The BSD license is one of the open source licenses that allows you to freely use, modify, and distribute software and source code. This license was originally created for the University of California, Berkeley’s Berkeley Software Distribution (BSD) operating system.
The BSD license is a type of open-source license that broadly allows the use, modification, and redistribution of software and source code. It is characterized by flexibility and conciseness, and is employed in many projects. There are several variations of this license, but the main ones are the “BSD 2-Clause License” and the “BSD 3-Clause License”.
Purpose of the BSD License
The BSD license aims to promote the widespread adoption of open-source software without restricting the use or distribution of the software. In particular, it is also allowed for commercial use and integration into proprietary projects, so it can be used in a wide range of applications.
Main features
- Flexible Permissions
- It can be freely used and redistributed in source code and binary form.
- Software with modifications and modifications can also be redistributed freely.
- Commercial use is also permitted.
- Concise conditions
- Maintaining copyright notices and disclaimers is the main condition.
- Depending on the variant, there are some additional conditions.
- License compatibility
- It is highly compatible with other open-source licenses (e.g., MIT, GPL) and commercial licenses, making it easy to integrate into any project.
- disclaimer
- It clearly states that the software is provided “as is” and guarantees that no copyright holders or contributors are responsible.
The main variations of the BSD license are:
- 2-clause BSD license (BSD-2-Clause) 2-clause BSD license
- 3-clause BSD license (BSD-3-Clause)
- 4 Section BSD License (BSD-4-Clause) *Initial version (published in 1990), now deprecated
We will explain them in detail below.
2-clause BSD license (BSD-2-Clause) 2-clause BSD license
Main features
- Concise conditions
It has only two conditions and is a version that removes the cumbersome advertising clauses of the old BSD license (4-clause BSD license). - Commercial Availability
It can be used for a wide range of applications, including modification, redistribution, commercial use, and binaries, without restrictions. - High compatibility
It is also compatible with other open source licenses (e.g., MIT, GPL, etc.). It can also be integrated into proprietary software. - Specify the disclaimer
It clearly states that the software is provided “as is” and stipulates that the copyright owner does not assume any warranty or liability.
License Terms
The following is an example of what a typical two-clause BSD license entails:
Copyright (c) [YEAR] [COPYRIGHT HOLDER]. All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.condition
- If you redistribute the source code, you must include the copyright notice, condition list, and disclaimer mentioned above.
- If you redistribute it in binary format, you must also include this information in the accompanying materials.
Official website: BSD 2-Clause License (Open Source Initiative)
Section 3 BSD License (BSD-3-Clause)The 3-Clause BSD License
Main features
- Additional Provisions (Article 3)
It includes the restriction that “the name of the copyright holder or contributor may not be used for advertising or product promotion without permission.” - Commercial Availability
Like other open source licenses, it can also be used for commercial projects. - High compatibility
It is compatible with other licenses (such as the MIT license and the GPL) while preventing the copyright holder’s name from being used without permission. - pliability
If you comply with the conditions, you are free to modify, redistribute, and create derivative works.
License Terms
The following is the content of the 3rd Section BSD License:
Copyright (c) [YEAR] [COPYRIGHT HOLDER]. All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.condition
- Copyright notice and disclaimer retention
When redistributing in source code or binary format, the original copyright notice, condition list, and disclaimer must be included as is. - Advertising usage restrictions
The name of the copyright holder or contributor may not be used for advertising or product promotion without permission.
Note: You must display the name of the copyright holder or contributor to the product to publish your product. However, approval is required if the name is used for promotional purposes. Otherwise, it can be published if you comply with the license terms. - disclaimer
It clearly states that the software is provided “as is” and that the copyright holder does not guarantee or be responsible.
Official website: BSD 3-Clause License (Open Source Initiative)
4 Terms BSD License (BSD-4-Clause) *Initial Version, Deprecated
The BSD 4-Clause License was published in 1990 and is one of the early versions of the BSD License, which is now deprecated. This license includes additional restrictions compared to the regular BSD license (BSD-3-Clause). Particularly noteworthy is the inclusion of an “advertising clause”.
Key Features of the BSD 4-Clause License
- Copyright Notice and Disclaimer Retention:
- Redistributions must include the original copyright notice and disclaimers.
- Terms for providing source code:
- If you redistribute the source code, you must include the original copyright notice and disclaimer as it is.
- Terms for distribution in binary format:
- Redistributions in binary format (e.g., pre-compiled files) must also include the original copyright notice and disclaimer.
- Advertising clause (this is a major difference from other BSD licenses):
- This clause states that advertisements or promotions for products or services that use the redistributed software must clearly state the original project in the form of “This product helped develop [project name].”
Note: The original BSD license included a clause called the “advertising clause” that was not found in later licenses. This clause required the author of all works derived from BSD-licensed works to include an acknowledgment of the original source in all advertising materials.
- This clause states that advertisements or promotions for products or services that use the redistributed software must clearly state the original project in the form of “This product helped develop [project name].”
Problems with advertising clauses
The main reason why the BSD 4-Clause License is deprecated is in this “advertising clause”. This clause raises the problem that the more software and related products are redistributed, the more advertising obligations will swell and the practical burden will increase.
For example, if you publish software that uses many libraries, you will have to meet the advertising obligation for all libraries, which is no longer practical. As a result, the BSD-3-Clause License, which has removed this clause, is now mainstream.
Current status of the BSD 4-Clause License
- Today, the BSD 4-Clause License is rarely used.
- New projects usually use BSD-3-Clause or MIT licenses.
- If you have older software that is licensed under the BSD 4-Clause license, you must include this advertising clause when redistributing.
Related Articles
References
Open Source Initiative (OSI): BSD 3-Clause License
https://opensource.org/licenses/BSD-3-Clause
Open Source Initiative (OSI): BSD 2-Clause License
https://opensource.org/licenses/BSD-2-Clause
Open Source Initiative
*You can also check for other than the major BSD licenses mentioned above
https://opensource.org/licenses?ls=BSD
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