Many companies, including IBM and Red Hat, make substantial revenue

from this model. IBM primarily chooses this model because they have

found that for higher-end hardware, the cost of the profit made from

proprietary software licensing fees is negligible. The real profit is

in the hardware, but it is essential that software be stable, reliable

and dependable, and the users be allowed to have unfettered access to

it. Free Software, and GPL'd software in particular (because IBM can

be assured that proprietary versions of the same software will not

exists to compete on their hardware) is the right choice.

Red Hat has actually found that a ``convenience fee'' for Free Software,

when set at a reasonable price (around \$60 or so), can produce some

profit. Even though Red Hat's system is fully downloadable on their

Web site, people still go to local computer stores and buy copies of their

box set, which is simply a printed version of the manual (available under

a Free license as well) and the Free Software system it documents.

\medskip

However, custom support, service, and software improvement contracts

are the most widely used models for GPL'd software. The GPL is

central to their success, because it ensures that the code base

remains common, and that large and small companies are on equal

footing for access to the technology. Consider, for example, the GNU

Compiler Collection (GCC). Cygnus Solutions, a company started in the

early 1990s, was able to grow steadily simply by providing services

for GCC --- mostly consisting of new ports of GCC to different or new,

embedded targets. Eventually, Cygnus was so successful that

it was purchased by Red Hat where it remains a profitable division.

However, there are very small companies like CodeSourcery, as well as

other medium-sized companies like MontaVista and OpenTV that compete in

this space. Because the code-base is protect by GPL, it creates and

demands industry trust. Companies can cooperate on the software and

improve it for everyone. Meanwhile, companies who rely on GCC for their

work are happy to pay for improvements, and for ports to new target

platforms. Nearly all the changes fold back into the standard

versions, and those forks that exist remain freely available.

\medskip

\label{Proprietary Relicensing}

A final common business model that is perhaps the most controversial is

proprietary relicensing of a GPL'd code base. This is only an option for

software in which a particular entity is the sole copyright holder. As

discussed earlier in this tutorial, a copyright holder is permitted under

copyright law to license a software system under her copyright as many

different ways as she likes to as many different parties as she wishes.

Some companies, such as MySQL AB and TrollTech, use this to their

financial advantage with regard to a GPL'd code base. The standard

version is available from the company under the terms of the GPL\@.

However, parties can purchase separate proprietary software licensing for

a fee.

This business model is problematic because it means that the GPL'd code

base must be developed in a somewhat monolithic way, because volunteer

Free Software developers may be reluctant to assign their copyrights to

the company because it will not promise to always and forever license the

software as Free Software. Indeed, the company will surely use such code

contributions in proprietary versions licensed for fees.

\section{Ongoing Compliance}

GPL compliance is in fact a very simple matter -- much simpler than

typical proprietary software agreements and EULAs. Usually, the most

difficult hurdle is changing from a proprietary software mindset to one

that seeks to foster a community of sharing and mutual support. Certainly

complying with the GPL from a users' perspective gives substantially fewer

headaches than proprietary license compliance.

For those who go into the business of distributing {\em modified\\}

versions of GPL'd software, the burden is a bit higher, but not by

much. The glib answer is that by releasing the whole product as Free

Software, it is always easy to comply with the GPL. However,

admittedly to the dismay of FSF, many modern and complex software

systems are built using both proprietary and GPL'd components that are

not legally derivative works of each other. Sometimes, it is easier simply to

improve existing GPL'd application than to start from scratch. In

exchange for that benefit, the license requires that the modifier give

back to the commons that made the work easier in the first place. It is a

reasonable trade-off and a way to help build a better world while also

making a profit.

Note that FSF does provide services to assist companies who need

assistance in complying with the GPL. You can contact FSF's GPL

Compliance Labs at $<$compliance@fsf.org$>$.

If you are particularly interested in matters of GPL compliance, we

recommend the second course in this series, {\em GPL Compliance Case

  Studies and Legal Ethics in Free Software Licensing\/}, in which we

discuss some real GPL violation cases that FSF has worked to resolve.

Consideration of such cases can help give insight on how to handle GPL

compliance in new situations.

\appendix

\begin{center}

{\parindent 0in

Version 2, June 1991

Copyright \copyright\ 1989, 1991 Free Software Foundation, Inc.

\bigskip

59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

\bigskip

Everyone is permitted to copy and distribute verbatim copies

of this license document, but changing it is not allowed.

}

\end{center}

\begin{center}

{\bf\large Preamble}

\end{center}

The licenses for most software are designed to take away your freedom

to share and change it. By contrast, the GNU General Public License is

intended to guarantee your freedom to share and change Free

Software---to make sure the software is free for all its users. This

General Public License applies to most of the Free Software

Foundation's software and to any other program whose authors commit to

using it. (Some other Free Software Foundation software is covered by

the GNU Library General Public License instead.) You can apply it to

your programs, too.

When we speak of Free Software, we are referring to freedom, not price.

Our General Public Licenses are designed to make sure that you have the

freedom to distribute copies of Free Software (and charge for this service

if you wish), that you receive source code or can get it if you want it,

that you can change the software or use pieces of it in new Free programs;

and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid anyone to

deny you these rights or to ask you to surrender the rights. These

restrictions translate to certain responsibilities for you if you

distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether gratis or

for a fee, you must give the recipients all the rights that you have. You

must make sure that they, too, receive or can get the source code. And

you must show them these terms so they know their rights.

We protect your rights with two steps: (1) copyright the software, and (2)

offer you this license which gives you legal permission to copy,

distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain that

everyone understands that there is no warranty for this Free Software. If

the software is modified by someone else and passed on, we want its

recipients to know that what they have is not the original, so that any

problems introduced by others will not reflect on the original authors'

reputations.

Finally, any Free program is threatened constantly by software patents.

We wish to avoid the danger that redistributors of a Free program will

individually obtain patent licenses, in effect making the program

proprietary. To prevent this, we have made it clear that any patent must

be licensed for everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution and

modification follow.

\begin{center}

{\Large \sc Terms and Conditions For Copying, Distribution and

  Modification}

\end{center}

\begin{enumerate}

\addtocounter{enumi}{-1}

\item

This License applies to any program or other work which contains a notice

placed by the copyright holder saying it may be distributed under the

terms of this General Public License. The ``Program,'' below, refers to

any such program or work, and a ``work based on the Program'' means either

the Program or any derivative work under copyright law: that is to say, a

work containing the Program or a portion of it, either verbatim or with

modifications and/or translated into another language. (Hereinafter,

translation is included without limitation in the term ``modification.'')

Each licensee is addressed as ``you.''

Activities other than copying, distribution and modification are not

covered by this License; they are outside its scope. The act of

running the Program is not restricted, and the output from the Program

is covered only if its contents constitute a work based on the

merchantability and fitness for a particular purpose. The entire risk as

to the quality and performance of the program is with you. Should the

program prove defective, you assume the cost of all necessary servicing,

repair or correction.}

\item {\sc In no event unless required by applicable law or agreed to

    in writing will any copyright holder, or any other party who may

    modify and/or redistribute the program as permitted above, be

    liable to you for damages, including any general, special,

    incidental or consequential damages arising out of the use or

    inability to use the program (including but not limited to loss of

    data or data being rendered inaccurate or losses sustained by you

    or third parties or a failure of the program to operate with any

    other programs), even if such holder or other party has been

    advised of the possibility of such damages.}

\end{enumerate}

\begin{center}

{\Large\sc End of Terms and Conditions}

\end{center}

\vfill

\pagebreak[4]

\section*{Appendix: How to Apply These Terms to Your New Programs}

If you develop a new program, and you want it to be of the greatest

possible use to the public, the best way to achieve this is to make it

Free Software which everyone can redistribute and change under these

terms.

  To do so, attach the following notices to the program. It is safest to

  attach them to the start of each source file to most effectively convey

  the exclusion of warranty; and each file should have at least the

  ``copyright'' line and a pointer to where the full notice is found.

\begin{quote}

one line to give the program's name and a brief idea of what it does. \\

Copyright (C) yyyy  name of author \\

This program is Free Software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

\end{quote}

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this

when it starts in an interactive mode:

\begin{quote}

Gnomovision version 69, Copyright (C) yyyy  name of author \\

Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. \\

This is Free Software, and you are welcome to redistribute it

under certain conditions; type `show c' for details.

\end{quote}

The hypothetical commands {\tt show w} and {\tt show c} should show the

appropriate parts of the General Public License. Of course, the commands

you use may be called something other than {\tt show w} and {\tt show c};

they could even be mouse-clicks or menu items---whatever suits your

program.

You should also get your employer (if you work as a programmer) or your

school, if any, to sign a ``copyright disclaimer'' for the program, if

necessary. Here is a sample; alter the names:

\begin{quote}

Yoyodyne, Inc., hereby disclaims all copyright interest in the program \\

`Gnomovision' (which makes passes at compilers) written by James Hacker. \\

signature of Ty Coon, 1 April 1989 \\

Ty Coon, President of Vice

\end{quote}

This General Public License does not permit incorporating your program

into proprietary programs. If your program is a subroutine library, you

may consider it more useful to permit linking proprietary applications

with the library. If this is what you want to do, use the GNU Library

General Public License instead of this License.

\begin{center}

{\parindent 0in

Version 2.1, February 1999

Copyright \copyright\ 1991, 1999 Free Software Foundation, Inc.

\bigskip

59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

\bigskip

Everyone is permitted to copy and distribute verbatim copies

of this license document, but changing it is not allowed.

\bigskip

[This is the first released version of the Lesser GPL. It also counts

 as the successor of the GNU Library Public License version 2, hence

 the version number 2.1.]

}

\end{center}

\begin{center}

{\bf\large Preamble}

\end{center}

The licenses for most software are designed to take away your freedom to

share and change it. By contrast, the GNU General Public Licenses are

intended to guarantee your freedom to share and change Free Software---to

make sure the software is free for all its users.

This license, the Lesser General Public License, applies to some specially

designated software packages---typically libraries---of the Free Software

Foundation and other authors who decide to use it. You can use it too,

but we suggest you first think carefully about whether this license or the

ordinary General Public License is the better strategy to use in any

particular case, based on the explanations below.

When we speak of Free Software, we are referring to freedom of use, not

price. Our General Public Licenses are designed to make sure that you

have the freedom to distribute copies of Free Software (and charge for

this service if you wish); that you receive source code or can get it if

you want it; that you can change the software and use pieces of it in new

Free programs; and that you are informed that you can do these things.

To protect your rights, we need to make restrictions that forbid

distributors to deny you these rights or to ask you to surrender these

rights. These restrictions translate to certain responsibilities for you

if you distribute copies of the library or if you modify it.

For example, if you distribute copies of the library, whether gratis or

for a fee, you must give the recipients all the rights that we gave you.

You must make sure that they, too, receive or can get the source code. If

you link other code with the library, you must provide complete object

files to the recipients, so that they can relink them with the library

after making changes to the library and recompiling it. And you must show

them these terms so they know their rights.

We protect your rights with a two-step method: (1) we copyright the

library, and (2) we offer you this license, which gives you legal

permission to copy, distribute and/or modify the library.

To protect each distributor, we want to make it very clear that there is

no warranty for the Free library. Also, if the library is modified by

someone else and passed on, the recipients should know that what they have

is not the original version, so that the original author's reputation will

not be affected by problems that might be introduced by others.

Finally, software patents pose a constant threat to the existence of any

Free program. We wish to make sure that a company cannot effectively

restrict the users of a Free program by obtaining a restrictive license

from a patent holder. Therefore, we insist that any patent license

obtained for a version of the library must be consistent with the full

freedom of use specified in this license.

Most GNU software, including some libraries, is covered by the ordinary

GNU General Public License. This license, the GNU Lesser General Public

License, applies to certain designated libraries, and is quite different

from the ordinary General Public License. We use this license for certain

libraries in order to permit linking those libraries into non-Free

programs.

When a program is linked with a library, whether statically or using a

shared library, the combination of the two is legally speaking a combined

work, a derivative of the original library. The ordinary General Public

License therefore permits such linking only if the entire combination fits

its criteria of freedom. The Lesser General Public License permits more

lax criteria for linking other code with the library.

We call this license the ``Lesser'' General Public License because it does

Less to protect the user's freedom than the ordinary General Public

License. It also provides other Free Software developers Less of an

  If you wish to incorporate parts of the library into other Free programs

  whose distribution conditions are incompatible with these, write to the

  author to ask for permission. For software which is copyrighted by the

  Free Software Foundation, write to the Free Software Foundation; we

  sometimes make exceptions for this. Our decision will be guided by the

  two goals of preserving the Free status of all derivatives of our Free

  software and of promoting the sharing and reuse of software generally.

\begin{center}

{\Large\sc

No Warranty

}

\end{center}

\item

{\sc Because the library is licensed free of charge, there is no

warranty for the library, to the extent permitted by applicable law.

Except when otherwise stated in writing the copyright holders and/or

other parties provide the library ``as is'' without warranty of any

kind, either expressed or implied, including, but not limited to, the

implied warranties of merchantability and fitness for a particular

purpose. The entire risk as to the quality and performance of the

library is with you. should the library prove defective, you assume

the cost of all necessary servicing, repair or correction.}

% \pagebreak[4]

\item

{\sc In no event unless required by applicable law or agreed to in writing

  will any copyright holder, or any other party who may modify and/or

  redistribute the library as permitted above, be liable to you for

  damages, including any general, special, incidental or consequential

  damages arising out of the use or inability to use the library

  (including but not limited to loss of data or data being rendered

  inaccurate or losses sustained by you or third parties or a failure of

  the library to operate with any other software), even if such holder or

  other party has been advised of the possibility of such damages.}

\end{enumerate}

\begin{center}

{\Large\sc End of Terms and Conditions}

\end{center}

\vfill

\pagebreak[4]

\section*{How to Apply These Terms to Your New Libraries}

If you develop a new library, and you want it to be of the greatest

possible use to the public, we recommend making it Free Software that

everyone can redistribute and change. You can do so by permitting

redistribution under these terms (or, alternatively, under the terms of

the ordinary General Public License).

To apply these terms, attach the following notices to the library. It is

safest to attach them to the start of each source file to most effectively

convey the exclusion of warranty; and each file should have at least the

``copyright'' line and a pointer to where the full notice is found.

\begin{quote}

one line to give the library's name and a brief idea of what it does. \\

Copyright (C) year  name of author \\

This library is Free Software; you can redistribute it and/or modify it

under the terms of the GNU Lesser General Public License as published by

the Free Software Foundation; either version 2.1 of the License, or (at

your option) any later version.

This library is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public

License for more details.

You should have received a copy of the GNU Lesser General Public License

along with this library; if not, write to the Free Software Foundation,

Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

\end{quote}

Also add information on how to contact you by electronic and paper mail.

You should also get your employer (if you work as a programmer) or your

school, if any, to sign a ``copyright disclaimer'' for the library, if

necessary. Here is a sample; alter the names:

\begin{quote}

Yoyodyne, Inc., hereby disclaims all copyright interest in the program \\

`Gnomovision' (which makes passes at compilers) written by James Hacker. \\

signature of Ty Coon, 1 April 1990 \\

Ty Coon, President of Vice

\end{quote}

\begin{center}

{\parindent 0in

Version 1, March 2002

Copyright \copyright\ 2002 Affero, Inc.

\bigskip

510 Third Street - Suite 225, San Francisco, CA 94107, USA

\bigskip

This license is a modified version of the GNU General Public License

copyright (C) 1989, 1991 Free Software Foundation, Inc. made with

their permission. Section 2(d) has been added to cover use of software

over a computer network.

Everyone is permitted to copy and distribute verbatim copies

of this license document, but changing it is not allowed.

}

\end{center}

\begin{center}

{\bf\large Preamble}

\end{center}

The licenses for most software are designed to take away your freedom

to share and change it. By contrast, the Affero General Public License

is intended to guarantee your freedom to share and change free

software--to make sure the software is free for all its users. This

Public License applies to most of Affero's software and to any other

program whose authors commit to using it. (Some other Affero software

is covered by the GNU Library General Public License instead.) You can

apply it to your programs, too.

When we speak of free software, we are referring to freedom, not price. This General Public License is designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.

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

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

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

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

Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.

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

\begin{center}

{\Large \sc Terms and Conditions For Copying, Distribution and

  Modification}

\end{center}

\begin{enumerate}

\addtocounter{enumi}{-1}

\item

This License applies to any program or other work which contains a

notice placed by the copyright holder saying it may be distributed

under the terms of this Affero General Public License.  The

``Program'', below, refers to any such program or work, and a ``work

based on the Program'' means either the Program or any derivative work

under copyright law: that is to say, a work containing the Program or

a portion of it, either verbatim or with modifications and/or

translated into another language.  (Hereinafter, translation is

included without limitation in the term ``modification''.)  Each

licensee is addressed as ``you''.

Activities other than copying, distribution and modification are not

covered by this License; they are outside its scope.  The act of

running the Program is not restricted, and the output from the Program

is covered only if its contents constitute a work based on the

Program (independent of having been made by running the Program).

Whether that is true depends on what the Program does.

\item You may copy and distribute verbatim copies of the Program's source

  code as you receive it, in any medium, provided that you conspicuously

  and appropriately publish on each copy an appropriate copyright notice

  and disclaimer of warranty; keep intact all the notices that refer to

  this License and to the absence of any warranty; and give any other

  recipients of the Program a copy of this License along 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 a fee.

\item

You may modify your copy or copies of the Program or any portion