Free software is computer software distributed under terms that allow users to run, study, change, and distribute the software and any modified versions. The concept emphasizes "freedom" over "price," meaning that while free software can be provided at no cost, it can also be sold. The key distinction lies in the liberties granted to the user, not merely the financial cost. This philosophy was formalized by Richard Stallman and the Free Software Foundation (FSF), which defines free software based on four essential freedoms.
The Four Essential Freedoms
According to the Free Software Foundation, a program is free software if the program's users have the following four essential freedoms:
- Freedom 0: The freedom to run the program as you wish, for any purpose. This means users can execute the software without restrictions on its use case or environment.
- Freedom 1: The freedom to study how the program works, and change it so it does your computing as you wish. Access to the software's source code is a precondition for this, as it allows users to understand, modify, and adapt the software to their needs.
- Freedom 2: The freedom to redistribute copies so you can help your neighbor. Users are allowed to make and distribute exact copies of the software to others, either gratis or for a fee.
- Freedom 3: The freedom to distribute copies of your modified versions to others. By doing this, you can give the whole community a chance to benefit from your changes. This freedom also requires access to the source code.
Distinction from Open Source and Freeware
While the terms "free software" and "open-source software" are often used interchangeably, they represent distinct philosophies, though they frequently refer to the same set of software. The free software movement prioritizes ethical and moral concerns regarding user freedom, viewing proprietary software as an ethical problem. The open-source movement, conversely, focuses more on pragmatic benefits such as quality, reliability, development methodology, and cost-effectiveness. Most software that is free software is also open source, and vice-versa, but their underlying motivations differ.
Free software is also distinct from freeware. Freeware is software that is available at no monetary cost, but it typically does not grant the user the four essential freedoms mentioned above. Freeware is often proprietary, meaning its source code is not available, and users are restricted from modifying or redistributing it. Similarly, shareware is another category of software distributed free of charge, often for a trial period, but it is also proprietary and typically requires payment for full use or after the trial expires.
History and Impact
The free software movement officially began in 1983 with Richard Stallman's announcement of the GNU Project, an ambitious effort to create a complete, free, Unix-like operating system. This led to the establishment of the Free Software Foundation (FSF) in 1985, which continues to advocate for software freedom and develop free software licenses, most notably the GNU General Public License (GPL).
The availability of free software has had a profound impact on technology and society. It fosters transparency, collaboration, and innovation, allowing developers worldwide to contribute to and improve software projects. It also empowers users by giving them control over their computing and promoting digital rights. Examples of widely used free software include the Linux kernel, the GNU operating system (e.g., Debian, Fedora, Ubuntu), the Firefox web browser, the LibreOffice suite, and the VLC media player.