Ethereal-dev: Re: [Ethereal-dev] Request: Change the allowed license of plugins

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From: "Mark H. Wood" <mwood@xxxxxxxxx>
Date: Thu, 21 Nov 2002 09:03:59 -0500 (EST)
I suspect that there is some confusion of ideas here.

(Preface:  this is not legal advice.  If you want legal advice, hire a
lawyer.)

I don't see how the GPL could "nullify a patent".  A patent merely says
that a method or abstract mechanism is the property of the holder and he
can control the use of that idea by others.  Allowing others to use the
idea is one kind of control.  The patent is still valid, whether the
holder chooses to permit or forbid any particular use; he still has the
power to make that choice.

And since public disclosure of trade secrets is an integral part of the
patent process, there's no new leakage of secrets caused by distributing
implementation sources under any particular terms.  Patent is used to
maintain control of ideas which cannot be expressed in a product without
revealing trade secrets, such as a novel mechanical linkage whose unique
character would be obvious to anyone who watched one operate.

LGPL really is aimed at making it easier to build on LGPL code without
disclosing trade secrets.  The main difference with the GPL seems to be
that the LGPL does not require disclosure of source code for a "work that
uses the library", even if a combined binary is shipped.  Admittedly there
is some wiggle room surrounding the requirement for "reverse engineering
for debugging such modifications".  But it looks to me as though the
fundamental difference between the two licenses is that LGPL requires
disclosure only of sources for changes you make to the LGPL code, while
GPL requires disclosure of *all* sources used to build the executable
code.

None of this has any direct bearing on whether switching some of
Ethereal's code to LGPL is or is not a good idea, but at least we should
understand why we're talking about it.

-- 
Mark H. Wood, Lead System Programmer   mwood@xxxxxxxxx
MS Windows *is* user-friendly, but only for certain values of "user".