What is Open Source?
You will learn the meaning of the term Open Source, what the GPL software license provides, why WordPress is an open-source project, and how important it is for both WordPress users and contributors.
What is the definition of Open Source?
Open-source software is software whose source code is available for everyone to view, modify, and improve. The source code represents computer instructions written in a programming language to alter the way software operates. Most proprietary software is distributed in executable file formats; here the source code has been compiled and encrypted for computer use without the source code being available. If the source code were available without compilation and encryption, it would be possible to examine and modify the program – this is what open-source software provides: the ability to read and modify the code behind the software.
What is the definition of Free Software?
Free software is not only software that is free of charge (although the term “free” software is often used to describe free software). “Free software is software that gives users the freedom to share, study, and modify it. According to the Free Software Foundation, it is called free software because users are free to it.”
Note: “Free software is a matter of liberty, not price. To understand the concept, you should think of freedom, not as in free beer, but as in freedom of speech.” —Richard Stallman Free software refers to software that adheres to the “four essential freedoms” – the freedom to run the program for any purpose without any legal restrictions, to study how the program works and adapt it to your needs (freedom 1). Access to the source code is a prerequisite for this. The freedom to distribute copies to help your neighbor (freedom 2). The freedom to distribute copies of your modified versions to others (freedom 3). By doing this, you can give the entire community the opportunity to benefit from your changes. Access to the source code is a prerequisite for this.
How does Open Source compare to Free Software?
While open-source software is characterized by the general accessibility of its code, free software focuses on the ability to use and share the software. These terms overlap in some ways but are not interchangeable. The abilities and conditions given to software users depend on the software license in question, and there are differences in licenses used for open-source and free software. Some additional terms explaining these overlapping ideologies for software projects are:
FOSS: Free [and] Open Source Software
FLOSS Free / Libre [free] / Open Source Software
The (brief) history of Open Source
Freely shared software was distributed among computer scientists working in academia in the 1950s. However, as computer systems became more complex, software development became more costly, and computer products markets expanded, in the 1960s, computer companies often bundled hardware products with the software they needed to run and sold them together. In the 1980s, in response to the expansion of personal computers and corporate networks and the ever-increasing costs associated with proprietary software and vendor lock-in, movements emerged. In 1984, the GNU Project was launched to create a computer operating system that would be independent of the restrictions on the use of source code (compatible with the “four freedoms”).
Note: GNU is a recursive acronym, standing for GNU’s not UNIX Open source development principles, which contrast two models of software development, were outlined in the book “The Cathedral and the Bazaar” by Eric Raymond in 1999 (expanding upon his article of the same name from 1997):
The Cathedral model, where code is developed between limited releases with a specific software developer group
The Bazaar model, where code is developed with public access over the internet, as in the Linux kernel project led by Linus Torvalds
An important inference drawn from the book is the idea that “given enough eyeballs, all bugs are shallow,” dubbed Linus’s Law, because the availability of source code to the public allows for a wider pool of participants to identify and rectify software issues. The term “open-source software” emerged in 1998 when Netscape released the source code for its web browser (Navigator), hoping that more people would find and correct errors by providing access to the code to a larger audience. This release garnered significant interest in the open-source development process. Some of the world’s most popular applications today are open-source software: Android, Mozilla Firefox, LibreOffice, Git, and many more
Why Choose Open Source?
As an end user, developer, or business manager, why should you consider using open-source software? Here are some key factors:
It often involves minimal cost (although some projects may add a small distribution fee)
There is no contract-based license; instead, the license outlines the sharing rules
The software is customizable, and public forums and documentation support:
No vendor lock-in for customization and bug fixes
Abandoned software projects can be adopted by new development teams
Open standards are generally used instead of proprietary standards.
Errors and security issues can be rapidly addressed with software patches
What is GPL?
GPL stands for the General Public License (GNU). Sometimes referred to as a copyleft license, it is unlike a copyright because it reverses the terms of copyright in software. Rather than restrict distribution, the GPL is used to specify ownership of the source code and the terms under which it can be shared. Created by Richard Stallman in 1989, the GPL is the founding license for open-source software. Its purpose is to preserve the four fundamental freedoms considered the foundation of free software. Therefore, if a derivative work of a GPL-licensed software is redistributed in its original or modified form, it must be licensed under the GPL, or else the license to use the source program expires, violating the terms of use. This forking makes it possible to turn an open-source software project into a new project as long as the new project is under the same license. Over time, there have been three versions of the GPL license. GPLv2 (or later) from the Free Software Foundation is the license under which the WordPress software falls. More information about GNU GPL can be found at:
GNU GPL FAQ
Free Software Foundation
How is Open Source Applied to WordPress?
WordPress is free open-source software distributed under the GPL license. WordPress began as the successor to the abandoned b2/cafelog software project, initiated by Matt Mullenweg, who first contemplated it in 2003 with the “Blogging Software Dilemma” post, later that year launching the original version with the “WordPress Now Available” post on WordPress.org. Since then, it has become the world’s largest self-hosted blogging tool, used on millions of sites and seen by tens of millions of people every day. The official WordPress About page says:
“Everything you see here, from the documentation to the code itself, was created by and for the community. WordPress is an open-source project, which means there are hundreds of people all over the world working on it. (More than most commercial platforms.) It also means you are free to use it for anything from your cat’s home page to a Fortune 500 web site without paying anyone a license fee and a number of other important freedoms.”
In addition to the GPL applied to the open-source code of WordPress, all related software on WordPress.org in the Plugins Directory and Themes Directory must be licensed under the GPL or a compatible license because they are considered derivatives of WordPress software. According to the Software Freedom Law Center:
“They are derivatives of WordPress because every piece of them is determined by the content of the WordPress functions they call. As separate works, they are designed to be combined with.”
While WordPress plugins and themes must comply with the GPL, they can still offer premium versions for a fee, even though they cannot be sold through the WordPress.org directories. This might seem confusing at first, but it provides users with greater freedom to choose how to customize the WordPress software and allows collaboration with third-party commercial markets to combine free software with paid services.
How Can You Contribute to WordPress?
WordPress is maintained and developed by a global community of volunteer contributors; some are employed by WordPress sponsor company Automattic, some work for other companies specializing in WordPress, and many more are independent users who use WordPress for any reason. While being a software developer who contributes code to WordPress plays an important role, it’s not necessary. There are many other ways that anyone can contribute to the project, such as helping out in support forums, writing documentation, doing language translations, and contributing through meetups or WordCamps. Visit make.wordpress.org for more information on the various teams working on WordPress and how to get involved.