Stockfish: Our lawsuit against ChessBase

[dkappe]

Now if what you say is true and there is nothing of legal value in SF’s public statements, then is this just a PR stunt designed to besmirch ChessBase’s reputation? I hope that’s not the case.

I presume the court has received a different document than we did.

I checked with my family friend in Germany on Tuesday. Nothing has been filed against ChessBase in a civil court, so we’ll have to wait and see.

[JohnWoe]

Since Linux was brought up somewhere. Linux foundation exists only to pay salary to Linus and Greg so they can work full time on Linux. Before that Linus did Linux for 20 years as "hobby".

[AlexChess]

I like Fischerov very much since 0.92 release. Often it performs better than Stockfish. But it seems that now authors cannot share Fisherov 98d anymore, due to the Stockfish Team request. I hope that they will show that is only inspired by SF.

https://chessengines.blogspot.com/2021/ ... rsion.html

I kindly ask to the authors to release the source code as required by GPLv3, and I ask to do the the same to Raubfisch, AI-15, KillFish, Eman, Zeus, Spider, As-130.2 authors. Please, we need that you share your knowledge to improve Stockfish competitors and SF itself.

I'll continue to privately test all them, never sharing the binaries, only for statistical purposes.

Libraries
According to the FSF, "The GPL does not require you to release your modified version or any part of it. You are free to make modifications and use them privately, without ever releasing them."[62] However, if one releases a GPL-licensed entity to the public, there is an issue regarding linking: namely, whether a proprietary program that uses a GPL library is in violation of the GPL.

This key dispute is whether non-GPL software can legally statically link or dynamically link to GPL libraries. Different opinions exist on this issue. The GPL is clear in requiring that all derivative works of code under the GPL must themselves be under the GPL. Ambiguity arises with regards to using GPL libraries, and bundling GPL software into a larger package (perhaps mixed into a binary via static linking). This is ultimately a question not of the GPL per se, but of how copyright law defines derivative works. The following points of view exist:

Point of view: dynamic and static linking violate GPL
The Free Software Foundation (which holds the copyright of several notable GPL-licensed software products and of the license text itself) asserts that an executable that uses a dynamically linked library is indeed a derivative work. This does not, however, apply to separate programs communicating with one another.[63]

The Free Software Foundation also created the LGPL, which is nearly identical to the GPL, but with additional permissions to allow linking for the purposes of "using the library".

Richard Stallman and the FSF specifically encourage library writers to license under the GPL so that proprietary programs cannot use the libraries, in an effort to protect the free-software world by giving it more tools than the proprietary world.[64]

Point of view: static linking violates GPL but unclear as of dynamic linking
Some people believe that while static linking produces derivative works, it is not clear whether an executable that dynamically links to a GPL code should be considered a derivative work (see weak copyleft). Linux author Linus Torvalds agrees that dynamic linking can create derived works but disagrees over the circumstances.[65]

A Novell lawyer has written that dynamic linking not being derivative "makes sense" but is not "clear-cut", and that evidence for good-intentioned dynamic linking can be seen by the existence of proprietary Linux kernel drivers.[66]

In Galoob v. Nintendo, the United States Ninth Circuit Court of Appeals defined a derivative work as having "'form' or permanence" and noted that "the infringing work must incorporate a portion of the copyrighted work in some form",[67] but there have been no clear court decisions to resolve this particular conflict.

Point of view: linking is irrelevant
According to an article in the Linux Journal, Lawrence Rosen (a one-time Open Source Initiative general counsel) argues that the method of linking is mostly irrelevant to the question about whether a piece of software is a derivative work; more important is the question about whether the software was intended to interface with client software and/or libraries.[68] He states, "The primary indication of whether a new program is a derivative work is whether the source code of the original program was used [in a copy-paste sense], modified, translated or otherwise changed in any way to create the new program. If not, then I would argue that it is not a derivative work,"[68] and lists numerous other points regarding intent, bundling, and linkage mechanism. He further argues on his firm's website[69] that such "market-based" factors are more important than the linking technique.

There is also the specific issue of whether a plugin or module (such as the NVidia or ATI graphics card kernel modules) must also be GPL, if it could reasonably be considered its own work. This point of view suggests that reasonably separate plugins, or plugins for software designed to use plugins, could be licensed under an arbitrary license if the work is GPLv2. Of particular interest is the GPLv2 paragraph:

You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions: ...

b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License. ... These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

The GPLv3 has a different clause:

You may convey a work based on the Program, or the modifications to produce it from the Program, in the form of source code under the terms of Section 4, provided that you also meet all of these conditions: ...

c) You must license the entire work, as a whole, under this License to anyone who comes into possession of a copy. This License will therefore apply, along with any applicable Section 7 additional terms, to the whole of the work, and all its parts, regardless of how they are packaged. This License gives no permission to license the work in any other way, but it does not invalidate such permission if you have separately received it. ... A compilation of a covered work with other separate and independent works, which are not by their nature extensions of the covered work, and which are not combined with it such as to form a larger program, in or on a volume of a storage or distribution medium, is called an "aggregate" if the compilation and its resulting copyright are not used to limit the access or legal rights of the compilation's users beyond what the individual works permit. Inclusion of a covered work in an aggregate does not cause this License to apply to the other parts of the aggregate.

As a case study, some supposedly proprietary plugins and themes/skins for GPLv2 CMS software such as Drupal and WordPress have come under fire, with both sides of the argument taken.[70]

The FSF differentiates on how the plugin is being invoked. If the plugin is invoked through dynamic linkage and it performs function calls to the GPL program then it is most likely a derivative work.[71]

[mclane]

Why do you play with clones of stockfish?!

Why do you test these engines ?!

[amanjpro]

Why do you play with clones of stockfish?!

Why do you test these engines ?!

Personal preference, I mean who we are to even ask a user why and how he uses a product


That said, I fully agree with SF action, violations need to be corrected

[mclane]

A product?!
A clone is no „product“
A clone is stolen copyright material.

[wickedpotus]

But it seems that now authors cannot share Fisherov 98d anymore, due to the Stockfish Team request.

And how exactly does SFs request stop author from sharing his "version" ???? I don't follow your thinking here.

[amanjpro]

A product?!
A clone is no „product“
A clone is stolen copyright material.

You mean an illegal clone is not a product, that is debatable

But you shouldn't blame/question the user for what they are using, but the dev who did something illegal

[Sopel]

A product?!
A clone is no „product“
A clone is stolen copyright material.

It's only stolen if you don't respect the license. Nothing wrong with clones, some are actually useful. Like crystal or brainlearn for example.

I'm also happy to see that Fisherov is now compliant with GPLv3 too, good that other people are taking a stance.

[supersharp77]

Why do you play with clones of stockfish?!

Why do you test these engines ?!

Hahahahaha...What An Amazing Question! "Why Do You Drive a Audi Instead of A Volkswagon...Volkswagon is The Original Audi is a Copy..(Some Say).....Or "Why Do You Drink Pepsi (Pepsi Stole The Coca Cola Formula some say) instead of Coca Cola?" "Why do you use Burger King Instead of The Original McDonalds?" LMAO...
The "Engine Purists" Run Themselves Ragged.....Meanwhile in Reality The "Authors" Cut and Paste everthing they can find on the net and create "new" chess engines (clones) in days or even hours...And most say nothing at All....Perhaps Court is The Best Solution...That way we can sort out The Financial Side Of This Stockfish Open Source Nonsense...(Legal Discovery)