Differences Between Open Source and Free Software
The biggest difference between the two types of software is their focus. Note that the second requirement for Open Source software is that the source code must be available. The ability to access the source code is a fundamental part of the Open Source concept; in fact, it’s the origin of the name. In contrast, the Free Software movement is interested in source code only as a means to an end.
The defining document for the Open Source movement is Eric S. Raymond’s "The Cathedral and the Bazaar." This text outlines the way in which a distributed development model can be superior to a closed, internal version. The basic idea of Open Source is that the availability of the source code makes for a better product. In contrast, the Free Software movement believes that a program that provides the user with the four freedoms is intrinsically superior to one that doesn’t, irrespective of its other features.
This difference is so fundamental that it’s worth repeating. From the perspective of their related movements,
- Free Software is superior because it’s Free.
- Open Source software will become superior because the development is Open.
Taking this difference into account, it’s worth noting that some projects are not really Open Source, even though they technically meet the definition. Apple’s Darwin, for example, is licensed under terms that meet these conditions, but isn’t developed in an open manner. As such, it only technically counts as Open Source, but is definitely Free Software.