Computer Licence Types -- Please read

[Dann Corbit]

Geschrieben von:/Posted by: Dann Corbit at 23 March 2004 20:00:52:

In an email I got from Tom Kerrigan, I found the actual cause of his complaint against Tuxedo, and he was quite right about it.
The copyright information from TSCP had actually been removed. And then, two different (and strangely incompatible licence types had been used to replace it).
Quite frankly, you can't do that. This is not a unique case. I have actually seen it happen on every continent except I don't remember seeing it happen in Australia. Anyway, time for a license type refresher.
There are many possible license types. Some have few or no restrictions. Some have many restrictions. Let's examine some of them.
1. PUBLIC DOMAIN.
A Public Domain license means that anyone can use it, for any purpose. They don't have to say where they found the code that they used. They don't have to give back their changes. They can add new stuff and copyright that stuff and keep it to themselves or whatever. Basically, public domain has no restriction at all. There are two ways that something can become public domain. One way is to age until the copyright expires. Basically, this will never happen in software because Copyrights last a very long time and software loses all of its value in a couple decades (Anybody want to run programs written in then 1970's)?
The other way a program can become public domain is to be explicitly donated to the public domain. This has to be a public act by the originator of the software. Not including a copyright notice does NOT have this effect. It must be explicitly granted by the originator of the software. I have made several public domain software products. For instance, I have donated a few things to Snippets, and also on my FTP site, you will find public domain donations like this one:
ftp://cap.connx.com/Public_CAP_Results/ ... IPLIST.HPP
I do not know of any chess software that is Public Domain.
2. Berkeley style licences (there are many others very similar such as the ACE license).
A Berkeley style license has almost no restrictions. The only thing you must do with that sort of license is to say that you have used it. Otherwise, the conditions for use are the same as public domain. The PostgreSQL database and BSD Unix are two products manufactured under this banner. I have donated to projects of this nature also (e.g. ACE). Once again, the only thing you must do to comply to this sort of license is to say that you have used it. I do not know of any chess software that is Berkeley style license.
3. GPL style licenses. A GPL license comes in two flavors -- Library style and code style. If the license is the LGPL flavor, then you can link against the library and not expose your own code. However, if you improve the code that is used to make the library, you must return that to the GPL. The code modified from the project itself is not owned by you. The GPL software is permanently open. You cannot make changes and keep those changes to yourself. It is illegal to do that with a GPL license. If you get that software and make changes, then you absolutely, positively must return them to the project. To not do this is a criminal act. There are many GPL style chess projects. Probably most of the open source chess programs have this license. I have contributed many items to this sort of license (most of the programs on my site are programs that are GPL licensed and which I have modified). Note that I am actually compelled to release all changes that I make. I cannot keep them for myself.
4. Copyright style licenses.
A copyright holder owns the code that he has written. In order for you to use that code you must obtain explicit, written permission. It takes a very long time for a copyright to expire. You must observe all the terms that the author sets out. If you are not willing to observe those terms, you are not allowed to use the software. Examples of Copyrighted software include Crafty and TSCP. This is probably the second most populuar software license for open source chess programs after GPL. Notice that you cannot deflect this license to another type. And you cannot claim copyright on someone else's work. Note (however) that you do not own the algorithm with a copyright. You only own your implementation of it. So (for instance) everyone can write their own Alpha-beta algorithm by reading a book about it. The inventor of Alpha-beta cannot complain unless he owns a:
5. Software Patent. (with my digressions)
A software patent means that you literally own the algorithm. An example of a patented software algorithm is the LZW compression algorithm used in many software tools including the GIF image format. The patent was owned by AT&T and they could literally have sued anyone they wanted to that used GIF images unless you paid a royalty. While I will obey any patent, I think that software patents are immoral. If (for instance) the inventor of Alpha-beta had obtained a patent on it, then all of our chess programs would totally suck unless we paid him a ransom. But if the actual inventor had not come up with the idea, it is fairly certain that someone else would have. Calculus was simultaneously invented by Newton and Leibnitz (and some say Pascal). The telescope was simultaneously invented by many persons in Europe. So as knowledge reaches a certain level, these things are likely to pop up. I cannot rail against software patents nearly so eloquently as Donald Knuth:
http://swpat.ffii.org/gasnu/knuth/index.en.html
I beg every reader here to consider his wise words.
At any rate, a Patent is the strongest and absolute protection for software ideas. Then come copyright. Then LGPL, then GPL, then Berkeley style and finally Public Domain.
The only one of those that you can have totally free reign with is Public Domain. Next comes Berkeley style where you MUST say that you have used the tools and who originally developed it. Then comes LGPL where you MUST return any improvement to the tool itself back to the original product (but not to things that just use the tool set). Then comes GPL where you must expose every piece of software that uses a GPL tool to the public (which is why it is sometimes called the "GPL VIRUS"). Then comes Copyright materials, where you must follow the wishes of the author and you cannot even use any of the materials without the written permission of the author. Finally, comes the software patent -- where even the underlying mathematical idea belongs to the originator and you cannot use it at all without paying a royalty or whatever condition the author imposes.
Please recognize that you cannot change these licenses at your whim. You must do exactly as they say or you are breaking the law.



my ftp site {remove http:// unless you like error messages}

[Roger Brown]

Geschrieben von:/Posted by: Roger Brown at 23 March 2004 20:15:53:
Als Antwort auf:/In reply to: Computer Licence Types -- Please read geschrieben von:/posted by: Dann Corbit at 23 March 2004 20:00:52:

Concise.
Informative.
Well-resarched.
Relevant.
Clearly presented.
Typical Corbit prose.
Thanks much for this information Dann. Hopefully it will make recent happenings less frequent.
Later.