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0 Preface
The most common thing people say is that so-and-so is a pseudo-open source, and has been sued for using open source software. What exactly do we mean by open source? In fact, I have heard the following problems from many classmates. Maybe you have been troubled by open source-related issues to some extent. For example, you introduced a component and your leader told you that it cannot be used, and you cannot change other people's code, etc.
- What is a pseudo open source project?
- Why would someone choose to create an open source project but still license it?
- Can our company's projects use open source components under the GPL open source license?
- How are code contributions and copyrights handled in open source projects?
- How to choose the right open source license for your project?
- How to ensure the reliability and security of open source software?
- What types of open source agreements are there?
- How do open source projects protect intellectual property?
- Does the open source license allow commercial use?
- Does the open source license allow modifications to the code?
- How do open source projects get funding?
Today we take these questions to understand the open source agreement.
Overview of open source software
Open source software refers to making the source code of the software public so that anyone can view, modify and distribute the software. Compared with closed source software, open source software has more transparency and flexibility, can stimulate innovation and cooperation, and improve software quality and security.
The importance of open source agreements
The open source agreement is the legal framework that protects open source software and defines the conditions for the use, modification and distribution of the software. They ensure the freedom and sustainability of open source software and provide clear rights and obligations for developers and users. Open source protocols facilitate knowledge sharing and collaboration, encourage innovation, and provide developers with broad community support and contribution opportunities.
In addition, open source agreements help protect software intellectual property and prevent abuse and infringement. By choosing a suitable open source protocol, developers can control how the software is used and distributed, and protect their own rights and interests.
Let’s take a look at Spring’s license description
The Spring framework is licensed under the Apache License 2.0. This license is an open source software license that allows you to freely use, modify and distribute the Spring framework. The Apache License 2.0 also allows you to use the Spring Framework source code and derivative works for commercial purposes. Additionally, under this license, you must also include the original license and disclaimer with your products that use the Spring Framework.
1. Several key concepts of open source protocols
Let’s first understand some key concepts in open source protocols
1. Linking
Link open source software as a library into other software to implement specific functions, call functions, or extend functionality.
2. Modification
Make changes or modifications to the source code of open source software to meet specific needs, improve performance, or fix bugs, etc.
3. Derivative works
New products that are developed or built based on open source software. Derivatives may be formed by adding new functions, modifying core functions, adding plug-ins, etc.
4. Right to access source code
Open source licenses typically require authors to make the source code public so that users can freely view, study, and modify the code.
5. Right to modify source code
Open source licenses give users the right to modify the source code to adapt it to specific needs and improve the software.
6. Right to distribute derivative works
Open source licenses typically allow users to distribute software as derivative works, even if modified, improved, or extended.
7. Obligations of the licensor
Software publishers who follow open source licenses need to meet specific obligations, such as including a copyright notice in the software, retaining the original license, and complying with the conditions of use.
8. Public Domain
Refers to works that are no longer legally protected by copyright and intellectual property rights and can be used, modified and distributed by anyone without restrictions.
2. Detailed explanation of open source protocols
Let’s first look at two pictures to understand it in a simple way.
2.2. GNU General Public License (GPL)
2.1 Background and purpose
The GNU General Public License (GPL) is a widely used open source software license created and maintained by the Free Software Foundation (FSF). Its purpose is to protect user freedom and ensure the freedom and sustainable development of open source software.
2.2 Main features
- Code Sharing: The GPL requires that software licensed under the GPL must be released under the same license and the source code must be publicly available.
- Modification permissions: Users can freely modify and extend GPL-licensed software, and redistribute the modified software.
- Distribution restrictions: If you distribute GPL-licensed software in binary form, you must provide the source code or provide a way to obtain the source code.
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
2.3 Scope and limitations of application
The GPL applies to all parties who use and distribute open source software, including developers, users, and distributors. It ensures that users can freely use, modify and distribute the software, and requires that all copies and modified versions must comply with the provisions of the GPL.
The GPL has some restrictions, including:
- Enforcing the same license: If users use source code or binaries of GPL-licensed software, they must release their own code as GPL-licensed as well.
- Source code availability: If users distribute GPL-licensed software in binary form, they must provide the source code or provide a way to obtain the source code.
2.4 Advantages and Disadvantages
Advantages of the GPL include:
- Freedom: GPL protects users' freedom and ensures that they can freely use, modify and distribute software.
- Community development: GPL encourages cooperation and sharing, promoting the prosperity and development of the community.
- Legal protection: GPL provides clear rights and obligations and protects the rights of developers and users.
Disadvantages of the GPL include:
- Restrictive: GPL requires releases under the same license, which may restrict certain commercial use scenarios.
- Developer obligations: When using GPL-licensed software, developers must disclose source code and modified code, which may cause inconvenience to commercial developers.
2.5 Practical application cases
GPL is widely used in many well-known open source software projects, such as GNU tool chain, Linux operating system, MySQL database, etc. These projects protect the freedom of software through GPL licenses, attract developers and users around the world to participate and contribute code, and promote the development and innovation of the open source community.
2.3. MIT License
3.1 Background and purpose
The MIT license is an open source software license first developed and used by the Massachusetts Institute of Technology. The purpose of this license is to encourage the free use and distribution of the software to promote innovation and knowledge sharing.
3.2 Main features
- Code Sharing: The MIT license allows users to freely use, modify and distribute the source code or binary form of the software.
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
- Disclaimer: The MIT license does not provide any express or implied warranty, and users use the software at their own risk.
3.3 Scope and limitations of application
The MIT license applies to the use and distribution of any software, not just open source software. It allows users to freely use and modify the software without forcing users to release modified software under the same license.
The MIT license has relatively few restrictions, mainly including:
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
- Disclaimer: The MIT license does not provide any express or implied warranty, and users use the software at their own risk.
3.4 Advantages and Disadvantages
Advantages of the MIT license include:
- Flexibility: The MIT license allows users to freely use and modify the software, and does not force users to release modified software under the same license.
- Business-friendly: The MIT license can be used with commercial software and has no restrictions on commercial developers.
Disadvantages of the MIT license include:
- Legal protection: Compared with other licenses, the MIT license has relatively few legal protections and limited protection for the rights and interests of developers and users.
3.5 Practical application cases
The MIT license is widely used in many well-known open source software projects, such as jQuery, Node.js, Ruby on Rails, etc. These projects encourage the free use and distribution of software through the MIT license, attracting developers and users around the world to participate and contribute code, and promote the development and innovation of the open source community.
2.4. Apache License
4.1 Background and purpose
The Apache License is an open source software license developed and promoted by the Apache Software Foundation. The purpose of this license is to promote the innovation and development of open source software while protecting the intellectual property rights of the software and the rights and interests of users.
4.2 Main features
- Code Sharing: The Apache license allows users to freely use, modify and distribute the source code or binary form of the software.
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
- Disclaimer: The Apache license does not provide any express or implied warranties, and you use the software at your own risk.
- Contribution specifications: The Apache license requires that contributors must clearly declare the content of their contributions and comply with the provisions of the license.
4.3 Scope and limitations of application
The Apache license applies to the use and distribution of any software, not just open source software. It allows users to freely use and modify the software without forcing users to release modified software under the same license.
The Apache license has relatively few restrictions, mainly including:
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
- Disclaimer: The Apache license does not provide any express or implied warranties, and you use the software at your own risk.
4.4 Advantages and Disadvantages
Advantages of the Apache license include:
- Flexibility: The Apache license allows users to freely use and modify the software, and does not force users to release modified software under the same license.
- Business Friendly: The Apache license can be used with commercial software and has no restrictions on commercial developers.
- Contribution specifications: The Apache license requires contributors to clearly declare the content of their contributions so that the intellectual property rights of the software are protected.
Disadvantages of the Apache license include:
- Legal protection: Compared with other licenses, the Apache license has relatively few legal protections and limited protection for the rights and interests of developers and users.
4.5 Practical application cases
The Apache license is widely used in many well-known open source software projects, such as Apache HTTP Server, Hadoop, Tomcat, etc. These projects encourage the free use and distribution of software through the Apache license, attracting developers and users around the world to participate and contribute code, and promote the development and innovation of the open source community.
2.5.BSD License
5.1 Background and purpose
The BSD license is an open source software license that was first developed and used by the University of California, Berkeley (UC Berkeley) on its BSD operating system. The purpose of this license is to promote the free use, modification and distribution of the software, while protecting the intellectual property rights of the software and the rights of users.
5.2 Main features
- Code Sharing: The BSD license allows users to freely use, modify and distribute the source code or binary form of the software.
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
- Disclaimer: The BSD license does not provide any express or implied warranty, and users use the software at their own risk.
- Restricted Retention: The BSD license allows users to retain the original author's name and copyright notice in their modified versions.
5.3 Scope and limitations of application
The BSD license applies to the use and distribution of any software, not just open source software. It allows users to freely use and modify the software without forcing users to release modified software under the same license.
The BSD license has relatively few restrictions, mainly including:
- Copyright Notice: All copies and modified versions must contain the original license and copyright notice.
- Disclaimer: The BSD license does not provide any express or implied warranty, and users use the software at their own risk.
- Restricted retention: The BSD license requires users to retain the original author's name and copyright notice in their modified versions.
5.4 Advantages and Disadvantages
Advantages of the BSD license include:
- Flexibility: The BSD license allows users to freely use and modify the software, and does not force users to release modified software under the same license.
- Business Friendly: The BSD license can be used with commercial software and has no restrictions on commercial developers.
- Intellectual property protection: The BSD license requires users to retain the original author's name and copyright statement in their modified versions, which protects the intellectual property of the software.
Disadvantages of the BSD license include:
- Legal protection: Compared with other licenses, the BSD license has relatively few legal protections and limited protection for the rights and interests of developers and users.
5.5 Practical application cases
The BSD license is widely used in many well-known open source software projects, such as FreeBSD, NetBSD, OpenBSD, etc. These projects encourage the free use and distribution of software through the BSD license, attracting developers and users around the world to participate and contribute code, and promote the development and innovation of the open source community.
2.6. Mozilla Public License (MPL)
6.1 Background and purpose
The Mozilla Public License (MPL) is an open source software license created by the Mozilla Foundation to promote free and open software development and protect the rights of original authors.
6.2 Main features
MPL has the following main features:
- Mandatory Copyright Notice: Software licensed under the MPL must contain a copyright notice and license text.
- Source code availability: The MPL requires that all modified code be made publicly available upon release.
- Multiple Licenses: MPL allows software to be released under multiple licenses, including MPL itself, the GNU General Public License (GPL), and the GNU Lesser General Public License (LGPL).
- Compatibility: MPL is compatible with other open source licenses (such as GPL, LGPL).
6.3 Scope and limitations of application
MPL applies to any software project, both commercial and non-commercial. However, if software licensed using the MPL is merged with software licensed under the GPL, then the entire project must be released under the GPL license.
6.4 Advantages and Disadvantages
Advantages of MPL include:
- Protect the rights and interests of original authors: MPL ensures that the copyright and intellectual property rights of original authors are protected.
- Commercial Use Allowed: MPL allows the software to be used and distributed in a commercial environment.
Disadvantages of MPL include:
- Source code availability requirements: MPL requires that all modified code must be made public, which may pose challenges to the confidentiality of commercial projects.
- Restrictions on merging with GPL: If merged with GPL-licensed software, the entire project must be released under a GPL license, restricting some usage scenarios.
6.5 Practical application cases
MPL is widely used in open source software projects, the most famous of which is the Mozilla Firefox browser. Some other projects using MPL include the Mozilla Thunderbird mail client and the SeaMonkey Internet suite. These projects rely on MPL features to protect the rights of original authors and promote free and open software development.