The world of licenses: we understand with the MIT license

In previous articles, I tried to tell about the GPL and BSD licenses , their history, types and how they differ from each other. This time I will try to consider another, slightly less popular license - X11 (MIT) license.

X11 (MIT) license

The history of this license begins in 1984, when the idea of ​​creating a graphic subsystem, which was called the "X", appeared in the laboratory of computer science at the Massachusetts Institute of Technology. The name originated as the follower name of a similar system "W" used for the operating system "V". In the English alphabet, as is known, "X" follows "W". The first release of the X1 was the first truly hardware-independent graphics system.
')
The development went at a fast pace and in the beginning of 1985 the X6 came out. It seems that the license under which this version was released was not free, because the product was distributed to interested groups of developers for money. However, the X9 was already released in September 1985 under a free license, which later began to be called the MIT license (MIT license). Later, the version number in the product name grew to 11 and the system began to develop as X11 (released in September 1987). By this time, the institute had ceded the rights to the system of the specially created organization X Consortium, Inc. After that, all versions of the product began to be called "X11", and its releases began to be called differently, starting with X11R2 (released in January 1988) through X11R7.3 (released in September 2007). True, not all versions were released by the X Consortium, since this organization dissolved in 1996 and the banner of the project was first raised by The Open Group (1997), which eventually formed the X.Org Foundation in 2004. But this is another story that deserves a separate article.

What does the X11 license contain? It practically repeats the BSD 2-point license (FreeBSD license), only lists more detailed permissions instead of “Redistribution and use is allowed, both as source code and in binary form, with or without modifications.” MIT license says the following (my translation): “We hereby give permission, free of charge, to any person who receives a copy of this software and related documentation, to use the software without prohibition, without limiting the rights to use, copy, modify, combine, publish, distribute wounding, sublicensing, and / or selling copies of the software, and allowing individuals to whom this software is provided to do so . ” It is noticeable that the X11 license is more verbose, and besides it does not contain a listing of items, who knows, maybe this also served to the fact that the license gained considerable popularity. It must be said that the original version of the X11 license, among other things, also contained a ban on using the X Consortium without permission in promotional and other materials used to promote its software. In this, it looked like a license of 3 BSD points.

The “final” version of the license in the form in which it is now distributed, the license received in the form of the so-called Expat license . This option differs only in that it lacks a proposal for the X Consortium.

It is obvious that in such a large organization as MIT, there is more than one license. Below I would like to give the results of my research in the field of what other licenses exist from the Massachusetts Institute of Technology:

• license for non-commercial use of the JHU-MIT Proxy Re-cryptography Library;
• GSEA Software License;
• jRNE Freeware License;
• END-USER LICENSE AGREEMENT FOR MIT LFM SOFTWARE ;
• Paradoja license ;
• CONSORTIUM AGREEMENT ;
• In addition, there are licenses such as EXCLUSIVE PATENT LICENSE AGREEMENT and MIT PRESS INSTITUTIONAL LICENSE AGREEMENT.

As you can see, the licenses from MIT do not end with the simplest one, therefore, historically it is more correct to call the MIT license - the X11 license or Expat. But nowadays, a large cohort of software has already been formed, which is released under a license, which the software authors themselves called MIT. Today, many developers and organizations (including the Open Source Initiative ) do not distinguish between the X11, Expat and MIT licenses, calling all licenses one common term “MIT license”.

In general, the MIT license allows you to freely use someone else’s work. In case you will distribute your product, in which there will be other people's codes licensed under the MIT license, you are required to specify the copyright of the authors of the codes, the text of the license and the disclaimer. In essence, you should duplicate the text of the license you received in your product. The MIT license is not a copyleft license, that is, it does not require that the product that you will distribute be open, you can use any MIT-licensed codes in any of your open or closed projects.

It should also be noted that the MIT license is compatible with the GPL. That is, you can release a product under a GPL license, part of which will be a code with a MIT license.

XFree86 license v1.1

In the context of the MIT license, it’s worth telling a little about the XFree86 v1.1 license. The XFree86 product is a version of the X Window, which in its early stages was designed for UNIX-based systems running IBM PC-compatible computers. Initially, this product was distributed under the MIT-license and only in 2004 the license was changed . The changes were serious: there were 4 points, an emphasis on the requirements for the mandatory indication of copyrights in binary and source codes and the obligatory indication of a specific line in the software documentation. The last moment related to the documentation made this license incompatible with GPLv2, at that time the latest version of the GPL. Compatibility with the GPL brought only released in 2007 GPLv3. XFree86 license v1.1 is considered compatible with this version.

Sources

[1] X11
[2] XFree86
[3] en.wikipedia.org/wiki/XFree86

PS: if you find in the article inaccuracies or errors, then please report in the comments or to my personal mail