Revision sheet: Understanding Software Licensing and Open Source

📋 Course Outline

1. Copyright basics and proprietary software model
2. License categories and spectrum from permissive to strong copyleft
3. Characteristics and effects of GPL and MIT licenses
4. Real-world license case studies and compatibility challenges

📖 1. Copyright basics and proprietary software model

🔑 Key Concepts & Definitions

• 2 Copyright : A legal right automatically granted upon software creation that gives the author exclusive control over use, copying, and modification.
• **Version)
• Automatic** : A specific release or iteration of software that may be subject to licensing terms.
• Condition : Modified versions must use same license 4.
• Result : Freedom is ”inherited” by all future versions!

📝 Essential Points

• Copyright is automatic upon software creation, granting exclusive rights to the author by default as 'All Rights Reserved'.
• Proprietary software licenses allow use but do not grant ownership or rights to share the software.
• Copyleft uses copyright law to grant rights with the condition that modified versions must use the same license, ensuring freedom is inherited by all future versions.
• Author User 1 User 2 License + Condition Same Condition Original Code Modified Code Further Modified 4 License Categories The License Spectrum Public Domain (No restrictions) Permissive (MIT, Apache) Weak Copyleft (MPL, LGPL) Strong Copyleft (GPL) Max Freedom for User Max Protection of Code Permissive
• ”Do what you want”
• Can make proprietary versions
• Example: iOS uses BSD code Copyleft

💡 Key Takeaway

Copyright is automatic upon software creation, granting exclusive rights to the author by default as 'All Rights Reserved'.

📖 2. License categories and spectrum from permissive to strong copyleft

🔑 Key Concepts & Definitions

• Answer : The purpose of licensing is to protect the user’s freedom from being taken away.
• License Spectrum : A range of license categories from no restrictions to strict copyleft, representing levels from maximum user freedom to maximum code protection.

📝 Essential Points

• License categories range from Public Domain (no restrictions) through Permissive (e.g., MIT, Apache), Weak Copyleft (e.g., MPL, LGPL), to Strong Copyleft (e.g., GPL).
• Permissive licenses allow users to do almost anything including making proprietary versions.
• Copyleft licenses require derivative works to remain open source, protecting code freedom.
• Weak copyleft licenses apply copyleft conditions at a file level, allowing proprietary extensions.
• Strong copyleft licenses impose the strictest conditions, requiring entire derivative works to adopt the same license.

💡 Key Takeaway

License categories range from Public Domain (no restrictions) through Permissive (e.g., MIT, Apache), Weak Copyleft (e.g., MPL, LGPL), to Strong Copyleft (e.g., GPL).

📖 3. Characteristics and effects of GPL and MIT licenses

🔑 Key Concepts & Definitions

• Math Library : A software component used for mathematical computations, licensed under GPL v3, which requires source code disclosure and that derivative works also be licensed under GPL.
• MIT License : A permissive software license that allows commercial use, modification without sharing, and creation of proprietary versions, with minimal obligations limited to including the license text and copyright notice.

📝 Essential Points

• GPL is a strong copyleft license requiring source code disclosure when distributing binaries and that derivative works must also be GPL.
• The 'viral' effect of GPL means that using GPL code forces the entire project to adopt GPL, which can deter some companies.
• MIT License is widely adopted for easy adoption and minimal legal concerns, used in projects like Node.js and Ruby on Rails.
• ” You Can:
  • Use commercially
  • Modify without sharing
  • Make proprietary versions You Must:
  • Include license text
  • Include copyright notice
  • That’s it!
• MIT License Allow Proprietary?

💡 Key Takeaway

Contrasting the strict copyleft nature of GPL with the permissive freedom of MIT helps understand their practical impacts.

📖 4. Real-world license case studies and compatibility challenges

🔑 Key Concepts & Definitions

• Mozilla Public License (MPL) : A file-level copyleft license allowing proprietary files alongside MPL-licensed files, enabling hybrid development.
• Real world : Practical examples of license use and challenges in software development and distribution.
• License Compatibility Exercise Scenario : Building an aircraft monitoring system.

📝 Essential Points

• Linux Kernel under GPL v2 has over 30,000 developers, used in 96.3% of web servers, with contributions from IBM and Google.
• VLC changed licenses from GPL v2 to GPL v2+ and LGPL to overcome library restrictions and App Store issues.
• MPL's file-level copyleft allows proprietary files to coexist with MPL files, enabling hybrid open source and proprietary development.
• GPL v3 'infects' projects, preventing proprietary combination with GPL v3 components, requiring alternatives like LGPL or open sourcing.
• License compatibility issues can prevent combining components under different licenses while keeping code proprietary, as in the aircraft monitoring system example.

💡 Key Takeaway

Learning from examples shows how license choices impact software development, distribution, and compatibility.

🧩 Additional Source Details

1. Study this source detail: and Open Source Software Chapter 2: Legal Framework and Licenses Dr. Mohamed Lichouri [email protected] 1st Year Aeronautics - Semester 2 Week 3-4 University of Blida 1 Institute of Aeronautics and Space Stu (Source: "and Open Source Software Chapter 2: Legal Framework and Licenses Dr. Mohamed Lichouri [email protected] 1st Year Aeronautics - Semester 2 Week 3-4 University of Blida 1 Institute of Aeronautics and Space Studies Copyright vs. Copyleft From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project")
2. Study this source detail: Framework and Licenses Dr. Mohamed Lichouri [email protected] 1st Year Aeronautics - Semester 2 Week 3-4 University of Blida 1 Institute of Aeronautics and Space Studies Copyright vs. Copyleft From Chapter 1 (Source: "Framework and Licenses Dr. Mohamed Lichouri [email protected] 1st Year Aeronautics - Semester 2 Week 3-4 University of Blida 1 Institute of Aeronautics and Space Studies Copyright vs. Copyleft From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter")
3. Study this source detail: 1 Institute of Aeronautics and Space Studies Copyright vs. Copyleft From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter (Source: "1 Institute of Aeronautics and Space Studies Copyright vs. Copyleft From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need")
4. Study this source detail: • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers (Source: "• 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? 2 From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live")
5. Study this source detail: vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? 2 From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live (Source: "vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? 2 From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,”")
6. Study this source detail: Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why (Source: "Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? Answer: To protect the user’s freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What")
7. Study this source detail: of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? Answer: To protect the user’s freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What is (Source: "of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? Answer: To protect the user’s freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify")
8. Study this source detail: freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify w (Source: "freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”All Rights Reserved” = No rights for others Proprietary Model ƞ All Rights Reserved • You buy a license to")
9. Study this source detail: you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”All Rights Reserved” = No rights for others Proprietary Model ƞ All Rights Reserved • You buy a license t (Source: "you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”All Rights Reserved” = No rights for others Proprietary Model ƞ All Rights Reserved • You buy a license to use • You don’t own the software • Cannot share with friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” The")
10. Study this source detail: No rights for others Proprietary Model ƞ All Rights Reserved • You buy a license to use • You don’t own the software • Cannot share with friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” Th (Source: "No rights for others Proprietary Model ƞ All Rights Reserved • You buy a license to use • You don’t own the software • Cannot share with friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” The Clever Hack Copyleft uses copyright law to ensure freedom, not restrict it. How it works: 1. Author owns copyright (as usual) 2. Author")
11. Study this source detail: friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” The Clever Hack Copyleft uses copyright law to ensure freedom, not restrict it. How it works: 1. Author owns copyright (as usual) 2. Author (Source: "friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” The Clever Hack Copyleft uses copyright law to ensure freedom, not restrict it. How it works: 1. Author owns copyright (as usual) 2. Author grants rights via license with condition 3. Condition: Modified versions must use same license 4. Result: Freedom is ”inherited” by all")
12. Study this source detail: freedom, not restrict it. How it works: 1. Author owns copyright (as usual) 2. Author grants rights via license with condition 3. Condition: Modified versions must use same license 4. Result: Freedom is ”inherited” by al (Source: "freedom, not restrict it. How it works: 1. Author owns copyright (as usual) 2. Author grants rights via license with condition 3. Condition: Modified versions must use same license 4. Result: Freedom is ”inherited” by all future versions! Author User 1 User 2 License + Condition Same Condition Original Code Modified Code Further Modified 4 License")
13. Study this source detail: Modified versions must use same license 4. Result: Freedom is ”inherited” by all future versions! Author User 1 User 2 License + Condition Same Condition Original Code Modified Code Further Modified 4 License Categories (Source: "Modified versions must use same license 4. Result: Freedom is ”inherited” by all future versions! Author User 1 User 2 License + Condition Same Condition Original Code Modified Code Further Modified 4 License Categories The License Spectrum Public Domain (No restrictions) Permissive (MIT, Apache) Weak Copyleft (MPL, LGPL) Strong Copyleft (GPL) Max")
14. Study this source detail: Permissive (MIT, Apache) Weak Copyleft (MPL, LGPL) Strong Copyleft (GPL) Max Freedom for User Max Protection of Code Permissive • ”Do what you want” • Can make proprietary versions • Example: iOS uses BSD code Copyleft • (Source: "Permissive (MIT, Apache) Weak Copyleft (MPL, LGPL) Strong Copyleft (GPL) Max Freedom for User Max Protection of Code Permissive • ”Do what you want” • Can make proprietary versions • Example: iOS uses BSD code Copyleft • ”Share and share alike” • Must stay open source • Example: Android uses Linux 5 Major License Types The GPL: GNU General Public")
15. Study this source detail: what you want” • Can make proprietary versions • Example: iOS uses BSD code Copyleft • ”Share and share alike” • Must stay open source • Example: Android uses Linux 5 Major License Types The GPL: GNU General Public Licen (Source: "what you want” • Can make proprietary versions • Example: iOS uses BSD code Copyleft • ”Share and share alike” • Must stay open source • Example: Android uses Linux 5 Major License Types The GPL: GNU General Public License Characteristics: • Strong Copyleft (most restrictive) • Created by Richard Stallman (1989) • Key Rule: Distribute binaries → Provide")
16. Study this source detail: Example: Android uses Linux 5 Major License Types The GPL: GNU General Public License Characteristics: • Strong Copyleft (most restrictive) • Created by Richard Stallman (1989) • Key Rule: Distribute binaries → Provide s (Source: "Example: Android uses Linux 5 Major License Types The GPL: GNU General Public License Characteristics: • Strong Copyleft (most restrictive) • Created by Richard Stallman (1989) • Key Rule: Distribute binaries → Provide source • Derivative works: Must also be GPL Famous GPL Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code,")
17. Study this source detail: • Created by Richard Stallman (1989) • Key Rule: Distribute binaries → Provide source • Derivative works: Must also be GPL Famous GPL Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code, y (Source: "• Created by Richard Stallman (1989) • Key Rule: Distribute binaries → Provide source • Derivative works: Must also be GPL Famous GPL Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code, your entire project must become GPL. Protects freedom, scares some companies. Compatibility GPL code cannot mix with Apache 2.0 code. 6")
18. Study this source detail: Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code, your entire project must become GPL. Protects freedom, scares some companies. Compatibility GPL code cannot mix with Apache 2.0 code. 6 (Source: "Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code, your entire project must become GPL. Protects freedom, scares some companies. Compatibility GPL code cannot mix with Apache 2.0 code. 6 The MIT License: Ultimate Freedom The MIT License (1 paragraph only!): MIT License Text (Abridged) ”Permission is hereby granted... to")
19. Study this source detail: scares some companies. Compatibility GPL code cannot mix with Apache 2.0 code. 6 The MIT License: Ultimate Freedom The MIT License (1 paragraph only!): MIT License Text (Abridged) ”Permission is hereby granted... to use, (Source: "scares some companies. Compatibility GPL code cannot mix with Apache 2.0 code. 6 The MIT License: Ultimate Freedom The MIT License (1 paragraph only!): MIT License Text (Abridged) ”Permission is hereby granted... to use, copy, modify, merge, publish, distribute... subject to the condition: The above copyright notice... shall be included in all")
20. Study this source detail: paragraph only!): MIT License Text (Abridged) ”Permission is hereby granted... to use, copy, modify, merge, publish, distribute... subject to the condition: The above copyright notice... shall be included in all copies.. (Source: "paragraph only!): MIT License Text (Abridged) ”Permission is hereby granted... to use, copy, modify, merge, publish, distribute... subject to the condition: The above copyright notice... shall be included in all copies...” You Can: • Use commercially • Modify without sharing • Make proprietary versions You Must: • Include license text • Include copyright")
21. Study this source detail: to the condition: The above copyright notice... shall be included in all copies...” You Can: • Use commercially • Modify without sharing • Make proprietary versions You Must: • Include license text • Include copyright no (Source: "to the condition: The above copyright notice... shall be included in all copies...” You Can: • Use commercially • Modify without sharing • Make proprietary versions You Must: • Include license text • Include copyright notice • That’s it! Examples: Node.js, Ruby on Rails, jQuery 7 License Comparison Matrix Feature MIT Apache 2.0 LGPL GPL v3 Requires")
22. Study this source detail: • Make proprietary versions You Must: • Include license text • Include copyright notice • That’s it! Examples: Node.js, Ruby on Rails, jQuery 7 License Comparison Matrix Feature MIT Apache 2.0 LGPL GPL v3 Requires Source (Source: "• Make proprietary versions You Must: • Include license text • Include copyright notice • That’s it! Examples: Node.js, Ruby on Rails, jQuery 7 License Comparison Matrix Feature MIT Apache 2.0 LGPL GPL v3 Requires Source Disclosure o o Partial n Allows Commercial Use n n n n Allows Private Changes n n n n Requires Same License o o For mods only n")
23. Study this source detail: jQuery 7 License Comparison Matrix Feature MIT Apache 2.0 LGPL GPL v3 Requires Source Disclosure o o Partial n Allows Commercial Use n n n n Allows Private Changes n n n n Requires Same License o o For mods only n Patent (Source: "jQuery 7 License Comparison Matrix Feature MIT Apache 2.0 LGPL GPL v3 Requires Source Disclosure o o Partial n Allows Commercial Use n n n n Allows Private Changes n n n n Requires Same License o o For mods only n Patent Grant Included o n n n Can Link with Proprietary n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice:")
24. Study this source detail: n n n Allows Private Changes n n n n Requires Same License o o For mods only n Patent Grant Included o n n n Can Link with Proprietary n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice: (Source: "n n n Allows Private Changes n n n n Requires Same License o o For mods only n Patent Grant Included o n n n Can Link with Proprietary n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice: GPL Protects contributions from exploitation 8 Real World Cases Case Study 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+")
25. Study this source detail: n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice: GPL Protects contributions from exploitation 8 Real World Cases Case Study 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+ d (Source: "n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice: GPL Protects contributions from exploitation 8 Real World Cases Case Study 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+ developers since 1991 • Used in 96.3% of web servers • Android is based on Linux • TVs, cars, space stations use it The GPL v2 Effect: •")
26. Study this source detail: World Cases Case Study 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+ developers since 1991 • Used in 96.3% of web servers • Android is based on Linux • TVs, cars, space stations use it The GPL v2 Effect: • Co (Source: "World Cases Case Study 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+ developers since 1991 • Used in 96.3% of web servers • Android is based on Linux • TVs, cars, space stations use it The GPL v2 Effect: • Companies must contribute back • IBM, Intel, Google all contribute • Code stays free forever The Tivoization Debate Tivo used Linux but")
27. Study this source detail: Android is based on Linux • TVs, cars, space stations use it The GPL v2 Effect: • Companies must contribute back • IBM, Intel, Google all contribute • Code stays free forever The Tivoization Debate Tivo used Linux but lo (Source: "Android is based on Linux • TVs, cars, space stations use it The GPL v2 Effect: • Companies must contribute back • IBM, Intel, Google all contribute • Code stays free forever The Tivoization Debate Tivo used Linux but locked hardware → GPL v3 created to prevent this (but Linux stayed v2!) Valuation Estimated value: $15 billion+ Dev cost if built by one")
28. Study this source detail: contribute \bullet{} Code stays free forever The Tivoization Debate Tivo used Linux but locked hardware → GPL v3 created to prevent this (but Linux stayed v2!) Valuation Estimated value: $15 billion+ Dev cost if built by one com _(Source: "contribute • Code stays free forever The Tivoization Debate Tivo used Linux but locked hardware → GPL v3 created to prevent this (but Linux stayed v2!) Valuation Estimated value:$15 billion+ Dev cost if built by one company: $15B+ 9 Case Study 2: VLC Media Player VLC’s License Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries •")_
29. Study this source detail: stayed v2!) Valuation Estimated value: $15 billion+ Dev cost if built by one company:$15B+ 9 Case Study 2: VLC Media Player VLC’s License Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries • 200 (Source: "stayed v2!) Valuation Estimated value: $15 billion+ Dev cost if built by one company:$15B+ 9 Case Study 2: VLC Media Player VLC’s License Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries • 2007: Changed to GPL v2+ • 2015: Parts moved to LGPL Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS")
30. Study this source detail: Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries • 2007: Changed to GPL v2+ • 2015: Parts moved to LGPL Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS version • (Source: "Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries • 2007: Changed to GPL v2+ • 2015: Parts moved to LGPL Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS version • Shows license evolution ￿ VLC ”Plays everything” Fun Fact VLC cone is based on traffic cones collected by students at École Centrale")
31. Study this source detail: Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS version • Shows license evolution ￿ VLC ”Plays everything” Fun Fact VLC cone is based on traffic cones collected by students at École Central (Source: "Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS version • Shows license evolution ￿ VLC ”Plays everything” Fun Fact VLC cone is based on traffic cones collected by students at École Centrale Paris! 10 Case Study 3: Firefox (MPL) Mozilla Public License (MPL): • File-level copyleft: Each file stays free, new files can be")
32. Study this source detail: Fun Fact VLC cone is based on traffic cones collected by students at École Centrale Paris! 10 Case Study 3: Firefox (MPL) Mozilla Public License (MPL): • File-level copyleft: Each file stays free, new files can be propri (Source: "Fun Fact VLC cone is based on traffic cones collected by students at École Centrale Paris! 10 Case Study 3: Firefox (MPL) Mozilla Public License (MPL): • File-level copyleft: Each file stays free, new files can be proprietary • Hybrid approach: Between GPL and MIT • Business friendly: Can extend without ”infecting” whole codebase How MPL Works • You use")
33. Study this source detail: License (MPL): • File-level copyleft: Each file stays free, new files can be proprietary • Hybrid approach: Between GPL and MIT • Business friendly: Can extend without ”infecting” whole codebase How MPL Works • You use f (Source: "License (MPL): • File-level copyleft: Each file stays free, new files can be proprietary • Hybrid approach: Between GPL and MIT • Business friendly: Can extend without ”infecting” whole codebase How MPL Works • You use firefox_engine.js (MPL) • You create my_plugin.js (Proprietary) → OK! • But firefox_engine.js must stay MPL FIREFOX-BROWSER Firefox 11")
34. Study this source detail: friendly: Can extend without ”infecting” whole codebase How MPL Works • You use firefox_engine.js (MPL) • You create my_plugin.js (Proprietary) → OK! • But firefox_engine.js must stay MPL FIREFOX-BROWSER Firefox 11 Licen (Source: "friendly: Can extend without ”infecting” whole codebase How MPL Works • You use firefox_engine.js (MPL) • You create my_plugin.js (Proprietary) → OK! • But firefox_engine.js must stay MPL FIREFOX-BROWSER Firefox 11 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 •")
35. Study this source detail: → OK! • But firefox_engine.js must stay MPL FIREFOX-BROWSER Firefox 11 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine (Source: "→ OK! • But firefox_engine.js must stay MPL FIREFOX-BROWSER Firefox 11 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12")
36. Study this source detail: aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12 (Source: "aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 •")
37. Study this source detail: BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engi (Source: "BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? Answer")
38. Study this source detail: BSD-3 Question: Can you combine these and keep your code proprietary? Answer NO! GPL v3 ”infects” your project. Solutions: 1. Use LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choos (Source: "BSD-3 Question: Can you combine these and keep your code proprietary? Answer NO! GPL v3 ”infects” your project. Solutions: 1. Use LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3")
39. Study this source detail: LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3 BSD (Source: "LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL")
40. Study this source detail: Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free (Source: "Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You")
41. Study this source detail: 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You modi (Source: "1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original")
42. Study this source detail: original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original au (Source: "original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your")
43. Study this source detail: do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your (Source: "do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back?")
44. Study this source detail: source distribution) 14 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GP (Source: "source distribution) 14 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected]")
45. Study this source detail: MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyle (Source: "MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure freedom, not to restrict it.” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating")
46. Study this source detail: 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyleft u (Source: "15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure freedom, not to restrict it.” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating Systems")
47. Study this source detail: Copyleft From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MI (Source: "Copyleft From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers")
48. Study this source detail: o we need lawyers? Answer: To protect the user’s freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create (Source: "o we need lawyers? Answer: To protect the user’s freedom from being taken away! 2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create")
49. Study this source detail: 2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”A (Source: "2 Copyright: The Default ”All Rights Reserved” What is Copyright? (Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”All Rights Reserved” = No rights for others Proprietary Model")
50. Study this source detail: • You don’t own the software • Cannot share with friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” The Clever Hack Copyleft uses copyright law to ensure freedom, not (Source: "• You don’t own the software • Cannot share with friend Copyright Symbol ƞ All Rights Reserved 3 Copyleft: ”Some Rights Reserved” The Clever Hack Copyleft uses copyright law to ensure freedom, not")
51. Study this source detail: Author owns copyright (as usual) 2. Author grants rights via license with condition 3. Condition: Modified versions must use same license 4. Result: Freedom is ”inherited” by all future versions! Author User 1 User 2 Lic (Source: "Author owns copyright (as usual) 2. Author grants rights via license with condition 3. Condition: Modified versions must use same license 4. Result: Freedom is ”inherited” by all future versions! Author User 1 User 2 License + Condition Same Condition Original Code Modified Code Further Modified 4 License Categories The License Spectrum Public Domain (No...")
52. Study this source detail: Share and share alike” • Must stay open source • Example: Android uses Linux 5 Major License Types The GPL: GNU General Public License Characteristics: • Strong Copyleft (most restrictive) • Created by (Source: "Share and share alike” • Must stay open source • Example: Android uses Linux 5 Major License Types The GPL: GNU General Public License Characteristics: • Strong Copyleft (most restrictive) • Created by")
53. Study this source detail: hard Stallman (1989) • Key Rule: Distribute binaries → Provide source • Derivative works: Must also be GPL Famous GPL Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code, (Source: "hard Stallman (1989) • Key Rule: Distribute binaries → Provide source • Derivative works: Must also be GPL Famous GPL Projects: • Linux Kernel (GPL v2) • GCC, Git The ”Viral” Effect If you use GPL code,")
54. Study this source detail: 6 The MIT License: Ultimate Freedom The MIT License (1 paragraph only (Source: "6 The MIT License: Ultimate Freedom The MIT License (1 paragraph only")
55. Study this source detail: subject to the condition: The above copyright notice. (Source: "subject to the condition: The above copyright notice.")
56. Study this source detail: ant Included o n n n Can Link with Proprietary n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice: GPL Protects contributions from exploitation 8 Real World Cases Case (Source: "ant Included o n n n Can Link with Proprietary n n n o Business Choice: MIT/Apache Easy adoption, no legal worries Community Choice: GPL Protects contributions from exploitation 8 Real World Cases Case")
57. Study this source detail: dy 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+ developers since 1991 • Used in 96. (Source: "dy 1: The Linux Kernel (GPL v2) The Success Story: • 30,000+ developers since 1991 • Used in 96.")
58. Study this source detail: es must contribute back • IBM, Intel, Google all contribute • Code stays free forever The Tivoization Debate Tivo used Linux but locked hardware → GPL v3 created to prevent this (but Linux stayed v2! (Source: "es must contribute back • IBM, Intel, Google all contribute • Code stays free forever The Tivoization Debate Tivo used Linux but locked hardware → GPL v3 created to prevent this (but Linux stayed v2!")
59. Study this source detail: 2007: Changed to GPL v2+ (Source: "2007: Changed to GPL v2+")
60. Study this source detail: 2015: Parts moved to LGPL Why This Matters: (Source: "2015: Parts moved to LGPL Why This Matters:")
61. Study this source detail: 10 Case Study 3: Firefox (MPL) Mozilla Public License (MPL): • File-level copyleft: Each file stays free, new files can be proprietary • Hybrid approach: Between GPL and MIT • Business friendly: Can extend without ”infec (Source: "10 Case Study 3: Firefox (MPL) Mozilla Public License (MPL): • File-level copyleft: Each file stays free, new files can be proprietary • Hybrid approach: Between GPL and MIT • Business friendly: Can extend without ”infecting” whole codebase How MPL Works • You use fi")
62. Study this source detail: Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2 (Source: "Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2")
63. Study this source detail: 0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 (Source: "0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring system. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Net")
64. Study this source detail: 3. Open source your project 12 Flowchart: Choosing Your License Creating Software (Source: "3. Open source your project 12 Flowchart: Choosing Your License Creating Software")
65. Study this source detail: A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, (Source: "A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source d...")
66. Study this source detail: A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your code (Source: "A) Nothing, GPL is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A)...")
67. Study this source detail: A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back (Source: "A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back")
68. Study this source detail: ons? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure freedom, not to restrict it.” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating Systems (Source: "ons? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure freedom, not to restrict it.” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating Systems")
69. Study this source detail: A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions (Source: "A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions")
70. Study this source detail: 3. Condition: Modified versions must use same license 4 (Source: "3. Condition: Modified versions must use same license 4")
71. Study this source detail: A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri lichouri_m (Source: "A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure")
72. Study this source detail: A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure freedom, not to restrict it.” — Free Software Foundat (Source: "A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 Questions? Dr. Mohamed Lichouri [email protected] ”Copyleft uses copyright law to ensure freedom, not to restrict it.” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating Systems 15")
73. Study this source detail: Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Q (Source: "Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache 2.0 Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it. What")
74. Study this source detail: B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your code without giving back? A) (Source: "B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license a")
75. Study this source detail: 0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? Answer NO! GPL v3 ”infects” your project. Solutions: 1. Use LGPL math library 2. Replace GPL component 3. Open source your project 12 (Source: "0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? Answer NO! GPL v3 ”infects” your project. Solutions: 1. Use LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent C")
76. Study this source detail: GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it (Source: "GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it")
77. Study this source detail: 1. Author owns copyright (as usual) 2 (Source: "1. Author owns copyright (as usual) 2")
78. Study this source detail: Open source your project 12 Flowchart: Choosing Your License Creating Software (Source: "Open source your project 12 Flowchart: Choosing Your License Creating Software")
79. Study this source detail: 12 License Compatibility Exercise Scenario: Building an aircraft monitoring system (Source: "12 License Compatibility Exercise Scenario: Building an aircraft monitoring system")
80. Study this source detail: 2 From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Rea (Source: "2 From Chapter 1 to Chapter 2 Chapter 1 Recap • Free Software = Liberty • 4 Essential Freedoms • GNU Project history • Installed Live Linux on USB Chapter 2 Focus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers")
81. Study this source detail: 2 Copyright: The Default ”All Rights Reserved” What is Copyright (Source: "2 Copyright: The Default ”All Rights Reserved” What is Copyright")
82. Study this source detail: Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is (Source: "Community Contributions? MIT License Allow Proprietary? GPL v3 BSD/MIT Yes No No Yes No Yes 13 Knowledge Check Question 1: You modify a GPL program and distribute it. What must you do? A) Nothing, GPL is")
83. Study this source detail: without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15 (Source: "without giving back? A) GPL v3 B) LGPL C) MIT D) MPL 15 Question 2: Which license allows Apple to sell your code without giving back? A) GPL v3 B) LGPL C) MIT D) MPL Answer: C (MIT is permissive) 15")
84. Study this source detail: Answer: To protect the user’s freedom from being taken away (Source: "Answer: To protect the user’s freedom from being taken away")
85. Study this source detail: (Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”All Rights Reserved” = No rights for others Proprietary Model ƞ All (Source: "(Non-Legal Version) • Automatic: When you create software, you own it immediately • Exclusive: Nobody can use/copy/modify without permission • Default: ”All Rights Reserved” = No rights for others Proprietary Model ƞ All Rights Reserved • You buy a license to use • You don’t own the software • Cannot share with friend Copyright Symbol ƞ All Rights Reserve...")
86. Study this source detail: cus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers? (Source: "cus • Copyright basics • Types of licenses • GPL vs MIT • Real world analysis Question: If software is ”free,” why do we need lawyers?")
87. Study this source detail: ! GPL v3 ”infects” your project. Solutions: 1. Use LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache (Source: "! GPL v3 ”infects” your project. Solutions: 1. Use LGPL math library 2. Replace GPL component 3. Open source your project 12 Flowchart: Choosing Your License Creating Software? Patent Concerns? Apache")
88. Study this source detail: ation Estimated value: $15 billion+ Dev cost if built by one company:$15B+ 9 Case Study 2: VLC Media Player VLC’s License Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries • (Source: "ation Estimated value: $15 billion+ Dev cost if built by one company:$15B+ 9 Case Study 2: VLC Media Player VLC’s License Journey: • Started: GPL v2 (2001) • Problem: Couldn’t use certain libraries •")
89. Study this source detail: : Changed to GPL v2+ • 2015: Parts moved to LGPL Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS version • Shows license evolution ￿ VLC ”Plays everything” Fun Fact VLC (Source: ": Changed to GPL v2+ • 2015: Parts moved to LGPL Why This Matters: • Apple App Store: Initially rejected GPL • LGPL allowed iOS version • Shows license evolution ￿ VLC ”Plays everything” Fun Fact VLC")
90. Study this source detail: Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring (Source: "Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? 12 License Compatibility Exercise Scenario: Building an aircraft monitoring")
91. Study this source detail: ystem. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? Answer (Source: "ystem. Components You Want to Use: • Math Library: GPL v3 • Graphics Engine: MIT License • Database: Apache 2.0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? Answer")
92. Study this source detail: 0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary? (Source: "0 • Networking: BSD-3 Question: Can you combine these and keep your code proprietary?")
93. Study this source detail: ree B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it. (Source: "ree B) Provide source code to customers C) Pay the original author D) Only use it for education 14 Knowledge Check Question 1: You modify a GPL program and distribute it.")
94. Study this source detail: is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your (Source: "is free B) Provide source code to customers C) Pay the original author D) Only use it for education Answer: B (GPL requires source distribution) 14 Question 2: Which license allows Apple to sell your")
95. Study this source detail: ” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating Systems 15 (Source: "” — Free Software Foundation Next Week: Chapter 3 - GNU/Linux Operating Systems 15")
96. Copyright is automatic: When you create software, you own it immediately (Source: "Automatic: When you create software, you own it immediately")

📅 Key Dates

Date	Event
1989	GPL License Introduction
1991	MIT License Adoption
2001	GPL v3 Draft
2007	GPL v3 Release
2015	VLC License Change

📊 Synthesis Tables

License Spectrum Comparison

Category	Characteristics	Examples
Public Domain	No restrictions	None
Permissive	Minimal restrictions, allows proprietary use	MIT, BSD, Apache
Weak Copyleft	File-level copyleft, some restrictions	MPL, LGPL
Strong Copyleft	Project-wide copyleft, restrictions on modifications	GPL

⚠️ Common Pitfalls & Confusions

1. Confusing proprietary licenses with open source licenses
2. Misunderstanding copyleft requirements for derivative works
3. Assuming all licenses are compatible without verification
4. Overlooking license obligations when combining code from different licenses
5. Ignoring license evolution and changes over time
6. Misinterpreting the viral nature of GPL as a restriction rather than a protection of freedoms
7. Underestimating the importance of license compatibility in projects

✅ Exam Checklist

1. Understand the difference between proprietary and open source licenses
2. Identify the license category of a given software
3. Recognize the implications of copyleft licenses on derivative works
4. Compare permissive and copyleft licenses in terms of restrictions and freedoms
5. Analyze real-world case studies for license compatibility issues
6. Evaluate the impact of license choice on software distribution
7. Understand license evolution and its effects on projects
8. Assess license obligations when integrating multiple licensed components
9. Learn the characteristics and effects of GPL and MIT licenses