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 noncommercially in academic environments\footnote{See

  \href{http://turtle.ee.ncku.edu.tw/docs/samba/history}{Andrew Tridgell's

    ``A bit of history and a bit of fun''}.  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

running such servers 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 noncommercial users, however, were not concerned when these two

fellows began collecting paychecks off of their GPL'd 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 noncommercial 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 noncommercial

developers.  Those two now-long-since graduated students continue to

contribute to Samba altruistically, but also get paid 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 noncommercially 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 noncommercial 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 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 noncommercial Free Software

economy.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\chapter{A Tale of Two Copyleft Licenses}

\section{Historical Motivations for the General Public License}

\section{Proto-GPLs And Their Impact}

\section{The GNU General Public License, Version 1}

\section{The GNU General Public License, Version 2}

\section{The GNU General Public License, Version 3}

\section{The Innovation of Optional ``Or Any Later'' Version}

\section{Complexities of Two Simultaneously Popular Copylefts}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\chapter{GPLv2: Running Software and Verbatim Copying}

\label{run-and-verbatim}

This chapter begins the deep discussion of the details of the terms of

GPLv2\@. In this chapter, we consider the first two sections: GPLv2 \S\S

0--2. These are the straightforward sections of the GPL that define the

simplest rights that the user receives.

\section{GPLv2 \S 0: Freedom to Run}

\label{GPLs0}

\S 0, the opening section of GPLv2, 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 GPLv2

(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. GPLv2 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 would with or 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

program's source code like an instruction book for the purpose of learning

how to be a better programmer.

\medskip

Thus, the GPLv2 protects users fair and unregulated use rights precisely by

not attempting to cover them. Furthermore, the GPLv2 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

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 attempted 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{GPLv2 \S 1: Verbatim Copying}

\label{GPLs1}

GPLv2 \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 the software she got was licensed under GPL\@. Thus

throughout the GPL, there are specific references 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 few 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.)