Open Source Licenses

Summary

Memorize terminology surrounding open source licenses, software, and projects.

Terms

These are very informal descriptions of terms people often use when discussing open source licenses and software. Many licenses and organizations define these terms differently and/or more precisely.

Terms I

Term	Overview
Source	source code - files created by programmers using a programming language
Open Source (software)	source code that can be used, studied, changed, and redistributed
Redistribution	giving software to another party (possibly with modifications)
Fork	project started by modifying another project's source
Shared Source	source can be obtained, but with restrictions
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Terms II

Term	Overview
Free Software	term similar to 'open source'
Proprietary / Closed Source	traditional software with unobtainable source
Copyright	most open source licenses derive their power from copyright law
Copyleft	requires redistributions to be open source
Permissive	permitting most options - usually including proprietary forking
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Acronyms

Question	Answer
OSI	Open Source Initiative
OSD	Open Source Definition
GPL	General Public License
LGPL	Lesser General Public License
GNU	GNU's Not Unix (it's a "recursive" acronym)
FSF	Free Software Foundation
BSD	Berkely Software Distribution
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Projects

Question	Answer
License of Linux	GPL
License of Java	GPL
License of Firefox	Mozilla
License of Apache web server	Apache License
License of BSD Unix	BSD License
Most popular open source license	GPL
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People and Groups

Person/Group	Overview
Linus Torvalds	created Linux
Richard Stallman	created GPL / leader of GNU/FSF
SourceForge	web site that hosts open source projects
GNU/FSF	created the GPL
Open Source Initiative	group which created OSD, and approves open source licenses
Open Source Definition	OSI's detailed definition of open source
Microsoft	advocates Shared Source
Free Software Foundation	group affiliated with GNU
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Licenses

Question	Answer
GPL	Popular copyleft license
LGPL	Like LGPL but allows linking with proprietary apps
X11 License	Very simple permissive license (also called "MIT License")
BSD license	Permissive license
Apache License	Permissive license
Mozilla Public License	Permissive license
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