Introduction to open-source protocols-GPL Protocol

 

Among the various licenses used by Free Software, the most important thing is the General Public License (GPL ).

Like other free software licenses, GPL permits the public the freedom to run and copy software, the freedom to distribute and Disseminate software, and the freedom to obtain the source code of software, the freedom to improve the software and disseminate the improved version to the community.

GPL also stipulates that as long as the modified text is overall or a part of it comes fromProgramThe overall modification text must be circulated according to GPL. Not only must the source code of the modified text be disclosed to the public, but the circulation of the modified text cannot be subject to the limitations of the modifier. Therefore, a program that follows GPL circulation cannot be merged with a non-free software. This circulation rule expressed by GPL is called Copyleft, indicating that it is "Opposite" to the copyright concept ".

The main principles of the GPL protocol are as follows:

1. Ensure that the software is open from beginning to endSource codeForm release to protect development results from being stolen and used for commercial release. Any software, as long as the source program of third-party software protected by the GPL protocol is used and released to non-developers, the software itself automatically becomes the Entity protected and restricted by the GPL. That is to say, it must open the sourceCode.

2. GPL is generally a manifestation of the copyright on the left (Copyleft, or translated as "anti-copyright", "copyright to the left", "Copyright not owned", and "Copyright responsibility. You can remove all copyright information from the original version, as long as you keep it open-source and attach a GPL license to the source code and binary version, so that future generations can clearly learn the authorization information of the software. The essence of GPL is that, as long as the software is fully open-source, users are given free space as much as possible, so that the software can develop faster and better.

3. No matter how the software is released, the source code must be included. For example, to provide download on the web, you must download the source code on the same page of the binary version (if any. If it is released in the form of a CD, the source file must be attached to the CD.

4. companies or individuals who develop or maintain software that complies with the GPL protocol may charge users a certain amount of service fees. The old saying is that the complete source code of the software must be provided free of charge, and the source code and service must not be bundled or sold in disguised form.

 

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