\item The redistribution options under the GPLv2 and GPLv3.

  \item The obligations when modifying GPLv2'd or GPLv3'd 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'd software can be used in existing enterprises.

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

    differs from the GPLv2 and GPLv3, respectively.

  \item The basics to begin understanding the complexities regarding

    derivative and combined works of software.

\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?}

Study 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 software freedom. 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 they are designed to defend and uphold these

principles.

\section{The Free Software Definition}

\label{Free Software Definition}

The Free Software Definition is set forth in full on FSF's website at

\verb0http://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 GPL\@.

A particular program grants software freedom to a particular user if that

user is granted the following freedoms:

\begin{itemize}

\teim The freedom to run the program, for any purpose.

\item The freedom to study how the program works, and modify it

\item The freedom to redistribute copies.

\item The freedom to distribute copies of  modified versions to others.

\end{itemize}

The focus on ``a particular user'' is particularly 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 unfortunately happen even if a program is released under the GPL\@.

Many 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 often focused on a side

issue.  Specifically, 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.

Software freedom is only complete when no restrictions are imposed on how

these freedoms are 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.  Even the Open Source Initiative

(\defn{OSI}) (the arbiter of what is considered ``Open Source'') also rules

such licenses not in fitting with their ``Open Source Definition''.

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).

\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.