The GNU General Public License (GPL) is one of the most widely used free software licenses and plays a pivotal role in the open-source movement. Created by Richard Stallman for the GNU Project, the GPL ensures that software remains free for all users to use, study, share, and modify.
History
- 1985: The Free Software Foundation (FSF) was founded by Richard Stallman to support the free software movement.
- 1989: The first version of the GPL, GPLv1, was released. This version was relatively simple and focused on ensuring that the software could be freely distributed and modified.
- 1991: GPLv2 was introduced, which included more detailed terms to address potential loopholes in the first version, particularly concerning software distribution and patent issues.
- 2007: GPLv3 was published, responding to changes in technology and legal environments, like the rise of software as a service (SaaS) and issues around digital rights management (DRM).
Core Principles
The GPL embodies several key principles:
- Freedom to Run: Users have the freedom to run the program as they wish.
- Freedom to Study: Users can study how the program works and change it to suit their needs.
- Freedom to Share: Users are allowed to redistribute copies of the software to others.
- Freedom to Improve: Users can improve the software and release their improvements to the public.
License Versions
- GPLv1: Focused on basic copyleft provisions.
- GPLv2: Added more protections against proprietary software practices, including a clause to prevent tivoization, which refers to devices running GPL software but preventing users from modifying or replacing the software.
- GPLv3: Addressed issues like patent retaliation, compatibility with other licenses, and the prevention of software patents from restricting user freedoms.
Compatibility
The GPL has different compatibility rules with other licenses:
- GPLv2 software can be combined with software under the MIT License or BSD license, but the resulting work must be licensed under GPLv2.
- GPLv3 has additional compatibility issues due to its more restrictive patent clauses.
Impact
The GPL has significantly influenced the software industry:
- It has been adopted by major projects like Linux Kernel and many others in the GNU Project.
- It has led to debates and discussions on software freedom, licensing, and intellectual property rights.
- It has spurred the creation of alternative licenses and movements, both for and against the principles of the GPL.
External Links
See Also