Some of the differences in the terms Free Software and Open Source Software.
Open Source Software
For software to be considered “Open Source” it must meet ten conditions. Of these ten conditions, it’s the first three that are really at the core of Open Source and differentiates it from other software. Those three conditions are;
- Free Redistribution: the software can be freely given away or sold.
- Source Code: the source code must either be included or freely obtainable.
- Derived Works: redistribution of modifications must be allowed.
The other conditions are:
- Integrity of The Author's Source Code: licenses may require that modifications are redistributed only as patches.
- No Discrimination Against Persons or Groups: no one can be locked out.
- No Discrimination Against Fields of Endeavor: commercial users cannot be excluded.
- 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.
- License Must Not Be Specific to a Product: the program cannot be licensed only as part of a larger distribution.
- License Must Not Restrict Other Software: the license cannot insist that any other software it is distributed with must also be open source.
- License Must Be Technology-Neutral: no click-wrap licenses or other medium-specific ways of accepting the license must be required.
Free Software
Unlike the Open Source term, Free Software only has 4 “Freedoms” with its definition and are numbered 0-3:
- The freedom to run the program for any purpose (Freedom 0)
- The freedom to study how the program works and adapt it to your needs (Freedom 1)
- The freedom of redistribution of software (Freedom 2)
- The freedom to improve the program and release your improvements to the public to benefit the while community. (Freedom 3)
Although not explicitly outlined as a freedom, access to source code is implied with Freedoms 1 and 3. You need to have the source code in order to study or modify it.