diff --git a/GPL-LGPL/gpl-lgpl-overview.txt b/GPL-LGPL/gpl-lgpl-overview.txt new file mode 100644 index 0000000000000000000000000000000000000000..bc0dc1148aa82809834b32749fe10dbea1348ec2 --- /dev/null +++ b/GPL-LGPL/gpl-lgpl-overview.txt @@ -0,0 +1,180 @@ + Detailed Study and Analysis of GPL and LGPL + +This one-day course gives a section-by-section explanation of the most +popular Free Software copyright license, the GNU General Public License +(GNU GPL), and teaches lawyers, software developers, managers and business +people how to use the GPL (and GPL'ed software) successfully in a new Free +Software business and in existing, successful enterprises. + +Prerequisites: + + Attendees should have a general familiarity with software development + processes. A basic understanding of how copyright law typically + applies to software is also helpful. + +Audience: + + The course is of most interest to lawyers, software developers and + managers who run (or have clients who run) software businesses that + modify and/or redistribute software under terms of the GNU GPL or + LGPL, or who wish to make use of existing GPL'd and LGPL'd software + in their enterprise. + +The course will include the topics listed below, along with ample time for +questions and discussions. Lunch is included, with a lunch speaker to be +announced. + + * Free Software Principles and the Free Software Definition + + The ethical principles that motivated the creation of these licenses + are presented. Unlike licenses that seek to lock up software in a + proprietary fashion, the GPL and LGPL are designed to grant freedom to + innovate, learn and improve. Those principles influence licensing + policy decisions. We present the specific definition of the concept + of "Free Software" (software whose license grants freedoms to copy, + share, modify and redistribute the software either gratis or for a + fee) for-profit companies. + + * Preamble of the GNU General Public License (GPL) + + The preamble presents the intent of the license. The preamble puts + forth the motivations for the detailed terms and conditions that + follow in the license. We discuss the language of the preamble in + detail to show how it frames the legal details that follow. + + * GPL, Section 0: Definitions, etc. + + GPL's section 0 defines and presents the terms that make the basis of + this copyright license. We discuss those definitions and the + copyright scope of the license. + + * GPL, Section 1: Grant for Verbatim Source Copying + + Section 1 defines the terms for making source-only copies of software + programs. We discuss how those rules work and the requirements and + obligations for distributors of GPL'd source, whether they choose to + distribute at no charge or for fees. + + * Derivative Works: Statute and Case Law + + Free Software licensing in general, and the GPL and LGPL in + particular, relies critically on the concept of derivative work since + software that is independent (i.e., not derivative) of Free Software + need not abide by any of the terms of the applicable Free Software + license. If a work is a derivative work of Free Software, then the + terms of the license are triggered, and one has obligations 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?" We will show how the answer to that question + depends on which court is being asked. We also present the best + background information available to build a working understanding of + what is generally considered a derivate work in the rapidly changing + field of software copyright law. + + * GPL, Section 2: Grants for Source Derivative Works + + Section 2 sets forth the rules for creation of derivative works of + GPL'd software. We discuss the intent of this section of GPL and how + it relates to the copyright situation discussed in our discussion of + derivative works. We also explain the details of preparing derivative + source in a GPL-compliant way. + + * GPL, Section 3: Grants for Creating Binary Derivative Works + + Source-only distribution works well for technically savvy clients and + users, but most want runnable binary programs as well. Section 3 + gives permission for the creation and distribution of such binary + works. We explain how GPL's requirement for corresponding source code + operate, and detail what distribution options are available to + distributors of binary GPL'd software. We explore the benefits and + downsides of each of those options. + + * The Implied Patent Grant in GPL + + Patent rights are most often granted expressly, through detailed + language in a license. However, express patent grants are not the + exclusive way rights in patents are granted by patentees. Even + without express language, patent rights can be granted by a patentee's + actions or behavior. The GPL contains no express patent grant. Does + that mean it grants less rights in the licensor's patents than other + licenses which do? Or, does the GPL, in its silence, actually result + in a grant of patent rights to the licensee greater than occurs + through many other Free Software and "Open Source" licenses? + + We will consider these questions and provide detailed answers to them. + + * GPL, Section 4: Termination of License + + Section 4 terminates rights under GPL for those who violate it. We + discuss how such termination works, what it means for violators, what + risks one takes in violating, and how rights are typically restored. + We briefly mention how Section 4 is used as the central tool in GPL + enforcement. + + * GPL, Section 5: Acceptance of License + + GPL is not a contract, so acceptance of the license works differently + than it does for contracts. We discuss how this acceptance works + under the copyright rules that govern GPL. + + * GPL, Section 6: Prohibition on Further Restrictions + + Other licensing terms cannot be placed on GPL'd software that would + trump the rights granted under GPL. We discuss how Section 6 is used + to ensure that no such additional restrictions occur. We briefly + discuss how this leads to the concept of GPL-incompatible Free + Software licenses. + + * GPL, Section 7: Conflicts with other Agreements or Orders + + Just as additional licensing restrictions cannot trump GPL, outside + agreements, patent licenses or court orders cannot do so either. We + discuss how Section 7 ensures that other rules outside of the direct + software license cannot take rights away from users, distributors, and + modifiers of GPL'd software. + + * GPL, Section 8: International Licensing Issues + + Section 8 is rarely used part of the GPL that helps copyright holders + when certain technologies are prohibited from full international + distribution due to draconian rules elsewhere in the world. We + explain how Section 8 helps such copyright holders. + + * GPL, Section 9: FSF as GPL's Stewards + + We discuss how the update process and release of new GPL versions + happens. + + * GPL, Section 10: Copyright Holder's Exceptions to GPL + + Section 10 reminds licensees that under copyright law, other + relicensing arrangements can be made. We discuss how this can often + be used as a business model and we explicate that model's benefits and + downsides. + + * GPL, Section 11: Disclaimer of Warranties + GPL, Section 12: Limitation of Liability + + Almost all software licenses, including Free Software licenses such as + the GPL, contain sections, typically in all caps, regarding warranties + and liability. The purposes of these sections are lost on most + non-lawyers, but attorneys understand the importance their language + provides to both the licensor and the licensee. Some have argued that + the GPL's Sections 11 and 12 render it entirely unenforceable. We + consider whether that is true, and present the likely interpretation + and implementation of the GPL's Warranty Disclaimer and Liability + Limitation provisions. + + * Lesser General Public License (LGPL) + + The LGPL is a "scaled back" version of GPL, designed specifically to + allow creation of a very well-defined class of proprietary derivative + works. However, it does prohibit turning the LGPL'd software itself + directly into proprietary software. + + We discuss the basic design of LGPL and how it compares and contrasts + with GPL. We introduce the two classes of derivative works covered + by LGPL -- "works that use the library" and "works based on the + library" -- and give some concrete examples of what proprietary + derivative works are prohibited and permitted when basing the + software on an LGPL'd work. diff --git a/GPL-LGPL/gpl-lgpl.tex b/GPL-LGPL/gpl-lgpl.tex new file mode 100644 index 0000000000000000000000000000000000000000..b0b1473546ed35c9ab9ce63f6ccdef095c3c1b9e --- /dev/null +++ b/GPL-LGPL/gpl-lgpl.tex @@ -0,0 +1,2389 @@ +% gpl-lgplg.tex -*- LaTeX -*- +% Tutorial Text for the Detailed Study and Analysis of GPL and LGPL course +% +% Copyright (C) 2003, 2004 Free Software Foundation, Inc. + +% Verbatim copying and distribution of this entire document is permitted in +% any medium, provided this notice is preserved. + +\documentclass[12pt]{report} +% FILTER_PS: \input{generate-ps-file} +% FILTER_PDF: \input{generate-pdf-file} +% FILTER_HTML: \input{generate-html-file} +\input{one-inch-margins} + +%\setlength\parskip{0.7em} +%\setlength\parindent{0pt} + +\newcommand{\defn}[1]{\emph{#1}} + +%\pagestyle{empty} + +\begin{document} + +\begin{titlepage} + + +\begin{center} + +\vspace{.5in} + +{\Large +{\sc Detailed Study and Analysis of GPL and LGPL } \\ + +\vspace{.7in} + +Sponsored by the Free Software Foundation \\ + + +\vspace{.3in} + +Columbia Law School, New York, NY, USA \\ +Tuesday 20 January 2003 + + + +{\large +Bradley M. Kuhn + +Executive Director + +Free Software Foundation +} + + +{\large +Daniel Ravicher + +Senior Counsel + +Free Software Foundation +} + +\end{center} + +\vfill + +{\parindent 0in +Copyright \copyright{} 2003, 2004 \hspace{.2in} Free Software Foundation, Inc. + +\vspace{.3in} + +Verbatim copying and distribution of this entire document is permitted in +any medium, provided this notice is preserved. +} + +\end{titlepage} + +\pagestyle{plain} +\pagenumbering{roman} + +\begin{abstract} + + +This one-day course gives a section-by-section explanation of the most +popular Free Software copyright license, the GNU General Public License +(GNU GPL), and teaches lawyers, software developers, managers and business +people how to use the GPL (and GPL'ed software) successfully in a new Free +Software business and in existing, successful enterprises. + +Attendees should have a general familiarity with software development +processes. A vague understanding of how copyright law applies to software +is also helpful. The tutorial is of most interest to lawyers, software +developers and managers who run software businesses that modify and/or +redistribute software under terms of the GNU GPL (or who wish to do so in +the future), and those who wish to make use of existing GPL'ed software in +their enterprise. + +Upon completion of the tutorial, successful attendees can expect to have +learned the following: + +\begin{itemize} + + \item the freedom-defending purpose of each term of the GNU GPL. + + \item the redistribution options under the GPL. + + \item the obligations when modifying GPL'ed software. + + \item how to build a plan for proper and successful compliance with the GPL. + + \item the business advantages that the GPL provides. + + \item the most common business models used in conjunction with the GPL. + + \item how existing GPL'ed software can be used in existing enterprises. + + \item the basics of the LGPL and how it differs from GPL. + + \item how best to understand the complexities regarding derivative + works of software. +\end{itemize} + +\end{abstract} + +\tableofcontents + +\pagebreak + +\pagenumbering{arabic} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\chapter{What Is Free Software?} + +Consideration of the GNU General Public License (herein, abbreviated as +\defn{GNU GPL} or just \defn{GPL}) must begin by first considering the broader +world of Free Software. The GPL was not created from a void, rather, +it was created to embody and defend a set of principles that were set +forth at the founding of the GNU project and the Free Software Foundation +(FSF)---the organization that upholds, defends and promotes the philosophy +of software freedom. A prerequisite for understanding the GPL and its +terms and conditions is a basic understanding of the principles behind it. +The GPL is unlike almost all other software licenses in that it is +designed to defend and uphold these principles. + +\section{The Free Software Definition} +\label{Free Software Definition} + +The Free Software Definition is set forth in full on FSF's website at +\verb0http://www.fsf.org/0 \verb0philosophy/free-sw.html0. This section +presents an abbreviated version that will focus on the parts that are most +pertinent to the terms of the GPL\@. + +A particular program is Free Software if it grants a particular user of +that program, the following freedoms: + +\begin{itemize} + +\item the freedom to run the program for any purpose. + +\item the freedom to change and modify the program. + +\item the freedom to copy and share the program. + +\item the freedom to share improved versions of the program. + +\end{itemize} + +The focus on ``a particular user'' is very pertinent here. It is not +uncommon for the same version of a specific program to grant these +freedoms to some subset of its user base, while others have none or only +some of these freedoms. Section~\ref{Proprietary Relicensing} talks in +detail about how this can happen even if a program is released under the +GPL\@. + +Some people refer to software that gives these freedoms as ``Open +Source''. Besides having a different political focus than those who call +it Free Software\footnote{The political differences between the Free +Software Movement and the Open Source Movement are documented on FSF's +website at +{\tt http://www.fsf.org/philosophy/free-software-for-freedom.html}}, +those who call the software ``Open Source'' are focused on a side issue. +User access to the source code of a program is a prerequisite to make use +of the freedom to modify. However, the important issue is what freedoms +are granted in the license of that source code. Microsoft's ``Shared +Source'' program, for example, gives various types of access to source +code, but almost none of the freedoms described in this section. + +One key issue that is central to these freedoms is that there are no +restrictions on how these freedoms can be exercised. Specifically, users +and programmers can exercise these freedoms non-commercially or +commercially. Licenses that grant these freedoms for non-commercial +activities but prohibit them for commercial activities are considered +non-Free. + +In general, software for which most or all of these freedoms are +restricted in any way is called ``non-Free Software''. Typically, the +term ``proprietary software'' is used more or less interchangeably with +``non-Free Software''. Personally, I tend to use the term ``non-Free +Software'' to refer to non-commercial software that restricts freedom +(such as ``shareware'') and ``proprietary software'' to refer to +commercial software that restricts freedom (such as nearly all of +Microsoft's and Oracle's offerings). + +The remainder of this section considers each of the four freedoms in +detail. + +\subsection{The Freedom to Run} + +For a program to be Free Software, the freedom to run the program must be +completely unrestricted. This means that any use for that software that +the user can come up with must be permitted. Perhaps, for example, the +user has discovered an innovative new use for a particular program, one +that the programmer never could have predicted. Such a use must not be +restricted. + +It was once rare that this freedom was restricted by even proprietary +software; today it is not so rare. Most End User Licensing Agreements +(EULAs) that cover most proprietary software restrict some types of use. +For example, some versions of Microsoft's FrontPage software prohibit use +of the software to create websites that generate negative publicity for +Microsoft. Free Software has no such restrictions; everyone is free to +use Free Software for any purpose whatsoever. + +\subsection{The Freedom to Change and Modify} + +Free Software programs allow users to change, modify and adapt the +software to suit their needs. Access to the source code and related build +scripts are an essential part of this freedom. Without the source code +and the ability to build the binary applications from that source, the +freedom cannot be properly exercised. + +Programmers can take direct benefit from this freedom, and often do. +However, this freedom is also important to users who are not programmers. +Users must have the right to exercise this freedom indirectly in both +commercial and non-commercial settings. For example, users often seek +non-commercial help with the software on email lists and in users groups. +When they find such help, they must have the freedom to recruit +programmers who might altruistically assist them to modify their software. + +The commercial exercise of this freedom is also essential for users. Each +user, or group of users, must have the right to hire anyone they wish in a +competitive free market to modify and change the software. This means +that companies have a right to hire anyone they wish to modify their Free +Software. Additionally, such companies may contract with other companies +to commission software modification. + +\subsection{The Freedom to Copy and Share} + +Users may share Free Software in a variety of ways. Free Software +advocates work to eliminate a fundamental ethical dilemma of the software +age: choosing between obeying a software license, and friendship (by +giving away a copy of a program your friend who likes the software you are +using). Free Software licenses, therefore, must permit this sort of +altruistic sharing of software among friends. + +The commercial environment must also have the benefits of this freedom. +Commercial sharing typically takes the form of selling copies of Free +Software. Free Software can be sold at any price to anyone. Those who +redistribute Free Software commercially have the freedom to selectively +distribute (you can pick your customers) and to set prices at any level +the redistributor sees fit. + +It is true that many people get copies of Free Software very cheaply (and +sometimes without charge). The competitive free market of Free Software +tends to keep prices low and reasonable. However, if someone is willing +to pay a billion dollars for one copy of the GNU Compiler Collection, such +a sale is completely permitted. + +Another common instance of commercial sharing is service-oriented +distribution. For example, a distribution vendor may provide immediate +security and upgrade distribution via a special network service. Such +distribution is completely permitted for Free Software. + +(Section~\ref{Business Models} of this tutorial talks in detail about +various Free Software business models that take advantage of the freedom +to share commercially.) + +\subsection{The Freedom to Share Improvements} + +The freedom to modify and improve is somewhat empty without the freedom to +share those improvements. The Free Software community is built on the +pillar of altruistic sharing of improved Free Software. Inevitably, a +Free Software project sprouts a mailing list where improvements are shared +freely among members of the development community. Such non-commercial +sharing must be permitted for Free Software to thrive. + +Commercial sharing of modified Free Software is equally important. For a +competitive free market for support to exist, all developers --- from +single-person contractors to large software companies --- must have the +freedom to market their services as improvers of Free Software. All forms +of such service marketing must be equally available to all. + +For example, selling support services for Free Software is fully +permitted. Companies and individuals can offer themselves as ``the place +to call'' when software fails or does not function properly. For such a +service to be meaningful, the entity offering that service must have the +right to modify and improve the software for the customer to correct any +problems that are beyond mere user error. + +Entities must also be permitted to make available modified versions of +Free Software. Most Free Software programs have a ``standard version'' +that is made available from the primary developers of the software. +However, all who have the software have the ``freedom to fork'' --- that +is, make available non-trivial modified versions of the software on a +permanent or semi-permanent basis. Such freedom is central to vibrant +developer and user interaction. + +Companies and individuals have the right to make true value-added versions +of Free Software. They may use freedom to share improvements to +distribute distinct versions of Free Software with different functionality +and features. Furthermore, this freedom can be exercised to serve a +disenfranchised subset of the user community. If the developers of the +standard version refuse to serve the needs of some of the software's +users, other entities have the right to create long- or short-lived fork +that serves that sub-community. + +\section{How Does Software Become Free?} + +The last section set forth the freedoms and rights are respected by Free +Software. It presupposed, however, that such software exists. This +section discusses how Free Software comes into existence. But first, it +addresses how software can be non-free in the first place. + +Software can be made proprietary only because it is governed by copyright +law\footnote{This statement is a bit of an oversimplification. Patents + and trade secrets can cover software and make it effectively non-free, + one can contract away their rights and freedoms regarding software, or + source code can be practically obscured in binary-only distribution + without reliance on any legal system. However, the primary control + mechanism for software is copyright.}. Copyright law, with respect to +software, governs copying, modifying, and redistributing that +software\footnote{Copyright law in general also governs ``public + performance'' of copyrighted works. There is no generally agreed + definition for public performance of software and version 2 of the GPL + does not govern public performance.}. By law, the copyright holder (aka +the author) of the work controls how others may copy, modify and/or +distribute the work. For proprietary software, these controls are used to +prohibit these activities. In addition, proprietary software distributors +further impede modification in a practical sense by distributing only +binary code and keeping the source code of the software secret. + +Copyright law is a construction. In the USA, the Constitution permits, +but does not require, the creation of copyright law as federal +legislation. Software, since it is an idea fixed in a tangible medium, is +thus covered by the statues, and is copyrighted by default. + +However, this legal construction is not necessarily natural. Software, in +its natural state without copyright, is Free Software. In an imaginary +world, which has no copyright, the rules would be different. In this +world, when you received a copy of a program's source code, there would be +no default legal system to restrict you from sharing it with others, +making modifications, or redistributing those modified +versions\footnote{There could still exist legal systems, like our modern + patent system, which could restrict the software in other ways.}. + +Software in the real world is copyrighted by default, and that default +legal system does exist. However, it is possible to move software out of +the domain of the copyright system. A copyright holder is always +permitted to \defn{disclaim} their copyright. If copyright is disclaimed, +the software is not governed by copyright law. Software not governed by +copyright is in the ``public domain''. + +\subsection{Public Domain Software} + +An author can create public domain software by disclaiming all copyright +interest on the work. In the USA and other countries that have signed the +Berne convention on copyright, software is copyrighted automatically by +the author when she ``fixes the software into a tangible medium''. In +the software world, this usually means typing the source code of the +software into a file. + +However, an author can disclaim that default control given to her by the +copyright laws. Once this is done, the software is in the public domain +--- it is no longer covered by copyright. Since it is copyright law that +allows for various controls on software (i.e., prohibition of copying, +modification, and redistribution), removing the software from the +copyright system and placing it into the public domain does yield Free +Software. + +Carefully note that software in the public domain is \emph{not} licensed +in any way. It is nonsensical to say software is ``licensed for the +public domain'', or any phrase that implies the copyright holder gave +expressed permission to take actions governed by copyright law. + +By contrast, what the copyright holder has done is renounce her copyright +controls on the work. The law gave her controls over the work, and she +has chosen to waive those controls. Software in the public domain is +absent copyright and absent a license. The software freedoms discussed in +Section~\ref{Free Software Definition} are all granted because there is no +legal system in play to take them away. + +\subsection{Why Copyright Free Software?} + +If simply disclaiming copyright on software yields Free Software, then it +stands to reason that putting software into the public domain is the +easiest and most straightforward way to produce Free Software. Indeed, +some major Free Software projects have chosen this method for making their +software Free. However, most of the Free Software in existence \emph{is} +copyrighted. In most cases (particularly in that of FSF and the GNU +Project), this was done due to very careful planning. + +Software released into the public domain does grant freedom to those users +who receive the standard versions on which the original author disclaimed +copyright. However, since the work is not copyrighted, any non-trivial +modification made to the work is fully copyrightable. + +Free Software released into the public domain initially is Free, and +perhaps some who modify the software choose to place their work into the +public domain as well. However, over time, some entities will choose to +proprietarize their modified versions. The public domain body of software +feeds the proprietary software. The public commons disappears, because +fewer and fewer entities have an incentive to contribute back to the +commons. They know that any of their competitors can proprietarize their +enhancements. Over time, almost no interesting work is left in the public +domain, because nearly all new work is done by proprietarization. + +A legal mechanism is needed to redress this problem. FSF was in fact +originally created primarily as a legal entity to defend software freedom, +and that work of of defending software freedom is a substantial part of +its work today. Specifically because of this ``embrace, proprietarize and +extend'' cycle, FSF made a conscious choice to copyright its Free Software, +and then license it under ``copyleft'' terms, and many, including the +developers of the kernel named Linux, have chosen to follow this paradigm. + +Copyleft is a legal strategy to defend, uphold and propagate software +freedom. The basic technique of copyleft is as follows: copyright the +software, license it under terms that give all the software freedoms, but +use the copyright law controls to ensure that all who receive a copy of +the software have equal rights and freedom. In essence, copyleft grants +freedom, but forbids others to forbid that freedom from anyone else along +the distribution and modification chains. + +Copyleft is a general concept. Much like ideas for what a computer might +do must be \emph{implemented} by a program that actually does the job, so +too must copyleft be implemented in some concrete legal structure. +``Share and share alike'' is a phrase that is often enough to explain the +concept behind copyleft, but to actually make it work in the real world, a +true implementation in legal text must exist. The GPL is the primary +implementation of copyleft in copyright licensing language. + +\section{An Ecosystem of Equality} + +The GPL uses copyright law to defend freedom and equally ensure users' +rights. This ultimately creates an ecosystem of equality for both +business and non-commercial users. + +\subsection{The Non-Commercial Ecosystem} + +A GPL'ed code base becomes a center of a vibrant development and user +community. Traditionally, volunteers, operating non-commercially out of +keen interest or ``scratch an itch'' motivations, produce initial versions +of a GPL'ed system. Because of the efficient distribution channels of the +Internet, any useful GPL'ed system is adopted quickly by non-commercial +users. + +Fundamentally, the early release and quick distribution of the software +gives birth to a thriving non-commercial community. Users and developers +begin sharing bug reports and bug fixes across a shared intellectual +commons. Users can trust the developers, because they know that if the +developers fail to address their needs or abandon the project, the GPL +ensures that someone else has the right to pick up development. +Developers know that the users cannot redistribute their software without +passing along the rights granted by GPL, so they are assured that every +one of their users is treated equally. + +Because of the symmetry and fairness inherent in GPL'ed distribution, +nearly every GPL'ed package in existence has a vibrant non-commercial user +and developer base. + +\subsection{The Commercial Ecosystem} + +By the same token, nearly all established GPL'ed software systems have a +vibrant commercial community. Nearly every GPL'ed system that has gained +wide adoption from non-commercial users and developers eventually begins +to fuel a commercial system around that software. + +For example, consider the Samba file server system that allows Unix-like +systems (including GNU/Linux) to serve files to Microsoft Windows systems. +Two graduate students originally developed Samba in their spare time and +it was deployed non-commercially in academic environments. However, very +soon for-profit companies discovered that the software could work for them +as well, and their system administrators began to use it in place of +Microsoft Windows NT file-servers. This served to lower the cost of +running such servers by orders of magnitude. There was suddenly room in +Windows file-server budgets to hire contractors to improve Samba. Some of +the first people hired to do such work were those same two graduate +students who originally developed the software. + +The non-commercial users, however, were not concerned when these two +fellows began collecting paychecks off of their GPL'ed work. They knew +that because of the nature of the GPL that improvements that were +distributed in the commercial environment could easily be folded back into +the standard version. Companies are not permitted to proprietarize +Samba, so the non-commercial users, and even other commercial users are +safe in the knowledge that the software freedom ensured by GPL will remain +protected. + +Commercial developers also work in concert with non-commercial developers. +Those two now-long-since graduated students continue to contribute to +Samba altruistically, but also get work doing it. Priorities change when a +client is in the mix, but all the code is contributed back to the +standard version. Meanwhile, many other individuals have gotten involved +non-commercially as developers, because they want to ``cut their teeth on +Free Software'' or because the problems interest them. When they get good +at it, perhaps they will move on to another project or perhaps they will +become commercial developers of the software themselves. + +No party is a threat to another in the GPL software scenario because +everyone is on equal ground. The GPL protects rights of the commercial +and non-commercial contributors and users equally. The GPL creates trust, +because it is a level playing field for all. + +\subsection{Law Analogy} + +In his introduction to Stallman's \emph{Free Software, Free Society}, +Lawrence Lessig draws an interesting analogy between the law and Free +Software. He argues that the laws of a Free society must be protected +much like the GPL protects software. So that I might do true justice to +Lessig's argument, I quote it verbatim: + +\begin{quotation} + +A ``free society'' is regulated by law. But there are limits that any free +society places on this regulation through law: No society that kept its +laws secret could ever be called free. No government that hid its +regulations from the regulated could ever stand in our tradition. Law +controls. But it does so justly only when visibly. And law is visible +only when its terms are knowable and controllable by those it regulates, +or by the agents of those it regulates (lawyers, legislatures). + +This condition on law extends beyond the work of a legislature. Think +about the practice of law in American courts. Lawyers are hired by their +clients to advance their clients' interests. Sometimes that interest is +advanced through litigation. In the course of this litigation, lawyers +write briefs. These briefs in turn affect opinions written by judges. +These opinions decide who wins a particular case, or whether a certain law +can stand consistently with a constitution. + +All the material in this process is free in the sense that Stallman means. +Legal briefs are open and free for others to use. The arguments are +transparent (which is different from saying they are good) and the +reasoning can be taken without the permission of the original lawyers. +The opinions they produce can be quoted in later briefs. They can be +copied and integrated into another brief or opinion. The ``source code'' +for American law is by design, and by principle, open and free for anyone +to take. And take lawyers do---for it is a measure of a great brief that +it achieves its creativity through the reuse of what happened before. The +source is free; creativity and an economy is built upon it. + +This economy of free code (and here I mean free legal code) doesn't starve +lawyers. Law firms have enough incentive to produce great briefs even +though the stuff they build can be taken and copied by anyone else. The +lawyer is a craftsman; his or her product is public. Yet the crafting is +not charity. Lawyers get paid; the public doesn't demand such work +without price. Instead this economy flourishes, with later work added to +the earlier. + +We could imagine a legal practice that was different---briefs and +arguments that were kept secret; rulings that announced a result but not +the reasoning. Laws that were kept by the police but published to no one +else. Regulation that operated without explaining its rule. + +We could imagine this society, but we could not imagine calling it +``free.'' Whether or not the incentives in such a society would be better +or more efficiently allocated, such a society could not be known as free. +The ideals of freedom, of life within a free society, demand more than +efficient application. Instead, openness and transparency are the +constraints within which a legal system gets built, not options to be +added if convenient to the leaders. Life governed by software code should +be no less. + +Code writing is not litigation. It is better, richer, more +productive. But the law is an obvious instance of how creativity and +incentives do not depend upon perfect control over the products created. +Like jazz, or novels, or architecture, the law gets built upon the work +that went before. This adding and changing is what creativity always is. +And a free society is one that assures that its most important resources +remain free in just this sense.\footnote{This quotation is Copyright + \copyright{} 2002, Lawrence Lessig. It is licensed under the terms of + \href{http://creativecommons.org/licenses/by/1.0/}{the ``Attribution + License'', version 1.0} or any later version as published by Creative + Commons.} +\end{quotation} + +In essence, lawyers are paid to service the shared commons of legal +infrastructure. Few citizens defend themselves in court or write their +own briefs (even though they are legally permitted to do so) because +everyone would prefer to have an expert do that job. + +The Free Software economy is a market that is ripe for experts. It +functions similarly to other well established professional fields like the +law. The GPL, in turn, serves as the legal scaffolding that permits the +creation of this vibrant commercial and non-commercial Free Software +economy. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\chapter{Copying, Modifying and Redistributing} + +This chapter begins the deep discussion of the details of the terms of +GPL\@. In this chapter, we consider the core terms: GPL \S\S 0--3. These +are the sections of the GPL that fundamentally define the legal details of +how software freedom is respected. + +\section{GPL \S 0: Freedom to Run} +\label{GPLs0} + +\S 0, the opening section of GPL, sets forth that the work is governed by +copyright law. 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, \S 0 makes an inference that copyright law is the only +system under which it is governed. 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 GPL +(which they cannot; see Sections~\ref{GPLs6} and~\ref{GPLs7}). This is +very important, because the Free Software community heavily supports +users' rights to ``fair use'' and ``unregulated use'' of copyrighted +material. GPL asserts through this clause that it supports users' rights +to fair and unregulated uses. + +Fair use of copyrighted material is an established legal doctrine that +permits certain 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 a very few lines (less than +seven or so), and reuse them as you with without licensing restrictions. + +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. + +\medskip + +Thus, the GPL protects users fair and unregulated use rights precisely by +not attempting to cover them. Furthermore, the GPL 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 \S 0. + +\medskip + +The bulk of \S 0 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 the +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, not the licenses that utilize it. + +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. + +\section{GPL \S 1: Verbatim Copying} +\label{GPLs1} + +GPL \S 1 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 \S 1. These are in some ways the most important part of +the redistribution, which is why they are mentioned by name. The 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 someone would be +surprised that the software she got was licensed under GPL\@. Thus +throughout the GPL, there are specific reference 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 +proposed state-level UCITA bills (which have never obtained widespread +adoption), there are little or no implied warranties with software. +However, just to be on the safe side, GPL clearly disclaims them, and the +GPL requires redistributors to keep the disclaimer very visible. (See +Sections~\ref{GPLs11} and~\ref{GPLs12} of this tutorial for more on GPL's +warranty disclaimers.) + +Note finally that \S 1 begins to set forth the important defense of +commercial freedom. \S 1 clearly states that in the case of verbatim +copies, one may make money. Redistributors are fully permitted to charge +for the redistribution 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.) + +\section{GPL \S 2: Share and Share Alike} + +For many, this is where the ``magic'' happens that defends software +freedom along the distribution chain. \S 2 is the only place in the GPL +that governs the modification controls of copyright law. If someone +modifies a GPL'ed program, she is bound in the making those changes by \S +2. The goal here is to ensure that the body of GPL'ed software, as it +continues and develops, remains Free as in freedom. + +To achieve that goal, \S 2 first sets forth that the rights of +redistribution of modified versions are the same as those for verbatim +copying, as presented in \S 1. Therefore, the details of charging, +keeping copyright notices intact, and other \S 1 provisions are in tact +here as well. However, there are three additional requirements. + +The first (\S 2(a)) requires that modified files carry ``prominent +notices'' explaining what changes were made and the date of such changes. +The goal here is not to put forward some specific way of marking changes, +or controlling the process of how changes get made. Primarily, \S 2(a) +seeks to ensure that those receiving modified versions know what path it +took to them. 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, \S 2(a) serves an academic +purpose --- ensuring that future developers can use a diachronic approach +to understand the software. + +\medskip + +The second requirement (\S 2(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. It is worth +the effort to carefully understand what each clause is saying, because \S +2(b) can be a source of great confusion when not properly understood. + +In considering \S 2(b), first note the qualifier: it only applies to +derivative works that ``you distribute or publish''. Despite years of +education efforts by FSF on this matter, many still believe that modifiers +of GPL'ed software are required by the license to publish or otherwise +share their changes. On the contrary, \S 2(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{FSF does maintain that there is an {\bf + ethical} obligation to redistribute changes that are generally useful, + and often encourages 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 \S 0, 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 +derived from'' the GPL'ed software, then the requirements of \S 2(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 \S 2(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: +\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 \S 2 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 worked distributed to +the programmer under GPL\@. Thus, the license of the original work +affects the license of the new whole derivative work. + +% {\cal I} +\newcommand{\gplusi}{$\mathcal{G\!\!+\!\!I}$} +\newcommand{\worki}{$\mathcal{I}$} +\newcommand{\workg}{$\mathcal{G}$} + +It is certainly possible to take an existing independent work (called +\worki{}) and combine it with a GPL'ed 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 derivative work, \gplusi{}, is jointly held by the original copyright +holder of each of the two works. + +In this case, \S 2 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 Microsoft +product --- would they give you permission to create and distribute +\gplusi{} without paying them a hefty sum?) The license of \workg{}, the +GPL, sets forth ahead of time options for the copyright holder of \worki{} +who may want to create and distribute \gplusi{}. This pre-granted +permission to create and distribute derivative works, provided the terms +of 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 restriction is any way unreasonable is simply ludicrous. + +\medskip + +The next phrase of note in \S 2(b) is ``licensed ... at no charge''. This +is a source of great confusion to many. Not a month goes by that FSF does +not receive an email that claims to point out ``a contradiction in GPL'' +because \S 2 says that redistributors cannot charge for modified versions +of GPL'ed software, but \S 1 says that they can. The ``at no charge'' +means not that redistributors cannot charge for 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'ed 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. + +\S 2(b) further states that the software must ``be licensed ... to all +third parties''. This too has led to some confusions, and feeds the +misconception mentioned earlier --- that all modified versions must 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 \S 2(b) does require redistributors to license the derivative works in +a way that is extends to all third parties who may ultimately receive a +copy of the software. + +In summary, \S 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 GPL. When an entity \emph{chooses} to redistribute +a derivative work of GPL'ed software, the license of that whole derivative +work must be GPL and only GPL\@. In this manner, \S 2(b) dovetails nicely +with \S 6 (as discussed in Section~\ref{GPLs6} of this tutorial). + +\medskip + +The final paragraph of \S 2 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'ed +code-base does not impact the license of other programs. Actual effort +must be expended by a programmer to cause a work to fall under the terms +of the GPL. Redistributors are always welcome to simply ship GPL'ed +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'ed. + +\section{GPL \S 3: Producing Binaries} + +% FIXME: need name of a novelist who writes very obscurely and obliquely. + +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 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., +``compilation'') 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'ed software to be useful, the GPL, since it governs the +rules for creation of derivative 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 +source code. \S 3 addresses the matter of creation and distribution of +binary versions. + +Under \S 3, binary versions may be created and distributed under the terms +of \S\S 1--2, so all the material previously discussed applies here. +However, \S 3 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. \S 3 must ensure that the binaries are never distributed +without the source code, so that these freedoms are ensured to be passed +along the distribution chain. + +\S 3 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 \S 3(a). + +\S 3(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 \S 3(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''. A later paragraph of \S 3 +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, \S 3 is defending against a tactic that has in fact been seen +in FSF's GPL enforcement. Under GPL, if you pay a high price for a copy +of GPL'ed 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), and then giving source code that does correspond, but not +giving the ``incantations'' and build plans they used to make that source +compile into the specialized binaries. Therefore, \S 3 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 from the sources provided. + +FSF (as authors of GPL) realizes that software distribution comes in many +forms. Embedded manufacturers, for example, have the freedom to put +GPL'ed software into their PDAs 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 infeasible. + +\S 3, therefore, allows source code to be provided on any physical +``medium customarily used for software interchange''. By design, this +phrase covers a broad spectrum. At best, FSF can viably release a new GPL +every ten years or so. Thus, phrases like this must be adaptive to +changes in the technology. When GPL version 2 was first published in June +1991, distribution on magnetic tape was still common, and CD was +relatively new. Today, CD is the default, and for larger systems DVD-R is +gaining adoption. This language 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, it is indeed customary to +simply download CDs worth of data over a T1 or email large file +attachments. However, even today in the USA, many computer users with +CD-ROM drives are not connected to the Internet, and most people connected +to the Internet are connected via a 56K dial-up connection. 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 have must have a worldwide scope in context, and 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 \S 3. \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 \S 3. + +\medskip + +As is shown above, Under \S 3(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'ed software. For this situation and others like it, \S +3(b) is available. + +\S 3(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 \S 3(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, that \S 3(b) does place lasting long-term obligations on the +binary distributor. The binary distributor must be prepared for three +years to honor that offer for source, and ship it out (just as they would +have had to do under \S 3(a)) at a moment's notice when they receive such +a request. There is real organizational cost here: support engineers for +three years 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 \S\S 1--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. + +\S 3(c) is created to save her some trouble, because by itself \S 3(b) +would unfairly favor large companies. compromise. \S 3(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 redistributors, 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, \S 3(b)'s compromise primarily benefits companies who +distribute binary software commercially. Without \S 3(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 \S 3(b)-compliant +offer, would be required under GPL (sans \S 3(c)) to acquire the source, +merely to give a copy of the software to a friend who needed it. \S 3(c) +reshifts this burden to entity who benefits from \S 3(b). + +\S 3(c) allows those who undertake \emph{non-commercial} distribution to +simply pass along a \S 3(b)-compliant source code offer. The customer who +wished 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 \S 3(a), or +write her own \S 3(b)-compliant source offer. + +This process is precisely the reason why a \S 3(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 non-commercially receiving a copy of the +software. Companies who choose to comply via \S 3(b) must thus be +prepared to honor all incoming source code requests. For this and the +many other additional necessary complications under \S\S 3(b--c), it is +only rarely a better option than complying via \S 3(a). + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\chapter{Defending Freedom On Many Fronts} + +The last chapter presented the core freedom-defending provisions of GPL\@, +which are in \S\S 0--3. \S\S 4--7 of the GPL are designed to ensure that +\S\S 0--3 are not infringed, are enforceable, are kept to the confines of +copyright law and are not trumped by other copyright agreements or +components of other entirely separate legal systems. In short, while \S\S +0--3 are the parts of the license that defend the freedoms of users and +programmers, \S\S 4--7 are the parts of the license that keep the playing +field clear so that \S\S 0--3 can do their jobs. + +\section{GPL \S 4: Termination on Violation} +\label{GPLs4} + +\S 4 is GPL's termination clause. Upon first examination, it seems +strange for a license that has 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 holder has the right to relicense the same +work under different licenses (see Section~\ref{Proprietary Relicensing} +of this tutorial), or to stop distributing the GPL'ed version (assuming \S +3(b) was never used), but the she may not revoke the rights under GPL +already granted. + +In fact, when an entity looses their right to copy, modify and distribute +GPL'ed software, it is because of their \emph{own actions}, not that of +the copyright holder. The copyright holder does not decided when \S 4 +termination occurs (if ever), the actions of the licensee does. + +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. \S 4 says that if you undertake any of +those other types (e.g., redistributing binary-only in violation of \S 3), +then all rights under the license --- even those otherwise permitted for +those who have not violated --- terminate automatically. + +\S 4 gives GPL teeth. If licensees fail to adhere to the license, then +they are stuck. They must to completely cease and desist from all +copying, modification and distribution of that GPL'ed software. + +At that point, violating licensees must gain the forgiveness of the +copyright holder to have their rights restored. Alternatively, they could +negotiate another agreement, separate from GPL, with the copyright +holder. Both are common practice. + +At FSF, it is part of the mission to spread software freedom. When FSF +enforces GPL, the goal is to bring the violator back into compliance as +quickly as possible, and redress the damage caused by the violation. +That is FSF's steadfast position in a violation negotiation --- comply +with the license and respect freedom. + +However, other entities who do not share the full ethos of software +freedom as institutionalized by FSF pursue GPL violations differently. MySQL +AB, a company that produces the GPL'ed MySQL database, upon discovering +GPL violations typically negotiates a proprietary software license +separately for a fee. While this practice is not one that FSF would ever +consider undertaking or even endorsing, it is a legal way for copyright +holders to proceed. + +\section{GPL \S 5: Acceptance, Copyright Style} +\label{GPLs5} + +\S 5 brings us to perhaps the most fundamental misconception and common +confusion about GPL\@. 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''. No rights are +transfered between parties. By contrast, the GPL is permission slip to +undertake activities that would otherwise been prohibited by copyright law. +As such, it needs no acceptance ceremony; the licensee is not even +required to accept the license. + +However, without the GPL, the activities of copying, modifying and +distributing the software would have otherwise been prohibited. So, the +GPL says that you only accepted the license by undertaking activities that +you would have otherwise been prohibited without your license under GPL\@. +This is a certainly subtle point, and requires a mindset quite different +from the contractual approach taken by EULA authors. + +An interesting side benefit to \S 5 is that the bulk of users of Free +Software are not required to accept the license. Undertaking fair and +unregulated use of the work, for example, does not bind you to the GPL, +since you are not engaging in activity that is otherwise controlled by +copyright law. Only when you engage in those activities that might have an +impact on the freedom of others does license acceptance occur and the +terms begin to bind you to fair and equitable sharing of the software. In +other words, the GPL only kicks in when it needs to for the sake of +freedom. + +\section{GPL \S 6: GPL, My One and Only} +\label{GPLs6} + +A point that was glossed over in Section~\ref{GPLs4}'s discussion of \S 4 +was the irrevocable nature of the GPL\@. The GPL is indeed irrevocable, +and it is made so formally \S 6. + +The first sentence in \S 6 ensures that as software propagates down the +distribution chain, that each licensor can pass along the license to each +new licensee. Under \S 6, the act of distributing automatically grants a +license from the original licensor to the next recipient. This creates a +chain of grants that ensure that everyone in the distribution has rights +under the GPL\@. In a mathematical sense, this bounds the bottom --- +making sure that future licensees get no fewer rights than than the +licensee before. + +The second sentence of \S 6 does the opposite; it bounds from the top. It +prohibits any licensor along the distribution chain from placing +additional restrictions on the user. In other words, no additional +requirements may trump the rights and freedoms given by GPL\@. + +The final sentence of \S 6 makes it abundantly clear that no individual +entity in the distribution chain is responsible for the compliance of any +other. This is particularly important for non-commercial users who have +passed along a source offer under \S 3(c), as they cannot be assured that +the issuer of the offer will honor their \S 3 obligations. + +In short, \S 6 says that your license for the software is your one and +only copyright license allowing you to copy, modify and distribute the +software. + +\section{GPL \S 7: ``Give Software Liberty of Give It Death!''} +\label{GPLs7} + +In essence, \S 7 is a verbosely worded way of saying for non-copyright +systems what \S 6 says for copyright. If there exists any reason that a +distributor knows of that would prohibit later licensees from exercising +their full rights under GPL, then distribution is prohibited. + +Originally, this was designed as the title of this section suggests --- as +a last ditch effort to make sure that freedom was upheld. However, in +modern times, it has come to give much more. Now that the body of GPL'ed +software is so large, patent holders who would want to be distributors of +GPL'ed software have a tough choice. They must choose between avoiding +distribution of GPL'ed software that exercises the teachings of their +patents, or grant a royalty-free, irrevocable, non-exclusive license to +those patents. Many companies, including IBM, the largest patent holder +in the world, have chosen the latter. + +Thus, \S 7 is rarely gives software death by stopping its distribution. +Instead, it is inspiring patent holders to share their patents in the same +freedom-defending way that they share their copyrighted works. + +\section{GPL \S 8: Excluding Unfreedonia} +\label{GPLs8} + +\S 8 is rarely used by copyright holders. Its intention is that, if +particular country, say Unfreedonia, grant particular patents or allow +copyrighted interfaces (no country to our knowledge even permits those +yet), that the GPL'ed software can continue in free and unabated +distribution in the countries where such controls do not exist. + +It is a partial ``out'' from \S 7. Without \S 8, if a copyright holder +knew of a patent in a particular country licensed in a GPL-incompatible +way, then she could not distribute under GPL, because the work would +legitimately end up in the hands of citizens of Unfreedonia. + +It is an inevitable but sad reality that some countries are freer than +others. \S 8 exists to permit distribution on those countries that are +free without otherwise negating parts of the license. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\chapter{Odds, Ends, and Absolutely No Warranty} + +\S 0--7 constitute the freedom-defending terms of the GPL. The balance +of the GPL handles administrivia and issues concerning warranties and +liability. + +\section{GPL \S 9: FSF as stewards of GPL} +\label{GPLs9} + +FSF reserves the exclusive right to publish future versions of the GPL\@; +\S 9 expresses this. While the stewardship of the copyrights on the body +of GPL'ed software around the world is shared among thousands of +individuals and organizations, the license itself needs a single steward. +Forking of the code is often regrettable but basically innocuous. Forking +of licensing is disastrous. + +FSF has only released two versions of GPL --- in 1989 and 1991. GPL, +version 3, is under current internal drafting. FSF's plan is to have a +long and engaging comment period. The goal of GPL is defend freedom, and +a gigantic community depends on that freedom now. FSF hopes to take all +stakeholders' opinions under advisement. + +\section{GPL \S 10: Relicensing Permitted} +\label{GPLs10} + +\S 10 reminds the licensee of what is already implied by the nature of +copyright law. Namely, the copyright holder of a particular software +program has the prerogative to grant alternative agreements under separate +copyright licenses. + +\section{GPL \S 11: No Warranty} +\label{GPLs11} + +All warranty disclaimer language tends to be shouted in all capital +letters. Apparently, there was once a case where the disclaimer language +of an agreement was negated because it was not ``conspicuous'' to one of +the parties. Therefore, to make such language ``conspicuous'', people +started placing it in bold or capitalizing the entire text. It now seems +to be voodoo tradition of warranty disclaimer writing. + +Finally, one important point to remember when reading \S 11 is that \S 1 +permits the sale of warranty as an additional service, which \S 11 +affirms. + +\section{GPL, \S 12: Limitation of Liability} +\label{GPLs12} + +There are many types of warranties, and in some jurisdictions some of them +cannot be disclaimed. Therefore, usually agreements will have both a +warranty disclaimer and a limitation of liability, as we have in \S 12. +\S 11 thus gets rid of all implied warranties that can legally be +disavowed. \S 12, in turn, limits the liability of the actor for any +warranties that cannot legally be disclaimed in a particular jurisdiction. + +So ends the terms and conditions of the GNU General Public License. + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\chapter{Integrating the GPL into Business Practices} + +Since GPL'ed software is now extremely prevalent through the industry, it +is useful to has some basic knowledge about using GPL'ed software in +business and how to build business models around GPL'ed software. + +\section{Using GPL'ed Software In-House} + +A discussed in Sections~\ref{GPLs0} and~\ref{GPLs5} of this tutorial, the +GPL only governs the activities of copying, modifying and distributing the +software 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 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 \S\S 1 and 3, but it is +encouraged! If the company simply deploy 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 there is also a +thriving market for Free Software-oriented business models. There is the +traditional model of selling copies of Free Software distributions. Many +companies, including IBM and Red Hat, make substantial revenue from this +model. IBM primarily chooses this model because they have found that for +higher-end hardware, the cost of 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'ed +software in particular (because IBM can be assured that proprietary +versions of the same software will not exists to compete on their +hardware) is the right choice. + +Red Hat has actually found that 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 +website, 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'ed software. The GPL is central to +their success, because it ensure 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 +porting GCC to new embedded chipset target platforms. Eventually, Cygnus +was so successful that it was purchased by Red Hat where it remains a +profitable division. + +However, there are very small companies like CodeSourcery, as well as +other medium sized companies like MontaVista and OpenTV that compete in +this space. Because the code-base is protect by 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, and 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'ed code base. This is only an option for +software in which a particular entity is the sole copyright holder. 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, such as MySQL AB and TrollTech, use this to their +financial advantage with regard to a GPL'ed 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 problematic because it means that the GPL'ed 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 or distributing +modified versions of GPL'ed software, the burden is a bit higher, but not +by much. The glib answer that is that it is always easy to comply with +the GPL by releasing the whole product as Free Software. However, +admittedly to the dismay of FSF, many modern and complex software systems +are built using both proprietary and GPL'ed components that are not +legally derivative works of each other. Usually, in product development +with Free Software tools, sometimes it is easier simply to improve +existing GPL'ed application than to start from scratch. In exchange for +that benefit, the license requires that the modifier give back to the +commons that made the work easier. It is a reasonable trade-off, and it +is 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 $<$compliance@fsf.org$>$. + +\appendix + +\chapter{The GNU General Public License} + +\begin{center} +{\parindent 0in + +Version 2, June 1991 + +Copyright \copyright\ 1989, 1991 Free Software Foundation, Inc. + +\bigskip + +59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + +\bigskip + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. +} +\end{center} + +\begin{center} +{\bf\large Preamble} +\end{center} + + +The licenses for most software are designed to take away your freedom to +share and change it. By contrast, the GNU General Public License is +intended to guarantee your freedom to share and change free software---to +make sure the software is free for all its users. This General Public +License applies to most of the Free Software Foundation's software and to +any other program whose authors commit to using it. (Some other Free +Software Foundation software is covered by the GNU Library General Public +License instead.) You can apply it to your programs, too. + +When we speak of free software, we are referring to freedom, not price. +Our General Public Licenses are designed to make sure that you have the +freedom to distribute copies of free software (and charge for this service +if you wish), that you receive source code or can get it if you want it, +that you can change the software or use pieces of it in new free programs; +and that you know you can do these things. + +To protect your rights, we need to make restrictions that forbid anyone to +deny you these rights or to ask you to surrender the rights. These +restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + +For example, if you distribute copies of such a program, whether gratis or +for a fee, you must give the recipients all the rights that you have. You +must make sure that they, too, receive or can get the source code. And +you must show them these terms so they know their rights. + +We protect your rights with two steps: (1) copyright the software, and (2) +offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + +Also, for each author's protection and ours, we want to make certain that +everyone understands that there is no warranty for this free software. If +the software is modified by someone else and passed on, we want its +recipients to know that what they have is not the original, so that any +problems introduced by others will not reflect on the original authors' +reputations. + +Finally, any free program is threatened constantly by software patents. +We wish to avoid the danger that redistributors of a free program will +individually obtain patent licenses, in effect making the program +proprietary. To prevent this, we have made it clear that any patent must +be licensed for everyone's free use or not licensed at all. + +The precise terms and conditions for copying, distribution and +modification follow. + +\begin{center} +{\Large \sc Terms and Conditions For Copying, Distribution and + Modification} +\end{center} + + +%\renewcommand{\theenumi}{\alpha{enumi}} +\begin{enumerate} + +\addtocounter{enumi}{-1} + +\item + +This License applies to any program or other work which contains a notice +placed by the copyright holder saying it may be distributed under the +terms of this General Public License. The ``Program'', below, refers to +any such program or work, and a ``work based on the Program'' means either +the Program or any derivative work under copyright law: that is to say, a +work containing the Program or a portion of it, either verbatim or with +modifications and/or translated into another language. (Hereinafter, +translation is included without limitation in the term ``modification''.) +Each licensee is addressed as ``you''. + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + +\item You may copy and distribute verbatim copies of the Program's source + code as you receive it, in any medium, provided that you conspicuously + and appropriately publish on each copy an appropriate copyright notice + and disclaimer of warranty; keep intact all the notices that refer to + this License and to the absence of any warranty; and give any other + recipients of the Program a copy of this License along with the Program. + +You may charge a fee for the physical act of transferring a copy, and you +may at your option offer warranty protection in exchange for a fee. + +\item + +You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + +\begin{enumerate} + +\item + +You must cause the modified files to carry prominent notices stating that +you changed the files and the date of any change. + +\item + +You must cause any work that you distribute or publish, that in +whole or in part contains or is derived from the Program or any +part thereof, to be licensed as a whole at no charge to all third +parties under the terms of this License. + +\item +If the modified program normally reads commands interactively +when run, you must cause it, when started running for such +interactive use in the most ordinary way, to print or display an +announcement including an appropriate copyright notice and a +notice that there is no warranty (or else, saying that you provide +a warranty) and that users may redistribute the program under +these conditions, and telling the user how to view a copy of this +License. (Exception: if the Program itself is interactive but +does not normally print such an announcement, your work based on +the Program is not required to print an announcement.) + +\end{enumerate} + + +These requirements apply to the modified work as a whole. If +identifiable sections of that work are not derived from the Program, +and can be reasonably considered independent and separate works in +themselves, then this License, and its terms, do not apply to those +sections when you distribute them as separate works. But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + +\item +You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + +\begin{enumerate} + +\item + +Accompany it with the complete corresponding machine-readable +source code, which must be distributed under the terms of Sections +1 and 2 above on a medium customarily used for software interchange; or, + +\item + +Accompany it with a written offer, valid for at least three +years, to give any third party, for a charge no more than your +cost of physically performing source distribution, a complete +machine-readable copy of the corresponding source code, to be +distributed under the terms of Sections 1 and 2 above on a medium +customarily used for software interchange; or, + +\item + +Accompany it with the information you received as to the offer +to distribute corresponding source code. (This alternative is +allowed only for noncommercial distribution and only if you +received the program in object code or executable form with such +an offer, in accord with Subsection b above.) + +\end{enumerate} + + +The source code for a work means the preferred form of the work for +making modifications to it. For an executable work, complete source +code means all the source code for all modules it contains, plus any +associated interface definition files, plus the scripts used to +control compilation and installation of the executable. However, as a +special exception, the source code distributed need not include +anything that is normally distributed (in either source or binary +form) with the major components (compiler, kernel, and so on) of the +operating system on which the executable runs, unless that component +itself accompanies the executable. + +If distribution of executable or object code is made by offering +access to copy from a designated place, then offering equivalent +access to copy the source code from the same place counts as +distribution of the source code, even though third parties are not +compelled to copy the source along with the object code. + +\item +You may not copy, modify, sublicense, or distribute the Program +except as expressly provided under this License. Any attempt +otherwise to copy, modify, sublicense or distribute the Program is +void, and will automatically terminate your rights under this License. +However, parties who have received copies, or rights, from you under +this License will not have their licenses terminated so long as such +parties remain in full compliance. + +\item +You are not required to accept this License, since you have not +signed it. However, nothing else grants you permission to modify or +distribute the Program or its derivative works. These actions are +prohibited by law if you do not accept this License. Therefore, by +modifying or distributing the Program (or any work based on the +Program), you indicate your acceptance of this License to do so, and +all its terms and conditions for copying, distributing or modifying +the Program or works based on it. + +\item +Each time you redistribute the Program (or any work based on the +Program), the recipient automatically receives a license from the +original licensor to copy, distribute or modify the Program subject to +these terms and conditions. You may not impose any further +restrictions on the recipients' exercise of the rights granted herein. +You are not responsible for enforcing compliance by third parties to +this License. + +\item +If, as a consequence of a court judgment or allegation of patent +infringement or for any other reason (not limited to patent issues), +conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot +distribute so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you +may not distribute the Program at all. For example, if a patent +license would not permit royalty-free redistribution of the Program by +all those who receive copies directly or indirectly through you, then +the only way you could satisfy both it and this License would be to +refrain entirely from distribution of the Program. + +If any portion of this section is held invalid or unenforceable under +any particular circumstance, the balance of the section is intended to +apply and the section as a whole is intended to apply in other +circumstances. + +It is not the purpose of this section to induce you to infringe any +patents or other property right claims or to contest validity of any +such claims; this section has the sole purpose of protecting the +integrity of the free software distribution system, which is +implemented by public license practices. Many people have made +generous contributions to the wide range of software distributed +through that system in reliance on consistent application of that +system; it is up to the author/donor to decide if he or she is willing +to distribute software through any other system and a licensee cannot +impose that choice. + +This section is intended to make thoroughly clear what is believed to +be a consequence of the rest of this License. + +\item +If the distribution and/or use of the Program is restricted in +certain countries either by patents or by copyrighted interfaces, the +original copyright holder who places the Program under this License +may add an explicit geographical distribution limitation excluding +those countries, so that distribution is permitted only in or among +countries not thus excluded. In such case, this License incorporates +the limitation as if written in the body of this License. + +\item +The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and ``any +later version'', you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + +\item +If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + +\begin{center} +{\Large\sc +No Warranty +} +\end{center} + +\item +{\sc Because the program is licensed free of charge, there is no warranty +for the program, to the extent permitted by applicable law. Except when +otherwise stated in writing the copyright holders and/or other parties +provide the program ``as is'' without warranty of any kind, either expressed +or implied, including, but not limited to, the implied warranties of +merchantability and fitness for a particular purpose. The entire risk as +to the quality and performance of the program is with you. Should the +program prove defective, you assume the cost of all necessary servicing, +repair or correction.} + +\item +{\sc In no event unless required by applicable law or agreed to in writing +will any copyright holder, or any other party who may modify and/or +redistribute the program as permitted above, be liable to you for damages, +including any general, special, incidental or consequential damages arising +out of the use or inability to use the program (including but not limited +to loss of data or data being rendered inaccurate or losses sustained by +you or third parties or a failure of the program to operate with any other +programs), even if such holder or other party has been advised of the +possibility of such damages.} + +\end{enumerate} + + +\begin{center} +{\Large\sc End of Terms and Conditions} +\end{center} + + +\pagebreak[2] + +\section*{Appendix: How to Apply These Terms to Your New Programs} + +If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these +terms. + + To do so, attach the following notices to the program. It is safest to + attach them to the start of each source file to most effectively convey + the exclusion of warranty; and each file should have at least the + ``copyright'' line and a pointer to where the full notice is found. + +\begin{quote} +one line to give the program's name and a brief idea of what it does. \\ +Copyright (C) yyyy name of author \\ + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. +\end{quote} + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + +\begin{quote} +Gnomovision version 69, Copyright (C) yyyy name of author \\ +Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. \\ +This is free software, and you are welcome to redistribute it +under certain conditions; type `show c' for details. +\end{quote} + + +The hypothetical commands {\tt show w} and {\tt show c} should show the +appropriate parts of the General Public License. Of course, the commands +you use may be called something other than {\tt show w} and {\tt show c}; +they could even be mouse-clicks or menu items---whatever suits your +program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a ``copyright disclaimer'' for the program, if +necessary. Here is a sample; alter the names: + +\begin{quote} +Yoyodyne, Inc., hereby disclaims all copyright interest in the program \\ +`Gnomovision' (which makes passes at compilers) written by James Hacker. \\ + +signature of Ty Coon, 1 April 1989 \\ +Ty Coon, President of Vice +\end{quote} + + +This General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications +with the library. If this is what you want to do, use the GNU Library +General Public License instead of this License. + + +\chapter{The GNU Lesser General Public License} + +\begin{center} +{\parindent 0in + +Version 2.1, February 1999 + +Copyright \copyright\ 1991, 1999 Free Software Foundation, Inc. + +\bigskip + +59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + +\bigskip + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. + +\bigskip + +[This is the first released version of the Lesser GPL. It also counts + as the successor of the GNU Library Public License, version 2, hence + the version number 2.1.] +} + +\end{center} + +\begin{center} +{\bf\large Preamble} +\end{center} + +The licenses for most software are designed to take away your freedom to +share and change it. By contrast, the GNU General Public Licenses are +intended to guarantee your freedom to share and change free software---to +make sure the software is free for all its users. + +This license, the Lesser General Public License, applies to some specially +designated software packages---typically libraries---of the Free Software +Foundation and other authors who decide to use it. You can use it too, +but we suggest you first think carefully about whether this license or the +ordinary General Public License is the better strategy to use in any +particular case, based on the explanations below. + +When we speak of free software, we are referring to freedom of use, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish); that you receive source code or can get it if +you want it; that you can change the software and use pieces of it in new +free programs; and that you are informed that you can do these things. + +To protect your rights, we need to make restrictions that forbid +distributors to deny you these rights or to ask you to surrender these +rights. These restrictions translate to certain responsibilities for you +if you distribute copies of the library or if you modify it. + +For example, if you distribute copies of the library, whether gratis or +for a fee, you must give the recipients all the rights that we gave you. +You must make sure that they, too, receive or can get the source code. If +you link other code with the library, you must provide complete object +files to the recipients, so that they can relink them with the library +after making changes to the library and recompiling it. And you must show +them these terms so they know their rights. + +We protect your rights with a two-step method: (1) we copyright the +library, and (2) we offer you this license, which gives you legal +permission to copy, distribute and/or modify the library. + +To protect each distributor, we want to make it very clear that there is +no warranty for the free library. Also, if the library is modified by +someone else and passed on, the recipients should know that what they have +is not the original version, so that the original author's reputation will +not be affected by problems that might be introduced by others. + +Finally, software patents pose a constant threat to the existence of any +free program. 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