Both of these terms seem to mean the same thing but the truth is that they are not interchangeable. Some say that the difference between these two is more philosophical than practical. To others, there are fundamental differences between the two. The term open source was coined back in 1997 as a substitute of “free software” because the term gave out the idea that since it was free, it was probably of low quality.
Let´s first try to find the definitions of these terms. In our blog post, we defined open source as software that is distributed along with its source code. This means that it can be used, studied, and modified to fit user’s convenience. So what would free software be? Technically speaking, free software is one that is available to the public free of charge. All free software is open source but not all open source is actually free, at least according to the Free Software Movement. There is, in fact, a term describing free and open-source software-FOSS.
Keep in mind that when defining free software, we are talking about freedom to use at own´s convenience, not price. This term must not be confused with freeware, which refers to available software at no monetary cost, but the source code has not been published. Free software has an advocacy that supports the distribution of free software, especially the GNU Project, which authors some of the most popular free software out there.
When we define open source software, we must consider that the term stemmed from the advocates of free software. The proponents of free software even call this term a marketing strategy in the name itself. It was actually born as a response to help rise up the feelings that due to the collaboration aspect of free software and the potential to being improved, it is technically superior to propriety property. This is when the open source movement was born. In very simple terms, the movement placed emphasis on practicality, on having superior quality software that was free for all. This as opposed to the free software movement that made emphasis on the ethical or political aspects.
The Open Source Initiative came to formally approve licenses as open source. To some, Open Source is just part of a marketing campaign for free software. Interestingly, we find ourselves with a distinction that taps into the ethical and political aspects more than in any technical distinction. They both have points that meet, which actually makes it more difficult for it to make any objective distinction between them.
To try to keep it simple and correct, and as stated before, all open source software is free software. It is also true that there is open source software that is not free. Some open source software is not completely free in rendering to tivoization. This means that some open-source is completely free to modify, use, study, and distribute, except when there is an update on the software where it is being used.
The Free Software Movement and the Open Source Initiative are at odds only when it comes to ideology, which appears to be an important aspect to consider when dubbing a software as “free” or “open-sourced”.