The open source movement can be traced back to the hacker culture in the ’60s and ’70s. In the early 1980s, the tenet of free software for sharing was explicitly raised by Richard Stallman, who was working on developing software systems and invited others to share, contribute, and give back to the community of cooperative hackers. Stallman, together with other volunteers, established the Free Software Foundation to host GNU (Gnu’s Not Unix, a set of UNIX-compatible software system). Eric Raymond, Stallman’s collaborator, is the primary founder of the Open Source Initiative. Both communities are considered the principal drivers of open source movement.