First, the introduction of open source agreement
1.1 Introduction to Apache Licene 2.0 protocol
Apache Licence protocol is well-known non-profit organization open source Apache used. The agreement is similar to BSD and also encourage code sharing and respect the original author copyright, also allows code changes, then released (as open source or commercial software). Conditions need to be met and BSD also similar:
1, need to give the user a code Apache Licence
2, if you modify the code, a description of the modified files.
3, extending in the code (and code modification of source code derived) requires agreement with the original code, trademarks, instructions and other patent statement contained in the original OF predetermined required.
4, if re-released product contains a Notice document, the document required in the Notice with Apache Licence. You can add your own license in the Notice, but not the performance of the Apache Licence to change the constitution.
Apache Licence also licensed for commercial use friendly. Users can also modify the code as needed to meet the needs and as open source or commercial product launches / sales.
1.2 Introduction BSD agreement
BSD open source license agreement is to give the user a lot of freedom. Basically users can "do whatever they want", you can freely use, modify the source code can also be modified code as open source or proprietary software re-release.
But "do whatever they want," the premise that when you publish using the BSD protocol code, or the code based on BSD license places to do secondary development of their own products, need to meet three conditions:
1. If the re-released product contains the source code, you must have the original BSD license code in the source code.
2. If the re-release only a binary library / software, you need to include the original BSD license code in the document libraries and copyright notices / software.
3. can not do with the marketing of open source code / agency name and the name of the original product.
BSD code that encourage code sharing, but the need to respect the copyright of the author of the code. BSD By allowing users to modify and redistribute the code, also allows the use or development of commercial software distribution and sales on the BSD code, so it is an integrated business-friendly agreement. And many of the companies in the selection of products when they are open source BSD protocol of choice, because you can completely control these third-party code can be modified or secondary development when necessary.
1.3 Introduction LGPL agreement
LGPL is a GPL is designed for use primarily open source libraries agreement. And the use of any software requirements GPL / modify / GPL-derived library must use different protocols GPL. LGPL allow commercial software library reference (link) mode without using the open source code library LGPL commercial software. This makes use of the LGPL open source code can be used as a reference library and publish and sell commercial software.
However, if the code changes the LGPL or derivatized, all the modified code, the code involves additional code modifications and derived portions must use the LGPL. Thus the LGPL open source code is very suitable as a third-party commercial software libraries are referenced, but not for those who want to the LGPL code base, and derived by modifying the way to do secondary development of business software used.
GPL / LGPL are the original author of protecting intellectual property rights, prevent people from copying and use of open-source development of similar products
1.4 Introduction GPL agreement
We are very familiar with Linux is to use the GPL. The GPL and BSD, Apache Licence and so encourage code reuse license very different. The starting point of the GPL open source code / free use and reference / modification / derivative code open source / free, but not allowed to modify the code and derived as a closed-source commercial software distribution and sales. This is why we can use a variety of free linux, including a variety of by individuals, organizations, and commercial software free software developed by commercial companies on the linux and linux.
The main content of the GPL is to simply use ( "use" refers to the class library reference, the revised code or derivative of this code) GPL agreement in a software product, the software product must also be GPL license must also be both open source and free . This is called "contagious." The GPL products as a separate product without any problems, you can also enjoy free advantage.
Due to the stringent requirements of the use of the GPL GPL library of software products must use the GPL, GPL agreement for the use of open source, commercial software or code division confidentiality requirement is not suitable for integration / adoption as the basis for the development of libraries and secondary .