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

%

% Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.

% 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

have a general familiarity with software development processes.  A vague

understanding of how copyright law applies to software is also helpful.  The

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

\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