Solve mojeun information about the open-source license at a time

License Introduction

+ Outline of Open Source SW

Open Source SW, which is SW with source code opened, can generally be used, reproduced, distributed, and revised freely. Typical examples of Open Source SW include Linux Kernel, Apache Web Server, FireFox, Web Browser, and MYSQL.

Throughout the world Open Source SW is being used in a comprehensive sense, including Free Software by Free Software Foundation. However, there are subtle differences between Free SW and Open Source SW in terms of history, philosophies pursued, and so on.

As software began to develop into a large value-added industry in the 1980s, there was a movement to place restrictions on use, reproduction, distribution, and revision of software through intellectual property right and license contract. Against such movement, Richard Stallman established FSF to develop Free Software movement.

However, as the word, free, in Free Software was recognized as free of charge by general people and the majority of enterprises were reluctant to participate in Free SW movement because strict GPL provisions prevented it from being used to develop commercial SW, some people, including Eric Raymond and Bruce Perens, suggested a new expression of Open Source to attract more participation in source code opening.

The Open Source began to be used widely with formation of Open Source Initiative (OSI) in charge of activating Open source SW and certifying Open Source SW. Defining the minimum criteria for license belonging to Open Source (Open Source Definition, OSD), OSI provides certification, management, and promotion according to this definition.

Open Source SW License certified by OSI gets an OSI certification mark

+ Intellecural Property Rights and License for Open Source SW

1. Intellectual Property Rights for SW

SW is currently protected by intellectual property rights, including copyright, patent, trademark rights, and business confidentiality, as follows.


  • As a right acquired for production by a creator (producer), copyright protects rests of production and occurs simtaneously with production. Therefore, when a programmer develops a certain type of SW, computer program copyright occurs automatically and is imposed on the programmer or on his or her company.
  • Patent

  • Patent, which is exclusive control occurring in relation to invention, must be applied for by a legally-defined procedure and is given through examination. It is necessary to get permission from a patentee to use a patent. For SW to implement a patented system, it is necessary to get explicit permission from a patentee, regardless of programming language or source codes.
  • Trademark Rights

  • A trademark right, which is an exclusive right that allows the trademark right holder to use the registered trademark for designated goods, must be registered according to a fixed procedure before it comes into force. It is necessary to get permission from a trademark right holder to use such a trademark; using the trademark without permission rests in punishment
  • Business Confidentiality

  • Unopened SW can be protected as business confidentiality; even for opened one, an idea-related part can possibly be protected as business confidentiality. But SW as business confidential can hardly be protected when it is widely opened and distributed, and a third party using it accidently cannot be legally accused.
  • 2. License and Open Source SW

    While it can be protected by three things mentioned above and can only be used, reproduced, distributed, and revised by a copyright holder, the rightful claimant needs to give others authority to do certain action on fixed terms. This authority is usually called license (permission to use). For instance, when we purchase Windows XP, we just get license (right) to install and use Windows XP in a computer from the SW rightful claimant, Microsoft. So we cannot reproduce or lend original Windows XP to others even if we purchased it.

    As of October 2007, there are 64 licenses according to OSI that is in charge of Open Source SW licensing. However, there are a limited number of licenses being frequently used in practice. Of around 43,722 projects registered in the portal site for Open Source Project Development, Freshmeat (, about 72% are GPL and LGPL licenses.

    3. Understanding and Use of Open Source SW License

    Open Source SW is legally protected by copyright as with proprietary software; on the ground of this right, an Open Source SW copyright holder gives license to an Open Source SW user. However, Open Source SW License is different in many ways from general proprietary SW license. Details of the license are as follows. Here, licensee is one who is granted a license, and licenser is one who grants it.

  • A licensee can freely use appropriate Open Source SW.
  • A licensee can freely reproduce appropriate Open Source SW and redistribute it on fixed terms.
  • A licensee can freely revise in using appropriate Open Source SW and redistribute the revision on fixed terms.
  • A licensee can freely obtain and access source code of appropriate Open Source SW.
  • Open Source SW License also imposes certain responsibility on SW users. You can see details of the responsibility through license distributed together with Open Source SW. License for appropriate Open Source SW is principally specified inside source code or on homepage.

    A user who fails to meet requirements of Open Source SW License can be sued for violation of copyright (or for breach of contract) by a rightf claimant. If he or she loses the suit, the user cannot distribute SW and can bear enormous responsibilities including payment for damage. Therefore, it is important to get a clear understanding of requirements for license and prevent such situation.

    As compared with requirements defined for proprietary SW license, however, requirements of Open Source SW License are never diffict; you can reduce much more expenses than proprietary SW by understanding and observing them well. Since only a few licenses demand to open independently-developed source code, there wod be little room for causing problems if you make thorough analysis before using it.

    It is therefore necessary to understand requirements for license before downloading Open Source SW for application to development. It is important to clearly analyze requirements for appropriate license and goals of using Open Source SW before starting development by asking advice of an outside expert in case independent judgment is impossible. Only this can make the best use of Open Source SW correctly and prevent possible problems in advance.

    + Details of Open Source SW License

    1. Common Requirements

    Requirements for Open Source SW License somewhat vary by licenses; common requirements include Maintain Copyright-Related Passage, Prevent Product Name Overlapping, and Confirm Possibility of Coordinating SWs with Different Licenses, while optional ones include Open Source Code and Observe Patent-Related Provisions.

    Common Requirements

    Requirements for Open Source SW License somewhat vary by licenses; common requirements include Maintain Copyright-Related Passage, Prevent Product Name Overlapping, and Confirm Possibility of Coordinating SWs with Different Licenses, while optional ones include Open Source Code and Observe Patent-Related Provisions.

      Maintain Copyright-Related Passage

    • Copyright is a right that occurs in relation to an expressed product and is given automatically with creation of product. In many cases SW has program name, developer, version, and contact information contained in source code, which are protected by such moral rights as right of paternity and integrity right.
    • Open Source SW mostly has information about a developer and contact information recorded at the upper part of source code, and this information about a developer may not be revised or deleted at will because it is protected by copyright. In particular, be careful about reciprocal licenses, such as GPL, which provide opening revision again, because if the fact that source code was opened to the outside with information about a developer on the code revised or deleted is revealed, an issue of copyright infringement can occur. Maintenance of copyright-related passages must be observed all the time since it can be judged with ease.
    • Prevent Product Name Overlapping

    • A product name of SW is protected by a trademark right. Therefore, even for Open Source SW, if the same name is used as a product name or as a service name, an issue of trademark right infringement occurs. In particular, be more careful about famous Open Source SW because in many cases its name is registered as a trademark (e.g. Linux).
    • Confirm Possibility of Coordinating SWs with Different Licenses

    • In many cases the existing codes are used again or combined to construct SW, which can result in conflict between licenses with different codes. This is called an issue of license compatibility. Therefore, you should confirm that two licenses are compatible with each other in combining Open Source SWs distributed in different licenses.

    Optional Requirements

    Optional requirements vary by licenses. For details, see the section of Requirements for Each License (3.2) in the Open Source License Guide (link to the page introducing the License Guide) provided in PDF.

      Specify Use

    • Many Open Source SW licenses demand to indicate that appropriate Open Source SW is used in using SW. This means definite description of use, like ¡°This SW used _____, which is Open Source SW. If you have a user manual or other media to replace the manual, make description in it.
    • Open Source Code

    • Some specify that if Open Source SW has a part revised or alied according to license, source code of the part should be opened as well. A typical license is GPL. However, a precise range of opening can also vary by the range defined by each license and by SW development methods.
    • Patent

    • If a technology is protected by patent, you should get permission from a patentee in implementing the technology. This term is irrelevant of whether it is Open Source SW or not. However, when you implement a patented technology in Open Source SW, the issue of patent related to Open Source SW is more complicated because of license. In particular, since the rapid increase in SW patents recently makes relevant problems more serious, patent-related provisions are increasingly included for new Open Source SW licenses.