GPLv2

GPLv2. The GNU General Public License version 2 is a widely used free software license created by the Free Software Foundation. First published in 1991, it legally enforces the copyleft principle, ensuring that modified versions of software remain free and open. It succeeded the original GNU General Public License and became the cornerstone license for projects like the Linux kernel and the GNU Compiler Collection.

History and development

The license was drafted by Richard Stallman with legal counsel from Eben Moglen, building upon the framework of the first version released for the GNU Project. Its development was influenced by the earlier GNU Emacs General Public License and sought to address perceived ambiguities. The release coincided with the growing popularity of Unix-like operating systems and the need for a robust legal instrument to protect communal software development. Key figures in the free software movement advocated for its adoption to counter the proliferation of proprietary software licenses from corporations like IBM and Microsoft.

Terms and conditions

The license grants recipients the freedoms to run, study, share, and modify the software. Core requirements mandate that any distributed modified versions must be licensed under the same terms, a condition central to its strong copyleft nature. It includes provisions for distributing source code alongside binaries and addresses scenarios like linking with libraries. Specific clauses, such as the "liberty or death" clause, prevent the imposition of additional restrictions that would conflict with the license's core freedoms. The text also contains explicit disclaimers of warranty, notably the "as is" clause, protecting original authors from liability.

Compatibility with other licenses

Compatibility with other free software licenses is a complex issue. It is generally incompatible with many permissive software licenses, such as the Apache License and the BSD licenses, because their terms do not include the same copyleft requirements. However, it is compatible with some licenses like the GNU Lesser General Public License. The Free Software Foundation maintains detailed compatibility lists, and the incompatibility with the Apache License 2.0 was a primary reason for drafting the subsequent GNU General Public License version 3. Projects like the Linux kernel have explicitly rejected moving to the newer version partly due to these compatibility concerns.

Impact and adoption

Its adoption was monumental, becoming the default license for the Linux kernel under the stewardship of Linus Torvalds and for core components of the GNU operating system. This helped fuel the rise of open-source software and commercial distributions from companies like Red Hat and SUSE. The license facilitated the development of the LAMP stack and underpinned major projects like MySQL before its acquisition by Oracle Corporation. Its legal framework supported the business models of many technology companies and was integral to the success of the Debian project and its Debian Free Software Guidelines.

Legal interpretation and enforcement

Enforcement has been led primarily by the Free Software Foundation and later by organizations like the Software Freedom Law Center. Landmark legal cases, such as those involving MySQL AB and disputes over the BusyBox tool, have tested its provisions in courts in Germany and the United States. The interpretation of key terms, like what constitutes a "derivative work" or the scope of the "system library" exception, has been the subject of significant analysis by lawyers like Lawrence Rosen. These cases have shaped how corporations like Google and IBM interact with licensed software, particularly regarding the use of code in the Android operating system. Category:Free software licenses Category:GNU Project Category:1991 software