Applying the Free Software Criteria

The four essential freedoms provide the criteria for whether a particular piece of code is free/libre (i.e., respects its users' freedom). How should we apply them to judge whether a software package, an operating system, a computer, or a web page is fit to recommend?

Whether a program is free affects first of all our decisions about our private activities: to maintain our freedom, we need to reject the programs that would take it away. However, it also affects what we should say to others and do with others.

A nonfree program is an injustice. To distribute a nonfree program, to recommend a nonfree program to other people, or more generally steer them into a course that leads to using nonfree software, means leading them to give up their freedom. To be sure, leading people to use nonfree software is not the same as installing nonfree software in their computers, but we should not lead people in the wrong direction.

At a deeper level, we must not present a nonfree program as a solution because that would grant it legitimacy. Nonfree software is a problem; to present it as a solution denies the existence of the problem.

This article explains how we apply the basic free software criteria to judging various kinds of things, so we can decide whether to recommend them or not.

Software packages

For a software package to be free, all the code in it must be free. But not only the code. Since documentation files including manuals, README, change log, and so on are essential technical parts of a software package, they must be free as well.

A software package is typically used alongside many other packages, and interacts with some of them. Which kinds of interaction with nonfree programs are ethically acceptable?

We developed GNU so that there would be a free operating system, because in 1983 none existed. As we developed the initial components of GNU, in the 1980s, it was inevitable that each component depended on nonfree software. For instance, no C program could run without a nonfree C compiler until GCC was working, and none could run without Unix libc until glibc was working. Each component could run only on nonfree systems, because all systems were nonfree.

After we released a component that could run on some nonfree systems, users ported it to other nonfree systems; those ports were no worse, ethically, than the platform-specific code we needed to develop these components, so we incorporated their patches.

When the kernel, Linux, was freed in 1992, it filled the last gap in the GNU system. (Initially, in 1991, Linux had been distributed under a nonfree license.) The combination of GNU and Linux made a complete free operating system—GNU/Linux.

At that point, we could have deleted the support for nonfree platforms, but we decided not to. A nonfree system is an injustice, but it's not our fault a user runs one. Supporting a free program on that system does not compound the injustice. And it's useful, not only for users of those systems, but also for attracting more people to contribute to developing the free program.

However, a nonfree program that runs on top of a free program is a completely different issue, because it leads users to take a step away from freedom. In some cases we disallow this: for instance, GCC prohibits nonfree plug-ins. When a program permits nonfree add-ons, it should at least not steer people towards using them. For instance, we choose LibreOffice over OpenOffice because OpenOffice suggests use of nonfree add-ons, while LibreOffice shuns them. We developed IceCat initially to avoid proposing the nonfree add-ons suggested by Firefox.

In practice, if the IceCat package explains how to run IceCat on MacOS, that will not lead people to run MacOS. But if it talked about some nonfree add-on, that would encourage IceCat users to install the add-on. Therefore, the IceCat package, including manuals and web site, shouldn't talk about such things.

Sometimes a free program and a nonfree program interoperate but neither is based on the other. Our rule for such cases is that if the nonfree program is very well known, we should tell people how to use our free program with it; but if the proprietary program is obscure, we should not hint that it exists. Sometimes we support interoperation with the nonfree program if that is installed, but avoid telling users about the possibility of doing so.

We reject “enhancements” that would work only on a nonfree system. Those would encourage people to use the nonfree system instead of GNU, scoring an own-goal.

GNU/Linux distros

After the liberation of Linux in 1992, people began developing GNU/Linux distributions (“distros”). Only a few distros are entirely free software.

The rules for a software package apply to a distro too: an ethical distro must contain only free software and steer users only towards free software. But what does it mean for a distro to “contain” a particular software package?

Some distros install programs from binary packages that are part of the distro; others build each program from upstream source, and literally contain only the recipes to download and build it. For issues of freedom, how a distro installs a given package is not significant; if it presents that package as an option, or its web site does, we say it “contains” that package.

The users of a free system have control over it, so they can install whatever they wish. Free distros provide general facilities with which users can install their own programs and their modified versions of free programs; they can also install nonfree programs. Providing these general facilities is not an ethical flaw in the distro, because the distro's developers are not responsible for what users get and install on their own initiative.

The developers become responsible for installation of nonfree software when they steer the users toward a nonfree program—for instance, by putting it in the distro's list of packages, or distributing it from their server, or presenting it as a solution rather than a problem. This is the point where most GNU/Linux distros have an ethical flaw.

People who install software packages on their own have a certain level of sophistication: if we tell them “Baby contains nonfree code, but Gbaby is free,” we can expect them to take care to remember which is which. But distros are recommended to ordinary users who would forget such details. They would think, “What name did they say I should use? I think it was Baby.”

Therefore, to recommend a distro to the general public, we insist that its name not be similar to a distro we reject, so our message recommending only the free distro can be reliably transmitted.

Another difference between a distro and a software package is how likely it is for nonfree code to be added. The developers of a program carefully check the code they add. If they have decided to make the program free, they are unlikely to add nonfree code. There have been exceptions, including the very harmful case of the “binary blobs” that were added to Linux, but they are a small fraction of the free programs that exist.

By contrast, a GNU/Linux distro typically contains thousands of packages, and the distro's developers may add hundreds of packages a year. Without a careful effort to avoid packages that contain some nonfree software, some will surely creep in. Since the free distros are few in number, we ask the developers of each free distro to make a commitment to keep the distro free software by removing any nonfree code or malware, as a condition for listing that distro. See the GNU free system distribution guidelines.

We don't ask for such promises for free software packages: it's not feasible, and fortunately not necessary. To get promises from the developers of 30,000 free programs to keep them free would avoid a few problems, at the cost of much work for the FSF staff; in addition, most of those developers have no relationship with the GNU Project and might have no interest in making us any promises. So we deal with the rare cases that change from free to nonfree, when we find out about them.


A computer peripheral needs software in the computer—perhaps a driver, perhaps firmware to be loaded by the system into the peripheral to make it run. Thus, a peripheral is acceptable to use and recommend if it can be used from a computer that has no nonfree software installed—the peripheral's driver, and any firmware that the system needs to load into it, are free.

It is simple to check this: connect the peripheral to a computer running a totally free GNU/Linux distro and see if it works. But most users would like to know before they buy the peripheral, so we list information about many peripherals in, a hardware database for fully free operating systems.


A computer contains software at various levels. On what criterion should we certify that a computer “Respects Your Freedom”?

Obviously the operating system and everything above it must be free. In the 90s, the startup software (BIOS, then) became replaceable, and since it runs on the CPU, it is the same sort of issue as the operating system. Thus, programs such as firmware and drivers that are installed in or with the system or the startup software must be free.

If a computer has hardware features that require nonfree drivers or firmware installed with the system, we may be able to endorse it. If it is usable without those features, and if we think most people won't be led to install the nonfree software to make them function, then we can endorse it. Otherwise, we can't. This will be a judgment call.

A computer can have modifiable preinstalled firmware and microcode at lower levels. It can also have code in true read-only memory. We decided to ignore these programs in our certification criteria today, because otherwise no computer could comply, and because firmware that is not normally changed is ethically equivalent to circuits. So our certification criteria cover only the code that runs on the computer's main processor and is not in true read-only memory. When and as free software becomes possible for other levels of processing, we will require free software at those levels too.

Since certifying a product is active promotion of it, we insist that the seller support us in return, by talking about free software rather than open source and referring to the combination of GNU and Linux as “GNU/Linux”. We have no obligation to actively promote projects that won't recognize our work and support our movement.

See our certification criteria.

Web pages

Nowadays many web pages contain complex JavaScript programs and won't work without them. This is a harmful practice since it hampers users' control over their computing. Furthermore, most of these programs are nonfree, an injustice. Often the JavaScript code spies on the user. JavaScript has morphed into a attack on users' freedom.

To address this problem, we have developed LibreJS, an add-on for Firefox that blocks nontrivial nonfree JavaScript code. (There is no need to block the simple scripts that implement minor user interface hacks.) We ask sites to please free their JavaScript programs and mark their licenses for LibreJS to recognize.

Meanwhile, is it ethical to link to a web page that contains a nonfree JavaScript program? If we were totally unyielding, we would link only to free JavaScript code. However, many pages do work even when their JavaScript code is not run. Also, you will most often encounter nonfree JavaScript in other ways besides following our links; to avoid it, you must use LibreJS or disable JavaScript. So we have decided to go ahead and link to pages that work without nonfree JavaScript, while urging users to protect themselves from nonfree JavaScript in general.

However, if a page can't do its job without running the nonfree JavaScript code, linking to it undeniably asks people to run that nonfree code. On principle, we do not link to such pages.


Applying the basic idea that software should be free to different situations leads to different practical policies. As new situations arise, the GNU Project and the Free Software Foundation will adapt our freedom criteria so as to lead computer users towards freedom, in practice and in principle. By recommending only freedom-respecting programs, distros, and hardware products, and stating your policy, you can give much-needed support to the free software movement.