% gpl-buisness.tex -*- LaTeX -*- % Tutorial Text for the GPL for Businesspeople and Developers course % % Copyright (C) 2003 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} {\Large \begin{center} \vspace{.5in} {\sc The GNU General Public License for Businesspeople and Developers } \\ \vspace{1in} A Tutorial By: \vspace{.3in} Bradley M. Kuhn Executive Director Free Software Foundation \end{center} } \vfill {\parindent 0in Copyright \copyright{} 2003 \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 tutorial gives a section-by-section explanation of the most popular Free Software copyright license, the GNU General Public License (GNU GPL), and teaches 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 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. This tutorial introduces the GNU GPL and its terms to professionals who are not well versed in the details of copyright law. Presented by a software developer and manager, this tutorial informs those who wish to have a deeper understanding of how the GNU GPL uses copyright law to protect software freedom and to assist in the formation of Free Software businesses, and of the organizational motivations behind the GNU GPL. 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 properly apply the GPL to a new 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. \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 \href{http://www.fsf.org/philosophy/free-sw.html}{http://www.fsf.org/philosophy/free-sw.html}. 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 \href{http://www.fsf.org/philosophy/free-software-for-freedom.html} {http://www.gnu.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 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 an 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 ownership 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} \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 programs 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 attempt 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} 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 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 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 Donald Barthelme, 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. \end{document} % LocalWords: proprietarize redistributors sublicense yyyy Gnomovision EULAs % LocalWords: Yoyodyne FrontPage improvers Berne copyrightable Stallman's GPLs % LocalWords: Lessig Lessig's UCITA pre PDAs CDs reshifts GPL's Gentoo % LocalWords: TrollTech