Open Source Principles

Open Source Principles

In preparing this book, I found that the official Open Source Definition was simply too confusing to focus readers on what really matters most about open source licenses. Therefore, I have chosen to rely on a somewhat different set of Open Source Principles to describe software that is open source .

These Open Source Principles are different from but consistent with the official Open Source Definition and with the Free Software Guidelines quoted earlier.

They guide us to what I believe are the key things to look for in open source licenses ”and the key things we'll find missing in non “open source licenses.

It will be useful to keep these Open Source Principles in mind as I describe specific open source licenses later in this book. You may also find the brief explanations of each principle helpful later in this book as I explore various actual open source license provisions and the laws relating to licenses and contracts.

1. Licensees are free to use open source software for any purpose whatsoever.

An open source license may not interfere in any way with the use of the software by licensees. Restrictions on use, such as "for research and noncommercial purposes only," are not allowed in open source licenses. The phrase free to use is also intended to mean "without any conditions that would impede use," such as a requirement for the licensee to report uses to the licensor , or to disclose the means or manner of internal uses of the software. Note also that the first word, licensees, means that open source software is only available under the terms of a license to which each licensee must agree .

2. Licensees are free to make copies of open source software and to distribute them without payment of royalties to a licensor.

This principle does not mean that a licensor cannot sell open source software. It merely says that a licensee need not pay the licensor for additional copies he makes himself, even if those copies are distributed to others. As a practical matter, this open source principle drives the price of mere copies of open source software toward its marginal cost of production and distribution.

3. Licensees are free to create derivative works of open source software and to distribute them without payment of royalties to a licensor.

Quality software is built upon the foundations of earlier software. Many advocates of free and open source software contend that the requirement for open source licenses to permit the unhindered creation and distribution of derivative works is essential to meet the goal of the intellectual property laws as stated in the U.S. Constitution, "to promote the progress of science and the useful arts." Under this open source principle, a licensor cannot charge a royalty for the privilege to create and distribute derivative works, or require a licensee to pay a royalty for copies of a derivative work that are distributed, or impose any restrictions on the type or character of those derivative works.

4. Licensees are free to access and use the source code of open source software.

Source code is written in a human language to instruct a computer how to perform certain functions. Since the source code must be changed in order to instruct the computer to perform different functions, access to the source code is essential to make the third open source principle ”the freedom to create derivative works of open source software ”a practical reality. Source code is a means to an end, not the end itself. The phrase free to access merely requires the licensor to make source code available to licensees upon request at zero price, not necessarily to distribute the source code to everyone.

5. Licensees are free to combine open source and other software.

Open source licenses may not impose conditions or restrictions on other software with which the licensed software is merely combined or distributed. This prevents restrictions regarding what other software can be placed on computer storage media or in computer memory. Open source is but one of many possible business and licensing models for software distribution, and customers must be free to select and use those software alternatives. This open source principle does not mean that licensors cannot impose reciprocal conditions upon licensees who create and distribute derivative works, for the activity of creating derivative works is not the same as merely combining software on media or on computers.