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Rationale for the Open Source Definition
The intent of the Open Source Definition is to write down a concrete set of criteria that we believe capture the essence of what the software development community wants ``Open Source'' to mean -- criteria that ensure that software distributed under an open-source license will be available for independent peer review and continuous evolutionary improvement and selection, reaching levels of reliability and power no closed product can attain.For the evolutionary process to work, we have to counter short-term incentives for people to stop contributing to the software gene pool. This means the license terms must prevent people from locking up software where very few people can see or modify it.
When software developers distribute their software under OSI approved software licenses, they can apply the "OSI Certified" mark to that software. This certification mark informs users of that software that the license complies with the intent of the Open Source Definition. More information about our certification mark and program is available here.
1. Free Redistribution (back)
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 (back)
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 (back)
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 (back)
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. (back)
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. (back)
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. (back)
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. (back)
This clause forecloses yet another class of license traps.
9. License Must Not Contaminate Other Software. (back)
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. GPLed libraries `contaminate' only software to which they will actively be linked at runtime, not software with which they are merely distributed.