OpenSource
Git (version control)
Git is a distributed version control system created by Linus Torvalds in 2005 for Linux kernel development. It models a repository as a content-addressed object database — blobs, trees, commits, and tags — identified by cryptographic hash.
GitHub
The largest hosted Git repository service, central to open-source collaboration since 2008 and owned by Microsoft since 2018.
Free Software Movement
Social movement launched in 1983 by Richard Stallman with the GNU Project, defining software freedom in terms of four user freedoms and treating proprietary software as an ethical problem. Distinct from the later open-source framing.
Open Source Initiative
Nonprofit founded February 1998 by Eric S. Raymond and Bruce Perens as steward of the Open Source Definition. Promotes open source as a pragmatic development methodology, distinct from the freedom-based framing of the Free Software Movement.
Copyleft
Copyleft is a licensing strategy that uses copyright law to require derivative works to be distributed under the same permissive terms as the original. Coined in the free-software movement and operationalized by the GNU GPL, it has since spread to content licensing through Creative Commons ShareAlike and to databases through the ODbL.
GitHub Repo Without LICENSE File: All Rights Reserved by Default
A public {{GitHub}} repository with no LICENSE file defaults to "all rights reserved" under copyright law. Despite being visible and downloadable, the code is legally not usable for any purpose.
Linus's Law
Aphorism coined by Eric S. Raymond in 1999 stating that 'given enough eyeballs, all bugs are shallow' — the claim that open-source code with many concurrent reviewers catches bugs faster than closed proprietary development. The empirical record is mixed.
The Cathedral and the Bazaar
Eric S. Raymond's 1997 essay (expanded into a 1999 book) contrasting two open-source development styles: the closed, infrequent-release "cathedral" and the open, release-early-release-often "bazaar." It popularized Linus's Law and helped persuade Netscape to open-source its browser, but later drew criticism over Raymond's politics and framing.