The Open Source Definition
Version 1.9
The indented, italicized sections below appear as annotations to the
Open Source Definition (OSD) and are not a part of the OSD. A plain
version of the OSD without annotations can be found
here.
Introduction
Open source doesn't just mean access to the source code. The
distribution terms of open-source software must comply with the
following criteria:
1. Free Redistribution
The license shall not restrict any party from selling or giving away the
software as a component of an aggregate software distribution containing
programs from several different sources. The license shall not require a
royalty or other fee for such sale.
Rationale: By constraining the license to require free
redistribution, we
eliminate the temptation to throw away many long-term gains in order
to make a few short-term sales dollars. If we didn't do this, there
would be lots of pressure for cooperators to defect.
2. Source Code
The program must include source code, and must allow distribution in
source code as well as compiled form. Where some form of a product is
not distributed with source code, there must be a well-publicized
means of obtaining the source code for no more than a reasonable
reproduction cost–preferably, downloading via the Internet without
charge. The source code must be the preferred form in which a
programmer would modify the program. Deliberately obfuscated source
code is not allowed. Intermediate forms such as the output of a
preprocessor or translator are not allowed.
Rationale: We require access to un-obfuscated source code because
you can't evolve
programs without modifying them. Since our purpose is to make
evolution easy, we require that modification be made easy.
3. Derived Works
The license must allow modifications and derived works, and must allow
them to be distributed under the same terms as the license of the original
software.
Rationale: The mere ability to read source isn't enough to support
independent
peer review and rapid evolutionary selection. For rapid evolution to
happen, people need to be able to experiment with and redistribute
modifications.
4. Integrity of The Author's Source Code
The license may restrict source-code from being distributed in modified
form only if the license allows the distribution of "patch files" with
the source code for the purpose of modifying the program at build time.
The license must explicitly permit distribution of software built from
modified source code. The license may require derived works to carry a
different name or version number from the original software.
Rationale: Encouraging lots of improvement is a good thing, but
users have a
right to know who is responsible for the software they are using.
Authors and maintainers have reciprocal right to know what they're
being asked to support and protect their reputations.
Accordingly, an open-source license must guarantee that
source be readily available, but may require that it be
distributed as pristine base sources plus patches. In this way,
"unofficial" changes can be made available but readily distinguished
from the base source.
5. No Discrimination Against Persons or Groups
The license must not discriminate against any person or group of persons.
Rationale: In order to get the maximum benefit from the process,
the maximum
diversity of persons and groups should be equally eligible to
contribute to open sources. Therefore we forbid any open-source
license from locking anybody out of the process.
Some countries, including the United States, have export restrictions
for certain types of software. An OSD-conformant license may warn
licensees of applicable restrictions and remind them that they are
obliged to obey the law; however, it may not incorporate such
restrictions itself.
6. No Discrimination Against Fields of Endeavor
The license must not restrict anyone from making use of the program in
a specific field of endeavor. For example, it may not restrict the program
from being used in a business, or from being used for genetic research.
Rationale: The major intention of this clause is to prohibit
license traps
that prevent open source from being used commercially. We want
commercial users to join our community, not feel excluded from it.
7. Distribution of License
The rights attached to the program must apply to all to whom the program
is redistributed without the need for execution of an additional license
by those parties.
Rationale: This clause is intended to forbid closing up software by
indirect means
such as requiring a non-disclosure agreement.
8. License Must Not Be Specific to a Product
The rights attached to the program must not depend on the program's being
part of a particular software distribution. If the program is extracted
from that distribution and used or distributed within the terms of the
program's license, all parties to whom the program is redistributed should
have the same rights as those that are granted in conjunction with the
original software distribution.
Rationale: This clause forecloses yet another class of license
traps.
9. The License Must Not Restrict Other Software
The license must not place restrictions on other software that is
distributed along with the licensed software. For example, the
license must not insist that all other programs distributed on the
same medium must be open-source software.
Rationale: Distributors of open-source software have the right to
make their own choices about their own software.
Yes, the GPL is conformant with this requirement. Software linked
with GPLed libraries only inherits the GPL if it forms a single
work, not any software with which they are merely distributed.