open source software primer

8/8/2019 Open Source Software Primer

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A PRIMER ON OPEN SOURCE SOFTWAREFOR BUSINESS PEOPLE AND LAWYERS

Stephen J. Davidson *

Leonard, Street and DeinardMinneapolis, Minnesota

Copyright 2004 by Stephen J. DavidsonAll Rights Reserved

Stephen Davidson is Chairman of the Intellectual Property and Information Technology Law Department at theMinneapolis, Minnesota-based law firm of Leonard, Street and Deinard, where he represents clients throughout theUnited States in development projects, transactions and litigation involving computer and information technology.He is a former president of the Computer Law Association and an adjunct Professor of Information Technology Lawat the University of Minnesota Law School. Mr. Davidson has appeared on the faculties of numerous computer lawconferences in the United States, Canada and Europe, Asia and Latin America, and he has served on the editorialboard of several leading information technology law journals. He can be reached at [email protected].


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CONTENTS

Topic Page

A Part of the Ecosystem 1

Some Helpful Definitions 2

Economic and Practical Realities 3

Development 4

Licensing Schemes 4

Standards 6

Total Cost of Ownership 7

The GPL and LGPL 8

Conclusion 13

Appendix

The GNU General Public License i

The GNU Lesser General Public License viiiThe GNU Free Documentation License xviii


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A Part of the Ecosystem

Open source software is a part of the software ecosystem that affords software developers

and users an alternative style of software development and distribution. It co-exists in that

environment along with a broad spectrum of other development and distribution methods, including

public domain software, freeware, shareware, proprietary commercial software and even vaporware.

Open source software is found in development tools, operating systems and applications.

The principal proponent of open source software if the Free Software Foundation, which

was founded in the mid-1980s by computer scientist Richard Stallman and which proclaims its

primary missions to be: 1) promoting computer users right to use, study, copy, modify, andredistribute computer programs; 2) promoting the development and use of free software and free

documentation; 3 spreading awareness of the ethical and political issues of freedom in the use of

software; 4) developing new free software; and 5) making that software into a coherent system

which can eliminate the need to use proprietary software.

The goal of this paper is to help the reader gain a basic understanding of the differences

between open source and commercial software in terms of some of the practical implications of

each and some of the broader issues that software developers, governments and commercial

enterprises might want to consider in terms of their own policies and acquisition activities, all

The word source in the phrase open source software refers to the source code of a computer program.Computer programs or operating systems are originally written by a human being in a programming language. Thisis called the source code of the software. To be actually used by a computer, the program has to be translated by thecomputer from the source code into the machine language that the computer understands and can execute. This

translation process is referred to as compiling. http://iet.ucdavis.edu/glossary.cfm#s . Source Code is the text thatprogrammers type in and edit in order to produce programs you can run. To change a program, a programmerchanges the source-code text and then generates a new version of the program from it. Without the source code onegenerally cannot modify or fix a program beyond narrow bounds foreseen by its original author.http://www.google.com/search?hl=en&lr=&oi=defmore&q=define:source+code .

For a directory of open source software, see http://directory.fsf.org/ .

See http://www.fsf.org/fsf/fsf.html .
http://www.fsf.org/philosophy/free-sw.htmlhttp://www.fsf.org/philosophy/categories.html#ProprietarySoftwarehttp://www.fsf.org/philosophy/free-sw.htmlhttp://www.fsf.org/philosophy/categories.html#ProprietarySoftware


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bearing in mind not only the immediate costs and benefits, but also the longer range implications

of how their decisions today will affect their economies and their standing in the world

technology market tomorrow.

Some Helpful Definitions

Traditionally, commercial or proprietary software is distributed only in binary, executable

form, and its developers reserve to themselves the ability to know the source code, to modify the

software, to distribute the software, and to authorize others to do those things. It is not unusual

for commercial software developers to refer to their software source code as the crown jewelsof the company and to jealously guard it against disclosure to others. At its most basic level,

open source software is distinguished from proprietary software by the availability of source

code to everyone who receives a license to use the software and, in many cases, by a broad

authorization to modify and redistribute it in both binary and source code form.

Over the past several years, market forces have operated to bring about numerous

variants of commercial and open source software, all of which have their own distinguishing

features. Along that spectrum we can now find: 1) commercial closed source software, for

which the source code is not available to anyone other than the original developer; 2)

commercial closed source software, for which the source code is licensed to authorized users

under strict confidentiality terms for their own use in maintaining and modifying the software; 3)

shared source software, for which the source code is made available to licensees for limited

purposes and subject to restrictions on use and disclosure; 4) community source software, for

which the source code is available to a limited community of users for broad purposes but still

subject to restrictions on use, modification and distribution; and 5) true open source software,


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for which the source code is made available for free use, modification and distribution, but the

license for which may be subject to conditions or obligations that make it unsuitable for

commercial use (more on that later). Market forces are causing these scenarios to overlap and

the distinctions between the various genre of software to become somewhat blurred, but they are

still sufficiently vivid to generate a lot of debate. Much of that debate has been engendered by

the free software movement, members of which advocate for free software with almost

religious fervor.

Despite its obvious differences from closed source, shared source and community source,

a precise definition of open source software is elusive. A recent Google search produced noless than 10 definitions from various sources, each of which gives a somewhat different

perspective and slant. ** One helpful and concise definition is:

Open Source Software is software for which the underlying programming code isavailable to the users so that they may read it, make changes to it, and build newversions of the software incorporating their changes. There are many types of Open Source Software, mainly differing in the licensing term under which(altered) copies of the source code may (or must) be redistributed.

Economic and Practical Realities

Among the most significant practical differences between commercial and open source

software are the way in which they are developed, the licensing schemes used in their

distribution, their relationship to standards, and the so-called total cost of ownership. While a

detailed discussion of these things is beyond the scope of this paper and has been the subject of

** See http://www.google.com/search?hl=en&lr=&oi=defmore&q=define:Open+source+software .

See www.cross-web.com/information/glossary.htm .


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several multi-day conferences over the past few years, it may be helpful to make some general

observations.

Development

Open source software is typically developed by very talented individuals or by informal

groups or communities of programmers who want to solve a technical problem and share the

results with the rest of the world. Some advocates claim that the open source model generates a

higher level of innovation, and some supporters claim that the open source model produces

software that is technically equal or even superior to competing commercial products. Becauseof the way it is distributed, there may be a great variety of any given open source software

product, including numerous derivatives that are relatively undocumented and may behave

differently in subtle or not-so-subtle ways.

Commercial or proprietary software is generally designed and developed in response to

market demand, or at least in response to a perceived market need. Its features tend to be market

driven and user driven. Development is relatively structured and disciplined, and the resulting

products tend to be relatively well documented, quality tested and supported. Features of

commercial software generally are the subject of long term, market driven evolution. Of course

the user pays for all these things, whether it wants them or not.

Licensing Schemes

Commercial software developers use licensing schemes that: 1) exploit their intellectual

property in ways that will generate enough revenue to pay their research, development,

marketing and support costs and leave something left over for profit (sometimes a small profit,


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and sometimes a monumental profit); and 2) limit scope of use, limit transferability, prohibit

reverse engineering, limit warranties and limit liability. With commercial software, users pay for

whatever benefit they get, and possibly for some benefit they dont need. Still, the fundamental

economics of commercial software licensing is that each party gets an anticipated benefit at an

anticipated cost.

The same is true for open source software, but the licensing model is very different.

Open source does not necessarily mean that one can do whatever it wants to do with the

software, although that is sometimes the case. There are two principal models. One, the BSD

(an acronym for Berkeley Software Distribution) model, is highly permissive and permitstaking the software and doing pretty much whatever you wish with it, including modification and

distribution of free or proprietary derivatives, provided that that each copy contains a specified

form of license that includes a copyright notice and a disclaimer of warranties and liability. The

UNIX operating system is an example of software that was distributed under the BSD license

(among other licensing channels), and Sun Microsystems Solaris operating system is an

example of a proprietary derivative of BSD UNIX.

The other principal model permits free use, modification and redistribution of the

software, but is highly restrictive. The most frequently encountered examples are the Free

Software Foundations General Public License (GPL) and Lesser General Public License

(LGPL), which permit modification and distribution of free derivatives, but which preclude the

creation of proprietary derivatives. The Linux operating system is an example of an open source

derivative of UNIX, and a number of popular software development tools such as the GNU C

compiler are also distributed under the GPL. Because they are so frequently encountered and


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have become the subject of much attention and debate, the GPL and LGPL are set forth in their

entirety in the Appendix to this paper.

Another type of open source license is the community source license, the terms of

which can vary widely depending on the community in which used. For example, an academic

community license may be highly permissive, while the Sun Microsystems community license

for the Java platform is highly restrictive in important ways. For those interested in exploring

the subject more deeply, the website of the Open Source Initiative provides more than 50

examples of different open source licenses in use today.

Standards

Two of the things that make proprietary software proprietary are the ability of its owners

to maintain intellectual property rights in its features and control its specifications. This can

include application program interfaces (APIs) or other aspects that affect interoperability.

Because of this, there has been a tendency among some open source advocates to equate open

source with open standards. One could argue, however, that there are two primary ways in

which standards come into being. One is by widespread adoption in the user market. The

second is through standards setting organizations.

The reality is that virtually all of the important open standards have been developed by

consortia of representatives of private industry. Another reality is that open source software, by

its very nature, tends to become non-standard because of the relative ease and freedom of making

modifications. In fact, commercial distributors of open source software often deliberately

modify it to distinguish themselves. So, for example, while IBM Corporation, The SCO Group,

http://www.opensource.org/licenses/bsd-license.php .


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Inc., Red Hat, Inc. and Sun Microsystems, Inc. all distribute all distribute derivatives of the

UNIX operating system, they are not all the same and do not represent a standard.

Total Cost of Ownership

The term open source is commonly equated with the term free software, and many

open source advocates argue that a key advantage of the open source solution is the ability to

acquire software without paying a license fee. However, as the Free Software Foundation says,

Free software is a matter of liberty, not price. To understand the concept, you should think of

free as in free speech, not as in free beer.

The software we typically think of as opensource is indeed more or less free at the acquisition stage that is, it can be acquired, copied

and used without charge. However, when one considers the cost of software, it is important to

consider the total cost of acquisition and use i.e., the total cost of ownership.

For example, consider the cost of customizing free software to meet the needs of a

particular user. The features of commercial software tend to be the product of market research

and investment in development with the needs of the user community or marketplace in mind.

Even if not always a perfect fit, commercial software tends to be designed to provide a

substantial solution for most users. In contrast, open source software is often developed without

much regard for end users and is distributed in a form that is conducive to modification. To meet

the needs of a particular user, it may need to be modified, sometimes at considerable expense. In

addition, commercial software is commonly maintained and supported by the developer, whereas

open source software commonly is not.

http://www.gnu.org/philosophy/free-sw.html .


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When considering the cost of free software, it is important to have in mind such things

as the cost of modifying, maintaining and supporting the software, the cost of required user and

technical documentation (free software generally is not accompanied by either), the cost of

quality assurance testing (free software is almost always devoid of warranties and most often is

produced and distributed without the type of rigorous testing done by developers of commercial

products), and the costs of customization, implementation, defect correction, ongoing

development, and dealing with security issues. The cost of training should be considered at two

levels training of technical personnel, and training of end users because the available labor

pool will more likely be possessed of knowledge and skills developed through experience withcommercial products and may lack the expertise needed to support and use free substitutes

without additional, specialized training.

Ultimately, the cost/benefit analysis must be performed with this fundamental question in

mind: does a proprietary solution require that the user pay too much for things it doesnt need, or

does it provide features and benefits that will enable the user to be productive in important ways

not enabled by free competitive offerings absent addition investment that exceeds the overall

cost of the commercial solution?

The GPL and LGPL

The open source variant that has received the most attention and that has caused the

most sleepless nights among commercial software developers, investors and those involved in

mergers and acquisitions of software companies is software distributed under the Free

Software Foundations General Public License (GPL) and Lesser General Public License


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(LGPL). The genesis of the Free Software Foundation and its free software initiative (the

GNU Project) is reported on its website as follows:

The GNU Project has developed a complete free software system named GNU

(GNUs Not Unix) that is upwardly compatible with Unix. Richard Stallman 'sinitial document on the GNU Project is called the GNU Manifesto, which hasbeen translated into several other languages. The name GNU was chosenbecause it met a few requirements; firstly, it was a recursive acronym for GNUsNot Unix', secondly, because it was a real word, and thirdly, it was fun to say (orSing ). We also have the Initial Announcement of the GNU Project, written in1983.

The word free above pertains to freedom, not price. You may or may not pay aprice to get GNU software. Either way, once you have the software you havethree specific freedoms in using it. First, the freedom to copy the program and

give it away to your friends and co-workers; second, the freedom to change theprogram as you wish, by having full access to source code; third, the freedom todistribute an improved version and thus help build the community. (If youredistribute GNU software, you may charge a fee for the physical act of transferring a copy, or you may give away copies.)

The GNU Project was conceived in 1983 as a way of bringing back thecooperative spirit that prevailed in the computing community in earlier days tomake cooperation possible once again by removing the obstacles to cooperationimposed by the owners of proprietary software.

In 1971, when Richard Stallman started his career at MIT, he worked in a groupwhich used free software exclusively. Even computer companies often distributedfree software. Programmers were free to cooperate with each other, and often did.

By the 1980s, almost all software was proprietary, which means that it hadowners who forbid and prevent cooperation by users. This made the GNU Projectnecessary. ***

In a paper entitled The GNU Operating System and the Free Software Movement,

originally published in the book Open Sources, FSF founder Richard Stallman wrote:

Shortly before beginning the GNU project, I heard about the Free UniversityCompiler Kit, also known as VUCK. (The Dutch word for free is written with aV.) This was a compiler designed to handle multiple languages, including C andPascal, and to support multiple target machines. I wrote to its author asking if GNU could use it.

*** http://www.gnu.org/gnu/gnu-history.html .
http://www.stallman.org/http://www.gnu.org/gnu/manifesto.htmlhttp://www.gnu.org/gnu/manifesto.html#translationshttp://www.poppyfields.net/poppy/songs/gnu.htmlhttp://www.poppyfields.net/poppy/songs/gnu.htmlhttp://www.gnu.org/gnu/initial-announcement.htmlhttp://www.gnu.org/philosophy/free-sw.htmlhttp://www.gnu.org/philosophy/free-sw.htmlhttp://www.gnu.org/philosophy/categories.html#ProprietarySoftwarehttp://www.stallman.org/http://www.gnu.org/gnu/manifesto.htmlhttp://www.gnu.org/gnu/manifesto.html#translationshttp://www.poppyfields.net/poppy/songs/gnu.htmlhttp://www.gnu.org/gnu/initial-announcement.htmlhttp://www.gnu.org/philosophy/free-sw.htmlhttp://www.gnu.org/philosophy/free-sw.htmlhttp://www.gnu.org/philosophy/categories.html#ProprietarySoftware


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He responded derisively, stating that the university was free but the compiler wasnot.

***

The goal of GNU was to give users freedom, not just to be popular. So we neededto use distribution terms that would prevent GNU software from being turned intoproprietary software. The method we use is called copyleft.

Copyleft uses copyright law, but flips it over to serve the opposite of its usualpurpose: instead of a means of privatizing software, it becomes a means of keeping software free.

The central idea of copyleft is that we give everyone permission to run theprogram, copy the program, modify the program, and distribute modified versions

but not permission to add restrictions of their own. Thus, the crucial freedomsthat define free software are guaranteed to everyone who has a copy; theybecome inalienable rights.

For an effective copyleft, modified versions must also be free. This ensures thatwork based on ours becomes available to our community if it is published. Whenprogrammers who have jobs as programmers volunteer to improve GNUsoftware, it is copyleft that prevents their employers from saying, You can'tshare those changes, because we are going to use them to make our proprietaryversion of the program.

The requirement that changes must be free is essential if we want to ensurefreedom for every user of the program. The companies that privatized the XWindow System usually made some changes to port it to their systems andhardware. These changes were small compared with the great extent of X, butthey were not trivial. If making changes were an excuse to deny the usersfreedom, it would be easy for anyone to take advantage of the excuse.

A related issue concerns combining a free program with non-free code. Such acombination would inevitably be non-free; whichever freedoms are lacking forthe non-free part would be lacking for the whole as well. To permit suchcombinations would open a hole big enough to sink a ship. Therefore, a crucialrequirement for copyleft is to plug this hole: anything added to or combined witha copylefted program must be such that the larger combined version is also freeand copylefted.

The specific implementation of copyleft that we use for most GNU software is theGNU General Public License, or GNU GPL for short. We have other kinds of copyleft that are used in specific circumstances. GNU manuals are copylefted


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also, but use a much simpler kind of copyleft, because the complexity of the GNUGPL is not necessary for manuals.

The thing that causes so many sleepless nights is that notion that supposedly proprietary

software can become subject to the GNU license terms if it is deemed to be based on, added

to, combined with, derived from, or a modified version of software distributed under one

of the GNU licenses. The problem is that except in extreme cases, it is difficult to know with

certainty exactly what these terms mean as used in the GNU licenses, and it is very easy for

undisciplined programmers to tread the gray areas that could subject their employers proprietary

software to the copyleft scheme. The most feared consequence is that their supposedly

proprietary software could thus become subject to conditions or obligations that it be distributed

free of charge with broad permissions to modify and redistribute and a requirement that the

source code be made freely available to all licensees.

Much of the software distributed under the GPL is useful for providing needed

functionality in larger systems, and programmers working on proprietary projects are sometimes

tempted to simply patch them in, rather than creating equivalent functionality from scratch. In

addition, many useful and popular programming and development tools are distributed under the

GPL or LGPL, and some of those tools inject pieces of themselves into the software they are

used to produce. In addition, it has been suggested that merely writing software to work with a

particular GPL component might be enough to render the new software subject to the GPL.

While it is fairly clear in some cases that the use of GPL code to built a new product would

render the resulting product subject to the GPL, there are many instances in which that is not at

all clear one way or the other. The notion that proprietary software can become subject to these

http://www.gnu.org/gnu/thegnuproject.html (footnote omitted).

See http://kerneltrap.org/node/view/1735 .


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open source license terms by the inadvertent inclusion of a small piece of open source code has

prompted some to refer to GPL/LGPL code as viral.

Many questions about the subtle implications of the GNU licenses and their impact on the

real world of software development and distribution will remain unanswered absent judicial

construction, and a full discussion of those issues is beyond the scope of this paper. To provide

some food for thought, however, here is a list of some of the open questions that are keeping

people awake at night:

1. Are the GPL and the LGPL contracts that impose affirmative obligations on thelicensees, thus exposing them to claims for specific performance in the event of

breach, or are they merely conditional authorizations, such that the failure forexample to make source code available to downstream licensees is a failure of condition that renders the licensee liable for copyright infringement?

2. Are employees of proprietary software companies generally deemed authorized tobind their employers to the terms of the GPL and LGPL merely by downloadingand using the open source tools?

3. Even if the GPL or LGPL is deemed to be accepted and enforceable in a giveninstance, are there particular terms of the license that may not be enforceablebecause they are unconscionable, preempted by federal law, contrary to publicpolicy, or for some other reason?

4. Does the notion of a derivative as used in the GPL and LGPL have its technicallegal meaning under traditional copyright law, or does it mean somethingdifferent in the context of a copyleft license?

5. What does it mean to combine proprietary software with a GPL or LGPLsoftware component? Does it mean only literally grafting it in or static linkingwhen the program is created, or can it also include dynamic linking when theprogram runs on the end users computer? And can it also include programs thatinteroperate with GPL or LGPL software if they are sufficiently tightly coupled?

6. Is it possible to cure the inadvertent or unauthorized use of GPL or LGPL codein a proprietary product by removing it or replacing it with a new proprietarycomponent, even after the initial infected version has been distributed?

7. Is the act of providing copies of software to corporate affiliates a distributionwithin the meaning of the GPL and LGPL?


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8. Is the act of making software passively available for download over the Internet adistribution within the meaning of the GPL and LGPL?

9. Is the act of making software functionality available over the Internet ( e.g., in thecase of an application service provider) a distribution of that software within themeaning of the GPL and LGPL?

10. What are the patent implications of the GPL and LGPL?

11. In the case of a dispute over the meaning of a particular term in the GPL orLGPL, whose intention governs i.e., the intention of the parties to the particularlicensing transaction in which the license was used, or the intention of the personor organization ( i.e., the Free Software Foundation) that created the licensedocument?

12. What policies and practices are appropriate for developers of proprietary softwareto ensure that their products are not affected by the GPL or LGPL?

13. What type of due diligence is appropriate for one planning to acquire or invest inan enterprise whose value depends on the proprietary character of its software?

14. What are the audit and disclosure obligations of a publicly held company whosevalue depends on the proprietary character of its software?

Conclusion

The members of the independent software industry have led us into a time of change notseen by the world since the industrial revolution. The billions of dollars of investment they have

made in the development of their technology never would have come about without protection of

the fruits of their intellectual labors. At the same time, open source software is well established

as part of the software ecosystem and affords software developers and users an important

alternative style of software development and distribution. There is a need and a purpose for both.

In making decisions about whether to adopt open source software solutions or pay for

commercial ones, it is important to consider how the open source solution compares to the

For the Free Software Foundations answers to questions about the GPL and LGPL, seehttp://www.fsf.org/licenses/gpl-faq.html .


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commercial one in terms of not only its technical characteristics, but also in terms of the overall

investment and total cost of ownership. It is also important to consider whether the use of an

open source solution would meet the users needs with respect to operational compatibility with

other programs and with respect to the users need to transact and interact with third parties in

industries and markets in which commercial products are the de facto standard.

Finally, it is important to be aware that the open source movement is motivated not only

to provide benefits to the software developer and user communities through the distribution of

free software, but also to eliminate the need to use proprietary software. Through lobbying

and other efforts, the open source movement has persuaded some companies and even somegovernments to adopt a bias toward open source products, and the GNU Projects GPL and

LGPL have raised many serious questions about the proprietary integrity of software developed

in private enterprise. It is hoped that this paper has provided some helpful background and food

for thought.
http://www.fsf.org/philosophy/categories.html#ProprietarySoftwarehttp://www.fsf.org/philosophy/categories.html#ProprietarySoftware


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APPENDIX

GNU GENERAL PUBLIC LICENSEVersion 2, June 1991

Copyright (C) 1989, 1991 Free Software Foundation, Inc. 59 TemplePlace, Suite 330, Boston, MA 02111-1307 USA

Everyone is permitted to copy and distribute verbatim copies of thislicense document, but changing it is not allowed.

Preamble

The licenses for most software are designed to take away yourfreedom to share and change it. By contrast, the GNU General PublicLicense is intended to guarantee your freedom to share and change freesoftware--to make sure the software is free for all its users. This

General Public License applies to most of the Free SoftwareFoundation's software and to any other program whose authors commit tousing it. (Some other Free Software Foundation software is covered bythe GNU Library General Public License instead.) You can apply it toyour programs, too.

When we speak of free software, we are referring to freedom, notprice. Our General Public Licenses are designed to make sure that youhave the freedom to distribute copies of free software (and charge forthis service if you wish), that you receive source code or can get itif you want it, that you can change the software or use pieces of it innew free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbidanyone to deny you these rights or to ask you to surrender the rights.These restrictions translate to certain responsibilities for you if youdistribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whethergratis or for a fee, you must give the recipients all the rights thatyou have. You must make sure that they, too, receive or can get thesource code. And you must show them these terms so they know theirrights.

We protect your rights with two steps: (1) copyright theSoftware, and (2) offer you this license which gives you legalpermission to copy, distribute and/or modify the software.

Also, for each author's protection and ours, we want to makecertain that everyone understands that there is no warranty for thisfree software. If the software is modified by someone else and passedon, we want its recipients to know that what they have is not theoriginal, so that any problems introduced by others will not reflect onthe original authors' reputations.

Finally, any free program is threatened constantly by softwarepatents. We wish to avoid the danger that redistributors of a free


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program will individually obtain patent licenses, in effect making theprogram proprietary. To prevent this, we have made it clear that anypatent must be licensed for everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution andmodification follow.

GNU GENERAL PUBLIC LICENSETERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License applies to any program or other work whichcontains a notice placed by the copyright holder saying it may bedistributed under the terms of this General Public License. The"Program", below, refers to any such program or work, and a "work basedon the Program" means either the Program or any derivative work undercopyright law: that is to say, a work containing the Program or aportion of it, either verbatim or with modifications and/or translatedinto another language. (Hereinafter, translation is included withoutlimitation in the term "modification".) Each licensee is addressed as

"you".

Activities other than copying, distribution and modification arenot covered by this License; they are outside its scope. The act ofrunning the Program is not restricted, and the output from the Programis covered only if its contents constitute a work based on the Program(independent of having been made by running the Program). Whether thatis true depends on what the Program does.

1. You may copy and distribute verbatim copies of theProgram's source code as you receive it, in any medium, provided thatyou conspicuously and appropriately publish on each copy an appropriatecopyright notice and disclaimer of warranty; keep intact all thenotices that refer to this License and to the absence of any warranty;and give any other recipients of the Program a copy of this Licensealong with the Program.

You may charge a fee for the physical act of transferring a copy,and you may at your option offer warranty protection in exchange for afee.

2. You may modify your copy or copies of the Program or anyportion of it, thus forming a work based on the Program, and copy anddistribute such modifications or work under the terms of Section 1above, provided that you also meet all of these conditions:

a) You must cause the modified files to carry prominent

notices stating that you changed the files and the date of anychange.

b) You must cause any work that you distribute orpublish, that in whole or in part contains or is derived from theProgram or any part thereof, to be licensed as a whole at nocharge to all third parties under the terms of this License.

c) If the modified program normally reads commandsinteractively when run, you must cause it, when started running


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for such interactive use in the most ordinary way, to print ordisplay an announcement including an appropriate copyright noticeand a notice that there is no warranty (or else, saying that youprovide a warranty) and that users may redistribute the programunder these conditions, and telling the user how to view a copyof this License. (Exception: if the Program itself isinteractive but does not normally print such an announcement,your work based on the Program is not required to print anannouncement.)

These requirements apply to the modified work as a whole. Ifidentifiable sections of that work are not derived from the Program,and can be reasonably considered independent and separate works inthemselves, then this License, and its terms, do not apply to thosesections when you distribute them as separate works. But when youdistribute the same sections as part of a whole which is a work basedon the Program, the distribution of the whole must be on the terms ofthis License, whose permissions for other licensees extend to theentire whole, and thus to each and every part regardless of who wroteit.

Thus, it is not the intent of this section to claim rights orcontest your rights to work written entirely by you; rather, the intentis to exercise the right to control the distribution of derivative orcollective works based on the Program.

In addition, mere aggregation of another work not based on theProgram with the Program (or with a work based on the Program) on avolume of a storage or distribution medium does not bring the otherwork under the scope of this License.

3. You may copy and distribute the Program (or a work based onit, under Section 2) in object code or executable form under the termsof Sections 1 and 2 above provided that you also do one of thefollowing:

a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the termsof Sections 1 and 2 above on a medium customarily used forsoftware interchange; or,

b) Accompany it with a written offer, valid for at leastthree years, to give any third party, for a charge no more thanyour cost of physically performing source distribution, acomplete machine-readable copy of the corresponding source code,to be distributed under the terms of Sections 1 and 2 above on amedium customarily used for software interchange; or,

c) Accompany it with the information you received as tothe offer to distribute corresponding source code. (Thisalternative is allowed only for noncommercial distribution andonly if you received the program in object code or executableform with such an offer, in accord with Subsection b above.)

The source code for a work means the preferred form of the workfor making modifications to it. For an executable work, completesource code means all the source code for all modules it contains, plus


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any associated interface definition files, plus the scripts used tocontrol compilation and installation of the executable. However, as aspecial exception, the source code distributed need not includeanything that is normally distributed (in either source or binary form)with the major components (compiler, kernel, and so on) of theoperating system on which the executable runs, unless that componentitself accompanies the executable.

If distribution of executable or object code is made by offeringaccess to copy from a designated place, then offering equivalent accessto copy the source code from the same place counts as distribution ofthe source code, even though third parties are not compelled to copythe source along with the object code.

4. You may not copy, modify, sublicense, or distribute theProgram except as expressly provided under this License. Any attemptotherwise to copy, modify, sublicense or distribute the Program isvoid, and will automatically terminate your rights under this License.However, parties who have received copies, or rights, from you underthis License will not have their licenses terminated so long as such

parties remain in full compliance.

5. You are not required to accept this License, since you havenot signed it. However, nothing else grants you permission to modifyor distribute the Program or its derivative works. These actions areprohibited by law if you do not accept this License. Therefore, bymodifying or distributing the Program (or any work based on theProgram), you indicate your acceptance of this License to do so, andall its terms and conditions for copying, distributing or modifyingthe Program or works based on it.

6. Each time you redistribute the Program (or any work basedon the Program), the recipient automatically receives a license fromthe original licensor to copy, distribute or modify the Program subjectto these terms and conditions. You may not impose any furtherrestrictions on the recipients' exercise of the rights granted herein.You are not responsible for enforcing compliance by third parties tothis License.

7. If, as a consequence of a court judgment or allegation ofpatent infringement or for any other reason (not limited to patentissues), conditions are imposed on you (whether by court order,agreement or otherwise) that contradict the conditions of this License,they do not excuse you from the conditions of this License. If youcannot distribute so as to satisfy simultaneously your obligationsunder this License and any other pertinent obligations, then as aconsequence you may not distribute the Program at all. For example, if

a patent license would not permit royalty-free redistribution of theProgram by all those who receive copies directly or indirectly throughyou, then the only way you could satisfy both it and this License wouldbe to refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceableunder any particular circumstance, the balance of the section isintended to apply and the section as a whole is intended to apply inother circumstances.


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It is not the purpose of this section to induce you to infringeany patents or other property right claims or to contest validity ofany such claims; this section has the sole purpose of protecting theintegrity of the free software distribution system, which isimplemented by public license practices. Many people have madegenerous contributions to the wide range of software distributedthrough that system in reliance on consistent application of thatsystem; it is up to the author/donor to decide if he or she is willingto distribute software through any other system and a licensee cannotimpose that choice.

This section is intended to make thoroughly clear what isbelieved to be a consequence of the rest of this License.

8. If the distribution and/or use of the Program is restrictedin certain countries either by patents or by copyrighted interfaces,the original copyright holder who places the Program under this Licensemay add an explicit geographical distribution limitation excludingthose countries, so that distribution is permitted only in or amongcountries not thus excluded. In such case, this License incorporates

the limitation as if written in the body of this License.

9. The Free Software Foundation may publish revised and/or newversions of the General Public License from time to time. Such newversions will be similar in spirit to the present version, but maydiffer in detail to address new problems or concerns.

Each version is given a distinguishing version number. If theProgram specifies a version number of this License which applies to itand "any later version", you have the option of following the terms andconditions either of that version or of any later version published bythe Free Software Foundation. If the Program does not specify aversion number of this License, you may choose any version everpublished by the Free Software Foundation.

10. If you wish to incorporate parts of the Program into otherfree programs whose distribution conditions are different, write to theauthor to ask for permission. For software which is copyrighted by theFree Software Foundation, write to the Free Software Foundation; wesometimes make exceptions for this. Our decision will be guided by thetwo goals of preserving the free status of all derivatives of our freesoftware and of promoting the sharing and reuse of software generally.

NO WARRANTY

11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NOWARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OROTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND,EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIEDWARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM ISWITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OFALL NECESSARY SERVICING, REPAIR OR CORRECTION.


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12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TOIN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFYAND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOUFOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL ORCONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THEPROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEINGRENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR AFAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IFSUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCHDAMAGES.

END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of thegreatest possible use to the public, the best way to achieve this is tomake it free software which everyone can redistribute and change underthese terms.

To do so, attach the following notices to the program. It issafest to attach them to the start of each source file to mosteffectively convey the exclusion of warranty; and each file should haveat least the "copyright" line and a pointer to where the full notice isfound.


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The hypothetical commands `show w' and `show c' should show theappropriate parts of the General Public License. Of course, thecommands you use may be called something other than `show w' and `showc'; they could even be mouse-clicks or menu items--whatever suits yourprogram.

You should also get your employer (if you work as a programmer)or your school, if any, to sign a "copyright disclaimer" for theprogram, if necessary. Here is a sample; alter the names:

Yoyodyne, Inc., hereby disclaims all copyright interest in theprogram `Gnomovision' (which makes passes at compilers) writtenby James Hacker.

, 1 April 1989Ty Coon, President of Vice

This General Public License does not permit incorporating yourprogram into proprietary programs. If your program is a subroutinelibrary, you may consider it more useful to permit linking proprietary

applications with the library. If this is what you want to do, use theGNU Library General Public License instead of this License.


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GNU LESSER GENERAL PUBLIC LICENSEVersion 2.1, February 1999

Copyright (C) 1991, 1999 Free Software Foundation, Inc. 59 TemplePlace, Suite 330, Boston, MA 02111-1307 USA


[This is the first released version of the Lesser GPL. It also countsas the successor of the GNU Library Public License, version 2, hencethe version number 2.1.]

Preamble

The licenses for most software are designed to take away yourfreedom to share and change it. By contrast, the GNU General PublicLicenses are intended to guarantee your freedom to share and changefree software--to make sure the software is free for all its users.

This license, the Lesser General Public License, applies to somespecially designated software packages--typically librariesof the FreeSoftware Foundation and other authors who decide to use it. You canuse it too, but we suggest you first think carefully about whether thislicense or the ordinary General Public License is the better strategyto use in any particular case, based on the explanations below.

When we speak of free software, we are referring to freedom ofuse, not price. Our General Public Licenses are designed to make surethat you have the freedom to distribute copies of free software (andcharge for this service if you wish); that you receive source code orcan get it if you want it; that you can change the software and usepieces of it in new free programs; and that you are informed that youcan do these things.

To protect your rights, we need to make restrictions that forbiddistributors to deny you these rights or to ask you to surrender theserights. These restrictions translate to certain responsibilities foryou if you distribute copies of the library or if you modify it.

For example, if you distribute copies of the library, whethergratis or for a fee, you must give the recipients all the rights thatwe gave you. You must make sure that they, too, receive or can get thesource code. If you link other code with the library, you must providecomplete object files to the recipients, so that they can relink themwith the library after making changes to the library and recompiling

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We protect your rights with a two-step method: (1) we copyrightthe library, and (2) we offer you this license, which gives you legalpermission to copy, distribute and/or modify the library.

To protect each distributor, we want to make it very clear thatthere is no warranty for the free library. Also, if the library ismodified by someone else and passed on, the recipients should know thatwhat they have is not the original version, so that the original


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author's reputation will not be affected by problems that might beintroduced by others.

Finally, software patents pose a constant threat to the existenceof any free program. We wish to make sure that a company cannoteffectively restrict the users of a free program by obtaining arestrictive license from a patent holder. Therefore, we insist thatany patent license obtained for a version of the library must beconsistent with the full freedom of use specified in this license.

Most GNU software, including some libraries, is covered by theordinary GNU General Public License. This license, the GNU LesserGeneral Public License, applies to certain designated libraries, and isquite different from the ordinary General Public License. We use thislicense for certain libraries in order to permit linking thoselibraries into non-free programs.

When a program is linked with a library, whether statically orusing a shared library, the combination of the two is legally speakinga combined work, a derivative of the original library. The ordinary

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We call this license the "Lesser" General Public License becauseit does Less to protect the user's freedom than the ordinary GeneralPublic License. It also provides other free software developers Lessof an advantage over competing non-free programs. These disadvantagesare the reason we use the ordinary General Public License for manylibraries. However, the Lesser license provides advantages in certainspecial circumstances.

For example, on rare occasions, there may be a special need toencourage the widest possible use of a certain library, so that itbecomes a de-facto standard. To achieve this, non-free programs mustbe allowed to use the library. A more frequent case is that a freelibrary does the same job as widely used non-free libraries. In thiscase, there is little to gain by limiting the free library to freesoftware only, so we use the Lesser General Public License.

In other cases, permission to use a particular library in non-free programs enables a greater number of people to use a large body offree software. For example, permission to use the GNU C Library innon-free programs enables many more people to use the whole GNUoperating system, as well as its variant, the GNU/Linux operatingsystem.

Although the Lesser General Public License is Less protective ofthe users' freedom, it does ensure that the user of a program that islinked with the Library has the freedom and the wherewithal to run thatprogram using a modified version of the Library.

The precise terms and conditions for copying, distribution andmodification follow. Pay close attention to the difference between a"work based on the library" and a "work that uses the library". The


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former contains code derived from the library, whereas the latter mustbe combined with the library in order to run.

GNU LESSER GENERAL PUBLIC LICENSETERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

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Activities other than copying, distribution and modification arenot covered by this License; they are outside its scope. The act ofrunning a program using the Library is not restricted, and output fromsuch a program is covered only if its contents constitute a work basedon the Library (independent of the use of the Library in a tool forwriting it). Whether that is true depends on what the Library does andwhat the program that uses the Library does.

1. You may copy and distribute verbatim copies of theLibrary's complete source code as you receive it, in any medium,provided that you conspicuously and appropriately publish on each copyan appropriate copyright notice and disclaimer of warranty; keep intactall the notices that refer to this License and to the absence of anywarranty; and distribute a copy of this License along with the Library.

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b) You must cause the files modified to carry prominentnotices stating that you changed the files and the date of anychange.

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For example, a function in a library to compute square roots hasa purpose that is entirely well-defined independent of theapplication. Therefore, Subsection 2d requires that anyapplication-supplied function or table used by this function must

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These requirements apply to the modified work as a whole. Ifidentifiable sections of that work are not derived from the Library,and can be reasonably considered independent and separate works inthemselves, then this License, and its terms, do not apply to thosesections when you distribute them as separate works. But when youdistribute the same sections as part of a whole which is a work basedon the Library, the distribution of the whole must be on the terms ofthis License, whose permissions for other licensees extend to theentire whole, and thus to each and every part regardless of who wroteit.

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Once this change is made in a given copy, it is irreversible forthat copy, so the ordinary GNU General Public License applies to allsubsequent copies and derivative works made from that copy.


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This option is useful when you wish to copy part of the code ofthe Library into a program that is not a library.

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during execution displays copyright notices, you must include thecopyright notice for the Library among them, as well as a referencedirecting the user to the copy of this License. Also, you must do oneof these things:

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based on the Library and of the other library facilities is otherwisepermitted, and provided that you do these two things:

a) Accompany the combined library with a copy of thesame work based on the Library, uncombined with any other libraryfacilities. This must be distributed under the terms of theSections above.

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8. You may not copy, modify, sublicense, link with, ordistribute the Library except as expressly provided under this License.Any attempt otherwise to copy, modify, sublicense, link with, ordistribute the Library is void, and will automatically terminate yourrights under this License. However, parties who have received copies,or rights, from you under this License will not have their licensesterminated so long as such parties remain in full compliance.

9. You are not required to accept this License, since you havenot signed it. However, nothing else grants you permission to modifyor distribute the Library or its derivative works. These actions areprohibited by law if you do not accept this License. Therefore, bymodifying or distributing the Library (or any work based on theLibrary), you indicate your acceptance of this License to do so, andall its terms and conditions for copying, distributing or modifying theLibrary or works based on it.

10. Each time you redistribute the Library (or any work basedon the Library), the recipient automatically receives a license fromthe original licensor to copy, distribute, link with or modify theLibrary subject to these terms and conditions. You may not impose anyfurther restrictions on the recipients' exercise of the rights grantedherein. You are not responsible for enforcing compliance by thirdparties with this License.

11. If, as a consequence of a court judgment or allegation ofpatent infringement or for any other reason (not limited to patentissues), conditions are imposed on you (whether by court order,agreement or otherwise) that contradict the conditions of this License,they do not excuse you from the conditions of this License. If youcannot distribute so as to satisfy simultaneously your obligationsunder this License and any other pertinent obligations, then as aconsequence you may not distribute the Library at all. For example, ifa patent license would not permit royalty-free redistribution of the

Library by all those who receive copies directly or indirectly throughyou, then the only way you could satisfy both it and this License wouldbe to refrain entirely from distribution of the Library.

If any portion of this section is held invalid or unenforceableunder any particular circumstance, the balance of the section isintended to apply, and the section as a whole is intended to apply inother circumstances.


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It is not the purpose of this section to induce you to infringeany patents or other property right claims or to contest validity ofany such claims; this section has the sole purpose of protecting theintegrity of the free software distribution system which is implementedby public license practices. Many people have made generouscontributions to the wide range of software distributed through thatsystem in reliance on consistent application of that system; it is upto the author/donor to decide if he or she is willing to distributesoftware through any other system and a licensee cannot impose thatchoice.

This section is intended to make thoroughly clear what isbelieved to be a consequence of the rest of this License.

12. If the distribution and/or use of the Library is restrictedin certain countries either by patents or by copyrighted interfaces,the original copyright holder who places the Library under this Licensemay add an explicit geographical distribution limitation excludingthose countries, so that distribution is permitted only in or amongcountries not thus excluded. In such case, this License incorporates

the limitation as if written in the body of this License.

13. The Free Software Foundation may publish revised and/or newversions of the Lesser General Public License from time to time. Suchnew versions will be similar in spirit to the present version, but maydiffer in detail to address new problems or concerns.

Each version is given a distinguishing version number. If theLibrary specifies a version number of this License which applies to itand "any later version", you have the option of following the terms andconditions either of that version or of any later version published bythe Free Software Foundation. If the Library does not specify alicense version number, you may choose any version ever published bythe Free Software Foundation.

14. If you wish to incorporate parts of the Library into otherfree programs whose distribution conditions are incompatible withthese, write to the author to ask for permission. For software whichis copyrighted by the Free Software Foundation, write to the FreeSoftware Foundation; we sometimes make exceptions for this. Ourdecision will be guided by the two goals of preserving the free statusof all derivatives of our free software and of promoting the sharingand reuse of software generally.

NO WARRANTY

15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NOWARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW.EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OROTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY KIND,EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIEDWARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE LIBRARY ISWITH YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME THE COST OFALL NECESSARY SERVICING, REPAIR OR CORRECTION.


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16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TOIN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFYAND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOUFOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL ORCONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THELIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEINGRENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR AFAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IFSUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCHDAMAGES.

END OF TERMS AND CONDITIONS

How to Apply These Terms to Your New Libraries

If you develop a new library, and you want it to be of thegreatest possible use to the public, we recommend making it freesoftware that everyone can redistribute and change. You can do so bypermitting redistribution under these terms (or, alternatively, under

the terms of the ordinary General Public License).

To apply these terms, attach the following notices to thelibrary. It is safest to attach them to the start of each source fileto most effectively convey the exclusion of warranty; and each fileshould have at least the "copyright" line and a pointer to where thefull notice is found.


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, 1 April 1990Ty Coon, President of Vice

That's all there is to it!


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GNU Free Documentation LicenseVersion 1.2, November 2002

Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 59 TemplePlace, Suite 330, Boston, MA 02111-1307 USA


0. PREAMBLE

The purpose of this License is to make a manual, textbook, orother functional and useful document "free" in the sense of freedom: toassure everyone the effective freedom to copy and redistribute it, withor without modifying it, either commercially or noncommercially.Secondarily, this License preserves for the author and publisher a wayto get credit for their work, while not being considered responsiblefor modifications made by others.

This License is a kind of "copyleft", which means that derivativeworks of the document must themselves be free in the same sense. Itcomplements the GNU General Public License, which is a copyleft licensedesigned for free software.

We have designed this License in order to use it for manuals forfree software, because free software needs free documentation: a freeprogram should come with manuals providing the same freedoms that thesoftware does. But this License is not limited to software manuals; itcan be used for any textual work, regardless of subject matter orwhether it is published as a printed book. We recommend this Licenseprincipally for works whose purpose is instruction or reference.

1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium,that contains a notice placed by the copyright holder saying it can bedistributed under the terms of this License. Such a notice grants aworld-wide, royalty-free license, unlimited in duration, to use thatwork under the conditions stated herein. The "Document", below, refersto any such manual or work. Any member of the public is a licensee,and is addressed as "you". You accept the license if you copy, modifyor distribute the work in a way requiring permission under copyrightlaw.

A "Modified Version" of the Document means any work containingthe Document or a portion of it, either copied verbatim, or withmodifications and/or translated into another language.

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mathematics.) The relationship could be a matter of historicalconnection with the subject or with related matters, or of legal,commercial, philosophical, ethical or political position regardingthem.

The "Invariant Sections" are certain Secondary Sections whosetitles are designated, as being those of Invariant Sections, in thenotice that says that the Document is released under this License. Ifa section does not fit the above definition of Secondary then it is notallowed to be designated as Invariant. The Document may contain zeroInvariant Sections. If the Document does not identify any InvariantSections then there are none.

The "Cover Texts" are certain short passages of text that arelisted, as Front-Cover Texts or Back-Cover Texts, in the notice thatsays that the Document is released under this License. A Front-CoverText may be at most 5 words, and a Back-Cover Text may be at most 25words.

A "Transparent" copy of the Document means a machine-readable

copy, represented in a format whose specification is available to thegeneral public, that is suitable for revising the documentstraightforwardly with generic text editors or (for images composed ofpixels) generic paint programs or (for drawings) some widely availabledrawing editor, and that is suitable for input to text formatters orfor automatic translation to a variety of formats suitable for input totext formatters. A copy made in an otherwise Transparent file formatwhose markup, or absence of markup, has been arranged to thwart ordiscourage subsequent modification by readers is not Transparent. Animage format is not Transparent if used for any substantial amount oftext. A copy that is not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plainASCII without markup, Texinfo input format, LaTeX input format, SGML orXML using a publicly available DTD, and standard-conforming simpleHTML, PostScript or PDF designed for human modification. Examples oftransparent image formats include PNG, XCF and JPG. Opaque formatsinclude proprietary formats that can be read and edited only byproprietary word processors, SGML or XML for which the DTD and/orprocessing tools are not generally available, and the machine-generatedHTML, PostScript or PDF produced by some word processors for outputpurposes only.

The "Title Page" means, for a printed book, the title pageitself, plus such following pages as are needed to hold, legibly, thematerial this License requires to appear in the title page. For worksin formats which do not have any title page as such, "Title Page" means

the text near the most prominent appearance of the work's title,preceding the beginning of the body of the text.

A section "Entitled XYZ" means a named subunit of the Documentwhose title either is precisely XYZ or contains XYZ in parenthesesfollowing text that translates XYZ in another language. (Here XYZstands for a specific section name mentioned below, such as"Acknowledgements", "Dedications", "Endorsements", or "History".) To"Preserve the Title" of such a section when you modify the Document


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means that it remains a section "Entitled XYZ" according to thisdefinition.

The Document may include Warranty Disclaimers next to the noticewhich states that this License applies to the Document. These WarrantyDisclaimers are considered to be included by reference in this License,but only as regards disclaiming warranties: any other implication thatthese Warranty Disclaimers may have is void and has no effect on themeaning of this License.

2. VERBATIM COPYING

You may copy and distribute the Document in any medium, eithercommercially or noncommercially, provided that this License, thecopyright notices, and the license notice saying this License appliesto the Document are reproduced in all copies, and that you add no otherconditions whatsoever to those of this License. You may not usetechnical measures to obstruct or control the reading or furthercopying of the copies you make or distribute. However, you may accept

compensation in exchange for copies. If you distribute a large enoughnumber of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above,and you may publicly display copies.

3. COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonlyhave printed covers) of the Document, numbering more than 100, and theDocument's license notice requires Cover Texts, you must enclose thecopies in covers that carry, clearly and legibly, all these CoverTexts: Front-Cover Texts on the front cover, and Back-Cover Texts onthe back cover. Both covers must also clearly and legibly identify youas the publisher of these copies. The front cover must present thefull title with all words of the title equally prominent and visible.You may add other material on the covers in addition. Copying withchanges limited to the covers, as long as they preserve the title ofthe Document and satisfy these conditions, can be treated as verbatimcopying in other respects.

If the required texts for either cover are too voluminous to fitlegibly, you should put the first ones listed (as many as fitreasonably) on the actual cover, and continue the rest onto adjacentpages.

If you publish or distribute Opaque copies of the Documentnumbering more than 100, you must either include a machine-readableTransparent copy along with each Opaque copy, or state in or with eachOpaque copy a computer-network location from which the general network-using public has access to download using public-standard networkprotocols a complete Transparent copy of the Document, free of addedmaterial. If you use the latter option, you must take reasonablyprudent steps, when you begin distribution of Opaque copies inquantity, to ensure that this Transparent copy will remain thusaccessible at the stated location until at least one year after the


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last time you distribute an Opaque copy (directly or through youragents or retailers) of that edition to the public.

It is requested, but not required, that you contact the authorsof the Document well before redistributing any large number of copies,to give them a chance to provide you with an updated version of theDocument.

4. MODIFICATIONS

You may copy and distribute a Modified Version of the Documentunder the conditions of sections 2 and 3 above, provided that yourelease the Modified Version under precisely this License, with theModified Version filling the role of the Document, thus licensingdistribution and modification of the Modified Version to whoeverpossesses a copy of it. In addition, you must do these things in theModified Version:

A. Use in the Title Page (and on the covers, if any) a title

distinct from that of the Document, and from those ofprevious versions (which should, if there were any, belisted in the History section of the Document). You mayuse the same title as a previous version if the originalpublisher of that version gives permission.

B. List on the Title Page, as authors, one or more persons orentities responsible for authorship of the modifications inthe Modified Version, together with at least five of theprincipal authors of the Document (all of its principalauthors, if it has fewer than five), unless they releaseyou from this requirement.

C. State on the Title page the name of the publisher of theModified Version, as the publisher.

D. Preserve all the copyright notices of the Document.

E. Add an appropriate copyright notice for your modificationsadjacent to the other copyright notices.

F. Include, immediately after the copyright notices, a licensenotice giving the public permission to use the ModifiedVersion under the terms of this License, in the form shownin the Addendum below.

G. Preserve in that license notice the full lists of Invariant

Sections and required Cover Texts given in the Document'slicense notice.

H. Include an unaltered copy of this License.

I. Preserve the section Entitled "History", Preserve itsTitle, and add to it an item stating at least the title,year, new authors, and publisher of the Modified Version asgiven on the Title Page. If there is no section Entitled"History" in the Document, create one stating the title,


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year, authors, and publisher of the Document as given onits Title Page, then add an item describing the ModifiedVersion as stated in the previous sentence.

J. Preserve the network location, if any, given in theDocument for public access to a Transparent copy of theDocument, and likewise the network locations given in theDocument for previous versions it was based on. These maybe placed in the "History" section. You may omit a networklocation for a work that was published at least four yearsbefore the Document itself, or if the original publisher ofthe version it refers to gives permission.

K. For any section Entitled "Acknowledgements" or"Dedications", Preserve the Title of the section, andpreserve in the section all the substance and tone of eachof the contributor acknowledgements and/or dedicationsgiven therein.

L. Preserve all the Invariant Sections of the Document,

unaltered in their text and in their titles. Sectionnumbers or the equivalent are not considered part of thesection titles.

M. Delete any section Entitled "Endorsements". Such a sectionmay not be included in the Modified Version.

N. Do not retitle any existing section to be Entitled"Endorsements" or to conflict in title with any InvariantSection.

O. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections orappendices that qualify as Secondary Sections and contain no materialcopied from the Document, you may at your option designate some or allof these sections as invariant. To do this, add their titles to thelist of Invariant Sections in the Modified Version's license notice.These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided itcontains nothing but endorsements of your Modified Version by variousparties--for example, statements of peer review or that the text hasbeen approved by an organization as the authoritative definition of astandard.

You may add a passage of up to five words as a Front-Cover Text,

and a passage of up to 25 words as a Back-Cover Text, to the end of thelist of Cover Texts in the Modified Version. Only one passage ofFront-Cover Text and one of Back-Cover Text may be added by (or througharrangements made by) any one entity. If the Document already includesa cover text for the same cover, previously added by you or byarrangement made by the same entity you are acting on behalf of, youmay not add another; but you may replace the old one, on explicitpermission from the previous publisher that added the old one.


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The author(s) and publisher(s) of the Document do not by thisLicense give permission to use their names for publicity for or toassert or imply endorsement of any Modified Version.

5. COMBINING DOCUMENTS

You may combine the Document with other documents released underthis License, under the terms defined in section 4 above for modifiedversions, provided that you include in the combination all of theInvariant Sections of all of the original documents, unmodified, andlist them all as Invari

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