“Free software” means software that respects users’ freedom and community. Roughly, it means that the users have the freedom to run, copy, distribute, study, change and improve the software. Thus, “free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech,” not as in “free beer”.
Sometimes the word “libre” is used, as opposed to just “gratis”. Usually the underlying principles apply:
- The freedom to run the program as you wish, for any purpose (freedom 0).
- The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
- The freedom to redistribute copies so you can help your neighbour (freedom 2).
- The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.
“Free software” implies Open Source (because of freedom 1), and the two movements largely overlap. Sometimes the acronym FOSS is used, for Free and Open Source Software.
The Free software movement has been implicitly around since the very beginning of computer software: in the early days, sharing source code was the norm — most programmers were in academia, with a tradition of sharing results with their peers and with the public. However, as commercial software became more important in the 1970s, closed-source proprietary software became more common. The GNU project was launched in 1983 as a reaction to this trend, with the explicit goal of creating a completely Free operating system complete with all essential applications. In the early 1990s, the Linux kernel was created, with a Free software license (the GNU GPL), and it became increasingly popular. Today, GNU/Linux is the platform of choice for many applications where the robustness, power and the flexibility of FOSS software is greatly appreciated, from web servers and desktop computers to embedded devices or film industry render farms.