Before, " GPL to closed source? The court decision: One-day GPL, Life-long GPL " article raised an unpopular but important knowledge point: Can an open source project under the GPL license be forked out of closed source? It can be seen from the comments that people are very concerned about such issues, but generally lack the corresponding knowledge.
In fact, this is a drawback of open source in China—the knowledge of open source is not popular enough . Because many practitioners have limited access to such knowledge and lack of relevant awareness, they are prone to make mistakes, causing misunderstandings and troubles. For example, the plaintiff Luohe company in the above case, the reason why the open source project under the GPLv3 license will be closed in the later stage is probably this reason. For another example, the domestic company that was asked by the mechanical enchantress to ask for the source code later actually released the source code very cooperatively, which is also the reason for the root cause.
In general, many developers have not supplemented their knowledge in two aspects: first, when choosing an open source license, they do not know how to choose, let alone what this license means for the project. ? Second, it is difficult to choose the business model when the open source project is monetized, either to close the source GPL, or to add additional clauses indiscriminately.
Since the birth of Open Source, commercialization has never been rejected, but it just needs to master some knowledge and skills. The following are some popular science knowledge about open source licenses and open source business models. They are all excerpts from the treasure articles I found in the process of searching for information. I also give the relevant sources. If you are interested, you can view the original text and fully grasp it.
01 Open source licenses will retain copyright, the difference is sharing permissions
Since RMS (Richard Matthew Stallman) fiddled with the GPL, there have been hundreds of open source licenses, but not many are popular. Some of the fundamental principles can only be called open source licenses if they are recognized by OSI (Open Source Intiative) , while others such as SSPL, Elastic, etc. are commercial licenses. Those officially certified open source licenses are listed on the OSI website .
OSI's official website divides all its approved open source licenses into "popular and widely used or with strong community" licenses, international licenses, special-purpose licenses, non-reusable licenses, and superseded licenses. Category, you can click for details: https://opensource.org/licenses/category
Among them, the ones with the highest frequency and the most frequently used are the following:
Some popular science articles will draw intuitive and easy-to-understand schematic diagrams for everyone. The most famous one is this picture translated by Ruan Yifeng :
Open source licenses vary widely, but they all have copyright in common, but differ in commercial compatibility or sharing rights. In some popular science articles, these open source licenses are often divided into three categories. Here we select an excerpt from the "Open Source Governance White Paper" published by the China Academy of Information and Communications Technology in March 2018:
One is the infectious open source license (Copyleft):
The contagious open source license expressly modified version must be released under the same license, if a software contains part of the code under this agreement, the agreement must be applied as a whole when fully released, GNU General Public License Version 2 or Version 3 (hereinafter referred to as "GPL V2") ” or “GPL V3”) as an infectious open source license giving anyone the right to freely copy, modify and distribute the GPL code, but in return, all derivatives of the source code released under the GPL agreement must also be released under the GPL.
The second category is the weakly infectious open source license (Weak-Copyleft):
If a software contains part of the code under this agreement, some parts must be covered by this license when fully released, and other parts can be released under other agreements, such as LGPL, MPL, etc.
The third category is the permissible license:
There is no requirement to license the modified code. For example, BSD requires the license to attach the original text of the license and the copyright materials of all developers. It allows the original work and modified versions to be distributed without public source code or under other licenses.
Widely used open source licenses include Apache-2.0, BSD-3-Clause, BSD-2-Clause, GPL, LGPL, MIT, MPL-2.0, CDDL-1.0, Eclipse 2.0.
In addition, the "Open Source Governance White Paper" also lists the characteristics of some commonly used licenses:
-- GPL (GNU General Public License, GNU General Public License): A widely used free software license that guarantees users the freedom to run, learn, share and modify software. The license was originally written by the Free Software Foundation (FSF) Richard Stallman for the GNU Project. The GPL is a non-profit copyright license that requires derivative works to be released only under the same license terms. The starting point of the GPL is the open source use of the code and the open source use of the referenced code, and does not allow the release and sale of modified and derived code as closed-source commercial software.
--LGPL (GNU Lesser General Public License, GNU Lesser General Public License): A free software license issued by the FSF that allows developers or companies to use in proprietary software, and does not require software that uses LGPL-licensed code to be LGPL way to publish. Unlike GPL's mandatory open source approach, LGPL allows commercial software to use LGPL class libraries through class library references without requiring open source commercial software code.
--BSD (Berkeley Software Distribution): Allows users to modify and redistribute code, as well as use or develop commercial software on BSD code and publish and sell it.
--MIT License: Allows developers to do whatever they want with the software, including use, copy, modify, merge, publish, distribute, sublicense, or sell. The only limitation is that a license prompt must be included with the software.
--Apache License: A free software license issued by the Apache Software Foundation, which is relatively friendly, and the licensee can publish commercial software.
--MPL (Mozilla Public License 1.1): The MPL agreement allows free redistribution and free modification, but requires that the copyright of the modified code belongs to the originator of the software.
--CDDL (Common Development and Distribution License): CDDL open source license, which is an extension of MPL, allows public copyright use, has no royalties, and provides patent protection, which can be integrated into commercial software, allowing self-publishing licenses.
--EPL (Eclipse Public License 1.0 ): EPL allows Recipients to use, copy, distribute, disseminate, display, modify, and re-release closed-source secondary commercial releases at will.
*** There is another knowledge point worth paying attention to: how to deal with open source software patents? This question is mentioned in " What should I do if I have written an open source software and have not applied for a patent? " has been explained in the article, you can expand reading.
02 Different business models are suitable for different licenses
How can open source software companies continue to gain profits through a certain profit model? Before, Zhihu blogger Liu Bo used a long article " Analysis of the Evolution of Open Source Software from the Perspective of "Technology-Economic Paradigm" to analyze, in which the summary of the open source business model is very comprehensive. In order for you to quickly find the key points, I have excerpted a part:
According to the degree of closeness between the open source software business model and the software itself, 10 common business models at home and abroad can be divided into three categories: license, direct supporting, indirect supporting, and subsidiary products.
Typical mainstream business models include:
a. Selling professional services
The sales professional service model refers to profiting by providing professional services for open source software, such as training, technical support or technical consulting. Many enterprises do not have the resources and the ability to maintain their own IT systems, so there have emerged IT service companies that provide enterprises with open source software-based IT services. Because of the characteristics of open source software, the company's engineers with programming ability can master it proficiently, and use their professional expertise to provide corresponding services for other enterprises.
In this mode, free users can only obtain the source code of open source software without executable binary code, while paid users can obtain executable binary code at the same time, including commercial services such as software compilation and packaging; Physical installation media (eg DVD) may also be provided.
Red Hat has grown into the most successful open source software company by providing professional services to customers mainly through a subscription model.
b. Dual-licensing
The dual-licensing model is one of the most common open source software business models, in which developers provide software not only under an open source license, but also under a proprietary software license.
In this mode, the source code of the product mainly comes from the open source community or software vendor. The two parts of the source code together form the core product, and are licensed separately through two types of licenses (proprietary license and open source copyleft license). For free users and paid users. The revenue from the proprietary version will be used to develop the next version of the open source software.
In the dual-license model, users are attracted by the free open source version at the beginning, and then become customers who purchase the paid version by constantly learning about the commercial technical support and services that the manufacturer can provide. Taking the MySQL database as an example, the company launched both an open source version for individuals and a proprietary version for enterprises. The business model adopted is the dual license of the open source copyleft license (GPLv2) and the proprietary software license.
c. Re-licensing under aproprietary license
The sublicensing proprietary model means that under certain permissive licenses, software manufacturers are allowed to combine their own proprietary software with open source software under permissive licenses, and the combined software products may not provide source code.
Software suppliers in this model can sell the final software product under a proprietary license, or even directly modify some open source software for sale. A software product is a combination of software developed by two developers, the open source community and the software vendor (not the same software). Developers in the open source community develop an open source software that applies a permissive open source license, allowing closed-source licenses to be re-licensed; while software vendors develop proprietary software, which the software vendor applies to proprietary software. Software is developed in combination with open source software to form a new software product and sold under a proprietary license.
This business model is adopted by many companies, represented by Apple's operating system Mac OS, which uses the sublicensing proprietary model to develop its software products. Apple's Mac personal computer system is developed based on the BSD operating system kernel. For sale of Apple's proprietary software products.
d. Embedded advertising model (advertising-supported software)
The embedded advertisement mode refers to the spread of embedded advertisements in the software by the rapid promotion of open source software. Software manufacturers embed advertisements into the software products they develop, and the software products consist of the software itself and the advertisements embedded by the manufacturers. The entire software product is provided to the majority of users as open source software. The promotion of open source software will bring more and more customers, so that the advertisement embedded in the software has the value of dissemination, and the advertising manufacturer has achieved the effect of product promotion. Willing to advertise to software manufacturers, and software manufacturers profit will continue to invest in the development of open source software, forming a virtuous circle.
Most open source software companies tend to take the lead in adopting embedded advertising business models to generate revenue and maintain operations. For example, the Android platform brings a lot of mobile advertising traffic to Google.
With the development of open source software, enterprises have changed from the previous strategy of adopting a single open source software business model to a strategy of adopting multiple combinations. For example, Red Hat not only provides professional subscription services, but also sells supporting proprietary software.
Furthermore, the results of the structured analysis show that the types of licenses used by different business models of open source software vary widely.
From 2009 to 2015, the share of MIT licenses rose by 15.7%, while Apache's share rose by 12.4%, while the share of GPLv2 and v3 fell by 21.4%, according to open source license management firm Black Duck Software. GitHub survey data shows that MIT is the most popular license with a 45% share; this compares with 13% for GPLv2. Most open source software business models require permissive licenses, and trends show a shift from restrictive to permissive licenses for a large number of software, with associated business models increasingly leaning toward permissive licenses.
03 Related Links:
OSI official website: https://opensource.org
Ruan Yifeng Blog: https://www.ruanyifeng.com/blog/2011/05/how_to_choose_free_software_licenses.html
Download address of the 2018 White Paper on Open Source Governance issued by the China Academy of Information and Communications Technology: http://www.caict.ac.cn/kxyj/qwfb/ztbg/201804/P020180323313495961952.pdf
Liu Bozhihu Homepage: https://www.zhihu.com/people/liu-bo-66-15/posts