Open Source Licenses Are Not All the Same

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Open Source Licenses Are Not All the Same

by Stephen Fishman
11/18/2004

One of the most significant developments in the software and web development community in the past few years has been the increased use of open source software. It's vital for any programmer, web designer, or other computer professional to understand that open source licenses are not all the same. The differences between licenses can have a big impact on how you may use or distribute the software.

What Is Open Source?

Open source software is distributed under a license, just like regular proprietary software is. An open source license is a license with a difference: instead of keeping or expanding the software developer's rights, it gives them away. There is no single open source license; to date, more than 30 exist.

To help establish some degree of uniformity, the Open Source Initiative--a nonprofit corporation that helps promote and manage open source software--created the Open Source Definition. The Open Source Definition is not itself a software license. It is a specification of what must and must not appear in a license in order for the software covered by the license to be open source. However, it is important to understand that these are minimum requirements. Licensors are free to use licenses that go beyond the minimum. Thus, OSI-certified licenses are not all the same.

To meet the open source definition, a license must provide for all the following:

Free redistribution: First, the license must permit anyone who obtains and uses the covered software to sell or give it away to others without having to pay a royalty or other fee to the original copyright owner(s).

Source code access: An open source license requires everyone who distributes the software to provide unfettered access to the program source code. Although an open source arrangement does not require this, a popular approach is to provide the source code along with the object code form of the program. If the code does not come with the binaries, it must be available to users for free via Internet download, or on magnetic media for a reasonable fee at most.

Comparing the Open Source Licenses

Even with these characteristics in common, there is no single open source license. The OSI web site lists and links to all the OSI-certified open source licenses.

For conceptual convenience, there are four broad categories or families of open source licenses:

strong copyleft licenses
weak copyleft licenses
no copyleft licenses
other open source licenses

Strong copyleft licenses: GPL (General Public License)

Copyleft (a play on the word copyright) is the key factor that differentiates the various open software licenses. Copyleft is a license requirement that governs the distribution of modifications to the original open source software. If a license contains a strong copyleft provision, anyone who modifies the source code and distributes it to the public must license the modifications back to the public under the same terms as the original software. This means that you must give up private ownership of any changes you make to copyleft software, unless you elect not to make the modified software available publicly.

The GNU GPL (General Public License), one of the first open source licenses and still by far the most widely used, was the first to implement copyleft. Linux, the most famous open source application, uses the GPL. Richard Stallman and Eben Moglen created the GPL and formed the Free Software Foundation to help promote and manage its use. The Foundation's web site contains much useful information on the GPL as well as a downloadable copy of the license itself.

Weak copyleft licenses

Some programmers who create or contribute to open source software don't want to give up all their ownership rights in their modifications. To meet their needs, several licenses contain watered-down or weak copyleft provisions.

Mozilla Public License

The Mozilla Public License (MPL) is the most popular open source license that contains a weak copyleft provision. It came about to distribute the Mozilla web browser (the open source version of the Netscape browser). It requires the inclusion or publishing of the source code for all publicly distributed modifications. The length of time necessary to publish the code is limited to a period of one year or six months, depending on the situation. The MPL's copyleft provision entails only changes to files subject to the MPL or new files that contain MPL-licensed code. New files that don't contain MPL-licensed code do not fall under the MPL.

No copyleft licenses

The Open Source Definition does not require copylefting; many open source licenses contain no copyleft provisions at all. A whole family of licenses contain no copyleft and few other restrictions on users. The best-known of these no-copyleft licenses is the Berkeley Software Distribution (BSD) License. One of the earliest nonproprietary licenses, it permits users to do virtually anything they want with BSD-licensed code: they may distribute the software--either for free or commercially--without providing the source code; they also may modify it and distribute the changes without providing the source code. Anyone can turn software distributed under no-copyleft licenses into proprietary software (and then relicense it for a fee) as long as they credit the developers of the original open source software. Two other well-known licenses, the Apache Software License and the MIT License, are very similar to the BSD License.

Other open source licenses

Various other licenses combine elements from the other license families and contain additional provisions as well. Examples include the Artistic License and the Academic Free License.

Practical Considerations for Using Open Source Software

Before you jump on the open source bandwagon, you need to understand the practical implications of using open source software.

First of all, simply using an open source program on a day-to-day basis ordinarily has no legal implications for the user.

For example, Ralph, a freelance programmer, takes a job at the Acme Power Corporation to create a program to measure the pollution created by its coal-fired power plants. He uses the GNU Emacs text editor to write the program and the GNU Compiler to transform it into object code. Both programs are governed by the GPL, but Ralph's program need not be unless it includes code from the GPL-licensed programs he used.

Additionally, you may include proprietary programs along with open source software on a storage or distribution medium without bringing the propriety software under the open source license.

Say that Ralph independently creates a database program that runs atop the Linux operating system, which is licensed under the GPL. Ralph may keep his database program proprietary and distribute it with a copy of Linux, because his program does not contain any Linux or other open source code. The two programs are completely separate works--placing them on a single hard drive or CD-ROM does not change that. Thus, Ralph may require users to agree to a restrictive proprietary license to use his database program, but not Linux.

Anyone who uses open source software has the freedom to modify the program or to incorporate it into other programs. That is the reason for providing source code to users. However, as long as your organization only uses the new work internally, the open source license will not affect you.

Let's assume that Ralph doesn't want to go through the time and trouble of creating an entirely new program for Acme and doesn't want to have to pay to obtain the right to use an existing proprietary program. Ralph instead decides to use an open source program called Coal Source, which accomplishes most of the tasks his client needs done. Ralph obtains the source code for the program for free from the Internet. Coal Source, like most open source software, is governed by the GPL. He makes several modifications to the program's source code so that it will better meet his client's needs. Acme uses the resulting program to help monitor its power plants. Because the company never makes the program available to the public, either through commercial distribution or by publishing it on the Internet, the copyleft provisions contained in Coal Source's GPL have no effect on Ralph or Acme.

You may also use open source software to provide services to the public without any copyleft provisions applying. For example, you can modify open source e-commerce software and place it a server to help operate a commercial web site. You're not publishing or distributing the modified software to the public, so your modifications do not fall under copyleft provisions.

The copyleft provisions of the GPL and other open source licenses apply when a user creates a derivative work from open source code and publicly distributes it, whether for fun or profit. In this event, the new code must use the same open source license as the original code. This means that the distributor must license the program as a whole at no charge to all third parties under the terms of the GPL.

Editor's note: I disagree with the phrase at no charge in the previous paragraph; the entity must license the program under the GPL and can charge only a reasonable fee for access to the source code, but I see nothing in the GPL that prevents charging for distribution.

For example, assume that Ralph decides to market a commercial version of his modified Coal Source program. Because he obtained the original Coal Source under the terms of the GPL, Ralph must distribute his modified version of the program under the GPL as well. The GPL requires that Ralph do the following:

"Conspicuously and appropriately" publish on each copy an appropriate copyright notice and disclaimer of warranty
Keep intact all the notices that refer to this GPL and to the absence of any warranty
Give any other recipients of the program a copy of the GPL along with the program
Include prominent notices in the modified files stating that he changed the files and indicating the date of any changes
Provide a complete, machine-readable copy of the source code for the program either (1) with the executable form of the program, (2) downloadable from the Internet, or (3) made available at cost on CD-ROM or other medium for at least three years

Ralph cannot require that people who use his program agree to additional restrictions of the sort typically found in proprietary licenses--for example, he cannot forbid users from modifying the program.

Stephen Fishman is a San Francisco-based intellectual property attorney who has been writing about the law for more than 20 years.

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Showing messages 1 through 8 of 8.

Video overview
2008-06-11 08:16:39 br524 [Reply | View]

Here's a video explanation of the various licenses: http://digg.com/software/Overview_of_Open_Source_Licenses

author confused about the GPL
2005-01-04 09:03:43 stepheneb [Reply | View]

I found the writer of the article (and the writer of the first comment) confused about the GPL. The author writes:

"Copyleft (a play on the word copyright) is the key factor that differentiates the various open software licenses. Copyleft is a license requirement that governs the distribution of modifications to the original open source software. If a license contains a strong copyleft provision, anyone who modifies the source code and distributes it to the public must license the modifications back to the public under the same terms as the original software. This means that you must give up private ownership of any changes you make to copyleft software, unless you elect not to make the modified software available publicly."

The writer of the derivation has copyright to the modifications he or she makes to the original code. This copyright is a 'private ownership" of the work created and the control of distribution copyright law gives the author is the legal basis of the GPL. The GPL could not work if this "private ownership" didn't exist.

Copyleft does not control the distribution of modifications of software -- the modifications themselves can be distributed under any license. The confusion the author has comes from conflating the idea of modifications and derivation. The derivation is a combination of the original work and the modifications. Nothing in the GPl license gives the person making modifications any copyright control over the original code -- that means that the second author has no right to distribute the original code except in the manner the original license allows.

The commentor also make this confusion here:

"The offeree who accepts a non-negotiable open source
license offer must not just grant a waiver of rights to
the offeror but must also offer a waiver to all third
parties of his granted copyright monopoly -- the
offeree's "rights against the world" -- rights granted
by the Copyright Act. It's one thing to waive a legal
right in privity but an entirely different thing to
waive a right against the general public."

There is nothing in the GPL under which a person who creates a derivative work by creating modifications has to make the either the derivation or modification available to the original author or to the general public. The only obligation occurs when the derivation is distributed and only to the persons receiving the distribution. If the second author chooses to they can distribute only their modifications and as the author and copyright holder can choose any license they wish. If they choose to also distribute the first authors copyrighted code (which always happens when distributing a derivation) they must abide by the license the first author has chosen.

Open Licenses
2004-11-19 04:54:42 Gumout [Reply | View]

FOSS is slowly progressing toward licensing oblivion in
the United States. Open source licenses that attempt to
keep the source code open to the general public for
modification and derivative distribution are preempted
by U.S. copyright law.

A "preexisting" original author using an open source
"standard form" license is attempting to use his lawful
monopoly in authorizing derivative works of his
"preexisting" original work to control the exclusive
rights granted to all subsequent offerees' derivative
modifications to that "preexisting" work. The Copyright
Act states:

Section 103. Subject matter of copyright:
Compilations and derivative works.
(b) The copyright in a compilation or derivative work
extends only to the material contributed by the author
of such work, as distinguished from the preexisting
material employed in the work, and does not imply any
exclusive right in the preexisting material. THE
COPYRIGHT IN SUCH WORK IS INDEPENDENT OF, AND DOES NOT
AFFECT OR ENLARGE THE SCOPE, DURATION, OWNERSHIP, OR
SUBSISTENCE OF, ANY COPYRIGHT PROTECTION IN THE
PREEXISTING MATERIAL (my emphasis).

The Fourth Circuit Court of Appeals has ruled:
"The grant to the author of the special privilege of a
copyright carries out a public policy adopted by the
... United States Constitution, Art. I, 8, cl. 8, 17
U.S.C. 102. But the public policy which includes
original works within the granted monopoly excludes
from it all that is not embraced in the original
expression. It equally forbids the use of the copyright
to secure an exclusive right or limited monopoly not
granted by the Copyright Office and which is contrary
to public policy to grant." -- Lasercomb America Inc.
v. Reynolds 911 F.2d 970 (4th Cir. 1990);

The offeree who accepts a non-negotiable open source
license offer must not just grant a waiver of rights to
the offeror but must also offer a waiver to all third
parties of his granted copyright monopoly -- the
offeree's "rights against the world" -- rights granted
by the Copyright Act. It's one thing to waive a legal
right in privity but an entirely different thing to
waive a right against the general public.

All federal circuits now recognize "misuse of
copyright" as a valid defense to a copyright breach of
contract or infringement action.

"The doctrine of misuse 'prevents copyright holders
from leveraging their limited monopoly to allow them
control of areas outside the monopoly.' A&M Records,
Inc. v. Napster, Inc., 239 F.3d 1004, 1026-27 (9th Cir.
2001);" -- ASSESSMENT TECHNOLOGIES OF WI, INC., 350
F.3d 640 (7th Cir. 2003)

A generic adhesion contract is required to be offered
to the general public (all third parties) by an
accepting licensee as a term of the license... this is
nothing more than an attempt to regulate another's
"right against the world"... rights excluded by statute
from the preexisting licensor's original work.

It is the offer to the general public that violates
public policy. The Seventh Circuit Court of Appeals in
ProCd v. Zeitenburg, 86 F.3d 1447, stated:

"A copyright is a right against the world. Contracts,
by contrast, generally affect only their parties;
strangers may do as they please, so contracts do not
create “exclusive rights.” Someone who found a copy of
SelectPhoneTM on the street would not be affected by
the shrinkwrap license – though the federal copyright
laws of their own force would limit the finder’s
ability to copy or transmit the application program...
But whether a particular license is generous or
restrictive, a simple two-party contract is not
“equivalent to any of the exclusive rights within the
general scope of copyright” and therefore may be
enforced.

Recursive multi-party contracts are not simple
two-party contracts. Someone on the street finding a
copy of a program licensed under the Common Public
License would be affected by its license offer. It
invites any member of the general public to join and be
bound by the license.

This "copyright misuse" violates the will of Congress
as expressed by section 301(a) of the Copyright Act.
Congress' intent was that general copyright law be a
single uniform set of federal statutes. Non-negotiable
licenses to regulate copyrights that effect the general
public -- "rights against the world" -- may not be
created by contract law. Congress expressed its
desires:

"By substituting a single Federal system for the
present anachronistic, uncertain, impractical, and
highly complicated dual system, the bill would greatly
improve the operation of the copyright law and would be
much more effective in carrying out the basic
constitutional aims of uniformity and the promotion of
writing and scholarship." -- H.R. Rep. No. 94-1476

The federal courts will *never* enforce these canonical
form licenses whose primary purpose conflicts with
Congress' express wishes concerning public policy.

Flaming the public forums or name calling of critics
(the typical response from open source advocates) will
not change the jurists' minds. Stare decisis, "stand by
that which is decided", prevails in the real legal
world.

Daniel Wallace

Stare decisis does prevail
2006-07-18 11:05:17 erikschmidt [Reply | View]

Stare decisis, "stand by
that which is decided", prevails in the real legal
world.

Indeed it does. Mr. Wallace's case against the Free Software Foundation was dismissed in March, 2006 in the United States District Court for the Southern District of Indiana. Groklaw has the full story at http://www.groklaw.net/article.php?story=20060320201540127.

The federal courts will *never* enforce these canonical
form licenses whose primary purpose conflicts with
Congress' express wishes concerning public policy.

From Judge Tinder's opinion: "As alleged, the GPL in no way forecloses other operating systems from entering the market. Instead, it merely acts as a means by which certain software may be copied, modified and redistributed without violating the software�s copyright protection. As such, the GPL encourages, rather than discourages, free competition and the distribution of computer operating systems, the benefits of which directly pass to consumers. These benefits include lower prices, better access and more innovation."

Open Licenses
2004-12-09 06:39:19 ad21 [Reply | View]

IANAL, and therefore IAN completely following this post. Am I to deduce from the argument that GPL-style licenses are bad and BSD-style licenses are good? TIA.

Open Licenses
2004-11-19 06:36:02 msporleder [Reply | View]

>>A "preexisting" original author using an open source
>>"standard form" license is attempting to use his >>lawful monopoly in authorizing derivative works of >>his "preexisting" original work to control the >>exclusive rights granted to all subsequent >>offerees' derivative modifications to that >>"preexisting" work. The Copyright Act states:

I think that's a pretty strong assumption. I don't see any of your examples classifying open source software authors as monopolies. In fact, I think software has always been distributed under restrictive, creative, and otherwise weird terms.

It's the right the owner of a creative work to distribute it as he pleaases. It is, after all, his property. I think any court would agree that if you can change $10/end-user*5 (or whatever other obsurd licensing exists), then you can give your creative works away for free, demanding only a payment of intellectual property and credit to the original author (GPL vs BSD) when the end-user chooses to use it by modifying and redistributing it.

Open Licenses
2004-11-24 09:34:00 brianutterback [Reply | View]

all copyright holders are monopolies. they have a monopolistic as the copyright holder to grant those copyrights to those they choose and under the terms they choose. The point in this discussion is that new rights cannot be created that have not been previously granted by the law, except via contract. The kicker here is that the courts appear to maintain that a copyright license is not a genuine contract because a contract must be between limited parties and not just "the public". Therefore a license cannot place further restrictions than those granted by law.

Ok, so basically
2004-12-15 11:16:05 joodie [Reply | View]

You mean to say, that according to the US copyright law any software licence that allows the "general public" to use it (say, download it from a website), cannot be copyrighted?