Debian Free Software Guidelines (DFSG) FAQ


  1. Q: What is the purpose of this DFSG FAQ?

    A: To answer common questions about the Debian Free Software Guidelines and how we judge whether some piece of software is free.

  2. Q: What is debian-legal, aka

    A: Debian-legal is a mailing list on which we discuss legal questions related to Debian, including in particular whether some given piece of software is free. This usually depends on its "license".

  3. Q: Why does it matter whether some given piece of software is free?

    A: Debian only includes free software. So aside from all its other wonderful properties, if some bit of software isn't free software (by our standards) we won't include it in Debian.

  4. Q: Does whether some software is free depend solely on its license?

    A: Almost always, but there are rare exceptions. When necessary we take other considerations into account. So two packages with the same license could be judged differently based on extra-license comments the copyright holder has made regarding intent or interpretation, or based on how the contents of the package interact with license stipulations.

    For a concrete example, the PINE mail client version 3.91 had an MIT-style license, which is generally considered free. The copyright holder told us they wished to interpret the license text in a somewhat counterintuitive fashion: the license allows modification and distribution, but the copyright holder said they interpreted this as allowing modification, and allowing distribution of unmodified copies, but as not allowing distribution of modified copies. We respected their wishes, considered the software non-free, and removed it from Debian.

  5. Q: Which license is best for my new previously-unreleased software? Which should I use? I think it would be fun to make up my own!

    A: We are computer programmers here, so we appreciate the fun to be had by trying to stretch the rules or game the system. And it certainly sounds fun to write your own license! But it is our strong and heartfelt advice that using a tried-and-true license is best for almost all purposes. Even large corporations with dozens of lawyers on staff itching to write their own license have found this out the hard way, as in the Mozilla license saga, or the Djvu license story, or the trouble Trolltech had with the Qt license.

    There are many advantages to using standard licenses: they're better understood by the community, they've been written by actual lawyers, people don't have to spend time figuring them out before using the program or helping with development, and they make it much easier to share code between your project and others.

    In our opinion (and we are not lawyers so please do not take this as formal legal advice) ...

    Other people who have investigated these issues give similar advice. For instance, see the essay Make Your Open Source Software GPL-Compatible. Or Else. by David A. Wheeler, which includes some compelling statistics.

  6. Q: I've flouted your advice and written a new license. I strongly believe that it conforms to the DFSG and is a free software license. People on debian-legal don't seem to agree though. They give explanations for their decision which I find completely unconvincing. I keep trying to explain the flaws in their reasoning to them, but to no avail. Is there any way for me to compel Debian to accept that my license is free?

    A: No.

  7. Q: Should I use the GFDL for documentation I write?

    A: The GFDL seems designed mainly for book-length printed documents rather than digital materials. We would recommend against use of the GFDL v1.2 (GNU Free Documentation License version 1.2), for a couple reasons. A summary of the issues is presented in the essay Why You Shouldn't Use the GNU FDL, by Nathanael Nerode. See also this list of what needs to be done to make a man page using material extracted from a GFDL'ed document. If you must use the GFDL for compatibility, or for some other reason, we would encourage you to put your material under a dual license, like GFDL/GPL.

  8. Q: How can I tell if a license is a free software license, by Debian's standards?

    A: The process involves human judgement. The DFSG is an attempt to articulate our criteria. But the DFSG is not a contract. This means that if you think you've found a "loophole" in the DFSG then you don't quite understand how this works. The DFSG is a potentially imperfect attempt to express what "freeness" in software means to Debian. It is not something whose letter we argue about. It is not a law. Rather, it is a set of guidelines.

    That said, the DFSG is a good start. You might also consider a few thought experiments which we often apply. But do keep in mind that passing some set of tests is not all there is to freeness. These tests aren't the final word either - some other tricky bit of nonfreeness might be invented which is not covered by any of our current tests, or something might fail a test as it's currently worded but still be determined to be free software.

    1. The Desert Island test.

      Imagine a castaway on a desert island with a solar-powered computer. This would make it impossible to fulfil any requirement to make changes "publicly available" or to send patches to some particular place. This holds even if such requirements are only "upon request", as the castaway might be able to receive messages but be unable to send them. To be free, software must be modifiable by this unfortunate castaway, who must also be able to legally share modifications with friends on the island.

    2. The Dissident test.

      Consider a dissident in a totalitarian state who wishes to share a modified bit of software with fellow dissidents, but does not wish to reveal the identity of the modifier, or directly reveal the modifications themselves, or even possession of the program, to the government. Any requirement for sending source modifications to anyone other than the recipient of the modified binary---in fact any forced distribution at all, beyond giving source to those who receive a copy of the binary---would put the dissident in danger. For Debian to consider software free it must not require any such "excess" distribution.

    3. The Tentacles of Evil test.

      Imagine that the author is hired by a large evil corporation and, now in their thrall, attempts to do the worst to the users of the program: to make their lives miserable, to make them stop using the program, to expose them to legal liability, to make the program non-free, to discover their secrets, etc. The same can happen to a corporation bought out by a larger corporation bent on destroying free software in order to maintain its monopoly and extend its evil empire. The license cannot allow even the author to take away the required freedoms!

  9. Q: Does the DFSG apply only to computer programs?

    A: No, we apply our standards of freedom to all parts of all packages in Debian. This includes computer programs, documentation, images, sounds, etc. The text of licenses themselves in general need not be free, although legal wording itself is often not subject to copyright and hence effectively in the public domain. Sometimes little snippets of non-free text, generally of historic or humorous or intellectual value, are included (eg /usr/share/emacs/21.2/etc/{JOKES,MOTIVATION}). These should not be integral parts of the package, nor included in a non-removable fashion, nor constitute functional parts of the package such as code or documentation. Sometimes relevant scientific papers or technical reports of unclear copyright status are included, and although they are not approved of there has been no systematic effort to find and remove such manuscripts.

    We do not consider any of this a precedent for the inclusion of non-free code or documentation.

  10. Q: If something is free software according to Debian's standards, do I still face legal risks when I use, modify or distribute it?

    A: You should take this answer as a total disclaimer of everything.

    Even if we were lawyers (which we are not) neither this document nor Debian's acceptance of some license or inclusion of some software should be taken as legal advice. If you need legal advice, you need to hire your own attorney.

    We sincerely hope you don't face any serious risks, but our process does not guarantee this. In truth, no process could. As stated above, Debian mainly looks at the license accompanying some software to decide whether it meets the project's standards for free software. This leaves open a number of avenues through which legal problems might conceivably arise, including:

    Debian's conclusion that a particular computer program is free software, and our choice to distribute it, is an evaluation made for our own purposes. It is not a legal statement on which you can rely, either as a user, software developer, or distributor. We do our best, but we are not lawyers. We are unpaid volunteers. We make no guarantees.

  11. Q: People put the darndest things in their licenses, could you explain their impact on the freedom of the license?

    A: Sure, here are some examples:

    1. "Send me a postcard if you like this software."

      This makes the license non-free. (But "please send me a postcard if you like this software" would be okay, because that would be a request rather than a requirement.)

    2. "If you distribute this software, you must pet a cat."

      This makes the license non-free. (Even if it didn't, it would be cruel to people who are allergic to cats.)

    3. "You may modify this software, but all bugfixes must be sent to the author."

      This makes the license non-free. (But a request rather than a demand would be okay.))

    4. Q: Are "clickwrap" licenses okay? (Clickwrap meaning they require anyone receiving the software to click on an "I AGREE" button indicating ascent to the terms.)

      A: No, not unless the clickwrap stuff can be removed. Even aside from freeness, as a practical matter such a clickwrap requirement would be an unreasonable burden upon our users.

      To be technical, in principle one could put the GPL in a clickwrap and the license would be perfectly fine. But once you add a requirement that the software must be distributed via the clickwrap, or that clickwrap code cannot be removed from the software, your license becomes non-free. Since clickwraps without such a requirement are a bit pointless, clickwrap licenses are almost always non-free.

    5. Q: What about licenses that grant different rights to different groups? Isn't that discrimination, banned by DFSG#5/6?

      A: For Debian's purposes, if all the different groups can exercise their DFSG rights, it's OK if there are other people who can do more. For example, if a work were distributed to everyone under the GPL, but elementary school teachers were given the extra right to distribute binaries without distributing the corresponding source code, it would still be DFSG-Free.

    6. Q: I've just made up a new license which requires people using the software to agree to a contract which forbids them from doing some bad stuff (like finding security flaws and not reporting them) that copyright law would otherwise allow as fair use. We can force everyone to cooperate even more! Isn't that a great idea?

      A: We do not think so. Such a license does not meet our standards of freedom. Freedom means not only the freedom to modify, and to help others; it also means the freedom to enjoy one's own privacy.

    7. Q: I'd like users of my software to send me a postcard, so I can get a collection of postcards from cool places. Should I put this in the program's license as a condition of use?

      A: So-called "postcardware", or similarly "emailware" which requires users to send email to the author, fails the Desert Island test, so it is not free. So our advice here is: no.

      However we understand your desire to receive postcards from users, and would like suggest another way to achieve this goal. Instead of making this a requirement in the license, make it a personal request! Just add a "personal note from the author", which is clearly not part of the license itself, saying "Although it is not required, I'd personally very much appreciate it if users would send me postcards telling me how they are making use of this program." You should still get postcards, but they will be voluntary. Which is actually nicer, when you think about it.

    8. Q: I'm a working scientist, and would like to release code implementing my work. However I want to make sure that people using the software mention its use, and cite my papers, in papers they write. Should I include this in the license?

      A: You have a valid concern. Computer scientists often receive inadequate credit for their scientific contributions. But putting such a clause in the license would render your software non-free. Instead we suggest a note, not part of the license itself, reminding users of the rules of scientific propriety. Eg:

      SCIENTISTS: please be aware that the fact that this software is released under the GPL (or whatever) does not excuse you from scientific propriety, which obligates you to give appropriate credit! If you write a scientific paper describing research that made substantive use of this program, please (a) mention the fashion in which this software was used, including the version number, with a citation to the literature, in the "Methods" section, to allow replication; (b) mention this software in the "Acknowledgements" section, to acknowledge its contribution to your work; and (c) use the following citation, eg in the "References" section: John Q. Doe (2003) "BLOBBER: A program to analyze blobs", J. Comp. Neurobio. Meth. Eng. 12(34):567-89. Moreover, as a personal note, I would very much appreciate it if you would send email to with citations of papers referencing this work so I can mention them to my funding agent and tenure committee.

    9. Q: Can I say "You must not charge money for distributing the program"?

      A: This is non-free. We want Debian to be distributed by for-profit CD vendors and improved by corporate resellers. We can only include programs whose authors allow this.

      For many users buying Debian on disks will be more convenient (and cheaper) than downloading it from an FTP site. For-profit distribution is the most reliable and convenient way to ensure that Debian disks are easily available everywhere where there is a demand. Because everyone can download the CD images and start producing their own disks, competition will make sure that nobody can make undeserved fortunes selling Debian (or any other free software, for that matter.)

    10. Q: Can I say "You must not use the program for commercial purposes"?

      A: This is non-free. We want businesses to be able to use Debian for their computing needs. A business should be able to use any program they find in Debian without checking what its license says.

    11. Q: Can I say "You must not change the program such that it does not implement what I say is the correct interface"?

      A: This is non-free because it denies the user the freedom to adapt the software to a different problem which requires different interfaces.

      We consider a very important facet of software freedom to be the freedom to adapt old tools to new problems. If I find a program in Debian which I think can be adapted to solve a problem I have (and which nobody ever thought about before), I expect to be allowed to make that adaptation - even if that means I need to change some of the external interfaces of the program. And I shouldn't need to worry about the fact that my adapted tool does not solve the original problem anymore if the original problem is not what I need to solve.

      Additionally: This kind of clause gives the author (authors are free to ignore their own rules) a de facto monopoly on experiments with alternative ways of doing things. It therefore fails the Tentacles of Evil test. One of the points of free software is that everyone should be free to try out new ways of doing things. This license clause denies the users the freedom to try out and exchange new ideas. This freedom is one of the most important driving factors for progress in computing---and we like progress.

    12. Q: Can I say "You must only distribute the program to people who have agreed to this license"?

      A: This is non-free because it makes it hard to mass distribute the program together with other programs, for example on an FTP site or CDs. Such clauses effectively forbid FTP distribution, and CD distribution would be prohibitively expensive and inconvenient if the CD manufacturer was required to make every customer sign a gazillion different licenses. (See CLICKWRAP above.)


      A: There are certain rights granted to anyone who is in lawful possession of copy of a work, even when that work is under copyright. Free software gives you those rights (at least as they hold in the US, where this is called fair use) plus a whole bunch more. Anything that tries to get the user to agree to "be bound by" something is almost certainly doing so in order to get them to agree to give up some of the rights they would otherwise automatically have! After all, one does not need the user's agreement in order to give them extra rights. So boilerplate like the above is generally a promise that the license will, upon close examination, be found to contain something non-free. In other words, free software licenses do not need such an agreement.

    14. Q: Can I say "If you modify the program [and distribute your modifications] you must send your patch to me"?

      A: This is non-free because it fails the Desert Island test and also the Dissident test.

    15. Q: Can I say "I reserve my right to withdraw your license if anyone claims they have copyright [or patent rights] to the program"?

      A: This is non-free because (among other things) it fails the Tentacles of Evil test.

    16. Q: Can I say "You must obey U.S. export laws"?

      A: This is non-free because it imposes restrictions on people outside the US which they might otherwise not be subject to. To protect yourself while keeping the license free you can rephrase this as a warning instead of a condition: "Please be aware that this license does not release you from your obligation to follow the law. We note in particular the US Export laws which may impact what you are legally allowed to do with this software, especially with regard to redistribution."

      A stronger way to phrase this is: It is not the job of a copyright license to reiterate what is or is not legal in a particular jurisdiction. The job of a copyright license is to grant permissions to do things that would otherwise be forbidden under copyright law.

    17. Q: Can I say "You must monitor my website"?

      A: This is non-free because it fails the Desert Island test. It is also an unreasonable burden - imagine if you had to constantly monitor 400 web sites in order to legally use the software on your computer.

    18. Q: I understand all the above logic, but my program is special and I'm really a very nice corporation and I have very innocuous and socially beneficial reasons for wanting to include a very small extra technically non-free clause that is not so inconvenient as you seem to think. Plus the software in question was very expensive to develop, and is truly wonderful, and I'm trying very hard to contribute to the free software community in a way that is acceptable to my lawyers. Could you please make an exception just this once? You should at least compromise a little bit, because I have been very flexible on many other points.

      A: No.

      There are over 10,000 packages in Debian. If we made exceptions for just 1%, users would have to carefully evaluate how much of a burden the non-free parts of 100 licenses might be. It is just not feasible, and we think we've drawn the line at the right place: where it is best for our users and for the free software community.

      (In any case, these matters are not subject to negotiation or compromise. Think satisfying the fire code rather than negotiating a deal.)

      As a bit of practical advice, you would really be better off using a "standard" license. It might be less fun for your lawyers, but your software will be more readily accepted, and more people will contribute to it, and after all isn't that what you want?

  12. Q: What does "no discrimination" mean? Doesn't the GPL discriminate against companies making proprietary software?

    A: The intent is to prevent prohibitions against use by people fighting their own government, or building weapons of mass destruction, or Jews, or the French Postal Service. The DFSG contains a few more examples. The GPL does not discriminate against companies that want to make proprietary software based on GPLed code because they are given the same rights to GPLed software that anyone else has. They happen to also want the right to sell non-free derivative works, but no one is given that right so this does not constitute discrimination.

  13. Q: Since software "placed in the public domain" has no license isn't it not under a free software license, and therefore not acceptable as free software according to the DFSG?

    A: Software placed in the public domain has all the freedoms required by the DFSG, and is free software.

  14. Q: The program FOO is free according to the DFSG and its license, can I now demand that Debian package FOO and include it in Debian GNU/Linux?

    A: Although Debian includes only free software, we do not include all the free software in the whole world. (Although we do include so much that one can understand people thinking we include it all.) What software we choose to distribute is Debian's own decision, and no one else's. In particular, we are not obligated to distribute FOO.

    Here is what must occur for FOO to get into Debian GNU/Linux. First, it must be free, by our standards. Then it must be properly packaged, either by a Debian developer or by someone else. Then it must be "uploaded" by a Debian developer. (This is called "sponsoring" if someone else actually did the packaging.) Then the Debian ftp masters must allow it in; they are a final screen against license issues or software integration problems. At this point the package is being distributed by Debian, but is not part of the official release. For that to occur it must be of sufficiently high quality to make it through a semi-automatic Q/A process involving the Debian BTS, and the release manager must allow it to be included in the next major release.

    To get this rolling you can file an RFP, see Work-Needing and Prospective Packages for details.

  15. Q: What are "compatible" licenses, and what does "GPL compatible" mean?

    A: In order for two licenses to be compatible it must be possible to mingle code under both licenses in a new work. When this is done the result is that the terms of both licenses must be met for the work as a whole. The GPL makes this feature of copyright law explicit by stating that if you cannot for any reason (e.g., because of another license) meet the terms of the GPL, the GPL grants no rights at all. In order for a license to be GPL compatible, then, you must be able to meet both the terms of the GPL and the other license simultaneously.

  16. Q: What is a "dual license"?

    A: When a work is released under a dual license the recipient is explicitly given the option to choose which license to apply to a derivative work. Someone making modifications may include new code under either license, or (as is most common) under the same dual license.

  17. Q: Why are almost all these "dual" licenses dualed with the GPL?

    A: The GPL is particularly common in dual licenses because it allows the code to link with the large body of GPLed code available including many important libraries, and to be incorporated into other GPLed works. Many common works are under dual GPL/??? licenses: perl is under GPL/Artistic, Qt is under GPL/QPL, Mozilla is under GPL/MPL. This is almost always due to a project starting with a home-brewed GPL-incompatible license, then realizing they'd made a mistake and finding relicensing in this fashion to be the most convenient resolution.

  18. Q: What is an almost-free license?

    A: XXX

  19. Q: Do people really release programs under almost-free licenses?

    A: Unfortunately yes. For instance xlock (which has been superseded by the superior xscreensaver) and the SQUEAK Smalltalk system.

  20. Q: What license does the Free Software Foundation (which sponsors the GNU project) advise?

    A: The GPL. The FSF has declared the LGPL obsolete, and urges libraries to be released under the GPL unless there is a compelling reason to use the LGPL.

  21. Q: The FSF project asks for code assignments, doesn't this put software at risk if the FSF should be acquired or infiltrated by Microsoft, or lose a court battle and have its assets confiscated?

    A: No, the FSF has clever lawyers who wrote the copyright assignment carefully to preclude any such danger.

  22. Q: What does GNU LGPL stand for?

    A: The LGPL stands for Lesser General Public License. (It used to stand for Library General Public License, but no longer.)

  23. Q: Doesn't even Debian include some non-free software?

    A: No.

    We do allow some non-free packages to use our distribution infrastructure, but they are not actually part of Debian proper. (There are some requirements on licenses for such non-free programs, so debian-legal does sometimes examine the licenses of non-free programs for distributability; it is not a priority though.) The existence of this non-free area can lead to confusion, so some members of Debian would like to remove non-free from our servers. On the other hand, many packages in non-free have migrated into Debian proper when their authors changed their almost-free licenses to make them actually free, and other programs have had their functionality painlessly migrated to newly available free alternatives. For this reason, other Debian developers want to retain the status quo.

  24. Q: What is the story with KDE and Debian and some license problem? I heard that Debian hates KDE.

    A: KDE is currently in Debian. There is no license problem. We love KDE and always have, and included it in Debian the moment we were able to.

    Some time ago there was a license problem, but it has been resolved. The problem was that KDE was under the GPL while the Qt library, which it relied on, was under a rather odd license called the QPL, which although (debatably) free was not "GPL compatible." (And before that, Qt was under a license that didn't allow modifications at all.) This meant that Debian did not have permission to distribute KDE, at least as pre-compiled binaries, without a "Qt waiver" on all the KDE code, which we did not have. Debian was thus (very reluctantly) unable to distribute KDE. This license issue caused a fuss, and the upshot was (a) GNOME, and (b) TrollTech re-released the Qt library under a "QPL/GPL dual license" which solved the problem.

  25. Q: What is a "waiver" on a GPL-licensed program?

    A: It is generally permission to create and distribute derived works that are linked to some particular library which is under a non-GPL-compatible license. For instance, "libssl" is such a library, and some GPLed programs use libssl. In order for such a program to be included in Debian, a note accompanying the license giving some extra permission must be present. Here is one such note (taken from /usr/share/doc/wget/copyright) which allows binaries of the GPLed program "wget" which are linked to the non-GPL-compatible OpenSSL library to be distributed:

    "In addition, as a special exception, the Free Software Foundation gives permission to link the code of its release of Wget with the OpenSSL project's "OpenSSL" library (or with modified versions of it that use the same license as the "OpenSSL" library), and distribute the linked executables. You must obey the GNU General Public License in all respects for all of the code used other than "OpenSSL". If you modify this file, you may extend this exception to your version of the file, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version."

  26. Q: If I release software under a free software license that does not allow others to make proprietary derived works, does this preclude me from making proprietary derived works myself?

    A: No.

    Licenses gives others permissions that you already have. It is your code. You don't need your own permission to make a proprietary version, or to release a version under a different license, or to sell someone else the right to make a proprietary version, or to sell someone else the right to incorporate parts of the code in a proprietary program. (One caveat: if you incorporate non-trivial changes other people have made into your code base you are no longer the sole author. You would then need their permission to make a proprietary version, just as they would need yours.)

  27. Q: I want to release my code as free software, but am willing to allow people to pay for the right to include it in their proprietary programs. Should I say so in the license?

    We believe it is better (ie simpler and less confusing for everyone) to mention that in a separate note, rather than in the license. This allows you to use a "standard" free software license.

  28. Q: What is the difference between "free software" and "open source software"?

    A: There isn't any difference, or at least there isn't meant to be.

    "Open source software" was coined as a new name for "free software" which was supposed to avoid the confusion arising from the fact that you're allowed to charge money for free software which might seem counterintuitive. It was also meant to give the community some branding power, because it was hoped that "open source software" could be controlled and legally permitted for use only on actual free software, whereas any company can distribute some proprietary software at no charge (eg Internet Explorer) and, since they are not charging any money, call it "free software". (What we mean by the "free" in "free software" is of course a set of freedoms, not a price; "free as in free speech" rather than "free as in free beer".) OSS was also meant to sound more professional and hence more attractive to businesses. In practice there are slight differences in emphasis between the people who use the two terms, and having two terms has caused confusion and a surprising amount of friction. Some people have begun to use terms like FLOSS (Free/Libre Open Source Software) to avoid both possible confusion and taking a side in the terminological debate.

    Some of the people who helped coin and popularize the term "open source software" have had second thoughts about it, and some of the legal measures originally planned (formal registration of the term "open source" as applied to software) did not actually come to fruition. The term "open source" itself is also ambiguous, in that some companies "open" their source code for examination without granting the right to make changes or to pass on copies. The organization controlling the "open source software" certification mark made some borderline (ie controversial) determinations about some licenses, which served to dilute the standing of the mark itself.

    A number of people who made enormous contributions to Debian (eg Bruce Perens, former Debian project leader) and to free software in general have or held prominent positions in the Open Source Initiative. Nonetheless Debian in general, and this document in particular, uses the term "free software". This is in part out of respect for the Free Software Foundation and the GNU project, in part to emphasize the large body of GNU code in Debian GNU/Linux, in part because the term "free software" seems more appropriate in technical forums because it sounds less corporate-speak, and in part due to the issues discussed above.

  29. Q: What is the difference between "commercial" and "proprietary" software?

    A: To quote the 1913 Webster's,

    {Proprietary articles}, manufactured articles which some person or persons have exclusive right to make and sell.
    --U. S. Statutes.

    {Commercial}. Of or pertaining to commerce; carrying on or occupied with commerce or trade; mercantile; as, commercial advantages; commercial relations. "Princely commercial houses."

    "Proprietary" software is software that can be legally modified or distributed only by some authorized set of persons. So by definition "proprietary software" cannot be "free software".

    Software is "commercial" if some corporation is distributing it and trying to make money from it, either via direct sales or via maintenance and support. Many corporations have made money by distributing, supporting, and maintaining free software, so it is possible for a piece of software to be both free and commercial. Anyone can sell a support contract for free software, and access to the source code allows such support to include not just hand-holding but also bug fixes and new features. This is a major advantage of free software as it makes for competition in such services, which is greatly to the benefit of users of free software. Corporations offering support contracts for free software include IBM, Redhat, LinuxCare, SAP, Trolltech, Ximbiot, and many others. Debian also encourages corporations to create products based on Debian GNU/Linux, such as Lindows. Many corporations pay employees to write and maintain free software from which they fully intend to make money, some of whom directly contribute their work to Debian as part of their jobs. Other employees of corporations are paid to maintain free software which is in internal use by the corporation in question, and contribute their modifications in order to ensure that their changes will not have to be re-applied to each new version.

  30. Q: If all software were free how could programmers make a living?

    A: This question is extremely misleading. There is no reason to think that free software puts programmers in the poorhouse. In fact, the economics of the situation argue for quite the reverse! The vast majority of working computer programmers (over 95%) work at businesses that do not sell software: they write software for in-house use, for embedded devices, for driving new hardware, etc. Free software makes programmers more productive, which has the effect of raising the average salaries of all programmers. It also makes programming more fun, since there is less need to re-invent the wheel. Moreover, even if free software reduced society's demand for programmers well below the current supply, so what? Automation and increased efficiency often reduce the number of jobs in some category and this is something we accept---buggy whip manufacturers come to mind---and Debian is not a trade union.

    Debian itself takes no stand on the "morality" of proprietary software, or whether aspects of the current legal system which encourage proprietary software should be modified. Many people who write free software, including some Debian developers, also write proprietary software.

  31. Q: What are the "four freedoms"?

    A: These four freedoms

    are the Free Software Foundation's articulation of the freedoms that the FSF believes all software users deserve. (Note that full exercise of Freedoms 1 and 3 requires access to the source code.) They are elegantly phrased, and arguably an improvement in some ways on the earlier DFSG. However they refer to exactly the same set of freedoms as the DFSG. If a license is inconsistent with the FSF's four freedoms, you can be sure that Debian will also consider it non-free.

    The term "four freedoms" is a play on words over the influential "four freedoms" speech of US President Franklin Delano Roosevelt in which he outlined the following four freedoms: Freedom of Speech, Freedom of Religion, Freedom from Want, and Freedom from Fear.

  32. Q: What FAQs remain to be added to this document?

    A: What fraction of Debian packages/lines-of-code are under what licenses? What is an almost-free license (eg xlock's) and why should I avoid them? Some historical material, both summaries and pointers to longer treatments, would be nice. Some references. More links, both cross-references and references to other documents, would be useful.

  33. Q: What version of this FAQ am a reading? When was it last updated?

    A: $Revision: 1.69 $ $Date: 2003/08/14 16:55:28 $

  34. Q: Who wrote this document?

    A: Barak A. Pearlmutter ( with help from Joe Moore (, Mark Rafn (, Thomas Bushnell, BSG (, Richard Braakman (, Henning Makholm (, Anthony Towns (, Jeremy Hankins (, Florian Weimer (, Thomas Hood (, James Devenish (