The MIT License

The lawyers at the Massachusetts Institute of Technology (MIT) created their own version of the BSD license. They cleaned up some of the vague language of the BSD license and made their version simpler to read and understand. A copy of the current version of the MIT license is shown in the Appendices.

The license grant of the MIT license reads as follows :

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions.... ( MIT license first paragraph.)

This improves on the BSD license by specifically mentioning all of the exclusive rights under copyright law and almost all of the exclusive rights under patent law (e.g., "make" is omitted, but that is probably unnecessary given the other verbs in that sentence ). No longer are we limited by the BSD's reference to redistribution and use . On the other hand, the new phrase deal in the software has no precise legal meaning. In light of the longer list of rights in the MIT license grant, it appears not to limit copyright or patent rights in any way.

Like the BSD license that preceded it, the scope of the patent grant in the MIT license is implicit rather than explicit. This means that a licensee cannot be sure that the implied patent rights granted by MIT are broad enough to cover derivative works.

The grant in the MIT license extends not just to the software itself but to its associated documentation files . It is not clear whether MIT is offering here to provide all documentation in its possession concerning the software or only certain files that are associated in some way with the software.

The phrase free of charge means that the licensor (MIT in this case) will not charge a royalty or license fee. But the word sell among the list of rights granted means that downstream licensees are not restricted in any way from charging their customers royalties or license fees for modified versions of the software.

The MIT license also serves as a license template. It is so short a license that only the copyright notice needs to be changed to fill in the template. Unfortunately, the phrase this software and associated documentation files doesn't clearly identify which software the license applies to. The only way to correlate particular software with a particular copy of the MIT license is to physically find the license text in the source code of the software.