as well as the disclaimer and the list of conditions, for redistributions in binary format.
3. Not claiming authorship for code that was not written by the user and not suing the author for undesired or unexpected functionality.
4. The name of the software, organization or authors in the copyright notice cannot be used to promote or advertise products derived from modifications of the redistributed code, without prior permission.

Subsequent BSD licenses may not include all these clauses. However, the first two clauses are generally used. The 2-clause license, otherwise known as the FreeBSD license, is one that only keeps the first two clauses, providing a more simplified version. The FreeBSD adds a disclaimer about views and opinions expressed in the software, and it is compatible with the GNU GPL, according to the Free Software Foundation.

MIT Licensing

The MIT license, having its origins at the Massachusetts Institute of Technology (MIT), is a permissive free software license. That means, it puts little restriction on its reuse.

Compatible with many copyleft licenses, it is possible to re-license MIT licensed software as GNU General Public License (GPL) software and integrate it with other GPL software. Also, MIT licensed software can be reused with proprietary software, under the condition to include a copy of the license terms and copyright notice with all the copies of the licensed software, or to re-license the software, removing this requirement.

MIT licensing is being used with some well-known projects, including X Window System, Node.js, Lua, jQuery and Ruby on Rails. Companies such as Google (Angular), Microsoft (.NET Core) and Facebook (React) use the MIT license.

The MIT license terms specify that the copies of the software can be used, copied, modified, published, distributed and/or sold free of charge by anyone with a copy of the software, provided that the copyright notice is included with all copies of the software. The software is redistributed without any warranty and its authors or copyright holders cannot be held liable for any claim or damages.

Similar to the BSD license, no express patent licenses are included in the MIT license.