Changeset - 2f2e5f9e4c32
[Not reviewed]
0 3 0
Bradley Kuhn (bkuhn) - 10 years ago 2014-10-16 02:14:45
bkuhn@ebb.org
Rework over-abundant use of term "derivative work"

The older portions of this tutorial tended to favor the term "derivative
work", since that was the popular catch-all term used at the time the
text was written.

However, as the newer text regarding GPLv3 now states, FSF abandoned the
use of the term "derivative work" in the text of GPLv3 itself, for
various reasons we already discuss in the tutorial.

Therefore, the tutorial text itself should likely not rely so heavily on
the phrase "derivative work" throughout. This change herein reworks a
number of places where "derivative work" was used in the tutorial and
replaced it with other terms.

Ultimately, some word-smithing happened as part of the process of doing
this patch.
3 files changed with 90 insertions and 88 deletions:
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compliance-guide.tex
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@@ -55,209 +55,209 @@ Early GPL enforcement efforts began soon after the GPL was written by
 
Richard M.~Stallman (RMS) in 1989, and consisted of informal community efforts,
 
often in public Usenet discussions.\footnote{One example is the public
 
  outcry over NeXT's attempt to make the Objective-C front-end to GCC
 
  proprietary.  RMS, in fact, handled this enforcement action personally and
 
  the Objective-C front-end is still part of upstream GCC today.}  Over the next decade, the Free Software Foundation (FSF),
 
which holds copyrights in many GNU programs, was the only visible entity
 
actively enforcing its GPL'd copyrights on behalf of the software freedom
 
community.
 
FSF's enforcement
 
was generally a private process; the FSF contacted violators
 
confidentially and helped them to comply with the license.  Most
 
violations were pursued this way until the early 2000's.
 

	
 
By that time, Linux-based systems such as GNU/Linux and BusyBox/Linux had become very common, particularly in
 
embedded devices such as wireless routers.  During this period, public
 
ridicule of violators in the press and on Internet fora supplemented
 
ongoing private enforcement and increased pressure on businesses to
 
comply.  In 2003, the FSF formalized its efforts into the GPL Compliance
 
Lab, increased the volume of enforcement, and built community coalitions
 
to encourage copyright holders to together settle amicably with violators.
 
Beginning in 2004, Harald Welte took a more organized public enforcement
 
approach and launched \verb0gpl-violations.org0, a website and mailing
 
list for collecting reports of GPL violations.  On the basis of these
 
reports, Welte successfully pursued many enforcements in Europe, including
 
formal legal action.  Harald earns the permanent fame as the first copyright
 
holder to bring legal action in a court regarding GPL compliance.
 

	
 
In 2007, two copyright holders in BusyBox, in conjunction with the
 
Software Freedom Conservancy (``Conservancy''), filed the first copyright infringement lawsuit
 
based on a violation of the GPL\@ in the USA. While  lawsuits are of course
 
quite public, the vast majority of Conservancy's enforcement actions 
 
are resolved privately via
 
cooperative communications with violators.  As both FSF and Conservancy have worked to bring
 
individual companies into compliance, both organizations have encountered numerous
 
violations resulting from preventable problems such as inadequate
 
attention to licensing of upstream software, misconceptions about the
 
GPL's terms, and poor communication between software developers and their
 
management.  This document highlights these problems and describe
 
best practices to encourage corporate Free Software users to reevaluate their
 
approach to GPL'd software and avoid future violations.
 

	
 
Both FSF and Conservancy continue GPL enforcement and compliance efforts
 
for software under the GPL, the GNU Lesser
 
Public License (LGPL) and other copyleft licenses.  In doing so, both organizations have
 
found that most violations stem from a few common, avoidable mistakes.  All copyleft advocates  hope to educate the community of
 
commercial distributors, redistributors, and resellers on how to avoid
 
violations in the first place, and to respond adequately and appropriately
 
when a violation occurs.
 

	
 
\chapter{Best Practices to Avoid Common Violations}
 
\label{best-practices}
 

	
 
Unlike highly permissive licenses (such as the ISC license), which
 
typically only require preservation of copyright notices, licensees face many
 
important requirements from the GPL.  These requirements are
 
carefully designed to uphold certain values and standards of the software
 
freedom community.  While the GPL's requirements may initially appear
 
counter-intuitive to those more familiar with proprietary software
 
licenses, by comparison, its terms are in fact clear and quite favorable to
 
licensees.  Indeed, the GPL's terms actually simplify compliance when
 
violations occur.
 

	
 
GPL violations occur (or, are compounded) most often when companies lack sound
 
practices for the incorporation of GPL'd components into their
 
internal development environment.  This section introduces some best
 
practices for software tool selection, integration and distribution,
 
inspired by and congruent with software freedom methodologies.  Companies should
 
establish such practices before building a product based on GPL'd
 
software.\footnote{This document addresses compliance with GPLv2,
 
  GPLv3, LGPLv2, and LGPLv3.  Advice on avoiding the most common
 
  errors differs little for compliance with these four licenses.
 
  \S~\ref{lgpl} discusses the key differences between GPL and LGPL
 
  compliance.}
 

	
 
\section{Evaluate License Applicability}
 
\label{derivative-works}
 
Political discussion about the GPL often centers around the ``copyleft''
 
requirements of the license.  Indeed, the license was designed primarily
 
to embody this licensing feature.  Most companies adding non-trivial
 
features (beyond mere porting and bug-fixing) to GPL'd software (and
 
thereby invoking these requirements) are already well aware of their
 
more complex obligations under the license.\footnote{There has been much legal
 
  discussion regarding copyleft and derivative works.  In practical
 
  reality, this issue is not relevant to the vast majority of companies
 
  distributing GPL'd software.  Those interested in this issue should study
 
  \tutorialpartsplit{\textit{Detailed Analysis of the GNU GPL and Related
 
      Licenses}'s Section on derivative works}{\S~\ref{derivative-works} of
 
    this tutorial}.}
 

	
 
However, experienced  GPL enforcers find that few redistributors'
 
compliance challenges relate directly to combined work issues in copyleft.
 
Instead, the distributions of GPL'd
 
systems most often encountered typically consist of a full operating system
 
including components under the GPL (e.g., Linux, BusyBox) and components
 
under the LGPL (e.g., the GNU C Library).  Sometimes, these programs have
 
been patched or slightly improved by direct modification of their sources,
 
and thus the result is unequivocally a derivative work.  Alongside these programs,
 
and thus the result is unequivocally a modified version.  Alongside these programs,
 
companies often distribute fully independent, proprietary programs,
 
developed from scratch, which are designed to run on the Free Software operating
 
system but do not combine with, link to, modify, derive from, or otherwise
 
create a combined work with
 
the GPL'd components.\footnote{However, these programs do often combine
 
  with LGPL'd libraries. This is discussed in detail in \S~\ref{lgpl}.}
 
In the latter case, where the work is unquestionably a separate work of
 
creative expression, no copyleft provisions are invoked.
 
The core compliance issue faced, thus, in such a situation, is not an discussion of what is or is not a
 
combined or derivative work, but rather, issues related to distribution and
 
combined, derivative, and/or modified version of the work, but rather, issues related to distribution and
 
conveyance of binary works based on GPL'd source, but without Complete,
 
Corresponding Source.  This tutorial therefore focuses primarily on that issue.
 

	
 
Admittedly, a tiny
 
minority of compliance situations relate to question of derivative and
 
combined words.  Those
 
minority of compliance situations relate to question of derivative,
 
combined, or modified versions of the work.  Those
 
situations are so rare, and the details from situation to situation differ
 
greatly.  Thus, such situations require a highly
 
fact-dependent analysis and cannot be addressed in a general-purpose
 
document such as this one.
 

	
 
\medskip
 

	
 
Most companies accused of violations lack a basic understanding
 
of how to comply even in the straightforward scenario.  This document
 
provides those companies with the fundamental and generally applicable prerequisite knowledge.
 
For answers to rarer and more complicated legal questions, such as whether
 
your software is a derivative or combined work of some copylefted software, consult
 
with an attorney.\footnote{If you would like more information on the
 
  application of derivative works doctrine to software, a detailed legal
 
  discussion is presented in our colleague Dan Ravicher's article,
 
  \textit{Software Derivative Work: A Circuit Dependent Determination} and in
 
  \tutorialpartsplit{\textit{Detailed Analysis of the GNU GPL and Related
 
      Licenses}'s Section on derivative works}{\S~\ref{derivative-works} of
 
    this tutorial}.}
 

	
 
This discussion thus assumes that you have already identified the
 
``work'' covered by the license, and that any components not under the GPL
 
(e.g., applications written entirely by your developers that merely happen
 
to run on a Linux-based operating system) distributed in conjunction with
 
those works are separate works within the meaning of copyright law and the GPL\@.  In
 
such a case, the GPL requires you to provide complete corresponding
 
source (CCS)\footnote{For more on CCS,  see
 
\tutorialpartsplit{\textit{Detailed Analysis of the GNU GPL and Related
 
      Licenses}'s Section on GPLv2~\S2 and GPLv3~\S1.}{\S~\ref{GPLv2s2} and \S~\ref{GPLv3s1} of
 
    this tutorial}.}
 
for the GPL'd components and your modifications thereto, but not
 
for independent proprietary applications.  The procedures described in
 
this document address this typical scenario.
 

	
 
\section{Monitor Software Acquisition}
 

	
 
Software engineers deserve the freedom to innovate and import useful
 
software components to improve products.  However, along with that
 
freedom should come rules and reporting procedures to make sure that you
 
are aware of what software that you include with your product.
 

	
 
The most typical response to an initial enforcement action is: ``We
 
didn't know there was GPL'd stuff in there''.  This answer indicates
 
failure in the software acquisition and procurement process.  Integration
 
of third-party proprietary software typically requires a formal
 
arrangement and management/legal oversight before the developers
 
incorporate the software.  By contrast, developers often obtain and
 
integrate Free Software without intervention nor oversight. That ease of acquisition, however,
 
does not mean the oversight is any less necessary.  Just as your legal
 
and/or management team negotiates terms for inclusion of any proprietary
 
software, they should gently facilitate all decisions to bring Free Software into your
 
product.
 

	
 
Simple, engineering-oriented rules help provide a stable foundation for
 
Free Software integration.  For example, simply ask your software developers to send an email to a
 
standard place describing each new Free Software component they add to the system,
 
and have them include a brief description of how they will incorporate it
 
into the product.  Further, make sure developers use a revision control
 
system (such as Git or Mercurial), and
 
store the upstream versions of all software in a ``vendor branch'' or
 
similar mechanism, whereby they can easily track and find the main version
 
of the software and, separately, any local changes.
 

	
 
Such procedures are best instituted at your project's launch.  Once 
 
chaotic and poorly-sourced development processes begin, cataloging the
 
presence of GPL'd components  becomes challenging.
 

	
 
Such a situation often requires use of a tool to ``catch up'' your knowledge
 
about what software your product includes.  Most commonly, companies choose
 
some software licensing scanning tool to inspect the codebase.  However,
 
there are few tools that are themselves Free Software.  Thus, GPL enforcers
 
usually recommend the GPL'd
 
\href{http://fossology.org/}{FOSSology system}, which analyzes a
 
source code base and produces a list of Free Software licenses that may apply to
 
the code.  FOSSology can help you build a catalog of the sources you have
 
already used to build your product.  You can then expand that into a more
 
structured inventory and process.
 

	
 
\section{Track Your Changes and Releases}
 

	
 
As explained in further detail below, the most important component of GPL
 
compliance is the one most often ignored: proper inclusion of CCS in all
 
distributions  of GPL'd
 
software.  To comply with GPL's CCS requirements, the distributor
 
\textit{must} always know precisely what sources generated a given binary
 
distribution.
 

	
 
In an unfortunately large number of our enforcement cases, the violating
 
company's engineering team had difficulty reconstructing the CCS
 
for binaries distributed by the company.  Here are three simple rules to
 
follow to decrease the likelihood of this occurrence:
 

	
 
\begin{itemize}
 

	
 
\item Ensure that your
 
developers are using revision control systems properly.
enforcement-case-studies.tex
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@@ -175,206 +175,206 @@ matter, allowing that company to join the GPL ecosystem as a contributor.
 
\section{How are Violations Discovered?}
 

	
 
Our enforcement of the GPL is not a fund-raising effort; in fact, FSF's GPL
 
Compliance Lab runs at a loss (in other words, it is subsided by our
 
donors). Our violation reports come from volunteers, who have encountered,
 
in their business or personal life, a device or software product that
 
appears to contain GPL'd software. These reports are almost always sent
 
via email to $<$license-violation@fsf.org$>$.
 

	
 
Our first order of business, upon receiving such a report, is to seek
 
independent confirmation. When possible, we get a copy of the software
 
product. For example, if it is an offering that is downloadable from a
 
Web site, we download it and investigate ourselves. When it is not
 
possible for us to actually get a copy of the software, we ask the
 
reporter to go through the same process we would use in examining the
 
software.
 

	
 
By rough estimation, about 95\% of violations at this stage can be
 
confirmed by simple commands. Almost all violators have merely made an
 
error and have no nefarious intentions. They have made no attempt to
 
remove our copyright notices from the software. Thus, given the
 
third-party binary, {\tt tpb}, usually, a simple command (on a GNU/Linux
 
system) such as the following will find a Free Software copyright notice
 
and GPL reference:
 
\begin{quotation}
 
{\tt strings tpb | grep Copyright}
 
\end{quotation}
 
In other words, it is usually more than trivial to confirm that GPL'd
 
software is included.
 

	
 
Once we have confirmed that a violation has indeed occurred, we must then
 
determine whose copyright has been violated. Contrary to popular belief,
 
FSF does not have the power to enforce the GPL in all cases. Since the GPL
 
operates under copyright law, the powers of enforcement --- to seek
 
redress once \S 4 has been invoked --- lie with the copyright holder of
 
the software. FSF is one of the largest copyright holders in the world of
 
GPL'd software, but we are by no means the only one. Thus, we sometimes
 
discover that while GPL'd code is present in the software, there is no
 
software copyrighted by FSF present.
 

	
 
In cases where FSF does not hold copyright interest in the software, but
 
we have confirmed a violation, we contact the copyright holders of the
 
software, and encourage them to enforce the GPL\@. We offer our good offices
 
to help negotiate compliance on their behalf, and many times, we help as a
 
third party to settle such GPL violations. However, what we will describe
 
primarily in this course is FSF's first-hand experience enforcing its own
 
copyrights and the GPL\@.
 

	
 
\section{First Contact}
 

	
 
The Free Software community is built on a structure of voluntary
 
cooperation and mutual help. Our community has learned that cooperation
 
works best when you assume the best of others, and only change policy,
 
procedures and attitudes when some specific event or occurrence indicates
 
that a change is necessary. We treat the process of GPL enforcement in
 
the same way. Our goal is to encourage violators to join the cooperative
 
community of software sharing, so we want to open our hand in friendship.
 

	
 
Therefore, once we have confirmed a violation, our first assumption is
 
that the violation is an oversight or otherwise a mistake due to confusion
 
about the terms of the license. We reach out to the violator and ask them
 
to work with us in a collaborative way to bring the product into
 
compliance. We have received the gamut of possible reactions to such
 
requests, and in this course, we examine four specific examples of such
 
compliance work.
 

	
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{Bortez: Modified GCC SDK}
 

	
 
In our first case study, we will consider Bortez, a company that
 
produces software and hardware toolkits to assist OEM vendors, makers
 
of consumer electronic devices.
 

	
 
\section{Facts}
 

	
 
One of Bortez's key products is a Software Development Kit (``SDK'')
 
designed to assist developers building software for a specific class of
 
consumer electronics devices.
 

	
 
FSF received a report that the SDK may be based on the GNU Compiler
 
Collection (which is an FSF-copyrighted collection of tools for software
 
development in C, C++ and other popular languages). FSF investigated the
 
claim, but was unable to confirm the violation. The violation reporter
 
was unresponsive to follow-up requests for more information.
 

	
 
Since FSF was unable to confirm the violation, we did not pursue it any
 
further. Bogus reports do happen, and we do not want to burden companies
 
with specious GPL violation complaints. FSF shelved the matter until
 
more evidence was discovered.
 

	
 
FSF was later able to confirm the violation when two additional reports
 
surfaced from other violation reporters, both of whom had used the SDK
 
professionally and noticed clear similarities to FSF's GNU GCC\@. FSF's
 
Compliance Engineer asked the reporters to run standard tests to confirm
 
the violation, and it was confirmed that Bortez's SDK was indeed a
 
derivative work of GCC\@. Bortez had ported to Windows and added a number
 
modified version of GCC\@. Bortez had ported to Windows and added a number
 
of features, including support for a specific consumer device chipset and
 
additional features to aid in the linking process (``LP'') for those
 
specific devices. FSF explained the rights that the GPL afforded these
 
customers and pointed out, for example, that Bortez only needed to provide
 
source to those in possession of the binaries, and that the users may need
 
to request that source (if \S 3(b) was exercised). The violators
 
confirmed that such requests were not answered.
 

	
 
FSF brought the matter to the attention of Bortez, who immediately
 
escalated the matter to their attorneys. After a long negotiation,
 
Bortez acknowledged that their SDK was indeed a derivative work of
 
Bortez acknowledged that their SDK was indeed a modified version of
 
GCC\@. Bortez released most of the source, but some disagreement
 
occurred over whether LP was a derivative work of GCC\@. After repeated
 
occurred over whether LP was also derivative of GCC\@. After repeated
 
FSF inquiries, Bortez reaudited the source to discover that FSF's
 
analysis was correct. Bortez determined that LP included a number of
 
source files copied from the GCC code-base.
 

	
 
\label{davrik-build-problems}
 
Once the full software release was made available, FSF asked the violation
 
reporters if it addressed the problem. Reports came back that the source
 
did not properly build. FSF asked Bortez to provide better build
 
instructions with the software, and such build instructions were
 
incorporated into the next software release.
 

	
 
At FSF's request as well, Bortez informed customers who had previously
 
purchased the product that the source was now available by announcing
 
the availability on its Web site and via a customer newsletter.
 

	
 
Bortez did have some concerns regarding patents. They wished to include a
 
statement with the software release that made sure they were not granting
 
any patent permission other than what was absolutely required by the GPL\@.
 
They understood that their patent assertions could not trump any rights
 
granted by the GPL\@. The following language was negotiated into the release:
 

	
 
\begin{quotation}
 
Subject to the qualifications stated below, Bortez, on behalf of itself
 
and its Subsidiaries, agrees not to assert the Claims against you for your
 
making, use, offer for sale, sale, or importation of the Bortez's GNU
 
Utilities or derivative works of the Bortez's GNU Utilities
 
(``Derivatives''), but only to the extent that any such Derivatives are
 
licensed by you under the terms of the GNU General Public License. The
 
Claims are the claims of patents that Bortez or its Subsidiaries have
 
standing to enforce that are directly infringed by the making, use, or
 
sale of an Bortez Distributed GNU Utilities in the form it was distributed
 
by Bortez and that do not include any limitation that reads on hardware;
 
the Claims do not include any additional patent claims held by Bortez that
 
cover any modifications of, derivative works based on or combinations with
 
the Bortez's GNU Utilities, even if such a claim is disclosed in the same
 
patent as a Claim. Subsidiaries are entities that are wholly owned by
 
Bortez.
 

	
 
This statement does not negate, limit or restrict any rights you already
 
have under the GNU General Public License version 2.
 
\end{quotation}
 

	
 
This quelled Bortez's concerns about other patent licensing they sought to
 
do outside of the GPL'd software, and satisfied FSF's concerns that Bortez
 
give proper permissions to exercise teachings of patents that were
 
exercised in their GPL'd software release.
 

	
 
Finally, a GPL Compliance Officer inside Bortez was appointed to take
 
responsibility for all matters of GPL compliance inside the company.
 
Bortez is responsible for informing FSF if the position is given to
 
someone else inside the company, and making sure that FSF has direct
 
contact with Bortez's Compliance Officer.
 

	
 
\section{Lessons}
 

	
 
This case introduces a number of concepts regarding GPL enforcement.
 

	
 
\begin{enumerate}
 

	
 
\item {\bf Enforcement should not begin until the evidence is confirmed.}
 
  Most companies that distribute GPL'd software do so in compliance, and at
 
  times, violation reports are mistaken. Even with extensive efforts in
 
  GPL education, many users do not fully understand their rights and the
 
  obligations that companies have. By working through the investigation
 
  with reporters, the violation can be properly confirmed, and {\bf the
 
    user of the software can be educated about what to expect with GPL'd
 
    software}. When users and customers of GPL'd products know their
 
  rights, what to expect, and how to properly exercise their rights
 
  (particularly under \S 3(b)), it reduces the chances for user
 
  frustration and inappropriate community outcry about an alleged GPL
 
  violation.
 

	
 
\item {\bf GPL compliance requires friendly negotiation and cooperation.}
 
  Often, attorneys and managers are legitimately surprised to find out
 
  GPL'd software is included in their company's products. Engineers
 
  sometimes include GPL'd software without understanding the requirements.
 
  This does not excuse companies from their obligations under the license,
 
  but it does mean that care and patience are essential for reaching GPL
 
  compliance. We want companies to understand that participating and
 
  benefiting from a collaborative Free Software community is not a burden,
 
  so we strive to make the process of coming into compliance as smooth as
 
  possible.
 

	
 
\item {\bf Confirming compliance is a community effort.}  The whole point
 
  of making sure that software distributors respect the terms of the GPL is to
 
  allow a thriving software sharing community to benefit and improve the
 
  work. FSF is not the expert on how a compiler for consumer electronic
 
  devices should work. We therefore inform the community who originally
 
  brought the violation to our attention and ask them to assist in
 
  evaluation and confirmation of the product's compliance. Of course, FSF
 
  coordinates and oversees the process, but we do not want compliance for
 
  compliance's sake; rather, we wish to foster a cooperating community of
 
  development around the Free Software in question, and encourage the
 
  once-violator to begin participating in that community.
 

	
 
\item {\bf Informing the harmed community is part of compliance.} FSF asks
...
 
@@ -527,293 +527,293 @@ role in GPL compliance.
 
  duty by ceasing distribution while the violation was being resolved.
 
  Under GPL \S 4, the redistributor loses the right to distribute the
 
  software, and thus they are in ongoing violation of copyright law if
 
  they distribute before rights are restored. It is FSF's policy to
 
  temporarily allow distribution while compliance negotiations are ongoing
 
  and only in the most extreme cases (where the other party appears to be
 
  negotiating in bad faith) does FSF even threaten an injunction on
 
  copyright grounds. However, Bracken --- as a good Free Software citizen
 
  --- chose to be on the safe side and do the legally correct thing while
 
  the violation case was pending. From start to finish, it took less
 
  than a month to resolve. This lapse in distribution did not, to FSF's
 
  knowledge, impact Bracken's business in any way.
 

	
 
\item {\bf EULAs are a common area for GPL problems.}  Often, EULAs
 
  are drafted from boilerplate text that a company uses for all its
 
  products. Even the most diligent attorneys forget or simply do not
 
  know that a product contains software licensed under the GPL and other
 
  Free Software licenses. Drafting a EULA that accounts for such
 
  licenses is straightforward; the text quoted above works just fine.
 
  The EULA must be designed so that it does not trump rights and
 
  permissions already granted by the GPL\@. The EULA must clearly state
 
  that if there is a conflict between it and the GPL, with regard to GPL'd
 
  code, the GPL is the overriding license.
 

	
 
\item {\bf Compliance Officers are rarely necessary when companies are
 
  educated about GPL compliance.}  As we saw in the Bortez case, FSF asks
 
  that a formal ``GPL Compliance Officer'' be appointed inside a
 
  previously violating organization to shepherd the organization to a
 
  cooperative approach to GPL compliance. However, when FSF
 
  sees that an organization already has such an approach, there is no
 
  need to request that such an officer be appointed.
 

	
 
\end{enumerate}
 

	
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{Vigorien: Security, Export Controls, and GPL Compliance}
 

	
 
This case study introduces how concerns of ``security through obscurity''
 
and regulatory problems can impact GPL compliance matters.
 

	
 
\section{The Facts}
 

	
 
Vigorien distributes a back-up solution product that allows system
 
administrators to create encrypted backups of file-systems on
 
Unix-like computers. The product is based on GNU tar, a backup utility
 
that replaces the standard Unix utility simply called tar, but has
 
additional features.
 

	
 
Vigorien's backup solution added cryptographic features to GNU tar, and
 
included a suite of utilities and graphical user interfaces surrounding
 
GNU tar to make backups convenient.
 

	
 
FSF discovered the violation from a user report, and determined that the
 
cryptographic features were the only part of the product that constituted
 
a derivative work of GNU tar; the extraneous utilities merely made
 
shell calls out to GNU tar. FSF requested that Vigorien come into
 
compliance with the GPL by releasing the source of GNU tar, with the
 
cryptographic modifications, to its customers.
 

	
 
Vigorien released the original GNU tar sources, but kept the cryptographic
 
modifications proprietary. They argued that the security of their system
 
depending on keeping the software proprietary and that regardless, USA
 
export restrictions on cryptographic software prohibited such a release.
 
FSF disputed the first claim, pointing out that Vigorien had only one
 
option if they did not want to release the source: they would have to
 
remove GNU tar from the software and not distribute it further. Vigorien
 
rejected this suggestion, since GNU tar was an integral part of the
 
product, and the security changes were useless without GNU tar.
 

	
 
Regarding the export control claims, FSF proposed a number of options,
 
including release of the source from one of Vigorien's divisions overseas
 
where no such restrictions occurred, but Vigorien argued that the problem
 
was insoluble because they operated primarily in the USA\@.
 

	
 
The deadlock on the second issue was resolved when those cryptographic
 
export restrictions were lifted shortly thereafter, and FSF again raised
 
the matter with Vigorien. At that point, they dropped the first claim and
 
agreed to release the remaining source module to their customers. They
 
did so, and the violation was resolved.
 

	
 

	
 
\section{Lessons Learned}
 

	
 
\begin{enumerate}
 

	
 
\item {\bf Removing the GPL'd portion of the product is always an
 
  option.}  Many violators' first response is to simply refuse to
 
  release the source code as the GPL requires. FSF offers the option to
 
  simply remove the GPL'd portions from the product and continue along
 
  without them. Every case where this has been suggested has led to
 
  the same conclusion. Like Vigorien, the violator argues that the
 
  product cannot function without the GPL'd components, and they
 
  cannot effectively replace them.
 

	
 
  Such an outcome is simply further evidence that the combined work in
 
  question is indeed a derivative work of the original GPL'd component.
 
  question is indeed a modified version of the original GPL'd component.
 
  If the other components cannot stand on their own and be useful without
 
  the GPL'd portions, then one cannot effectively argue that the work as a
 
  whole is not a derivative of the GPL'd portions.
 
  whole is not a based on the GPL'd portions.
 

	
 
\item {\bf The whole product is not always covered.}  In this case,
 
  Vigorien had additional works aggregated. The backup system was a suite
 
  of utilities, some of which were the GPL and some of which were not. While
 
  the cryptographic routines were tightly coupled with GNU tar and clearly
 
  derivative works, the various GUI utilities were separate and
 
  made a whole new combined work of both components, the various GUI utilities were separate and
 
  independent works merely aggregated with the distribution of the
 
  GNU-tar-based product.
 

	
 

	
 
\item {\bf ``Security'' concerns do not exonerate a distributor from GPL
 
  obligations, and ``security through obscurity'' does not work anyway.}
 
  The argument that ``this is security software, so it cannot be released
 
  in source form'' is not a valid defense for explaining why the terms of
 
  the GPL are ignored. If companies do not want to release source code
 
  for some reason, then they should not base the work on GPL'd software.
 
  No external argument for noncompliance can hold weight if the work as
 
  a whole is indeed a derivative work of a GPL'd program.
 
  a whole is indeed a modified version of a GPL'd program.
 

	
 
  The ``security concerns'' argument is often floated as a reason to keep
 
  software proprietary, but the computer security community has on
 
  numerous occasions confirmed that such arguments are entirely specious.
 
  Security experts have found --- since the beginnings of the field of
 
  cryptography in the ancient world --- that sharing results about systems
 
  and having such systems withstand peer review and scrutiny builds the
 
  most secure systems. While full disclosure may help some who wish to
 
  compromise security, it helps those who want to fix problems even more
 
  by identifying them early.
 

	
 
\item {\bf External regulatory problems can be difficult to resolve.}
 
  The GPL, though grounded in copyright law, does not have the power to trump
 
  regulations like export controls. While Vigorien's ``security
 
  concerns'' were specious, their export control concerns were not. It is
 
  indeed a difficult problem that FSF acknowledges. We want compliance
 
  with the GPL and respect for users' freedoms, but we certainly do not expect
 
  companies to commit criminal offenses for the sake of compliance. We
 
  will see more about this issue in our next case study.
 
\end{enumerate}
 

	
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{Haxil, Polgara, and Thesulac: Mergers, Upstream Providers and Radio Devices}
 

	
 
This case study considers an ongoing (at the time of writing) violation
 
that has occurred. By the end of the investigation period, three
 
companies were involved and many complex issues arose.
 

	
 
\section{The Facts}
 

	
 
Haxil produced a consumer electronics device which included a mini
 
GNU/Linux distribution to control the device. The device was of interest
 
to many technically-minded consumers, who purchased the device and very
 
quickly discovered that Free Software was included without source.
 
Mailing lists throughout the Free Software community erupted with
 
complaints about the problem, and FSF quickly investigated.
 

	
 
FSF confirmed that FSF-copyrighted GPL'd software was included. In
 
addition, the whole distribution included GPL'd works from hundreds of
 
individual copyright holders, many of whom were, at this point, up in
 
arms about the violation.
 

	
 
Meanwhile, Haxil was in the midst of being acquired by Polgara. Polgara
 
was as surprised as everyone else to discover the product was based on
 
GPL'd software; this fact had not been part of the disclosures made during
 
acquisition. FSF contacted Haxil, Polgara, and the product managers
 
who had transitioned into the ``Haxil division'' of the newly-merged
 
Polgara company. Polgara's General Counsel's office worked with FSF on
 
the matter.
 

	
 
FSF formed a coalition with the other primary copyright holders
 
to pursue the enforcement effort on their behalf. FSF communicated
 
directly with Polgara's representatives to begin working through the
 
issues on behalf of itself and the Free Software community at large.
 

	
 
Polgara pointed out that the software distribution they used was mostly
 
contributed by an upstream provider, Thesulac, and Haxil's changes to that
 
code base were minimal. Polgara negotiated with Thesulac to obtain the
 
source, although the issue moved very slowly in the channels between
 
Polgara and Thesulac.
 

	
 
FSF encouraged a round-table meeting so that high bandwidth communication
 
could occur between FSF, Polgara and Thesulac. Polgara and Thesulac
 
agreed, and that discussion began. Thesulac provided nearly complete
 
sources to Polgara, and Polgara made a full software release on their
 
Web site. At the time of writing, that software still has some build
 
problems (similar to those that occurred with Bortez, as described in
 
Section~\ref{davrik-build-problems}). FSF continues to negotiate with
 
Polgara and Thesulac to resolve these problems, which have a clear path to
 
a solution and are expected to resolve.
 

	
 
Similar to the Vigorien case, Thesulac has regulatory concerns. In this
 
case, it is not export controls --- an issue that has since been resolved
 
--- but radio spectrum regulation. Since this consumer electronic device
 
contains a software-programmable radio transmitter, regulations in (at
 
least) the USA and Japan prohibit release of those portions of the code
 
that operate the device. Since this is a low-level programming issue, the
 
changes to operate the device are a derivative work of the kernel named
 
changes to operate the device form a single combined work with the kernel named
 
Linux.  A decade later, this situation remains largely unresolved.
 

	
 
\section{Lessons Learned}
 

	
 
\begin{enumerate}
 

	
 
\item {\bf Community outrage, while justified, can often make negotiation
 
  more difficult.}  FSF has a strong policy never to publicize names of
 
  GPL violators if they are negotiating in a friendly way and operating in
 
  good faith toward compliance. Most violations are honest mistakes, and
 
  FSF sees no reason to publicly admonish violators who genuinely want to
 
  come into compliance with the GPL and to work hard staying in compliance.
 

	
 
  This case was so public in the Free Software community that both Haxil's
 
  and Polgara's representatives were nearly shell-shocked by the time FSF
 
  began negotiations. There was much work required to diffuse the
 
  situation. We empathize with our community and their outrage about GPL
 
  violations, but we also want to follow a path that leads expediently
 
  to compliance. In our experience, public outcry works best as a last
 
  resort, not the first.
 

	
 
\item {\bf For software companies, GPL compliance belongs on a corporate
 
  acquisition checklist. }  Polgara was truly amazed that Haxil had used
 
  GPL'd software in a major new product line but never informed Polgara
 
  during the acquisition process. While GPL compliance is not a
 
  particularly difficult matter, it is an additional obligation that comes
 
  along with the product line. When planning mergers and joint ventures,
 
  one should include lists of GPL'd components contained in the products
 
  discussed.
 

	
 
\item {\bf Compliance problems of upstream providers do not excuse a
 
  violation for the downstream distributor.}  To paraphrase \S 6, upstream
 
  providers are not responsible for enforcing compliance of their
 
  downstream, nor are downstream distributors responsible for compliance
 
  problems of upstream providers. However, engaging in distribution of
 
  GPL'd works out of compliance is still just that: a compliance problem.
 
  When FSF carries out enforcement, we are patient and sympathetic when
 
  the problem appears to be upstream. In fact, we urge the violator to
 
  point us to the upstream provider so we may talk to them directly. In
 
  this case, we were happy to begin negotiations with Thesulac. However,
 
  Polgara still has an obligation to bring their product into compliance,
 
  regardless of Thesulac's response.
 

	
 
\item {\bf It behooves upstream providers to advise downstream
 
  distributors about compliance matters.}  FSF has encouraged Thesulac to
 
  distribute a ``good practices for GPL compliance'' document with their
 
  product. Polgara added various software components to Thesulac's
 
  product, and it is conceivable that such additions can introduce
 
  compliance. In FSF's opinion, Thesulac is in no way legally responsible
 
  for such a violation introduced by their customer, but it behooves them
 
  from a marketing standpoint to educate their customers about using the
 
  product. We can argue whether or not it is your coffee vendor's fault
 
  if you burn yourself with their product, but (likely) no one on either
 
  side would dispute the prudence of placing a ``caution: hot'' label on
 
  the cup.
 

	
 
\item {\bf FSF enforcement often avoids redundant enforcement cases from
 
  many parties.}  Most Free Software systems have hundreds of copyright
 
  holders. Some have thousands. FSF is in a unique position as one of
 
  the largest single copyright holders on GPL'd software and as a
 
  respected umpire in the community, neutrally enforcing the rules of the
 
  GPL road. FSF works hard in the community to convince copyright
 
  holders that consolidating GPL claims through FSF is better for them,
 
  and more likely to yield positive compliance results.
 

	
 
  A few copyright holders engage in the ``proprietary relicensing''
 
  business, so they use GPL enforcement as a sales channel for that
 
  business. FSF, as a community-oriented, not-for-profit organization,
 
  seeks only to preserve the freedom of Free Software in its enforcement
 
  efforts. As it turns out, most of the community of copyright holders
 
  of Free Software want the same thing. Share and share alike is a
 
  simple rule to follow, and following that rule to FSF's satisfaction
 
  usually means you are following it to the satisfaction of the entire
 
  Free Software community.
 

	
 
\end{enumerate}
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
% COMMENT OUT THIS CHAPTER.
 
% FIXME: is this material moot now that we include the compliance guide?
 
% Either way, it should be merged into compliance guide.
 
%\chapter{Good Practices for Compliance}
 

	
 
Generally, from the experience of GPL enforcement, we glean the following
 
general practices that can help in GPL compliance for organizations that
 
distribute products based on GPL'd software:
 

	
 
\begin{itemize}
 

	
 
\item Talk to your software engineers and ask them where they got the
 
  components they use in the products they build. Find out if GPL'd
 
  components are present.
 

	
 
\item Teach your engineering staff to pay attention to license documents.
 
  Give them easy-to-follow policies to get approval for using a Free
 
  Software component.
gpl-lgpl.tex
Show inline comments
...
 
@@ -968,202 +968,202 @@ its authority for future licensing decisions to the FSF.  In fact, the FSF
 
considered this possibility for GPLv3 and chose not to do so, instead opting
 
for the third-party steward designation clause discussed in
 
Section~\ref{GPLv3s14}.
 

	
 
\section{Complexities of Two Simultaneously Popular Copylefts}
 

	
 
Obviously most GPL advocates would prefer widespread migration to GPLv3, and
 
many newly formed projects who seek a copyleft license tend to choose a
 
GPLv3-based license.  However, many existing copylefted projects continue
 
with GPLv2-only or GPLv2-or-later as their default license.
 

	
 
While GPLv3 introduces many improvements --- many of which were designed to
 
increase adoption by for-profit companies --- GPLv2 remains a widely used and
 
extremely popular license.  The GPLv2 is, no doubt, a good and useful
 
license.
 

	
 
However, unlike GPLv1 before it,
 
GPLv2 remains an integral part of the copyleft licensing infrastructure.  As such, those who seek to have expertise in current
 
topics of copyleft licensing need to study both the GPLv2 and GPLv3 family of
 
licenses.
 

	
 
Furthermore, GPLv3 is more easily understood by first studying GPLv2.
 
This is not only because of their chronological order, but also because much
 
of the discussion material available for GPLv3 tends to talk about GPLv3 in
 
contrast to GPLv2.  As such, a strong understanding of GPLv2 helps in
 
understanding most of the third-party material found regarding GPLv3.  Thus,
 
the following chapter begins a deep discussion of GPLv2.
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{Running Software and Verbatim Copying}
 
\label{run-and-verbatim}
 

	
 

	
 
This chapter begins the deep discussion of the details of the terms of
 
GPLv2\@. In this chapter, we consider the first two sections: GPLv2 \S\S
 
0--2. These are the straightforward sections of the GPL that define the
 
simplest rights that the user receives.
 

	
 
\section{GPLv2~\S0: Freedom to Run}
 
\label{GPLv2s0}
 

	
 
GPLv2~\S0, the opening section of GPLv2, sets forth that copyright law governs
 
the work.  It specifically points out that it is the ``copyright
 
holder'' who decides if a work is licensed under its terms and explains
 
how the copyright holder might indicate this fact.
 

	
 
A bit more subtly, GPLv2~\S0 makes an inference that copyright law is the only
 
system that can restrict the software.  Specifically, it states:
 
\begin{quote}
 
Activities other than copying, distribution and modification are not
 
covered by this License; they are outside its scope.
 
\end{quote}
 
In essence, the license governs \emph{only} those activities, and all other
 
activities are unrestricted, provided that no other agreements trump GPLv2
 
(which they cannot; see Sections~\ref{GPLv2s6} and~\ref{GPLv2s7}).  This is
 
very important, because the Free Software community heavily supports
 
users' rights to ``fair use'' and ``unregulated use'' of copyrighted
 
material.  GPLv2 asserts through this clause that it supports users' rights
 
to fair and unregulated uses.
 

	
 
Fair use (called ``fair dealing'' in some jurisdictions) of copyrighted
 
material is an established legal doctrine that permits certain activities
 
regardless of whether copyright law would otherwise restrict those activities.
 
Discussion of the various types of fair use activity are beyond the scope of
 
this tutorial.  However, one important example of fair use is the right to
 
quote portions of the text in a larger work so as to criticize or suggest
 
changes.  This fair use right is commonly used on mailing lists when
 
discussing potential improvements or changes to Free Software.
 

	
 
Fair use is a doctrine established by the courts or by statute.  By
 
contrast, unregulated uses are those that are not covered by the statue
 
nor determined by a court to be covered, but are common and enjoyed by
 
many users.  An example of unregulated use is reading a printout of the
 
program's source code like an instruction book for the purpose of learning
 
how to be a better programmer.  The right to read something that you have
 
access to is and should remain unregulated and unrestricted.
 

	
 
\medskip
 

	
 
Thus, the GPLv2 protects users' fair and unregulated use rights precisely by
 
not attempting to cover them.  Furthermore, the GPLv2 ensures the freedom
 
to run specifically by stating the following:
 
\begin{quote}
 
''The act of running the Program is not restricted.''
 
\end{quote}
 
Thus, users are explicitly given the freedom to run by GPLv2~\S0.
 

	
 
\medskip
 

	
 
The bulk of GPLv2~\S0 not yet discussed gives definitions for other terms used
 
throughout.  The only one worth discussing in detail is ``work based on
 
the Program''.  The reason this definition is particularly interesting is
 
not for the definition itself, which is rather straightforward, but
 
because it clears up a common misconception about the GPL\@.
 

	
 
The GPL is often mistakenly criticized because it fails to give a
 
definition of ``derivative work''.  In fact, it would be incorrect and
 
problematic if the GPL attempted to define this.  A copyright license, in
 
fact, has no control over what may or may not be a derivative work.  This
 
matter is left up to copyright law and the courts --- not the licenses that utilize it.
 
definition of ``derivative work'' or ``combined work''.  In fact, it would be incorrect and
 
problematic if the GPL attempted to define these terms.  A copyright license, in
 
fact, has no control over the rules of copyright themselves.  Such rules are
 
the domain of copyright law and the courts --- not the licenses that utilize
 
those systems.
 

	
 
It is certainly true that copyright law as a whole does not propose clear
 
and straightforward guidelines for what is and is not a derivative
 
software work under copyright law.  However, no copyright license --- not
 
even the GNU GPL --- can be blamed for this.  Legislators and court
 
opinions must give us guidance to decide the border cases.
 
Copyright law as a whole doesn't propose clear and straightforward guidelines
 
for identifying the derivative and/or combined works of software.  However,
 
no copyright license --- not even the GNU GPL --- can be blamed for this.
 
Legislators and court opinions must give us guidance in borderline cases.
 

	
 
\section{GPLv2~\S1: Verbatim Copying}
 
\label{GPLv2s1}
 

	
 
GPLv2~\S1 covers the matter of redistributing the source code of a program
 
exactly as it was received. This section is quite straightforward.
 
However, there are a few details worth noting here.
 

	
 
The phrase ``in any medium'' is important.  This, for example, gives the
 
freedom to publish a book that is the printed copy of the program's source
 
code.  It also allows for changes in the medium of distribution.  Some
 
vendors may ship Free Software on a CD, but others may place it right on
 
the hard drive of a pre-installed computer.  Any such redistribution media
 
is allowed.
 

	
 
Preservation of copyright notice and license notifications are mentioned
 
specifically in GPLv2~\S1.  These are in some ways the most important part of
 
the redistribution, which is why they are mentioned by name.  GPL
 
always strives to make it abundantly clear to anyone who receives the
 
software what its license is.  The goal is to make sure users know their
 
rights and freedoms under GPL, and to leave no reason that users might be
 
surprised the software is GPL'd. Thus
 
throughout the GPL, there are specific references to the importance of
 
notifying others down the distribution chain that they have rights under
 
GPL.
 

	
 
Also mentioned by name is the warranty disclaimer. Most people today do
 
not believe that software comes with any warranty.  Notwithstanding the
 
\href{http://mlis.state.md.us/2000rs/billfile/hb0019.htm}{Maryland's} and \href{http://leg1.state.va.us/cgi-bin/legp504.exe?001+ful+SB372ER}{Virginia's} UCITA bills, there are few or no implied warranties with software.
 
However, just to be on the safe side, GPL clearly disclaims them, and the
 
GPL requires re-distributors to keep the disclaimer very visible. (See
 
Sections~\ref{GPLv2s11} and~\ref{GPLv2s12} of this tutorial for more on GPL's
 
warranty disclaimers.)
 

	
 
Note finally that GPLv2~\S1 creates groundwork for the important defense of
 
commercial freedom.  GPLv2~\S1 clearly states that in the case of verbatim
 
copies, one may make money.  Re-distributors are fully permitted to charge
 
for the re-distribution of copies of Free Software. In addition, they may
 
provide the warranty protection that the GPL disclaims as an additional
 
service for a fee. (See Section~\ref{Business Models} for more discussion
 
on making a profit from Free Software redistribution.)
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 

	
 
\chapter{Derivative Works: Statute and Case Law}
 
\label{derivative-works}
 

	
 
We digress for this chapter from our discussion of GPL's exact text to
 
consider the matter of derivative works --- a concept that we must
 
understand fully before considering GPLv2~\S\S2--3\@. The GPL, and Free
 
Software licensing in general, relies critically on the concept of
 
``derivative work'' since software that is ``independent,'' (i.e., not
 
``derivative'') of Free Software need not abide by the terms of the
 
applicable Free Software license. As much is required by \S~106 of the
 
Copyright Act, 17 U.S.C. \S~106 (2002), and admitted by Free Software
 
licenses, such as the GPL, which (as we have seen) states in GPLv2~\S0 that ``a
 
`work based on the Program' means either the Program or any derivative
 
work under copyright law.'' It is being a derivative work of Free Software
 
that triggers the necessity to comply with the terms of the Free Software
 
license under which the original work is distributed. Therefore, one is
 
left to ask, just what is a ``derivative work''? The answer to that
 
question differs depending on which court is being asked.
 

	
 
The analysis in this chapter sets forth the differing definitions of
 
derivative work by the circuit courts. The broadest and most
 
established definition of derivative work for software is the
 
abstraction, filtration, and comparison test (``the AFC test'') as
 
created and developed by the Second Circuit. Some circuits, including
 
the Ninth Circuit and the First Circuit, have either adopted narrower
 
versions of the AFC test or have expressly rejected the AFC test in
 
favor of a narrower standard. Further, several other circuits have yet
 
to adopt any definition of derivative work for software.
 

	
 
As an introductory matter, it is important to note that literal copying of
 
a significant portion of source code is not always sufficient to establish
 
that a second work is a derivative work of an original
 
program. Conversely, a second work can be a derivative work of an original
 
program even though absolutely no copying of the literal source code of
 
the original program has been made. This is the case because copyright
 
protection does not always extend to all portions of a program's code,
 
while, at the same time, it can extend beyond the literal code of a
 
program to its non-literal aspects, such as its architecture, structure,
 
sequence, organization, operational modules, and computer-user interface.
 

	
 
\section{The Copyright Act}
 

	
 
The copyright act is of little, if any, help in determining the definition
 
of a derivative work of software. However, the applicable provisions do
 
provide some, albeit quite cursory, guidance. Section 101 of the Copyright
 
Act sets forth the following definitions:
 

	
 
\begin{quotation}
 
A ``computer program'' is a set of statements or instructions to be used
 
directly or indirectly in a computer in order to bring about a certain
 
result.
 

	
...
 
@@ -1438,648 +1438,647 @@ programming language are entitled to copyright protection.  While the
 
court expressly declined to rule whether all APIs are free to use without 
 
license (872 F. Supp.2d 974 at 1002), the court held that the command 
 
structure and taxonomy of the APIs were not protectable under copyright law.
 
Specifically, the court characterized the command structure and taxonomy as
 
both a ``method of operation'' (using an approach not dissimilar to the 
 
First Circuit's analysis in Lotus) and a ``functional requirement for 
 
compatibility'' (using Sega v. Accolade, 977 F.2d 1510 (9th Cir. 1992) and
 
Sony Computer Ent. v. Connectix, 203 F.3d 596 (9th Cir. 2000) as analogies),
 
and thus unprotectable subject matter under \S~102(b). 
 

	
 
Perhaps not surprisingly, there have been few other cases involving a highly
 
detailed software derivative work analysis. Most often, cases involve
 
clearer basis for decision, including frequent bad faith on the part of
 
the defendant or over-aggressiveness on the part of the plaintiff.  
 

	
 
\section{How Much Do Derivative Works Matter?}
 

	
 
It is certainly true that GPL intends for any work that is determined a
 
``derivative work'' under copyright law must be licensed as a whole under
 
GPL\@, as will be discussed in the following chapter.  However, as we finish
 
up our discussion derivative works, we must note that preparation of a
 
derivative work is by far not the only way to create a new work covered by
 
GPL\@.
 

	
 
In fact, while derivative work preparation is perhaps the most exciting area
 
of legal issues to consider, the more mundane ways to create a new work
 
covered by GPL are much more common.  For example, copyright statutes
 
generally require permission from the copyright holder to grant explicit
 
permission to modify a work in any manner.  As discussed in the next chapter,
 
the GPL {\em does} grants such permission, but requires the modify work must
 
also be licensed under the terms of the GPL (and only GPL:
 
see\S~\label{GPLv2s6} in this tutorial).  Determining whether software was
 
modified is a substantially easier analysis than the derivative work
 
discussions and considerations in this chapter.
 

	
 
The question of derivative works, when and how they are made, is undoubtedly
 
an essential discussion in the interpretation and consideration of copyleft.
 
That is why this chapter was included in this tutorial.  However, as we
 
return from this digression and resume discussion of the detailed text of the
 
GPLv2, we must gain a sense of perspective: most GPL questions center around
 
questions of modification and distribution, not preparation of derivative
 
works.  Derivative work preparation is ultimately a small subset of the types
 
of modified versions of the software a developer might create, thus, while an
 
excessive focus on derivative works indulges us in the more exciting areas of
 
copyleft, we must keep a sense of perspective regarding their relative
 
importance.
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 

	
 
\chapter{Modified Source and Binary Distribution}
 
\label{source-and-binary}
 

	
 
In this chapter, we discuss the two core sections that define the rights
 
and obligations for those who modify, improve, and/or redistribute GPL'd
 
software. These sections, GPLv2~\S\S2--3, define the central core rights and
 
requirements of GPLv2\@.
 

	
 
\section{GPLv2~\S2: Share and Share Alike}
 
\label{GPLv2s2}
 

	
 
For many, this is where the ``magic'' happens that defends software
 
freedom upon redistribution.  GPLv2~\S2 is the only place in GPLv2
 
that governs the modification controls of copyright law.  If users
 
distribute modified versions a GPLv2'd program, they must follow the terms of GPLv2~\S2 in making
 
those changes.  Thus, this sections ensures that the body of GPL'd software, as it
 
continues and develops, remains Free as in freedom.
 

	
 
To achieve that goal, GPLv2~\S2 first sets forth that the rights of
 
redistribution of modified versions are the same as those for verbatim
 
copying, as presented in GPLv2~\S1.  Therefore, the details of charging money,
 
keeping copyright notices intact, and other GPLv2~\S1 provisions are intact
 
here as well.  However, there are three additional requirements.
 

	
 
The first (GPLv2~\S2(a)) requires that modified files carry ``prominent
 
notices'' explaining what changes were made and the date of such
 
changes. This section does not prescribe some specific way of
 
marking changes nor does it control the process of how changes are made.
 
Primarily, GPLv2~\S2(a) seeks to ensure that those receiving modified
 
versions know the history of changes to the software.  For some users,
 
it is important to know that they are using the standard version of
 
program, because while there are many advantages to using a fork,
 
there are a few disadvantages.  Users should be informed about the
 
historical context of the software version they use, so that they can
 
make proper support choices.  Finally, GPLv2~\S2(a) serves an academic
 
purpose --- ensuring that future developers can use a diachronic
 
approach to understand the software.
 

	
 
\medskip
 

	
 
The second requirement (GPLv2~\S2(b)) contains the four short lines that embody
 
the legal details of ``share and share alike''.  These 46 words are
 
considered by some to be the most worthy of careful scrutiny because
 
GPLv2~\S2(b), and they
 
can be a source of great confusion when not properly understood.
 

	
 
In considering GPLv2~\S2(b), first note the qualifier: it \textit{only} applies to
 
derivative works that ``you distribute or publish''.  Despite years of
 
derivative, combined and/or modified works that ``you distribute or publish''.  Despite years of
 
education efforts on this matter, many still believe that modifiers
 
of GPL'd software \textit{must} publish or otherwise
 
share their changes.  On the contrary, GPLv2~\S2(b) {\bf does not apply if} the
 
changes are never distributed.  Indeed, the freedom to make private,
 
personal, unshared changes to software for personal use only should be
 
protected and defended.\footnote{Most Free Software enthusiasts believe there is a {\bf
 
    moral} obligation to redistribute changes that are generally useful,
 
  and they often encourage companies and individuals to do so.  However, there
 
  is a clear distinction between what one {\bf ought} to do and what one
 
  {\bf must} do.}
 

	
 
Next, we again encounter the same matter that appears in GPLv2~\S0, in the
 
following text:
 
\begin{quote}
 
``...that in whole or part contains or is derived from the Program or any part thereof.''
 
\end{quote}
 
Again, the GPL relies here on what the copyright law says is a derivative
 
work.  If, under copyright law, the modified version ``contains or is
 
Again, the GPL relies here on copyright law.
 
If, under copyright law, the modified version ``contains or is
 
derived from'' the GPL'd software, then the requirements of GPLv2~\S2(b)
 
apply.  The GPL invokes its control as a copyright license over the
 
modification of the work in combination with its control over distribution
 
of the work.
 

	
 
The final clause of GPLv2~\S2(b) describes what the licensee must do if she is
 
distributing or publishing a work that is deemed a derivative work under
 
copyright law --- namely, the following:
 
The final clause of GPLv2~\S2(b) describes what the licensee must do if she
 
distributes or publishes a modified version of the work --- namely, the following:
 
\begin{quote}
 
[The work must] be licensed as a whole at no charge to all third parties
 
under the terms of this License.
 
\end{quote}
 
That is probably the most tightly-packed phrase in all of the GPL\@.
 
Consider each subpart carefully.
 

	
 
The work ``as a whole'' is what is to be licensed. This is an important
 
point that GPLv2~\S2 spends an entire paragraph explaining; thus this phrase is
 
worthy of a lengthy discussion here.  As a programmer modifies a software
 
program, she generates new copyrighted material --- fixing expressions of
 
ideas into the tangible medium of electronic file storage.  That
 
programmer is indeed the copyright holder of those new changes.  However,
 
those changes are part and parcel to the original work distributed to
 
the programmer under GPL\@. Thus, the license of the original work
 
affects the license of the new whole derivative work.
 
affects the license of the new whole combined and/or derivative work.
 

	
 
% {\cal I}
 
\newcommand{\gplusi}{$\mathcal{G\!\!+\!\!I}$}
 
\newcommand{\worki}{$\mathcal{I}$}
 
\newcommand{\workg}{$\mathcal{G}$}
 

	
 
\label{separate-and-independent}
 

	
 
It is certainly possible to take an existing independent work (called
 
\worki{}) and combine it with a GPL'd program (called \workg{}).  The
 
license of \worki{}, when it is distributed as a separate and independent
 
work, remains the prerogative of the copyright holder of \worki{}.
 
However, when \worki{} is combined with \workg{}, it produces a new work
 
that is the combination of the two (called \gplusi{}). The copyright of
 
this combined work, \gplusi{}, is held by the original copyright
 
holder of each of the two works.
 

	
 
In this case, GPLv2~\S2 lays out the terms by which \gplusi{} may be
 
distributed and copied.  By default, under copyright law, the copyright
 
holder of \worki{} would not have been permitted to distribute \gplusi{};
 
copyright law forbids it without the expressed permission of the copyright
 
holder of \workg{}. (Imagine, for a moment, if \workg{} were a proprietary
 
product --- would its copyright holders  give you permission to create and distribute
 
\gplusi{} without paying them a hefty sum?)  The license of \workg{}, the
 
GPL, states the  options for the copyright holder of \worki{}
 
who may want to create and distribute \gplusi{}. The  GPL's pre-granted
 
permission to create and distribute derivative works, provided the terms
 
permission to create and distribute combined and/or derivative works, provided the terms
 
of the GPL are upheld, goes far above and beyond the permissions that one
 
would get with a typical work not covered by a copyleft license.  (Thus, to
 
say that this condition is any way unreasonable is simply ludicrous.)
 

	
 
\medskip
 

	
 
\label{GPLv2s2-at-no-charge}
 
The next phrase of note in GPLv2~\S2(b) is ``licensed \ldots at no charge.''
 
This phrase  confuses many.  The sloppy reader points out this as ``a
 
contradiction in GPL'' because (in their confused view) that clause of GPLv2~\S2 says that re-distributors cannot
 
charge for modified versions of GPL'd software, but GPLv2~\S1 says that
 
they can.  Avoid this confusion: the ``at no charge'' \textbf{does not} prohibit re-distributors from
 
charging when performing the acts governed by copyright
 
law,\footnote{Recall that you could by default charge for any acts not
 
governed by copyright law, because the license controls are confined
 
by copyright.} but rather that they cannot charge a fee for the
 
\emph{license itself}.  In other words, redistributors of (modified
 
and unmodified) GPL'd works may charge any amount they choose for
 
performing the modifications on contract or the act of transferring
 
the copy to the customer, but they may not charge a separate licensing
 
fee for the software.
 

	
 
GPLv2~\S2(b) further states that the software must ``be licensed \ldots to all
 
third parties.''  This too yields some confusion, and feeds the
 
misconception mentioned earlier --- that all modified versions must be made
 
available to the public at large.  However, the text here does not say
 
that.  Instead, it says that the licensing under terms of the GPL must
 
extend to anyone who might, through the distribution chain, receive a copy
 
of the software.  Distribution to all third parties is not mandated here,
 
but GPLv2~\S2(b) does require re-distributors to license the derivative works in
 
but GPLv2~\S2(b) does require re-distributors to license the whole work in
 
a way that extends to all third parties who may ultimately receive a
 
copy of the software.
 

	
 
In summary, GPLv2\ 2(b) says what terms under which the third parties must
 
receive this no-charge license.  Namely, they receive it ``under the terms
 
of this License'', the GPLv2.  When an entity \emph{chooses} to redistribute
 
a derivative work of GPL'd software, the license of that whole 
 
a work based on GPL'd software, the license of that whole 
 
work must be GPL and only GPL\@.  In this manner, GPLv2~\S2(b) dovetails nicely
 
with GPLv2~\S6 (as discussed in Section~\ref{GPLv2s6} of this tutorial).
 

	
 
\medskip
 

	
 
The final paragraph of GPLv2~\S2 is worth special mention.  It is possible and
 
quite common to aggregate various software programs together on one
 
distribution medium.  Computer manufacturers do this when they ship a
 
pre-installed hard drive, and GNU/Linux distribution vendors do this to
 
give a one-stop CD or URL for a complete operating system with necessary
 
applications.  The GPL very clearly permits such ``mere aggregation'' with
 
programs under any license.  Despite what you hear from its critics, the
 
GPL is nothing like a virus, not only because the GPL is good for you and
 
a virus is bad for you, but also because simple contact with a GPL'd
 
code-base does not impact the license of other programs.  A programmer must
 
expend actual effort  to cause a work to fall under the terms
 
of the GPL.  Redistributors are always welcome to simply ship GPL'd
 
software alongside proprietary software or other unrelated Free Software,
 
as long as the terms of GPL are adhered to for those packages that are
 
truly GPL'd.
 

	
 
\subsection{Right to Private Modification} 
 
\label{gplv2-private-modification}
 

	
 
The issue of private modifications of GPLv2'd works deserves special
 
attention.  While these rights are clearly explicit in GPLv3~\S2\P2 (see
 
\S~\ref{GPLv3S2} of this tutorial for details), the permission to create
 
private modifications is mostly implicit in GPLv2.  Most notably, the
 
requirements of GPLv2~\S2 (and GPLv2~\S3, which will be discussed next) are
 
centered around two different copyright controls: both modification
 
\emph{and} distribution.  As such, GPLv2~\S2's requirements need only be met
 
when a modified version is distributed; one need not follow them for modified
 
versions that are not distributed\footnote{As a matter of best practice, it's
 
  useful to assume that all software may eventually be distributed later,
 
  even if there no plans for distribution at this time.  Too often, GPL
 
  violations occur because of a late distribution decision of software that
 
  was otherwise never intended for distribution.}.
 

	
 
However, the careful reader of GPLv2 will notice that, unlike GPLv3, no other
 
clauses of the license actually give explicit permission to make private
 
modifications.  Since modification of software is a control governed by
 
copyright, a modifier needs permission from the copyright holder to engage in
 
that activity.
 

	
 
In practice, however, traditional GPLv2 interpretation has always assumed
 
that blanket permission to create non-distributed modified versions was
 
available, and the
 
\href{http://www.gnu.org/licenses/gpl-faq.html#GPLRequireSourcePostedPublic}{FSF
 
  has long opined that distribution of modified versions is never mandatory}.
 
This issue is one of many where GPLv3 clarifies in explicit text the implicit
 
policy and intent that was solidified via long-standing interpretation of
 
GPLv2.
 

	
 
\section{GPLv2~\S3: Producing Binaries}
 
\label{GPLv2s3}
 

	
 
Software is a strange beast when compared to other copyrightable works.
 
It is currently impossible to make a film or a book that can be truly
 
obscured.  Ultimately, the full text of a novel, even one written by
 
William Faulkner, must be presented to the reader as words in some
 
human-readable language so that they can enjoy the work.  A film, even one
 
directed by David Lynch, must be perceptible by human eyes and ears to
 
have any value.
 

	
 
Software is not so.  While the source code --- the human-readable
 
representation of software --- is of keen interest to programmers, users and
 
programmers alike cannot make the proper use of software in that
 
human-readable form.  Binary code --- the ones and zeros that the computer
 
can understand --- must be predicable and attainable for the software to
 
be fully useful.  Without the binaries, be they in object or executable
 
form, the software serves only the didactic purposes of computer science.
 

	
 
Under copyright law, binary representations of the software are simply
 
derivative works of the source code.  Applying a systematic process (i.e.,
 
modified versions (and/or derivative works) of the source code.  Applying a systematic process (i.e.,
 
``compilation''\footnote{``Compilation'' in this context refers to the
 
  automated computing process of converting source code into binaries.  It
 
  has absolutely nothing to do with the term ``compilation'' in copyright statues.}) to a work of source code yields binary code. The binary
 
code is now a new work of expression fixed in the tangible medium of
 
electronic file storage.
 

	
 
Therefore, for GPL'd software to be useful, the GPL, since it governs the
 
rules for creation of derivative works, must grant permission for the
 
rules for creation of modified works, must grant permission for the
 
generation of binaries.  Furthermore, notwithstanding the relative
 
popularity of source-based GNU/Linux distributions like Gentoo, users find
 
it extremely convenient to receive distribution of binary software.  Such
 
distribution is the redistribution of derivative works of the software's
 
distribution is the redistribution of modified works of the software's
 
source code.  GPLv2~\S3 addresses the matter of creation and distribution of
 
binary versions.
 

	
 
Under GPLv2~\S3, binary versions may be created and distributed under the
 
terms of GPLv2~\S1--2, so all the material previously discussed applies
 
here.  However, GPLv2~\S3 must go a bit further.  Access to the software's
 
source code is an incontestable prerequisite for the exercise of the
 
fundamental freedoms to modify and improve the software.  Making even
 
the most trivial changes to a software program at the binary level is
 
effectively impossible.  GPLv2~\S3 must ensure that the binaries are never
 
distributed without the source code, so that these freedoms are passed
 
through the distribution chain.
 

	
 
GPLv2~\S3 permits distribution of binaries, and then offers three options for
 
distribution of source code along with binaries. The most common and the
 
least complicated is the option given under GPLv2~\S3(a).
 

	
 
GPLv2~\S3(a) offers the option to directly accompany the source code alongside
 
the distribution of the binaries.  This is by far the most convenient
 
option for most distributors, because it means that the source-code
 
provision obligations are fully completed at the time of binary
 
distribution (more on that later).
 

	
 
Under GPLv2~\S3(a), the source code provided must be the ``corresponding source
 
code.''  Here ``corresponding'' primarily means that the source code
 
provided must be that code used to produce the binaries being distributed.
 
That source code must also be ``complete''.   GPLv2~\S3's penultimate paragraph
 
explains in detail what is meant by ``complete''.  In essence, it is all
 
the material that a programmer of average skill would need to actually use
 
the source code to produce the binaries she has received.  Complete source
 
is required so that, if the licensee chooses, she should be able to
 
exercise her freedoms to modify and redistribute changes.  Without the
 
complete source, it would not be possible to make changes that were
 
actually directly derived from the version received.
 

	
 
Furthermore, GPLv2~\S3 is defending against a tactic that has in fact been
 
seen in GPL enforcement.  Under GPL, if you pay a high price for
 
a copy of GPL'd binaries (which comes with corresponding source, of
 
course), you have the freedom to redistribute that work at any fee you
 
choose, or not at all.  Sometimes, companies attempt a GPL-violating
 
cozenage whereby they produce very specialized binaries (perhaps for
 
an obscure architecture).  They then give source code that does
 
correspond, but withhold the ``incantations'' and build plans they
 
used to make that source compile into the specialized binaries.
 
Therefore, GPLv2~\S3 requires that the source code include ``meta-material'' like
 
scripts, interface definitions, and other material that is used to
 
``control compilation and installation'' of the binaries.  In this
 
manner, those further down the distribution chain are assured that
 
they have the unabated freedom to build their own derivative works
 
they have the unabated freedom to build their own modified works
 
from the sources provided.
 

	
 
Software distribution comes in many
 
forms.  Embedded manufacturers, for example, have the freedom to put
 
GPL'd software into mobile devices with very tight memory and space
 
constraints.  In such cases, putting the source right alongside the
 
binaries on the machine itself might not be an option.  While it is
 
recommended that this be the default way that people comply with GPL, the
 
GPL does provide options when such distribution is unfeasible.
 

	
 
\label{GPLv2s3-medium-customarily}
 
GPLv2~\S3, therefore, allows source code to be provided on any physical
 
``medium customarily used for software interchange.''  By design, this
 
phrase covers a broad spectrum --- the phrase seeks to pre-adapt to
 
changes in  technology.  When GPLv2 was first published in June
 
1991, distribution on magnetic tape was still common, and CD was
 
relatively new.  By 2002, CD was the default.  By 2007, DVD's were the
 
default.  Now, it's common to give software on USB drives and SD cards.  This
 
language in the license must adapt with changing technology.
 

	
 
Meanwhile, the binding created by the word ``customarily'' is key.  Many
 
incorrectly believe that distributing binary on CD and source on the
 
Internet is acceptable.  In the corporate world in industrialized countries, it is indeed customary to
 
simply download a CDs' worth of data quickly.  However, even today in the USA, many computer users are not connected to the Internet, and most people connected
 
to the Internet still have limited download speeds.  Downloading
 
CDs full of data is not customary for them in the least.  In some cities
 
in Africa, computers are becoming more common, but Internet connectivity
 
is still available only at a few centralized locations.  Thus, the
 
``customs'' here are normalized for a worldwide userbase.  Simply
 
providing source on the Internet --- while it is a kind, friendly and
 
useful thing to do --- is not usually sufficient.
 

	
 
Note, however, a major exception to this rule, given by the last paragraph
 
of GPLv2~\S3. \emph{If} distribution of the binary files is made only on the
 
Internet (i.e., ``from a designated place''), \emph{then} simply providing
 
the source code right alongside the binaries in the same place is
 
sufficient to comply with GPLv2~\S3.
 

	
 
\medskip
 

	
 
As is shown above, under GPLv2~\S3(a), embedded manufacturers can put the
 
binaries on the device and ship the source code along on a CD\@.  However,
 
sometimes this turns out to be too costly.  Including a CD with every
 
device could prove too costly, and may practically (although not legally)
 
prohibit using GPL'd software. For this situation and others like it, GPLv2\S~3(b) is available.
 

	
 
GPLv2~\S3(b) allows a distributor of binaries to instead provide a written
 
offer for source code alongside those binaries.  This is useful in two
 
specific ways.  First, it may turn out that most users do not request the
 
source, and thus the cost of producing the CDs is saved --- a financial
 
and environmental windfall.  In addition, along with a GPLv2~\S3(b) compliant
 
offer for source, a binary distributor might choose to \emph{also} give a
 
URL for source code.  Many who would otherwise need a CD with source might
 
turn out to have those coveted high bandwidth connections, and are able to
 
download the source instead --- again yielding environmental and financial
 
windfalls.
 

	
 
However, note that regardless of how many users prefer to get the
 
source online, GPLv2~\S3(b) does place lasting long-term obligations on the
 
binary distributor.  The binary distributor must be prepared to honor
 
that offer for source for three years and ship it out (just as they
 
would have had to do under GPLv2~\S3(a)) at a moment's notice when they
 
receive such a request.  There is real organizational cost here:
 
support engineers must be trained how to route source requests, and
 
source CD images for every release version for the last three years
 
must be kept on hand to burn such CDs quickly. The requests might not
 
even come from actual customers; the offer for source must be valid
 
for ``any third party''.
 

	
 
That phrase is another place where some get confused --- thinking again
 
that full public distribution of source is required.  The offer for source
 
must be valid for ``any third party'' because of the freedoms of
 
redistribution granted by GPLv2~\S\S1--2.  A company may ship a binary image
 
and an offer for source to only one customer.  However, under GPL, that
 
customer has the right to redistribute that software to the world if she
 
likes.  When she does, that customer has an obligation to make sure that
 
those who receive the software from her can exercise their freedoms under
 
GPL --- including the freedom to modify, rebuild, and redistribute the
 
source code.
 

	
 
GPLv2~\S3(c) is created to save her some trouble, because by itself GPLv2~\S3(b)
 
would unfairly favor large companies.  GPLv2~\S3(b) allows the
 
separation of the binary software from the key tool that people can use
 
to exercise their freedom. The GPL permits this separation because it is
 
good for re-distributors, and those users who turn out not to need the
 
source.  However, to ensure equal rights for all software users, anyone
 
along the distribution chain must have the right to get the source and
 
exercise those freedoms that require it.
 

	
 
Meanwhile, GPLv2~\S3(b)'s compromise primarily benefits companies that
 
distribute binary software commercially.  Without GPLv2~\S3(c), that benefit
 
would be at the detriment of the companies' customers; the burden of
 
source code provision would be unfairly shifted to the companies'
 
customers.  A customer, who had received binaries with a GPLv2~\S3(b)-compliant
 
offer, would be required under GPLv2 (sans GPLv2~\S3(c)) to acquire the source,
 
merely to give a copy of the software to a friend who needed it.  GPLv2~\S3(c)
 
reshifts this burden to entity who benefits from GPLv2~\S3(b).
 

	
 
GPLv2~\S3(c) allows those who undertake \emph{noncommercial} distribution to
 
simply pass along a GPLv2~\S3(b)-compliant source code offer.  The customer who
 
wishes to give a copy to her friend can now do so without provisioning the
 
source, as long as she gives that offer to her friend.  By contrast, if
 
she wanted to go into business for herself selling CDs of that software,
 
she would have to acquire the source and either comply via GPLv2~\S3(a), or
 
write her own GPLv2~\S3(b)-compliant source offer.
 

	
 
This process is precisely the reason why a GPLv2~\S3(b) source offer must be
 
valid for all third parties.  At the time the offer is made, there is no
 
way of knowing who might end up noncommercially receiving a copy of the
 
software.  Companies who choose to comply via GPLv2~\S3(b) must thus be
 
prepared to honor all incoming source code requests.  For this and the
 
many other additional necessary complications under GPLv2~\S\S3(b--c), it is
 
only rarely a better option than complying via GPLv2~\S3(a).
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{GPL's Implied Patent Grant}
 
\label{gpl-implied-patent-grant}
 

	
 
We digress again briefly from our section-by-section consideration of GPLv2
 
to consider the interaction between the terms of GPL and patent law. The
 
GPLv2, despite being silent with respect to patents, actually confers on its
 
licensees more rights to a licensor's patents than those licenses that
 
purport to address the issue. This is the case because patent law, under
 
the doctrine of implied license, gives to each distributee of a patented
 
article a license from the distributor to practice any patent claims owned
 
or held by the distributor that cover the distributed article. The
 
implied license also extends to any patent claims owned or held by the
 
distributor that cover ``reasonably contemplated uses'' of the patented
 
article. To quote the Federal Circuit Court of Appeals, the highest court
 
for patent cases other than the Supreme Court:
 

	
 
\begin{quotation}
 
Generally, when a seller sells a product without restriction, it in
 
effect promises the purchaser that in exchange for the price paid, it will
 
not interfere with the purchaser's full enjoyment of the product
 
purchased. The buyer has an implied license under any patents of the
 
seller that dominate the product or any uses of the product to which the
 
parties might reasonably contemplate the product will be put.
 
\end{quotation}
 
Hewlett-Packard Co. v. Repeat-O-Type Stencil Mfg. Corp., Inc., 123 F.3d
 
1445, 1451 (Fed. Cir. 1997).
 

	
 
Of course, Free Software is licensed, not sold, and there are indeed
 
restrictions placed on the licensee, but those differences are not likely
 
to prevent the application of the implied license doctrine to Free
 
Software, because software licensed under the GPL grants the licensee the
 
right to make, use, and sell the software, each of which are exclusive
 
rights of a patent holder. Therefore, although the GPLv2 does not expressly
 
grant the licensee the right to do those things under any patents the
 
licensor may have that cover the software or its reasonably contemplated
 
uses, by licensing the software under the GPLv2, the distributor impliedly
 
licenses those patents to the GPLv2 licensee with respect to the GPLv2'd
 
software.
 

	
 
An interesting issue regarding this implied patent license of GPLv2'd
 
software is what would be considered ``uses of the [software] to which
 
the parties might reasonably contemplate the product will be put.'' A
 
clever advocate may argue that the implied license granted by GPLv2 is
 
larger in scope than the express license in other Free Software
 
licenses with express patent grants, in that the patent license
 
clause of many of those other Free  Software licenses are specifically 
 
limited to the patent claims covered by the code as licensed by the patentee.
 

	
 
In contrast, a GPLv2 licensee, under the doctrine of implied patent license, 
 
is free to practice any patent claims held by the licensor that cover 
 
``reasonably contemplated uses'' of the GPL'd code, which may very well 
 
include creation and distribution of derivative works since the GPL's terms, 
 
include creation and distribution of modified works since the GPL's terms, 
 
under which the patented code is distributed, expressly permits such activity.
 

	
 

	
 
Further supporting this result is the Federal Circuit's pronouncement that
 
the recipient of a patented article has, not only an implied license to
 
make, use, and sell the article, but also an implied patent license to
 
repair the article to enable it to function properly, Bottom Line Mgmt.,
 
Inc. v. Pan Man, Inc., 228 F.3d 1352 (Fed. Cir. 2000). Additionally, the
 
Federal Circuit extended that rule to include any future recipients of the
 
patented article, not just the direct recipient from the distributor.
 
This theory comports well with the idea of Free Software, whereby software
 
is distributed among many entities within the community for the purpose
 
of constant evolution and improvement. In this way, the law of implied
 
patent license used by the GPLv2 ensures that the community mutually
 
benefits from the licensing of patents to any single community member.
 

	
 
Note that simply because GPLv2'd software has an implied patent license does
 
not mean that any patents held by a distributor of GPLv2'd code become
 
worthless. To the contrary, the patents are still valid and enforceable
 
against either:
 

	
 
\begin{enumerate}
 
 \renewcommand{\theenumi}{\alph{enumi}}
 
 \renewcommand{\labelenumi}{\textup{(\theenumi)}}
 

	
 
\item any software other than that licensed under the GPLv2 by the patent
 
  holder, and
 

	
 
\item any party that does not comply with the GPLv2
 
with respect to the licensed software.
 
\end{enumerate}
 

	
 
\newcommand{\compB}{$\mathcal{B}$}
 
\newcommand{\compA}{$\mathcal{A}$}
 

	
 
For example, if Company \compA{} has a patent on advanced Web browsing, but
 
also licenses a Web browsing program under the GPLv2, then it
 
cannot assert the patent against any party based on that party's use of 
 
Company \compA{}'s GPL'ed Web browsing software program, or on that party's
 
creation and use of derivative works of that GPL'ed program.  However, if a
 
creation and use of modified versions of that GPL'ed program.  However, if a
 
party uses that program without
 
complying with the GPLv2, then Company \compA{} can assert both copyright
 
infringement claims against the non-GPLv2-compliant party and
 
infringement of the patent, because the implied patent license only
 
extends to use of the software in accordance with the GPLv2. Further, if
 
Company \compB{} distributes a competitive advanced Web browsing program 
 
that is not a derivative work of Company \compA{}'s GPL'd Web browsing software
 
that is not a modified version of Company \compA{}'s GPL'd Web browsing software
 
program, Company \compA{} is free to assert its patent against any user or
 
distributor of that product. It is irrelevant whether Company \compB's
 
program is also distributed under the GPLv2, as Company \compB{} can not grant
 
implied licenses to Company \compA's patent.
 

	
 
This result also reassures companies that they need not fear losing their
 
proprietary value in patents to competitors through the GPLv2 implied patent
 
license, as only those competitors who adopt and comply with the GPLv2's
 
terms can benefit from the implied patent license. To continue the
 
example above, Company \compB{} does not receive a free ride on Company
 
\compA's patent, as Company \compB{} has not licensed-in and then
 
redistributed Company A's advanced Web browser under the GPLv2. If Company
 
\compB{} does do that, however, Company \compA{} still has not lost
 
competitive advantage against Company \compB{}, as Company \compB{} must then,
 
when it re-distributes Company \compA's program, grant an implied license
 
to any of its patents that cover the program. Further, if Company \compB{}
 
relicenses an improved version of Company A's program, it must do so under
 
the GPLv2, meaning that any patents it holds that cover the improved version
 
are impliedly licensed to any licensee. As such, the only way Company
 
\compB{} can benefit from Company \compA's implied patent license, is if it,
 
itself, distributes Company \compA's software program and grants an
 
implied patent license to any of its patents that cover that program.
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{Defending Freedom on Many Fronts}
 

	
 
Chapters~\ref{run-and-verbatim} and~\ref{source-and-binary} presented the
 
core freedom-defending provisions of GPLv2\@, which are in GPLv2~\S\S0--3.
 
GPLv2\S\S~4--7 of the GPLv2 are designed to ensure that GPLv2~\S\S0--3 are
 
not infringed, are enforceable, are kept to the confines of copyright law but
 
also  not trumped by other copyright agreements or components of other
 
entirely separate legal systems.  In short, while GPLv2~\S\S0--3 are the parts
 
of the license that defend the freedoms of users and programmers,
 
GPLv2~\S\S4--7 are the parts of the license that keep the playing field clear
 
so that \S\S~0--3 can do their jobs.
 

	
 
\section{GPLv2~\S4: Termination on Violation}
 
\label{GPLv2s4}
 

	
 
GPLv2~\S4 is GPLv2's termination clause.  Upon first examination, it seems
 
strange that a license with the goal of defending users' and programmers'
 
freedoms for perpetuity in an irrevocable way would have such a clause.
 
However, upon further examination, the difference between irrevocability
 
and this termination clause becomes clear.
 

	
 
The GPL is irrevocable in the sense that once a copyright holder grants
 
rights for someone to copy, modify and redistribute the software under terms
 
of the GPL, they cannot later revoke that grant.  Since the GPL has no
 
provision allowing the copyright holder to take such a prerogative, the
 
license is granted as long as the copyright remains in effect.\footnote{In
 
  the USA, due to unfortunate legislation, the length of copyright is nearly
 
  perpetual, even though the Constitution forbids perpetual copyright.} The
 
copyright holders have the right to relicense the same work under different
 
licenses (see Section~\ref{Proprietary Relicensing} of this tutorial), or to
 
stop distributing the GPLv2'd version (assuming GPLv2~\S3(b) was never used),
 
but they may not revoke the rights under GPLv2 already granted.
 

	
 
In fact, when an entity loses their right to copy, modify and distribute
 
GPL'd software, it is because of their \emph{own actions}, not that of the
 
copyright holder.  The copyright holder does not decide when GPLv2~\S4
 
termination occurs (if ever); rather, the actions of the licensee determine
 
that.
 

	
 
Under copyright law, the GPL has granted various rights and freedoms to
 
the licensee to perform specific types of copying, modification, and
 
redistribution.  By default, all other types of copying, modification, and
 
redistribution are prohibited.  GPLv2~\S4 says that if you undertake any of
 
those other types (e.g., redistributing binary-only in violation of GPLv2~\S3),
 
then all rights under the license --- even those otherwise permitted for
 
those who have not violated --- terminate automatically.
 

	
 
GPLv2~\S4 makes GPLv2 enforceable.  If licensees fail to adhere to the
 
license, then they are stuck without any permission under to engage in
 
activities covered by copyright law.  They must completely cease and desist
 
from all copying, modification and distribution of the GPL'd software.
 

	
 
At that point, violating licensees must gain the forgiveness of the copyright
 
holders to have their rights restored.  Alternatively, the violators could
 
negotiate another agreement, separate from GPL, with the copyright
 
holder.  Both are common practice, although
 
\tutorialpartsplit{as discussed in \textit{A Practical Guide to GPL
 
    Compliance}, there are }{Chapter~\ref{compliance-understanding-whos-enforcing}
 
  explains further} key differences between these two very different uses of GPL.
 

	
 
\section{GPLv2~\S5: Acceptance, Copyright Style}
 
\label{GPLv2s5}
 

	
 
GPLv2~\S5 brings us to perhaps the most fundamental misconception and common
 
confusion about GPLv2\@. Because of the prevalence of proprietary software,
 
most users, programmers, and lawyers alike tend to be more familiar with
 
EULAs. EULAs are believed by their authors to be contracts, requiring
 
formal agreement between the licensee and the software distributor to be
 
valid. This has led to mechanisms like ``shrink-wrap'' and ``click-wrap''
 
as mechanisms to perform acceptance ceremonies with EULAs.
 

	
 
The GPL does not need contract law to ``transfer rights.''  Usually, no rights
...
 
@@ -3712,726 +3711,729 @@ does not automatically apply to all GPLv3'd works.
 
%% transmission of source, and to the technically imprecise or inaccurate
 
%% use of the phrase ``same network session.''
 

	
 
%% We have concluded that any redrafting of the 7b4 clause would fail to
 
%% satisfy the concerns of both sets of its critics.  The first group
 
%% maintains that GPLv3 should do nothing about the problem of public
 
%% use. The second group would prefer for GPLv3 itself to have an
 
%% Affero-like condition, but that seems to us too drastic. By permitting
 
%% GPLv3-covered code to be linked with code covered by version 2 of the
 
%% Affero GPL, the new section 13 honors our original commitment to
 
%% achieving GPL compatibility for the Affero license.
 

	
 
%% Version 2 of the Affero GPL is not yet published.  We will work with
 
%% Affero, Inc., and with all other interested members of our community, to
 
%% complete the drafting of this license following the release of Draft 3,
 
%% with a goal of having a final version available by the time of our
 
%% adoption of the final version of GPLv3.  We hope the new Affero license
 
%% will satisfy those developers who are concerned about the issue of
 
%% public use of unconveyed versions but who have concerns about the
 
%% narrowness of the condition in the existing Affero license.
 

	
 
%% As the second sentence in section 13 indicates, when a combined work is
 
%% made by linking GPLv3-covered code with Affero-covered code, the
 
%% copyleft on one part will not extend to the other part.\footnote{The
 
%% plan is that the additional requirement of the new Affero license will
 
%% state a reciprocal limitation.} That is to say, in such combinations,
 
%% the Affero requirement will apply only to the part that was brought into
 
%% the combination under the Affero license.  Those who receive such a
 
%% combination and do not wish to use code under the Affero requirement may
 
%% remove the Affero-covered portion of the combination.
 

	
 
Meanwhile, those who criticize the permission to link with code under the Affero
 
GPL should recognize that most other free software licenses also permit
 
such linking. 
 

	
 
\section{GPLv3~\S14: So, When's GPLv4?}
 
\label{GPLv3s14}
 

	
 
No substantive change has been made in section 14. The wording of the section
 
has been revised slightly to make it clearer.
 

	
 
It's unclear when the FSF might consider publishing GPLv4.  However, this
 
section makes it clear that the FSF is the sole authority who can decide
 
such.
 

	
 
The main addition to this section allows a third-party proxy to be appointed
 
by contributors who wish someone else to make relicensing to new versions of
 
GPL when they are released.  This is a ``halfway'' point between using ``-only''
 
or ``-or-later'' by consolidating the decision-making on that issue to a
 
single authority.
 

	
 
% FIXME-LATER: better proxy description
 

	
 
\section{GPLv3~\S15--17: Warranty Disclaimers and Liability Limitation}
 

	
 
No substantive changes have been made in sections 15 and 16.
 

	
 
% FIXME-LATER: more, plus 17
 

	
 
% FIXME-LATER: Section header needed here about choice of law.
 

	
 
% FIXME-LATER: reword into tutorial
 

	
 
%% Some have asked us to address the difficulties of internationalization
 
%% by including, or permitting the inclusion of, a choice of law
 
%% provision.  We maintain that this is the wrong approach.  Free
 
%% software licenses should not contain choice of law clauses, for both
 
%% legal and pragmatic reasons.  Choice of law clauses are creatures of
 
%% contract, but the substantive rights granted by the GPL are defined
 
%% under applicable local copyright law. Contractual free software
 
%% licenses can operate only to diminish these rights.  Choice of law
 
%% clauses also raise complex questions of interpretation when works of
 
%% software are created by combination and extension.  There is also the
 
%% real danger that a choice of law clause will specify a jurisdiction
 
%% that is hostile to free software principles.
 

	
 
%% % FIXME-LATER: reword into tutorial, \ref to section 7.
 

	
 
%% Our revised version of section 7 makes explicit our view that the
 
%% inclusion of a choice of law clause by a licensee is the imposition of
 
%% an additional requirement in violation of the GPL.  Moreover, if a
 
%% program author or copyright holder purports to supplement the GPL with
 
%% a choice of law clause, section 7 now permits any licensee to remove
 
%% that clause.
 

	
 

	
 
% FIXME-LATER: does this need to be a section, describing how it was out then in
 
% then out then in? :)
 

	
 
Finally, the FSF shortened the section on ``How to Apply These
 
Terms to Your New Programs'' to just the bare essentials.
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{The Lesser GPL}
 

	
 
As we have seen in our consideration of the GPL, its text is specifically
 
designed to cover all possible derivative works under copyright law. Our
 
goal in designing the GPL was to make sure that any derivative work of GPL'd
 
software was itself released under the GPL when distributed. Reaching as far
 
as copyright law will allow is the most direct way to reach that goal.
 
designed to cover all possible derivative, modified and/or combined works under copyright law. Our
 
goal in designing the GPL was to maximize its use of the controls of
 
copyright law to maximize the number of works that were covered by GPL. 
 

	
 
However, while the strategic goal is to bring as much Free Software
 
However, while the strategic goal of software freedom is to bring as much Free Software
 
into the world as possible, particular tactical considerations
 
regarding software freedom dictate different means. Extending the
 
copyleft effect as far as copyright law allows is not always the most
 
prudent course in reaching the goal. In particular situations, even
 
those of us with the goal of building a world where all published
 
software is Free Software realize that full copyleft does not best
 
serve us. The GNU Lesser General Public License (``GNU LGPL'') was
 
designed as a solution for such situations.
 

	
 
\section{The First LGPL'd Program}
 

	
 
The first example that FSF encountered where such altered tactics were
 
needed was when work began on the GNU C Library. The GNU C Library would
 
become (and today, now is) a drop-in replacement for existing C libraries.
 
On a Unix-like operating system, C is the lingua franca and the C library
 
is an essential component for all programs. It is extremely difficult to
 
construct a program that will run with ease on a Unix-like operating
 
system without making use of services provided by the C library --- even
 
if the program is written in a language other than C\@. Effectively, all
 
user application programs that run on any modern Unix-like system must
 
make use of the C library.
 

	
 
By the time work began on the GNU implementation of the C libraries, there
 
were already many C libraries in existence from a variety of vendors.
 
Every proprietary Unix vendor had one, and many third parties produced
 
smaller versions for special purpose use. However, our goal was to create
 
a C library that would provide equivalent functionality to these other C
 
libraries on a Free Software operating system (which in fact happens today
 
on modern GNU/Linux systems, which all use the GNU C Library).
 

	
 
Unlike existing GNU application software, however, the licensing
 
implications of releasing the GNU C Library (``glibc'') under the GPL were
 
somewhat different. Applications released under the GPL would never
 
themselves become part of proprietary software. However, if glibc were
 
released under the GPL, it would require that any application distributed for
 
the GNU/Linux platform be released under the GPL\@.
 

	
 
Since all applications on a Unix-like system depend on the C library, it
 
means that they must link with that library to function on the system. In
 
other words, all applications running on a Unix-like system must be
 
combined with the C library to form a new whole derivative work that is
 
combined with the C library to form a new whole work that is
 
composed of the original application and the C library. Thus, if glibc
 
were GPL'd, each and every application distributed for use on GNU/Linux
 
would also need to be GPL'd, since to even function, such applications
 
would need to be combined into larger derivative works by linking with
 
would need to be combined into larger works by linking with
 
glibc.
 

	
 
At first glance, such an outcome seems like a windfall for Free Software
 
advocates, since it stops all proprietary software development on
 
GNU/Linux systems. However, the outcome is a bit more subtle. In a world
 
where many C libraries already exist, many of which could easily be ported
 
to GNU/Linux, a GPL'd glibc would be unlikely to succeed. Proprietary
 
vendors would see the excellent opportunity to license their C libraries
 
to anyone who wished to write proprietary software for GNU/Linux systems.
 
The de-facto standard for the C library on GNU/Linux would likely be not
 
glibc, but the most popular proprietary one.
 

	
 
Meanwhile, the actual goal of releasing glibc under the GPL --- to ensure no
 
proprietary applications on GNU/Linux --- would be unattainable in this
 
scenario. Furthermore, users of those proprietary applications would also
 
be users of a proprietary C library, not the Free glibc.
 

	
 
The Lesser GPL was initially conceived to handle this scenario. It was
 
clear that the existence of proprietary applications for GNU/Linux was
 
inevitable. Since there were so many C libraries already in existence, a
 
new one under the GPL would not stop that tide. However, if the new C library
 
were released under a license that permitted proprietary applications
 
to link with it, but made sure that the library itself remained Free,
 
an ancillary goal could be met. Users of proprietary applications, while
 
they would not have the freedom to copy, share, modify and redistribute
 
the application itself, would have the freedom to do so with respect to
 
the C library.
 

	
 
There was no way the license of glibc could stop or even slow the creation
 
of proprietary applications on GNU/Linux. However, loosening the
 
restrictions on the licensing of glibc ensured that nearly all proprietary
 
applications at least used a Free C library rather than a proprietary one.
 
This trade-off is central to the reasoning behind the LGPL\@.
 

	
 
Of course, many people who use the LGPL today are not thinking in these
 
terms. In fact, they are often choosing the LGPL because they are looking
 
for a ``compromise'' between the GPL and the X11-style liberal licensing.
 
However, understanding FSF's reasoning behind the creation of the LGPL is
 
helpful when studying the license.
 

	
 

	
 
\section{What's the Same?}
 

	
 
Much of the text of the LGPL is identical to the GPL\@. As we begin our
 
discussion of the LGPL, we will first eliminate the sections that are
 
identical, or that have the minor modification changing the word
 
``Program'' to ``Library.''
 

	
 
First, LGPLv2.1~\S1, the rules for verbatim copying of source, are
 
equivalent to those in GPLv2~\S1.
 

	
 
Second, LGPLv2.1~\S8 is equivalent GPLv2~\S4\@. In both licenses, this
 
section handles termination in precisely the same manner.
 

	
 
LGPLv2.1~\S9 is equivalent to GPLv2~\S5\@. Both sections assert that
 
the license is a copyright license, and handle the acceptance of those
 
copyright terms.
 

	
 
LGPLv2.1~\S10 is equivalent to GPLv2~\S6. They both protect the
 
distribution system of Free Software under these licenses, to ensure that
 
up, down, and throughout the distribution chain, each recipient of the
 
software receives identical rights under the license and no other
 
restrictions are imposed.
 

	
 
LGPLv2.1~\S11 is GPLv2~\S7. As discussed, it is used to ensure that
 
other claims and legal realities, such as patent licenses and court
 
judgments, do not trump the rights and permissions granted by these
 
licenses, and requires that distribution be halted if such a trump is
 
known to exist.
 

	
 
LGPLv2.1~\S12 adds the same features as GPLv2~\S8. These sections are
 
used to allow original copyright holders to forbid distribution in
 
countries with draconian laws that would otherwise contradict these
 
licenses.
 

	
 
LGPLv2.1~\S13 sets up the FSF as the steward of the LGPL, just as GPLv2~\S9
 
does for GPL. Meanwhile, LGPLv2.1~\S14 reminds licensees that copyright
 
holders can grant exceptions to the terms of LGPL, just as GPLv2~\S10
 
reminds licensees of the same thing.
 

	
 
Finally, the assertions of no warranty and limitations of liability are
 
identical; thus LGPLv2.1~\S15 and LGPLv2.1~\S16 are the same as GPLv2~\S11 and \S
 
12.
 

	
 
As we see, the entire latter half of the license is identical.
 
The parts which set up the legal boundaries and meta-rules for the license
 
are the same. It is our intent that the two licenses operate under the
 
same legal mechanisms and are enforced precisely the same way.
 

	
 
We strike a difference only in the early portions of the license.
 
Namely, in the LGPL we go into deeper detail of granting various permissions to
 
create derivative works, so the re-distributors can make
 
some proprietary derivatives. Since we simply do not allow the
 
license to stretch as far as copyright law does regarding what
 
derivative works must be relicensed under the same terms, we must go
 
further to explain which derivative works we will allow to be
 
proprietary. Thus, we'll see that the front matter of the LGPL is a
 
create certain types of combinations, modifications and derivations.
 
The LGPL does not stretch the requirements as far as copyright law does regarding what
 
works must be relicensed under the same terms.  Therefore, LGPL must
 
in detail explain which works can be proprietary.  Thus, we'll see that the front matter of the LGPL is a
 
bit more wordy and detailed with regards to the permissions granted to
 
those who modify or redistribute the software.
 

	
 
\section{Additions to the Preamble}
 

	
 
Most of the LGPL's Preamble is identical, but the last seven paragraphs
 
introduce the concepts and reasoning behind creation of the license,
 
presenting a more generalized and briefer version of the story with which
 
we began our consideration of the LGPL\@.
 

	
 
In short, FSF designed the LGPL for those edge cases where the freedom of the
 
public can better be served by a more lax licensing system. FSF doesn't
 
encourage use of the LGPL automatically for any software that happens to be a
 
library; rather, FSF suggests that it only be used in specific cases, such
 
as the following:
 

	
 
\begin{itemize}
 

	
 
\item To encourage the widest possible use of a Free Software library, so
 
  it becomes a de-facto standard over similar, although not
 
  interface-identical, proprietary alternatives
 

	
 
\item To encourage use of a Free Software library that already has
 
  interface-identical proprietary competitors that are more developed
 

	
 
\item To allow a greater number of users to get freedom, by encouraging
 
  proprietary companies to pick a Free alternative for its otherwise
 
  proprietary products
 

	
 
\end{itemize}
 

	
 
The LGPL's preamble sets forth the limits to which the license seeks to go in
 
chasing these goals. The LGPL is designed to ensure that users who happen to
 
acquire software linked with such libraries have full freedoms with
 
respect to that library. They should have the ability to upgrade to a newer
 
or modified Free version or to make their own modifications, even if they
 
cannot modify the primary software program that links to that library.
 

	
 
Finally, the preamble introduces two terms used throughout the license to
 
clarify between the different types of derivative works: ``works that use
 
clarify between the different types of combined works: ``works that use
 
the library,'' and ``works based on the library.''  Unlike the GPL, the LGPL must
 
draw some lines regarding derivative works. We do this here in this
 
draw some lines regarding permissibly proprietary combined works.  We do this here in this
 
license because we specifically seek to liberalize the rights afforded to
 
those who make derivative works. In the GPL, we reach as far as copyright law
 
those who make combined works. In the GPL, we reach as far as copyright law
 
allows. In the LGPL, we want to draw a line that allows some derivative works
 
copyright law would otherwise prohibit if the copyright holder exercised
 
his full permitted controls over the work.
 

	
 
\section{An Application: A Work that Uses the Library}
 

	
 
In the effort to allow certain proprietary derivative works and prohibit
 
others, the LGPL distinguishes between two classes of derivative works:
 
In the effort to allow certain proprietary works and prohibit
 
others, the LGPL distinguishes between two classes of works:
 
``works based on the library,'' and ``works that use the library.''  The
 
distinction is drawn on the bright line of binary (or runtime) derivative
 
works and source code derivatives. We will first consider the definition
 
distinction is drawn on the bright line of binary (or runtime) combined
 
works and modified versions of source code. We will first consider the definition
 
of a ``work that uses the library,'' which is set forth in LGPLv2.1~\S5.
 

	
 
We noted in our discussion of GPLv2~\S3 (discussed in
 
Section~\ref{GPLv2s3} of this document) that binary programs when
 
compiled and linked with GPL'd software are derivative works of that GPL'd
 
software. This includes both linking that happens at compile-time (when
 
compiled and linked with GPL'd software are covered as a whole by GPL\@.
 
This includes both linking that happens at compile-time (when
 
the binary is created) or at runtime (when the binary -- including library
 
and main program both -- is loaded into memory by the user). In GPL,
 
binary derivative works are controlled by the terms of the license (in GPLv2~\S3),
 
and distributors of such binary derivatives must release full
 
binary works are controlled by the terms of the license (in GPLv2~\S3),
 
and distributors of such binary works must release full
 
corresponding source\@.
 

	
 
In the case of LGPL, these are precisely the types of derivative works
 
we wish to permit. This scenario, defined in LGPL as ``a work that uses
 
the library,'' works as follows:
 
The LGPL, by contrast, allows partial proprietarization of such binary works.
 
This scenario, defined in LGPL as ``a work that uses the library,'' works as
 
follows:
 

	
 
\newcommand{\workl}{$\mathcal{L}$}
 
\newcommand{\lplusi}{$\mathcal{L\!\!+\!\!I}$}
 

	
 
\begin{itemize}
 

	
 
\item A new copyright holder creates a separate and independent work,
 
  \worki{}, that makes interface calls (e.g., function calls) to the
 
  LGPL'd work, called \workl{}, whose copyright is held by some other
 
  party. Note that since \worki{} and \workl{} are separate and
 
  independent works, there is no copyright obligation on this new copyright
 
  holder with regard to the licensing of \worki{}, at least with regard to
 
  the source code.
 

	
 
\item The new copyright holder, for her software to be useful, realizes
 
  that it cannot run without combining \worki{} and \workl{}.
 
  Specifically, when she creates a running binary program, that running
 
  binary must be a derivative work, called \lplusi{}, that the user can
 
  binary must be a combined work, called \lplusi{}, that the user can
 
  run.
 

	
 
\item Since \lplusi{} is a derivative work of both \worki{} and \workl{},
 
\item Since \lplusi{} is a based on both \worki{} and \workl{},
 
  the license of \workl{} (the LGPL) can put restrictions on the license
 
  of \lplusi{}. In fact, this is what the LGPL does.
 

	
 
\end{itemize}
 

	
 
We will talk about the specific restrictions LGPLv2.1 places on ``works
 
that use the library'' in detail in Section~\ref{lgpl-section-6}. For
 
now, focus on the logic related to how the LGPLv2.1 places requirements on
 
the license of \lplusi{}. Note, first of all, the similarity between
 
this explanation and that in Section~\ref{separate-and-independent},
 
which discussed the combination of otherwise separate and independent
 
works with GPL'd code. Effectively, what LGPLv2.1 does is say that when a
 
new work is otherwise separate and independent, but has interface
 
calls out to an LGPL'd library, then it is considered a ``work that
 
uses the library.''
 

	
 
In addition, the only reason that LGPLv2.1 has any control over the licensing
 
of a ``work that uses the library'' is for the same reason that GPL has
 
some say over separate and independent works. Namely, such controls exist
 
because the {\em binary combination\/} (\lplusi{}) that must be created to
 
make the separate work (\worki{}) at all useful is a derivative work of
 
make the separate work (\worki{}) at all useful is a  work based on
 
the LGPLv2.1'd software (\workl{}).
 

	
 
Thus, a two-question test that will help indicate if a particular work is
 
a ``work that uses the library'' under LGPLv2.1 is as follows:
 

	
 
\begin{enumerate}
 

	
 
\item Is the source code of the new copyrighted work, \worki{}, a
 
  completely independent work that stands by itself, and includes no
 
  source code from \workl{}?
 

	
 
\item When the source code is compiled, does it create a derivative work
 
  by combining with \workl{}, either by static (compile-time) or dynamic
 
\item When the source code is compiled, does it combine into a single work
 
  with \workl{}, either by static (compile-time) or dynamic
 
  (runtime) linking, to create a new binary work, \lplusi{}?
 
\end{enumerate}
 

	
 
If the answers to both questions are ``yes,'' then \worki{} is most likely
 
a ``work that uses the library.''  If the answer to the first question
 
``yes,'' but the answer to the second question is ``no,'' then most likely
 
\worki{} is neither a ``work that uses the library'' nor a ``work based on
 
the library.''  If the answer to the first question is ``no,'' but the
 
answer to the second question is ``yes,'' then an investigation into
 
whether or not \worki{} is in fact a ``work based on the library'' is
 
warranted.
 

	
 
\section{The Library, and Works Based On It}
 

	
 
In short, a ``work based on the library'' could be defined as any
 
derivative work of LGPL'd software that cannot otherwise fit the
 
work based on the LGPL'd software that cannot otherwise fit the
 
definition of a ``work that uses the library.''  A ``work based on the
 
library'' extends the full width and depth of copyright derivative works,
 
in the same sense that the GPL does.
 
library'' extends the full width and depth of derivative, combined and/or
 
modified works under copyright law, in the same sense that the GPL does.
 

	
 
Most typically, one creates a ``work based on the library'' by directly
 
modifying the source of the library. Such a work could also be created by
 
tightly integrating new software with the library. The lines are no doubt
 
fuzzy, just as they are with GPL'd works, since copyright law gives us no
 
litmus test for derivative works of a software program.
 
litmus test for determining if a given work is a derivative or otherwise a
 
modified version of another software program.
 

	
 
Thus, the test to use when considering whether something is a ``work
 
based on the library'' is as follows:
 

	
 
\begin{enumerate}
 

	
 
\item Is the new work, when in source form, a derivative work under
 
  copyright law of the LGPL'd work?
 
\item Is the new work, when in source form, a derivative and/or modified
 
  work of, and/or a combined work with the LGPL'd work under
 
  copyright law?
 

	
 
\item Is there no way in which the new work fits the definition of a
 
  ``work that uses the library''?
 
\end{enumerate}
 

	
 

	
 
If the answer is ``yes'' to both these questions, then you most likely
 
have a ``work based on the library.''  If the answer is ``no'' to the
 
first but ``yes'' to the second, you are in a gray area between ``work
 
based on the library'' and a ``work that uses the library.''
 

	
 
In our years of work with the LGPLv2.1, however, we have never seen a work
 
of software that was not clearly one or the other; the line is quite
 
bright. At times, though, we have seen cases where a derivative work
 
appeared in some ways to be a work that used the library and in other
 
ways a work based on the library. We overcame this problem by
 
bright. At times, though, we have seen cases where a particularly  large work
 
in some ways seemed to be both to both a work that used the library and 
 
a work based on the library. We overcame this problem by
 
dividing the work into smaller subunits. It was soon discovered that
 
what we actually had were three distinct components: the original
 
LGPL'd work, a specific set of works that used that library, and a
 
specific set of works that were based on the library. Once such
 
distinctions are established, the licensing for each component can be
 
considered independently and the LGPLv2.1 applied to each work as
 
prescribed.
 

	
 

	
 
\section{Subtleties in Defining the Application}
 

	
 
In our discussion of the definition of ``works that use the library,'' we
 
left out a few more complex details that relate to lower-level programming
 
details. The fourth paragraph of LGPLv2.1~\S5 covers these complexities,
 
and it has been a source of great confusion. Part of the confusion comes
 
because a deep understanding of how compiler programs work is nearly
 
mandatory to grasp the subtle nature of what LGPLv2.1~\S5, \P 4 seeks to
 
cover. It helps some to note that this is a border case that we cover in
 
the license only so that when such a border case is hit, the implications
 
of using the LGPL continue in the expected way.
 

	
 
To understand this subtle point, we must recall the way that a compiler
 
operates. The compiler first generates object code, which are the binary
 
representations of various programming modules. Each of those modules is
 
usually not useful by itself; it becomes useful to a user of a full program
 
when those modules are {\em linked\/} into a full binary executable.
 

	
 
As we have discussed, the assembly of modules can happen at compile-time
 
or at runtime. Legally, there is no distinction between the two --- both
 
create a derivative work by copying and combining portions of one work and
 
create a modified version of the work by copying and combining portions of one work and
 
mixing them with another. However, under LGPL, there is a case in the
 
compilation process where the legal implications are different.
 
Specifically, while we know that a ``work that uses the library'' is one
 
whose final binary is a derivative work, but whose source is not, there
 
To understand this phenomenon, we consider that a ``work that uses the
 
library'' is typically one whose final binary is a work based on the Program,
 
but whose source is not.  However, sometimes, there
 
are cases where the object code --- that intermediate step between source
 
and final binary --- is a derivative work created by copying verbatim code
 
and final binary --- is a work created by copying and modifying code
 
from the LGPL'd software.
 

	
 
For efficiency, when a compiler turns source code into object code, it
 
sometimes places literal portions of the copyrighted library code into the
 
object code for an otherwise separate independent work. In the normal
 
scenario, the derivative would not be created until final assembly and
 
scenario, the final combined work would not be created until final assembly and
 
linking of the executable occurred. However, when the compiler does this
 
efficiency optimization, at the intermediate object code step, a
 
derivative work is created.
 
combined work is created.
 

	
 
LGPLv2.1~\S5\P4 is designed to handle this specific case. The intent of
 
the license is clearly that simply compiling software to ``make use'' of
 
the library does not in itself cause the compiled work to be a ``work
 
based on the library.''  However, since the compiler copies verbatim,
 
copyrighted portions of the library into the object code for the otherwise
 
separate and independent work, it would actually cause that object file to be a
 
``work based on the library.''  It is not FSF's intent that a mere
 
compilation idiosyncrasy would change the requirements on the users of the
 
LGPLv2.1'd software. This paragraph removes that restriction, allowing the
 
implications of the license to be the same regardless of the specific
 
mechanisms the compiler uses underneath to create the ``work that uses the
 
library.''
 

	
 
As it turns out, we have only once had anyone worry about this specific
 
idiosyncrasy, because that particular vendor wanted to ship object code
 
(rather than final binaries) to their customers and was worried about
 
this edge condition. The intent of clarifying this edge condition is
 
primarily to quell the worries of software engineers who understand the
 
level of verbatim code copying that a compiler often does, and to help
 
them understand that the full implications of LGPLv2.1 are the same regardless
 
of the details of the compilation progress.
 

	
 
\section{LGPLv2.1~\S6 \& LGPLv2.1~\S5: Combining the Works}
 
\label{lgpl-section-6}
 
Now that we have established a good working definition of works that
 
``use'' and works that ``are based on'' the library, we will consider the
 
rules for distributing these two different works.
 

	
 
The rules for distributing ``works that use the library'' are covered in
 
LGPLv2.1~\S6\@. LGPLv2.1~\S6 is much like GPLv2~\S3, as it requires the release
 
of source when a binary version of the LGPL'd software is released. Of
 
course, it only requires that source code for the library itself be made
 
available. The work that ``uses'' the library need not be provided in
 
source form. However, there are also conditions in LGPLv2.1~\S6 to make sure
 
that a user who wishes to modify or update the library can do so.
 

	
 
LGPLv2.1~\S6 lists five choices with regard to supplying library source
 
and granting the freedom to modify that library source to users. We
 
will first consider the option given by \S~6(b), which describes the
 
most common way currently used for LGPLv2.1 compliance on a ``work that
 
uses the library.''
 

	
 
LGPLv2.1~\S6(b) allows the distributor of a ``work that uses the library'' to
 
simply use a dynamically linked, shared library mechanism to link with the
 
library. This is by far the easiest and most straightforward option for
 
distribution. In this case, the executable of the work that uses the
 
library will contain only the ``stub code'' that is put in place by the
 
shared library mechanism, and at runtime the executable will combine with
 
the shared version of the library already resident on the user's computer.
 
If such a mechanism is used, it must allow the user to upgrade and
 
replace the library with interface-compatible versions and still be able
 
to use the ``work that uses the library.''  However, all modern shared
 
library mechanisms function as such, and thus LGPLv2.1~\S6(b) is the simplest
 
option, since it does not even require that the distributor of the ``work 
 
based on the library'' ship copies of the library itself.
 

	
 
LGPLv2.1~\S6(a) is the option to use when, for some reason, a shared library
 
mechanism cannot be used. It requires that the source for the library be
 
included, in the typical GPL fashion, but it also has a requirement beyond
 
that. The user must be able to exercise her freedom to modify the library
 
to its fullest extent, and that means recombining it with the ``work based
 
on the library.''  If the full binary is linked without a shared library
 
mechanism, the user must have available the object code for the ``work
 
based on the library,'' so that the user can relink the application and
 
build a new binary.
 

	
 
The remaining options in LGPLv2.1~\S6 are very similar to the other choices
 
provided by GPLv2~\S3. There are some additional options, but time does
 
not permit us in this course to go into those additional options. In
 
almost all cases of distribution under LGPL, either LGPLv2.1~\S6(a) or LGPLv2.1~\S6(b) are
 
exercised.
 

	
 
\section{Distribution of the Combined Works}
 

	
 
Essentially, ``works based on the library'' must be distributed under the
 
same conditions as works under full GPL\@. In fact, we note that 
 
LGPLv2.1~\S2 is nearly identical in its terms and requirements to GPLv2~\S2.
 
There are again subtle differences and additions, which time does not
 
permit us to cover in this course.
 

	
 
\section{And the Rest}
 

	
 
The remaining variations between the LGPL and the GPL cover the following
 
conditions:
 

	
 
\begin{itemize}
 

	
 
\item Allowing a licensing ``upgrade'' from the LGPL to the GPL\@ (in LGPLv2.1~\S3)
 

	
 
\item Binary distribution of the library only, covered in LGPLv2.1~\S4,
 
  which is effectively equivalent to LGPLv2.1~\S3
 

	
 
\item Creating aggregates of libraries that are not derivative works of
 
\item Creating aggregates of libraries that are separate and independent works from
 
  each other, and distributing them as a unit (in LGPLv2.1~\S7)
 

	
 
\end{itemize}
 

	
 

	
 
Due to time constraints, we cannot cover these additional terms in detail,
 
but they are mostly straightforward. The key to understanding LGPLv2.1 is
 
understanding the difference between a ``work based on the library'' and a
 
``work that uses the library.''  Once that distinction is clear, the
 
remainder of LGPLv2.1 is close enough to GPL that the concepts discussed in
 
our more extensive GPL unit can be directly applied.
 

	
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
\chapter{Integrating the GPL into Business Practices}
 

	
 
Since GPL'd software is now extremely prevalent through the industry, it
 
is useful to have some basic knowledge about using GPL'd software in
 
business and how to build business models around GPL'd software.
 

	
 
\section{Using GPL'd Software In-House}
 

	
 
As discussed in Sections~\ref{GPLv2s0} and~\ref{GPLv2s5} of this tutorial,
 
the GPL only governs the activities of copying, modifying and
 
distributing software programs that are not governed by the license.
 
Thus, in FSF's view, simply installing the software on a machine and
 
using it is not controlled or limited in any way by the GPL\@. Using Free
 
Software in general requires substantially fewer agreements and less
 
license compliance activity than any known proprietary software.
 

	
 
Even if a company engages heavily in copying the software throughout the
 
enterprise, such copying is not only permitted by GPLv2~\S\S1 and 3, but it is
 
encouraged!  If the company simply deploys unmodified (or even modified)
 
Free Software throughout the organization for its employees to use, the
 
obligations under the license are very minimal. Using Free Software has a
 
substantially lower cost of ownership --- both in licensing fees and in
 
licensing checking and handling -- than the proprietary software
 
equivalents.
 

	
 
\section{Business Models}
 
\label{Business Models}
 

	
 
Using Free Software in house is certainly helpful, but a thriving
 
market for Free Software-oriented business models also exists. There is the
 
traditional model of selling copies of Free Software distributions.
 
Many companies make substantial revenue
 
from this model. Some choose this model because they have
 
found that for higher-end hardware, the profit made from proprietary
 
software licensing fees is negligible. The real profit is in the hardware,
 
but it is essential that software be stable, reliable and dependable, and
 
the users be allowed to have unfettered access to it. Free Software, and
 
GPL'd software in particular (because IBM can be assured that proprietary
 
versions of the same software will not exist to compete on their hardware)
 
is the right choice.
 

	
 
For example, charging a ``convenience fee'' for Free Software,
 
when set at a reasonable price (around \$60 or so), can produce some
 
profit. Even though Red Hat's system is fully downloadable on their
 
Web site, people still go to local computer stores and buy copies of their
 
box set, which is simply a printed version of the manual (available under
 
a Free license as well) and the Free Software system it documents.
 

	
 
\medskip
 

	
 
However, custom support, service, and software improvement contracts
 
are the most widely used models for GPL'd software. The GPL is
 
central to their success, because it ensures that the code base
 
remains common, and that large and small companies are on equal
 
footing for access to the technology. Consider, for example, the GNU
 
Compiler Collection (GCC). Cygnus Solutions, a company started in the
 
early 1990s, was able to grow steadily simply by providing services
 
for GCC --- mostly consisting of new ports of GCC to different or new,
 
embedded targets. Eventually, Cygnus was so successful that
 
it was purchased by Red Hat where it remains a profitable division.
 

	
 
However, there are very small companies that compete in
 
this space. Because the code-base is protected by the GPL, it creates and
 
demands industry trust. Companies can cooperate on the software and
 
improve it for everyone. Meanwhile, companies who rely on GCC for their
 
work are happy to pay for improvements, and for ports to new target
 
platforms. Nearly all the changes fold back into the standard
 
versions, and those forks that exist remain freely available.
 

	
 
\medskip
 

	
 
\label{Proprietary Relicensing}
 

	
 
A final common business model that is perhaps the most controversial is
 
proprietary relicensing of a GPL'd code base. This is only an option for
 
software in which a particular entity holds exclusive rights to
 
relicense\footnote{Entities typically hold exclusive relicensing rights
 
  either by writing all the software under their own copyrights, collecting
 
  copyright assignments from all contributors, or by otherwise demanding
 
  unconditional relicensing permissions from all contributors via some legal
 
  agreement}. As discussed earlier in this tutorial, a copyright holder is
 
permitted under copyright law to license a software system under her
 
copyright as many different ways as she likes to as many different parties as
 
she wishes.
 

	
 
Some companies use this to their
 
financial advantage with regard to a GPL'd code base. The standard
 
version is available from the company under the terms of the GPL\@.
 
However, parties can purchase separate proprietary software licensing for
 
a fee.
 

	
 
This business model is at best problematic and at worst predatory because it means that the GPL'd code
 
base must be developed in a somewhat monolithic way, because volunteer
 
Free Software developers may be reluctant to assign their copyrights to
 
the company because it will not promise to always and forever license the
 
software as Free Software. Indeed, the company will surely use such code
 
contributions in proprietary versions licensed for fees.
 

	
 
\section{Ongoing Compliance}
 

	
 
GPL compliance is in fact a very simple matter --- much simpler than
 
typical proprietary software agreements and EULAs. Usually, the most
 
difficult hurdle is changing from a proprietary software mindset to one
 
that seeks to foster a community of sharing and mutual support. Certainly
 
complying with the GPL from a users' perspective gives substantially fewer
 
headaches than proprietary license compliance.
 

	
 
For those who go into the business of distributing {\em modified}
 
versions of GPL'd software, the burden is a bit higher, but not by
 
much. The glib answer is that by releasing the whole product as Free
 
Software, it is always easy to comply with the GPL. However,
 
admittedly to the dismay of FSF, many modern and complex software
 
systems are built using both proprietary and GPL'd components that are
 
not legally derivative works of each other. Sometimes, it is easier simply to
 
clearly and legally separate and independent works, merely aggregated
 
together on the same device.
 

	
 
However, it's sometimes is easier, quicker, and cheaper to simply to
 
improve existing GPL'd application than to start from scratch.  In
 
exchange for that benefit, the license requires that the modifier gives
 
exchange for this amazing benefit, the license requires that the modifier gives
 
back to the commons that made the work easier in the first place. It is a
 
reasonable trade-off and a way to help build a better world while also
 
making a profit.
 

	
 
Note that FSF does provide services to assist companies who need
 
assistance in complying with the GPL. You can contact FSF's GPL
 
Compliance Labs at $<$licensing@fsf.org$>$.
 

	
 
%FIXME-LATER: should have \tutorialpart
 

	
 
If you are particularly interested in matters of GPL compliance, we
 
recommend the next two parts, which include both recommendations on good
 
compliance and compliance case studies.
 

	
 
% =====================================================================
 
% END OF FIRST DAY SEMINAR SECTION
 
% =====================================================================
 

	
 
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