What is Free/Libre, Open Source Software?¶
In the simplest terms, open source software is software you can share. But it is more than just shareware. Open source means that the source code of the software is available to the users. To understand what this means, we’ll need to take a little detour into how computer programs actually get made.
How Computer Programs Are Made¶
A computer program is a list of instructions given to a computer to make it perform a specific task or series of tasks. Computers do not understand English (we all wish that they did!), so programmers must communicate these instructions to the computer in a language the computer understands. Computers, however, can only operate on numbers, which makes a computer’s language very difficult for humans to understand.
The solution to this problem is to create an intermediate language that both humans and computers can understand. These are called programming languages. Programmers create a list of instructions for the computer in a programming language such as C, Pascal, or Fortran. This list of instructions is known as source code. It is textual in nature, and readable to humans (the ones who speak the language). Programmers do all their work in this source code, changing the instructions to fix bugs, add features, or alter the appearance of a program.
When the programmer believes he has perfected the instructions for his program, he uses a special program called a compiler to translate his human readable text instructions into computer readable numbers that correspond to the same instructions. The resulting file is usable by computers but incomprehensible to humans. This is called object code. The resulting executable file is often called binary, after the number system used by the computer. This translation from source code into binary object code is a one-way process. It is impossible to translate a binary executable back into the original source code.
The binary executable is what you need if you want to run and use a program. This is commonly what you will receive when you purchase shrink-wrapped software from a retail store. The source code is what you need if you want to understand how a program works internally, or if you want to change, add to, or improve a program. If you have the source code and an appropriate compiler, you can produce the binary executable, but the reverse is not true.
So, What is Open Source Again?¶
Software that is available only in binary executable format is proprietary software.
Open-source software is copyrighted software that is distributed as source code, under a license agreement which grants special rights to users of the software, rights that are normally reserved for the author. Such a license allows all users to make and distribute copies of the software binaries and source code, without special permission from the author. Furthermore, it allows users to modify the source code, and distribute modified copies.
What Does It Mean?¶
So what, you say? Why is Open Source important? Because it means that any programmer, anywhere in the world, can look at the source code, fix bugs and errors, add new features, and customize the system without limits. That is exactly how Linux has been developed from the beginning, and that is why Linux is a very stable system with few bugs, wide hardware support, and a feature set growing so fast that proprietary operating system vendors are jealous. The fact that the source code is open to review by experts all over the world ensures that any problems are found and solved quickly, and the fixes can be distributed without restriction. This is much more effective and efficient than relying on a corporation to squeeze a “service pack” somewhere into its busy release schedule. (After all, they don’t get paid for service packs.)
What really matters is that open source software is community owned. It is software that is maintained by the community of people (or companies) that use it. It is freely available on the Internet, and anyone may use it. More importantly, users are encouraged to improve upon it. By sharing our improvements and ideas, pooling our resources with thousands, even millions of others around the world via the Internet, the open source community is able to create powerful, stable, reliable software, at very little cost.
But the open source community is much larger than just the people who write the software. Everyone who uses the software participates in a real community and has a voice in its direction. You don’t have to be a programmer. By merely reporting a bug to a program’s author, or writing a simple “how-to” article, you contribute to the community and help to make the software better. Open-source software is written, documented, distributed and supported by the people who use it. That means that it is sensitive to your needs, not the needs of a corporation trying to sell it to you.
Of course, many companies also contribute to the development of open-source software, making their work available to the entire community, because they know the benefits of Open Source. Software that is supported by an entire community is by its nature better and more stable, and more and more companies are beginning to appreciate that fact.
The bottom line is that open source software is written by people who use it every day, people who have a personal interest in making it work and work well. They aren’t trying to add buzzword features, they are trying to add quality. They don’t spend time and money trying to convince people that their software is great, they spend it trying to make their software great.
Resources¶
“Open Source” is a trademark phrase describing software licenses that meet the Open Source Definition. The trademark is administered by the Open Source Initiative, an organization founded on the principles of cooperation that launched Linux and the free software movement. Only software that meets the criteria described in the Open Source Definition may describe itself as Open Source.
Long before the term “open source” came into use, there was a community of people devoted to the idea of “Free Software”, a phrase which refers not to cost, but to the freedom to use and modify it (think of free as in “free speech”, not “free beer”). This community still actively promotes the ideals of Free Software. To learn more about it, visit The Free Software Foundation.
For a detailed examination of how and why open source software is developed, read Eric S. Raymond’s excellent essay The Cathedral and the Bazaar.
If you’re considering open source software for your business, you should visit The Open Source Initiative to find out more. If you’re not considering it, you probably should be. Take a look anyway, and learn how the open source community can add stability, scalability, and power to your business, while actually reducing expenses.
What is open source software?
Open source software is released through a specific kind of license that makes its source code legally available to end-users. There are many such licenses, but typically software is considered open source if:
- It is available in source code form without additional cost, meaning users can view the code that comprises the software and make any kind of changes to it they want.
- The source code can be repurposed into other new software, meaning anyone can take the source code and distribute their own program from it.
Is open source software free?
Open source software does not necessarily mean that executable software is given away for free. It does, however, mean that its source code is available for free.
For instance, the source code for Red Hat® Enterprise Linux® is freely available to anyone (see for yourself), but converting that source code into runnable code requires expertise, time, and servers. When organizations want the production-ready code for Red Hat Enterprise Linux without having to reconstruct it themselves from source code, they obtain a subscription.
Open source software is also sometimes conflated with the free software movement, which can add to the confusion around whether open source means «free.» The free software movement grew out of the hacker culture of the 1970s and was formally founded by Richard Stallman as part of the GNU Project and the non-profit Free Software Foundation. Usually, «free software» is meant to emphasize a freedom in the rights of end-users, but can sometimes be confused as meaning «free of cost.»
In actuality, neither free software nor open source software denote anything about cost—both kinds of software can be legally sold or given away.
Free software and open source software share common values, and the terms are sometimes combined in the popular phrase «free and open source software» (FOSS).
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FOSS vs proprietary software
The key difference between proprietary software and FOSS is the availability of the source code. Proprietary or commercial software like Microsoft Windows and Adobe Photoshop are not available to end-users as source code. Free software like the Linux kernel (the basis of Red Hat Enterprise Linux) and open source software such as Google Chromium (the basis of the Chrome web browser) are available as source code through their respective licences.
There are also different types of open source licenses. For instance, if someone turns your source code into new software, will you require them to release it under the same license (as with the GNU GPL), or can they release it under a different license (as allowed in the GNU LGPL)? The internet and increasingly popular cloud computing model would be very different if their origins weren’t based on open source software.
Why does open source software matter?
Open source software matters to everyone, not just programmers, because it unlocks the potential of many more people to become innovators than a closed-source model. Open source communities, for instance, are organized around open source projects where anyone with skills can join and contribute code. These groups still maintain standards around contributing to open source projects just like proprietary software teams do, but they open up this process to anyone in the world who wants to contribute.
This open source development model has resulted in some of the most important applications and cloud platforms in use today. The most popular of which comprise LAMP, a model of service stacks that undergird much of the web. The LAMP acronym stands for:
- Linux: an open source operating system (OS) and the largest open source project in the world
- Apache: an open source cross-platform web server that played a key role in the early web
- MySQL: an open source relational database management system used by many database-driven web apps
- PHP: a general purpose scripting language used in software development (Perl or Python languages are sometimes substituted)
Other examples of popular open source technologies include the Android mobile OS, the Mozilla Firefox web browser, the widely-used version control system Git, and the two related office suites OpenOffice and LibreOffice. On a broader scale, most innovation in the areas of cloud computing, big data, and artificial intelligence have been derived from open source software projects.
In addition to its instrumental role in the early web and some of the most popular applications used today, open source software has other advantages for businesses and individual programmers. When source code is open, it makes it easier for anyone to study it to develop new programming skills. Open source licensing also allows students to get practice by editing the code and sharing it with friends and the broader open source community, or even contributing fixes to existing open source projects.
Open source software also offers businesses the ability to customize it to meet their specific needs, or innovate new customer experiences not included in the original source code. Some also prefer open source software because there are many more developers looking for security vulnerabilities when the source code is openly available and has an active community supporting it.
Open source software is the result of an open source development model. The open source development model is decentralized and encourages open collaboration and peer production. It has influenced a broader movement in software development, and people often refer to its core principles as «the open source way.»
The open source way is so effective because it can attract tremendous technical talent. Much of the innovation in technology is taking place in the open source community, and people all over the world end up using open source software. Behind many popular websites and applications you can find projects like Linux, Kubernetes, and Git, and people access the internet with open source browsers like Firefox and Chromium.