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%      Tutorial Text for the Detailed Study and Analysis of GPL and LGPL course

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% Copyright (C) 2014             Bradley M. Kuhn

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\newcommand{\defn}[1]{\emph{#1}}

\part{Detailed Analysis of the GNU GPL and Related Licenses}

\begin{center}

{\parindent 0in

This part is: \\

\begin{tabbing}

Copyright \= \copyright{} 2003, 2004, 2005 \= \hspace{.2in} Free Software Foundation, Inc. \\

\end{tabbing}

Authors of this Part Are: \\

Bradley M. Kuhn \\

David ``Novalis'' Turner \\

Daniel B. Ravicher \\

John Sullivan

\vspace{.3in}

The copyright holders of this part hereby grant the freedom to copy, modify,

convey, Adapt, and/or redistribute this work under the terms of the Creative

Commons Attribution Share Alike 4.0 International License.  A copy of that

license is available at

\verb=https://creativecommons.org/licenses/by-sa/4.0/legalcode=.  }

\end{center}

\bigskip

This part of the tutorial gives a comprehensive explanation of the most

To successfully benefit of from this part of the tutorial, readers should

tutorial is of most interest to lawyers, software developers and managers who

\begin{itemize}

  \item The differences between GPLv2 and GPLv3.

  \item The redistribution options under the GPLv2 and GPLv3.

  \item The basics of the Lesser GPLv2.1 and Lesser GPLv3, and how they

    differs from the GPLv2 and GPLv3, respectively.

\end{itemize}

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% END OF ABSTRACTS SECTION

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% START OF DAY ONE COURSE

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\chapter{What Is Software Freedom?}

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 both of the popular

versions of GPL (GPLv2 and GPLv3) and their

terms and conditions is a basic understanding of the principles behind it.

The GPL family of licenses are 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 Web site 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 Web site at {\tt

    http://www.fsf.org/licensing/essays/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 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 noncommercially or

commercially. Licenses that grant these freedoms for noncommercial

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 noncommercial 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 any use for software the user

can come up with must be permitted. Perhaps, for example, the user

has discovered an innovative 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 Web sites 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 noncommercial settings. For example, users often seek

noncommercial 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 to 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 noncommercial

sharing must be permitted for Free Software to thrive.

Commercial sharing of modified Free Software is equally important.

For commercial support to exist in a competitive free market, 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 nontrivial 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