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6  </HEAD>  <title>What is Free Software?
7  <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#1F00FF" ALINK="#FF0000" VLINK="#9900DD">  - GNU Project - Free Software Foundation</title>
8  <H3>The Free Software Definition</H3>  <style type="text/css" media="print,screen"><!--
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14  [  <meta http-equiv="Keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" />
15  <!-- Please keep this list alphabetical -->  <meta http-equiv="Description" content="Since 1983, developing the free Unix style operating system GNU, so that computer users can have the freedom to share and improve the software they use." />
16  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  <!--#include virtual="/philosophy/po/free-sw.translist" -->
17  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <!--#include virtual="/server/banner.html" -->
18  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  <!--#include virtual="/philosophy/ph-breadcrumb.html" -->
19  | <A HREF="/philosophy/free-sw.da.html">Danish</A>  <!--GNUN: OUT-OF-DATE NOTICE-->
20  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  <!--#include virtual="/server/top-addendum.html" -->
21  | <A HREF="/philosophy/free-sw.html">English</A>  <div class="reduced-width">
22  | <A HREF="/philosophy/free-sw.fr.html">French</A>  <h2>What is Free Software?</h2>
23  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  <div class="thin"></div>
24  | <A HREF="/philosophy/free-sw.de.html">German</A>  
25  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <div class="article">
26  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  <div class="important">
27  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  <p>
28  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  &ldquo;Free software&rdquo; means software that respects users'
29  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  freedom and community.  Roughly, it means that <b>the users have the
30  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  freedom to run, copy, distribute, study, change and improve the
31  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
32  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  liberty, not price.  To understand the concept, you should think of
33  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
34  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
35  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>  software,&rdquo; borrowing the French or Spanish word for
36  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  &ldquo;free&rdquo; as in freedom, to show we do not mean the software
37  | <A HREF="/philosophy/free-sw.sv.html">Swedish</A>    is gratis.
38  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  </p>
39  <!-- Please keep this list alphabetical -->  
40  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  <p>
41  ]  You may have paid money to get copies of a free program, or you may
42  <P>  have obtained copies at no charge.  But regardless of how you got your
43    copies, you always have the freedom to copy and change the software,
44  We maintain this free software definition to show clearly what must be  even to <a href="/philosophy/selling.html">sell copies</a>.
45  true about a particular software program for it to be considered  </p>
46  free software.  </div>
47    
48  <P>  <p>
49    We campaign for these freedoms because everyone deserves them.  With
50  ``Free software'' is a matter of liberty, not price.  To understand the  these freedoms, the users (both individually and collectively) control
51  concept, you should think of ``free'' as in ``free speech,'' not as in  the program and what it does for them.  When users don't control the
52  ``free beer.''  program, we call it a &ldquo;nonfree&rdquo; or
53  <P>  &ldquo;proprietary&rdquo; program.  The nonfree program controls the
54  Free software is a matter of the users' freedom to run, copy,  users, and the developer controls the program; this makes the
55  distribute, study, change and improve the software.  More precisely,  program <a href="/philosophy/free-software-even-more-important.html">
56  it refers to four kinds of freedom, for the users of the software:  an instrument of unjust power</a>.
57  <P>  </p>
58    
59  <UL>  <p>
60    <LI>The freedom to run the program, for any purpose (freedom 0).  &ldquo;Open source&rdquo; is something different: it has a very
61    <LI>The freedom to study how the program works, and adapt it to your needs  different philosophy based on different values.  Its practical
62        (freedom 1).   Access to the source code is a precondition for this.  definition is different too, but nearly all open source programs are
63    <LI>The freedom to redistribute copies so you can help your neighbor  in fact free.  We explain the
64    difference in <a href="/philosophy/open-source-misses-the-point.html">
65    Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
66    </p>
67    
68    <div class="toc">
69    <hr class="no-display" />
70    <h3 class="no-display">Table of contents</h3>
71    <ul>
72     <li><a href="#fs-definition">The Free Software Definition</a>
73      <ul>
74       <li><a href="#four-freedoms">The four essential freedoms</a></li>
75       <li><a href="#selling">Free software <em>can</em> be commercial</a></li>
76      </ul>
77     </li>
78     <li><a href="#clarifying">Clarifying the Boundary Between Free and Nonfree</a>
79      <ul>
80       <li><a href="#run-the-program">The freedom to run the program as you
81         wish</a></li>
82       <li><a href="#make-changes">The freedom to study the source code and make
83         changes</a></li>
84       <li><a href="#redistribute">The freedom to redistribute if you wish:
85         basic requirements</a></li>
86       <li><a href="#copyleft">Copyleft</a></li>
87       <li><a href="#packaging">Rules about packaging and distribution
88         details</a></li>
89       <li><a href="#exportcontrol">Export regulations</a></li>
90       <li><a href="#legal-details">Legal considerations</a></li>
91       <li><a href="#contracts">Contract-based licenses</a></li>
92      </ul>
93     </li>
94     <li><a href="#in-practice">The Free Software Definition in Practice</a>
95      <ul>
96       <li><a href="#interpretation">How we interpret these criteria</a></li>
97       <li><a href="#get-help">Get help with free licenses</a></li>
98       <li><a href="#terminology">Use the right words when talking about free
99         software</a></li>
100      </ul>
101     </li>
102     <li><a href="#beyond-software">Beyond Software</a></li>
103     <li><a href="#History">History</a></li>
104    </ul>
105    </div>
106    
107    <div class="edu-note" id="fsf-licensing">
108    <p style="font-size:80%">
109    Have a question about free software licensing not answered here?
110    See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
111    and if necessary contact the FSF Compliance Lab
112    at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
113    <hr class="no-display" />
114    </div>
115    
116    
117    <h3 id="fs-definition" class="subheader">The Free Software Definition</h3>
118    
119    <p>
120    The free software definition presents the criteria for whether a
121    particular software program qualifies as free software.  From time to
122    time we revise this definition, to clarify it or to resolve questions
123    about subtle issues.  See the <a href="#History">History section</a>
124    below for a list of changes that affect the definition of free
125    software.
126    </p>
127    
128    <h4 id="four-freedoms">The four essential freedoms</h4>
129    <p>
130    A program is free software if the program's users have the
131    four essential freedoms: <a href="#f1">[1]</a>
132    </p>
133    
134    <ul class="important">
135      <li>The freedom to run the program as you wish,
136          for any purpose (freedom 0).</li>
137      <li>The freedom to study how the program works, and change it so it
138          does your computing as you wish (freedom 1). Access to the source
139          code is a precondition for this.
140      </li>
141      <li>The freedom to redistribute copies so you can help others
142        (freedom 2).        (freedom 2).
143    <LI>The freedom to improve the program, and release your improvements    </li>
144       to the public, so that the whole community benefits    <li>The freedom to distribute copies of your modified versions
145        (freedom 3).   Access to the source code is a precondition for this.        to others (freedom 3).  By doing this you can give the whole
146  </UL>        community a chance to benefit from your changes.
147          Access to the source code is a precondition for this.
148  <P>    </li>
149  A program is free software if users have all of these freedoms.  </ul>
150  Thus, you should be free to redistribute copies, either with or  
151  without modifications, either gratis or charging a fee for  <p>
152  distribution, to <A HREF="#exportcontrol">anyone anywhere</A>.  Being  A program is free software if it gives users adequately all of these
153  free to do these things means (among other things) that you do not  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
154  have to ask or pay for permission.  nonfree distribution schemes in terms of how far they fall short of
155    being free, we consider them all equally unethical.</p>
156    
157    <p>In any given scenario, these freedoms must apply to whatever code
158    we plan to make use of, or lead others to make use of.  For instance,
159    consider a program A which automatically launches a program B to
160    handle some cases.  If we plan to distribute A as it stands, that
161    implies users will need B, so we need to judge whether both A and B
162    are free.  However, if we plan to modify A so that it doesn't use B,
163    only A needs to be free; B is not pertinent to that plan.</p>
164    
165    
166    <h4 id="selling">Free software <em>can</em> be commercial</h4>
167    
168    <p>
169    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.
170    On the contrary, a free program must be available for commercial use,
171    commercial development, and commercial distribution.  This policy is
172    of fundamental importance&mdash;without this, free software could not
173    achieve its aims.
174    </p>
175    
176    <p>
177    We want to invite everyone to use the GNU system, including businesses
178    and their workers.  That requires allowing commercial use.  We hope
179    that free replacement programs will supplant comparable proprietary
180    programs, but they can't do that if businesses are forbidden to use
181    them.  We want commercial products that contain software to include
182    the GNU system, and that would constitute commercial distribution for
183    a price.  Commercial development of free software is no longer
184    unusual; such free commercial software is very important.  Paid,
185    professional support for free software fills an important need.
186    </p>
187    
188    <p>
189    Thus, to exclude commercial use, commercial development or commercial
190    distribution would hobble the free software community and obstruct its
191    path to success.  We must conclude that a program licensed with such
192    restrictions does not qualify as free software.
193    </p>
194    
195    <p>
196    A free program must offer the four freedoms to any would-be user that
197    obtains a copy of the software, who has complied thus far with the
198    conditions of the free license covering the software in any previous
199    distribution of it.  Putting some of the freedoms off limits to some
200    users, or requiring that users pay, in money or in kind, to exercise
201    them, is tantamount to not granting the freedoms in question, and thus
202    renders the program nonfree.
203    </p>
204    
205    
206    <h3 id="clarifying" class="subheader">Clarifying the Boundary Between Free and Nonfree</h3>
207    
208    <p>In the rest of this article we explain more precisely how far the
209    various freedoms need to extend, on various issues, in order for a
210    program to be free.</p>
211    
212    <h4 id="run-the-program">The freedom to run the program as you wish</h4>
213    
214    <p>
215    The freedom to run the program means the freedom for any kind of person
216    or organization to use it on any kind of computer system, for any kind of
217    overall job and purpose, without being required to communicate about it
218    with the developer or any other specific entity.  In this freedom, it is
219    the <em>user's</em> purpose that matters, not the <em>developer's</em>
220    purpose; you as a user are free to run the program for your purposes,
221    and if you distribute it to someone else, she is then free to run it
222    for her purposes, but you are not entitled to impose your purposes on her.
223    </p>
224    
225    <p>
226    The freedom to run the program as you wish means that you are not
227    forbidden or stopped from making it run.  This has nothing to do with what
228    functionality the program has, whether it is technically capable of
229    functioning in any given environment, or whether it is useful for any
230    particular computing activity.</p>
231    
232    <p>For example, if the code arbitrarily rejects certain meaningful
233    inputs&mdash;or even fails unconditionally&mdash;that may make the
234    program less useful, perhaps even totally useless, but it does not
235    deny users the freedom to run the program, so it does not conflict
236    with freedom 0.  If the program is free, the users can overcome the
237    loss of usefulness, because freedoms 1 and 3 permit users and
238    communities to make and distribute modified versions without the
239    arbitrary nuisance code.</p>
240    
241    <p>&ldquo;As you wish&rdquo; includes, optionally, &ldquo;not at
242    all&rdquo; if that is what you wish.  So there is no need for a
243    separate &ldquo;freedom not to run a program.&rdquo;</p>
244    
245    <h4 id="make-changes">The freedom to study the source code and make changes</h4>
246    
247    <p>
248    In order for freedoms 1 and 3 (the freedom to make changes and the
249    freedom to publish the changed versions) to be meaningful, you need to have
250    access to the source code of the program.  Therefore, accessibility of
251    source code is a necessary condition for free software.  Obfuscated
252    &ldquo;source code&rdquo; is not real source code and does not count
253    as source code.
254    </p>
255    
256    <p>
257    Freedom 1 includes the freedom to use your changed version in place of
258    the original.  If the program is delivered in a product designed to
259    run someone else's modified versions but refuse to run yours &mdash; a
260    practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
261    or (in its practitioners' perverse terminology) as &ldquo;secure
262    boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
263    practical reality.  These binaries are not free
264    software even if the source code they are compiled from is free.
265    </p>
266    
267    <p>
268    One important way to modify a program is by merging in available free
269    subroutines and modules.  If the program's license says that you
270    cannot merge in a suitably licensed existing module &mdash; for instance, if it
271    requires you to be the copyright holder of any code you add &mdash; then the
272    license is too restrictive to qualify as free.
273    </p>
274    
275    <p>
276    Whether a change constitutes an improvement is a subjective matter.
277    If your right to modify a program is limited, in substance, to changes that
278    someone else considers an improvement, that program is not free.
279    </p>
280    
281    <p>
282    One special case of freedom 1 is to delete the program's code so it
283    returns after doing nothing, or make it invoke some other program.
284    Thus, freedom 1 includes the &ldquo;freedom to delete the program.&rdquo;
285    </p>
286    
287    <h4 id="redistribute">The freedom to redistribute if you wish: basic
288    requirements</h4>
289    
290    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
291    redistribute copies, either with or without modifications, either
292    gratis or charging a fee for distribution, to
293    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
294    things means (among other things) that you do not have to ask or pay
295    for permission to do so.
296    </p>
297    
298  <P>  <p>
299  You should also have the freedom to make modifications and use them  You should also have the freedom to make modifications and use them
300  privately in your own work or play, without even mentioning that they  privately in your own work or play, without even mentioning that they
301  exist.  If you do publish your changes, you should not be required to  exist.  If you do publish your changes, you should not be required to
302  notify anyone in particular, or in any particular way.  notify anyone in particular, or in any particular way.
303    </p>
304    
305  <P>  <p>
306  The freedom to use a program means the freedom for any kind of person  Freedom 3 includes the freedom to release your modified versions
307  or organization to use it on any kind of computer system, for any kind  as free software.  A free license may also permit other ways of
308  of overall job, and without being required to communicate subsequently  releasing them; in other words, it does not have to be
309  with the developer or any other specific entity.  a <a href="/licenses/copyleft.html">copyleft</a> license.  However, a
310    license that requires modified versions to be nonfree does not qualify
311    as a free license.
312    </p>
313    
314  <P>  <p>
315  The freedom to redistribute copies must include binary or executable  The freedom to redistribute copies must include binary or executable
316  forms of the program, as well as source code, for both modified and  forms of the program, as well as source code, for both modified and
317  unmodified versions.  (Distributing programs in runnable form is  unmodified versions.  (Distributing programs in runnable form is necessary
318  necessary for conveniently installable free operating systems.)  It is  for conveniently installable free operating systems.)  It is OK if there
319  ok if there is no way to produce a binary or executable form for a  is no way to produce a binary or executable form for a certain program
320  certain program (since some languages don't support that feature), but  (since some languages don't support that feature), but you must have the
321  you must have the freedom to redistribute such forms should you find  freedom to redistribute such forms should you find or develop a way to
322  or develop a way to make them.  make them.
323    </p>
324  <P>  
325  In order for the freedoms to make changes, and to publish improved  <h4 id="copyleft">Copyleft</h4>
 versions, to be meaningful, you must have access to the source code of  
 the program.  Therefore, accessibility of source code is a necessary  
 condition for free software.  
   
 <P>  
 In order for these freedoms to be real, they must be irrevocable as  
 long as you do nothing wrong; if the developer of the software has the  
 power to revoke the license, without your doing anything to give  
 cause, the software is not free.  
326    
327  <P>  <p>
328  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
329  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
330  freedoms.  For example, copyleft (very simply stated) is the rule that  freedoms.  For example, <a href="/licenses/copyleft.html">copyleft</a>
331  when redistributing the program, you cannot add restrictions to deny  (very simply stated) is the rule that when redistributing the program,
332  other people the central freedoms.  This rule does not conflict with  you cannot add restrictions to deny other people the central freedoms.
333  the central freedoms; rather it protects them.  This rule does not conflict with the central freedoms; rather it
334    protects them.
335  <P>  </p>
336  Thus, you may have paid money to get copies of free software, or you  
337  may have obtained copies at no charge.  But regardless of how you got  <p>
338  your copies, you always have the freedom to copy and change the  In the GNU project, we use copyleft to protect the four freedoms
339  software, even to <A HREF="/philosophy/selling.html">sell copies</A>.  legally for everyone.  We believe there are important reasons why
340  <P>  <a href="/philosophy/pragmatic.html">it is better to use
341    copyleft</a>.  However,
342  ``Free software'' does not mean ``non-commercial''.  A free program  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
343  must be available for commercial use, commercial development, and  noncopylefted free software</a> is ethical
344  commercial distribution.  Commercial development of free software is  too.  See <a href="/philosophy/categories.html">Categories of Free
345  no longer unusual; such free commercial software is very important.  Software</a> for a description of how &ldquo;free software,&rdquo;
346    &ldquo;copylefted software&rdquo; and other categories of software
347  <P>  relate to each other.
348  Rules about how to package a modified version are acceptable, if they  </p>
349  don't effectively block your freedom to release modified versions.  
350  Rules that ``if you make the program available in this way, you must  <h4 id="packaging">Rules about packaging and distribution details</h4>
351  make it available in that way also'' can be acceptable too, on the  
352  same condition.  (Note that such a rule still leaves you the choice of  <p>
353  whether to publish the program or not.)  It is also acceptable for the  Rules about how to package a modified version are acceptable,
354  license to require that, if you have distributed a modified version  if they don't substantively limit your freedom to release modified
355  and a previous developer asks for a copy of it, you must send one.  versions, or your freedom to make and use modified versions privately.
356    Thus, it is acceptable for the license to require that you change the
357  <P>  name of the modified version, remove a logo, or identify your
358  In the GNU project, we use <A HREF="/copyleft/copyleft.html">  modifications as yours.  As long as these requirements are not so
359  ``copyleft''</A> to protect these freedoms legally for everyone.  But  burdensome that they effectively hamper you from releasing your
360  <A HREF="/philosophy/categories.html#Non-CopyleftedFreeSoftware">  changes, they are acceptable; you're already making other changes to
361  non-copylefted free software</A> also exists.  We believe there are  the program, so you won't have trouble making a few more.
362  important reasons why <A HREF="/philosophy/pragmatic.html"> it is  </p>
363  better to use copyleft</A>, but if your program is non-copylefted free  
364  software, we can still use it.  <p>
365    Rules that &ldquo;if you make your version available in this way, you
366  <P>  must make it available in that way also&rdquo; can be acceptable too,
367  See <A HREF="/philosophy/categories.html">Categories of Free Software  on the same condition.  An example of such an acceptable rule is one
368         (18k characters)</A>  saying that if you have distributed a
369  for a description of how ``free software,'' ``copylefted software'' and  modified version and a previous developer asks for a copy of it, you
370  other categories of software relate to each other.  must send one.  (Note that such a rule still leaves you the choice of
371    whether to distribute your version at all.)  Rules that require release
372  <P>  of source code to the users for versions that you put into public use
373  Sometimes government <A NAME="exportcontrol">export control  are also acceptable.
374  regulations</A> and trade sanctions can constrain your freedom to  </p>
375  distribute copies of programs internationally.  Software developers do  
376  not have the power to eliminate or override these restrictions, but  <p>
377  what they can and must do is refuse to impose them as conditions of  A special issue arises when a license requires changing the name by
378  use of the program.  In this way, the restrictions will not affect  which the program will be invoked from other programs.  That
379  activities and people outside the jurisdictions of these governments.  effectively hampers you from releasing your changed version so that it
380    can replace the original when invoked by those other programs.  This
381  <P>  sort of requirement is acceptable only if there's a suitable aliasing
382  Most free software licenses are based on copyright, and there are  facility that allows you to specify the original program's name as an
383  limits on what kinds of requirements can be imposed through copyright.  alias for the modified version.</p>
384  If a copyright-based license respects freedom in the ways described  
385  above, it is unlikely to have some other sort of problem that we never  <h4 id="exportcontrol">Export regulations</h4>
386  anticipated (though this does happen occasionally).  However, some  
387  free software licenses are based on contracts, and contracts can  <p>
388  impose a much larger range of possible restrictions.  That means there  Sometimes government export control regulations
389  are many possible ways such a license could be unacceptably  and trade sanctions can constrain your freedom to distribute copies of
390  restrictive and non-free.  programs internationally.  Software developers do not have the power to
391  <P>  eliminate or override these restrictions, but what they can and must do
392  We can't possibly list all the possible contract restrictions that  is refuse to impose them as conditions of use of the program.  In this
393  would be unacceptable.  If a contract-based license restricts the user  way, the restrictions will not affect activities and people outside the
394  in an unusual way that copyright-based licenses cannot, and which  jurisdictions of these governments.  Thus, free software licenses
395  isn't mentioned here as legitimate, we will have to think about it,  must not require obedience to any nontrivial export regulations as a
396  and we will probably decide it is non-free.  condition of exercising any of the essential freedoms.
397  <P>  </p>
398  When talking about free software, it is best to avoid using terms like  
399  ``give away'' or ``for free'', because those terms imply that the  <p>
400  issue is about price, not freedom.  Some common terms such as  Merely mentioning the existence of export regulations, without making
401  ``piracy'' embody opinions we hope you won't endorse.  See <A  them a condition of the license itself, is acceptable since it does
402  HREF="/philosophy/words-to-avoid.html">Confusing Words and Phrases  not restrict users.  If an export regulation is actually trivial for
403  that are Worth Avoiding</A> for a discussion of these terms.  free software, then requiring it as a condition is not an actual
404  We also have a list of <A HREF="/philosophy/fs-translations.html">translations  problem; however, it is a potential problem, since a later change in
405  of "free software"</A> into various languages.  export law could make the requirement nontrivial and thus render the
406    software nonfree.
407  <P>  </p>
408    
409  Finally, note that criteria such as those stated in this free software  <h4 id="legal-details">Legal considerations</h4>
410  definition require careful thought for their interpretation.  To  
411  decide whether a specific software license qualifies as a free  <p>
412  software license, we judge it based on these criteria to determine  In order for these freedoms to be real, they must be permanent and
413  whether it fits their spirit as well as the precise words.  If a  irrevocable as long as you do nothing wrong; if the developer of the
414  license includes unconscionable restrictions, we reject it, even if we  software has the power to revoke the license, or retroactively add
415  did not anticipate the issue in these criteria.  Sometimes a license  restrictions to its terms, without your doing anything wrong to give
416  requirement raises an issue that calls for extensive thought,  cause, the software is not free.
417  including discussions with a lawyer, before we can decide if the  </p>
418  requirement is acceptable.  When we reach a conclusion about a new  
419  issue, we often update these criteria to make it easier to see why  <p>
420  certain licenses do or don't qualify.  A free license may not require compliance with the license of a
421    nonfree program.  Thus, for instance, if a license requires you to
422  <P>  comply with the licenses of &ldquo;all the programs you use&rdquo;, in
423    the case of a user that runs nonfree programs this would require
424  If you are interested in whether a specific license qualifies as a  compliance with the licenses of those nonfree programs; that makes the
425  free software license, see our <A  license nonfree.
426  HREF="/licenses/license-list.html">list of licenses</A>.  If the  </p>
427  license you are concerned with is not listed there, you can ask us  
428  about it by sending us email at <A  <p>
429  HREF="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</A>.  It is acceptable for a free license to specify which jurisdiction's
430    law applies, or where litigation must be done, or both.
431  <HR>  </p>
432    
433  <H4><A HREF="/philosophy/philosophy.html">Other Texts to Read</A></H4>  <h4 id="contracts">Contract-based licenses</h4>
434    
435  <P>  <p>
436  Another group has started using the term "open source" to mean  Most free software licenses are based on copyright, and there are limits
437  something close (but not identical) to "free software".  We prefer the  on what kinds of requirements can be imposed through copyright.  If a
438  term "free software" because, once you have heard it refers to freedom  copyright-based license respects freedom in the ways described above, it
439  rather than price, <A HREF="free-software-for-freedom.html">it calls  is unlikely to have some other sort of problem that we never anticipated
440  to mind freedom</A>.  (though this does happen occasionally).  However, some free software
441    licenses are based on contracts, and contracts can impose a much larger
442  <HR>  range of possible restrictions.  That means there are many possible ways
443  [  such a license could be unacceptably restrictive and nonfree.
444  <!-- Please keep this list alphabetical -->  </p>
445  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  
446  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <p>
447  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  We can't possibly list all the ways that might happen.  If a
448  | <A HREF="/philosophy/free-sw.da.html">Danish</A>  contract-based license restricts the user in an unusual way that
449  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  copyright-based licenses cannot, and which isn't mentioned here as
450  | <A HREF="/philosophy/free-sw.html">English</A>  legitimate, we will have to think about it, and we will probably conclude
451  | <A HREF="/philosophy/free-sw.fr.html">French</A>  it is nonfree.
452  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  </p>
453  | <A HREF="/philosophy/free-sw.de.html">German</A>  
454  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <h3 id="in-practice" class="subheader">The Free Software Definition in Practice</h3>
455  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  
456  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  <h4 id="interpretation">How we interpret these criteria</h4>
457  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  
458  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  <p>
459  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  Note that criteria such as those stated in this free software
460  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  definition require careful thought for their interpretation.  To decide
461  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  whether a specific software license qualifies as a free software license,
462  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  we judge it based on these criteria to determine whether it fits their
463  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  spirit as well as the precise words.  If a license includes unconscionable
464  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>        restrictions, we reject it, even if we did not anticipate the issue
465  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  in these criteria.  Sometimes a license requirement raises an issue
466  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  that calls for extensive thought, including discussions with a lawyer,
467  <!-- Please keep this list alphabetical -->  before we can decide if the requirement is acceptable.  When we reach
468  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  a conclusion about a new issue, we often update these criteria to make
469  ]  it easier to see why certain licenses do or don't qualify.
470  <P>  </p>
471  Return to <A HREF="/home.html">GNU's home page</A>.  
472  <P>  <h4 id="get-help">Get help with free licenses</h4>
473    
474  Please send FSF &amp; GNU inquiries &amp; questions to  <p>
475    If you are interested in whether a specific license qualifies as a free
476  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  software license, see our <a href="/licenses/license-list.html">list
477  There are also <A HREF="/home.html#ContactInfo">other ways to  of licenses</a>.  If the license you are concerned with is not
478  contact</A> the FSF.  listed there, you can ask us about it by sending us email at
479  <P>  <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
480    </p>
481  Please send comments on these web pages to  
482    <p>
483  <A HREF="mailto:webmasters@gnu.org"><EM>webmasters@gnu.org</EM></A>,  If you are contemplating writing a new license, please contact the
484  send other questions to  Free Software Foundation first by writing to that address. The
485  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  proliferation of different free software licenses means increased work
486  <P>  for users in understanding the licenses; we may be able to help you
487  Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, Free  find an existing free software license that meets your needs.
488  Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  </p>
489  02111,  USA  
490  <P>  <p>
491  Verbatim copying and distribution of this entire article is  If that isn't possible, if you really need a new license, with our
492  permitted in any medium, provided this notice is preserved.  help you can ensure that the license really is a free software license
493  <P>  and avoid various practical problems.
494  Updated:  </p>
495    
496    <h4 id="terminology">Use the right words when talking about free software</h4>
497    
498    <p>
499    When talking about free software, it is best to avoid using terms
500    like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
501    the issue is about price, not freedom.  Some common terms such
502    as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
503    <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
504    are Worth Avoiding</a> for a discussion of these terms.  We also have
505    a list of proper <a href="/philosophy/fs-translations.html">translations of
506    &ldquo;free software&rdquo;</a> into various languages.
507    </p>
508    
509    <p id="open-source">
510    Another group uses the term &ldquo;open source&rdquo; to mean
511    something close (but not identical) to &ldquo;free software&rdquo;.  We
512    prefer the term &ldquo;free software&rdquo; because, once you have heard that
513    it refers to freedom rather than price, it calls to mind freedom.  The
514    word &ldquo;open&rdquo; never refers to freedom.
515    </p>
516    
517    <h3 id="beyond-software" class="subheader">Beyond Software</h3>
518    
519    <p>
520    <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
521    for the same reasons that software must be free, and because the
522    manuals are in effect part of the software.
523    </p>
524    
525    <p>
526    The same arguments also make sense for other kinds of works of
527    practical use &mdash; that is to say, works that embody useful knowledge,
528    such as educational works and reference
529    works.  <a href="https://wikipedia.org">Wikipedia</a> is the best-known
530    example.
531    </p>
532    
533    <p>
534    Any kind of work <em>can</em> be free, and the definition of free software
535    has been extended to a definition of <a href="http://freedomdefined.org/">
536    free cultural works</a> applicable to any kind of works.
537    </p>
538    <hr class="column-limit" />
539    </div>
540    
541    <h3 id="History">History</h3>
542    
543    <p>From time to time we revise this Free Software Definition.  Here is
544    the list of substantive changes, along with links to show exactly what
545    was changed.</p>
546    
547    <ul>
548    
549    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.168&amp;r2=1.169">Version
550    1.169</a>: Explain more clearly why the four freedoms must apply
551    to commercial activity.  Explain why the four freedoms imply the
552    freedom not to run the program and the freedom to delete it, so there
553    is no need to state those as separate requirements.</li>
554    
555    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.164&amp;r2=1.165">Version
556    1.165</a>: Clarify that arbitrary annoyances in the code do not
557    negate freedom 0, and that freedoms 1 and 3 enable users to remove them.</li>
558    
559    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.152&amp;r2=1.153">Version
560    1.153</a>: Clarify that freedom to run the program means nothing stops
561    you from making it run.</li>
562    
563    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.140&amp;r2=1.141">Version
564    1.141</a>: Clarify which code needs to be free.</li>
565    
566    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.134&amp;r2=1.135">Version
567    1.135</a>: Say each time that freedom 0 is the freedom to run the program
568    as you wish.</li>
569    
570    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.133&amp;r2=1.134">Version
571    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
572    
573    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.130&amp;r2=1.131">Version
574    1.131</a>: A free license may not require compliance with a nonfree license
575    of another program.</li>
576    
577    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.128&amp;r2=1.129">Version
578    1.129</a>: State explicitly that choice of law and choice of forum
579    specifications are allowed.  (This was always our policy.)</li>
580    
581    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.121&amp;r2=1.122">Version
582    1.122</a>: An export control requirement is a real problem if the
583    requirement is nontrivial; otherwise it is only a potential problem.</li>
584    
585    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.117&amp;r2=1.118">Version
586    1.118</a>: Clarification: the issue is limits on your right to modify,
587    not on what modifications you have made.  And modifications are not limited
588    to &ldquo;improvements&rdquo;</li>
589    
590    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.110&amp;r2=1.111">Version
591    1.111</a>: Clarify 1.77 by saying that only
592    retroactive <em>restrictions</em> are unacceptable.  The copyright
593    holders can always grant additional <em>permission</em> for use of the
594    work by releasing the work in another way in parallel.</li>
595    
596    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.104&amp;r2=1.105">Version
597    1.105</a>: Reflect, in the brief statement of freedom 1, the point
598    (already stated in version 1.80) that it includes really using your modified
599    version for your computing.</li>
600    
601    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.91&amp;r2=1.92">Version
602    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
603    
604    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.89&amp;r2=1.90">Version
605    1.90</a>: Clarify that freedom 3 means the right to distribute copies
606    of your own modified or improved version, not a right to participate
607    in someone else's development project.</li>
608    
609    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.88&amp;r2=1.89">Version
610    1.89</a>: Freedom 3 includes the right to release modified versions as
611    free software.</li>
612    
613    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.79&amp;r2=1.80">Version
614    1.80</a>: Freedom 1 must be practical, not just theoretical;
615    i.e., no tivoization.</li>
616    
617    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.76&amp;r2=1.77">Version
618    1.77</a>: Clarify that all retroactive changes to the license are
619    unacceptable, even if it's not described as a complete
620    replacement.</li>
621    
622    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.73&amp;r2=1.74">Version
623    1.74</a>: Four clarifications of points not explicit enough, or stated
624    in some places but not reflected everywhere:
625    <ul>
626    <li>"Improvements" does not mean the license can
627    substantively limit what kinds of modified versions you can release.
628    Freedom 3 includes distributing modified versions, not just changes.</li>
629    <li>The right to merge in existing modules
630    refers to those that are suitably licensed.</li>
631    <li>Explicitly state the conclusion of the point about export controls.</li>
632    <li>Imposing a license change constitutes revoking the old license.</li>
633    </ul>
634    </li>
635    
636    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.56&amp;r2=1.57">Version
637    1.57</a>: Add &quot;Beyond Software&quot; section.</li>
638    
639    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.45&amp;r2=1.46">Version
640    1.46</a>: Clarify whose purpose is significant in the freedom to run
641    the program for any purpose.</li>
642    
643    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.40&amp;r2=1.41">Version
644    1.41</a>: Clarify wording about contract-based licenses.</li>
645    
646    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.39&amp;r2=1.40">Version
647    1.40</a>: Explain that a free license must allow to you use other
648    available free software to create your modifications.</li>
649    
650    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.38&amp;r2=1.39">Version
651    1.39</a>: Note that it is acceptable for a license to require you to
652    provide source for versions of the software you put into public
653    use.</li>
654    
655    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.30&amp;r2=1.31">Version
656    1.31</a>: Note that it is acceptable for a license to require you to
657    identify yourself as the author of modifications.  Other minor
658    clarifications throughout the text.</li>
659    
660    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.22&amp;r2=1.23">Version
661    1.23</a>: Address potential problems related to contract-based
662    licenses.</li>
663    
664    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.15&amp;r2=1.16">Version
665    1.16</a>: Explain why distribution of binaries is important.</li>
666    
667    <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.10&amp;r2=1.11">Version
668    1.11</a>: Note that a free license may require you to send a copy of
669    versions you distribute to previous developers on request.</li>
670    
671    </ul>
672    
673    <p>There are gaps in the version numbers shown above because there are
674    other changes in this page that do not affect the definition or its
675    interpretations.  For instance, the list does not include changes in
676    asides, formatting, spelling, punctuation, or other parts of the page.
677    You can review the complete list of changes to the page through
678    the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
679    interface</a>.</p>
680    <hr class="column-limit" />
681    
682    <h3 class="footnote">Footnote</h3>
683    <ol>
684    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
685    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
686    the freedom to run the program needed to be mentioned explicitly.
687    It was clearly more basic than the other three, so it properly should
688    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
689    </ol>
690    </div>
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703    <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
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705    
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