\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),

in existing, successful enterprises.

Attendees should have a general familiarity with software development

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

restricted.

It was once rare that this freedom was restricted by even proprietary

programmers who might altruistically assist them to modify their software.

The commercial exercise of this freedom is also essential.  Each user, or

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

  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

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

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

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

Copyleft is a legal strategy to defend, uphold and propagate software

freedom.  The basic technique of copyleft is as follows: copyright the

client is in the mix, but all the code is contributed back to the

canonical version.  Meanwhile, many other individuals have gotten involved

non-commercially as developers, because they want to ``cut their teeth on

at it, perhaps they will move on to another project or perhaps they will

become commercial developers of the software themselves.

In essence, lawyers are paid to service the shared commons of legal

infrastructure.  Few defend themselves in court or write their own briefs

prefer to have an expert do that job.

The Free Software economy is a market that is ripe for experts.  It

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

not for the definition itself, which is rather straightforward, but the

because it clears up a common misconception about the GPL\@.

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

\section{GPL \S 2: Share and Share Alike}

Many consider \S 2 the heart and soul of the GPL\@.  For many, this is

where the ``magic'' happens that defends software freedom along the

where it is.  However, I argue that the heart is in fact contained in \SS

4--5 (see Section~\ref{GPLs4} and~\ref{GPLs5} of this tutorial).  But, for

the moment, let us consider the soul.

changes are never distributed.  Indeed, the freedom to make private,

personal changes to software that are not shared should be protected and

defended\footnote{FSF does maintain that there is an {\bf ethical}

  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.}.

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 must presented to the

human eyes and ears to have any value.

representation of software is of keen interest to programmers, users and

programmers alike cannot make the proper use of software in that

be fully useful.  Without the binaries, be they in object or executable

Under copyright law, binary representations of the software are simply

derivative works of the source code.  Applying a systematic process (i.e.,

code is now a new work of expression fixed in the tangible medium of

electronic file storage.

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

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.

\section{GPL \S 6: GPL, My One and Only}

\label{GPLs6}

\label{GPLs7}

\label{GPLs8}

\section{GPL \S 9}

\label{GPLs9}