Licenses.md

Licenses

• First, some important terms (know them)
  • Free software
    • "Software that can be freely shared and modified, including in source code form"
    • Coined by FSF
    • "Free" ambiguity
      • Acceptable ambiguity to emphasize FREEDOM
  • Open Source
    • Coined by OSI
    • "goal at the time was largely to make such software a more palatable choice for corporations, by presenting it as a development methodology rather than as a political movement."
    • AKA: ...people in ties
  • Other terms:
    • OSS - Open Source Software
    • FOSS - Free/Open Source Software
    • FLOSS - Free/Libre Open Source Software
    • DFSG-Compliant
      • A note about Debian
      • Large amount of work went into definition of criteria
      • You KNOW that it is "free" if compliant
    • OSI-approved
      • Similar concept above
      • List maintained by OSI
    • FSF list
      • "Free" or not
      • Also GPL compatible or not
  • Proprietary or closed source
    • Important distinction
      • IS NOT whether the source can be seen
      • IS a matter of what you can do with the source
    • Proprietary code...
      • May be licensed without source being available
      • May have source available, but NO rights to modify or redistribute
  • Copyleft
    • Open Source that is licensed such that derivatives must also be Open
    • Also called 'viral'
  • Permissive
    • Open Source license that does NOT restrict derivatives
    • Still "free"
• Aspects of licenses
  • Nearly all say...
    • Anyone can modify the code
    • Anyone can redistribute it both in original and modified form
    • The copyright holders and authors provide no warranties whatsoever
  • Differences
    • Compatibility with proprietary licenses
      • Permissive allows incorporating into proprietary works
    • Compatibility with other Free licenses
    • Enforcement of attribution
    • Trademark protection
    • Patent protection
      • Copyrighter includes patent license rights with contribution
      • Litigation initiation also causes LOSS of the patent rights
• The special rights of the copyright holder
  • Copyright doesn't vanish when code is open
  • Copyright still grants "ownership" of your code
    • Giving or sharing the code DOES NOT grant copyright to the recipient
    • Unless your CLA grants copyright to the receiving project as part of your contribution
  • Copyright grants decision rights for distribution
  • Therefore the copyrighter...
    • CAN give the code away AND charge for it
    • CAN distribute under many terms
      • Copyleft license for the general public
      • ...but sell exceptions to paying clients
    • CAN have a free but paid component (freemium)
  • Copyright applies to OTHERS, not the copyrighter
• Quick tour of the popular ones
  • MIT
    • Massachusetts Institute of Technology
    • Permissive license
    • Has several derivatives
    • Derivatives must...
      • Include a copy of the license
      • Provide attribution
  • GPL
    • Created by FSF
    • Copyleft license
    • Has variations
      • AGPL - copyleft applies even to network usage of the code
      • LGPL - copyleft stops at binary linking and including in larger works
    • Derivatives must...
      • Be licensed under GPL
      • Provide attribution
      • Provide code
  • Apache 2
    • Created by ASF
    • Permissive license
    • Similar to MIT, but expressly grants patent rights
    • Derivatives must...
      • Include attribution
  • BSD
    • Created by University of California Berkeley
    • Has some variants and is a "collection" of licenses
      • 2 clause - (most common) Pretty much the same as MIT, but doesn't explicitly allow as much (though it is implicitly allowed)
      • 3 clause - No endorsement by copyright holder
      • 4 clause - Advertisements must acknowledge copyright holder
    • Derivatives must...
      • Include a copy of the license
      • Provide attribution

Resources: https://en.m.wikipedia.org/wiki/Comparison_of_free_and_open-source_software_licenses