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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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17  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <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." />
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23  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  <div class="reduced-width">
24  | <A HREF="/philosophy/free-sw.de.html">German</A>  <h2>What is Free Software?</h2>
25  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <div class="thin"></div>
26  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  
27  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  <div class="article">
28  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  <div class="important">
29  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  <p>
30  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  &ldquo;Free software&rdquo; means software that respects users'
31  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  freedom and community.  Roughly, it means that <b>the users have the
32  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  freedom to run, copy, distribute, study, change and improve the
33  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
34  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  liberty, not price.  To understand the concept, you should think of
35  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
36  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
37  | <A HREF="/philosophy/free-sw.sv.html">Swedish</A>    software,&rdquo; borrowing the French or Spanish word for
38  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  &ldquo;free&rdquo; as in freedom, to show we do not mean the software
39  <!-- Please keep this list alphabetical -->  is gratis.
40  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  </p>
41  ]  
42  <P>  <p>
43    You may have paid money to get copies of a free program, or you may
44  We maintain this free software definition to show clearly what must be  have obtained copies at no charge.  But regardless of how you got your
45  true about a particular software program for it to be considered  copies, you always have the freedom to copy and change the software,
46  free software.  even to <a href="/philosophy/selling.html">sell copies</a>.
47    </p>
48  <P>  </div>
49    
50  ``Free software'' is a matter of liberty, not price.  To understand the  <p>
51  concept, you should think of ``free'' as in ``free speech,'' not as in  We campaign for these freedoms because everyone deserves them.  With
52  ``free beer.''  these freedoms, the users (both individually and collectively) control
53  <P>  the program and what it does for them.  When users don't control the
54  Free software is a matter of the users' freedom to run, copy,  program, we call it a &ldquo;nonfree&rdquo; or
55  distribute, study, change and improve the software.  More precisely,  &ldquo;proprietary&rdquo; program.  The nonfree program controls the
56  it refers to four kinds of freedom, for the users of the software:  users, and the developer controls the program; this makes the
57  <P>  program <a href="/philosophy/free-software-even-more-important.html">
58    an instrument of unjust power</a>.
59  <UL>  </p>
60    <LI>The freedom to run the program, for any purpose (freedom 0).  
61    <LI>The freedom to study how the program works, and adapt it to your needs  <p>
62        (freedom 1).   Access to the source code is a precondition for this.  &ldquo;Open source&rdquo; is something different: it has a very
63    <LI>The freedom to redistribute copies so you can help your neighbor  different philosophy based on different values.  Its practical
64    definition is different too, but nearly all open source programs are
65    in fact free.  We explain the
66    difference in <a href="/philosophy/open-source-misses-the-point.html">
67    Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
68    </p>
69    
70    <div class="toc">
71    <hr class="no-display" />
72    <h3 class="no-display">Table of contents</h3>
73    <ul>
74     <li><a href="#fs-definition">The Free Software Definition</a>
75      <ul>
76       <li><a href="#four-freedoms">The four essential freedoms</a></li>
77       <li><a href="#selling">Free software <em>can</em> be commercial</a></li>
78      </ul>
79     </li>
80     <li><a href="#clarifying">Clarifying the Boundary Between Free and Nonfree</a>
81      <ul>
82       <li><a href="#run-the-program">The freedom to run the program as you
83         wish</a></li>
84       <li><a href="#make-changes">The freedom to study the source code and make
85         changes</a></li>
86       <li><a href="#redistribute">The freedom to redistribute if you wish:
87         basic requirements</a></li>
88       <li><a href="#copyleft">Copyleft</a></li>
89       <li><a href="#packaging">Rules about packaging and distribution
90         details</a></li>
91       <li><a href="#exportcontrol">Export regulations</a></li>
92       <li><a href="#legal-details">Legal considerations</a></li>
93       <li><a href="#contracts">Contract-based licenses</a></li>
94      </ul>
95     </li>
96     <li><a href="#in-practice">The Free Software Definition in Practice</a>
97      <ul>
98       <li><a href="#interpretation">How we interpret these criteria</a></li>
99       <li><a href="#get-help">Get help with free licenses</a></li>
100       <li><a href="#terminology">Use the right words when talking about free
101         software</a></li>
102      </ul>
103     </li>
104     <li><a href="#beyond-software">Beyond Software</a></li>
105     <li><a href="#History">History</a></li>
106    </ul>
107    </div>
108    
109    <div class="edu-note" id="fsf-licensing">
110    <p style="font-size:80%">
111    Have a question about free software licensing not answered here?
112    See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
113    and if necessary contact the FSF Compliance Lab
114    at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
115    <hr class="no-display" />
116    </div>
117    
118    
119    <h3 id="fs-definition" class="subheader">The Free Software Definition</h3>
120    
121    <p>
122    The free software definition presents the criteria for whether a
123    particular software program qualifies as free software.  From time to
124    time we revise this definition, to clarify it or to resolve questions
125    about subtle issues.  See the <a href="#History">History section</a>
126    below for a list of changes that affect the definition of free
127    software.
128    </p>
129    
130    <h4 id="four-freedoms">The four essential freedoms</h4>
131    <p>
132    A program is free software if the program's users have the
133    four essential freedoms: <a href="#f1">[1]</a>
134    </p>
135    
136    <ul class="important">
137      <li>The freedom to run the program as you wish,
138          for any purpose (freedom 0).</li>
139      <li>The freedom to study how the program works, and change it so it
140          does your computing as you wish (freedom 1). Access to the source
141          code is a precondition for this.
142      </li>
143      <li>The freedom to redistribute copies so you can help others
144        (freedom 2).        (freedom 2).
145    <LI>The freedom to improve the program, and release your improvements    </li>
146       to the public, so that the whole community benefits    <li>The freedom to distribute copies of your modified versions
147        (freedom 3).   Access to the source code is a precondition for this.        to others (freedom 3).  By doing this you can give the whole
148  </UL>        community a chance to benefit from your changes.
149          Access to the source code is a precondition for this.
150  <P>    </li>
151  A program is free software if users have all of these freedoms.  </ul>
152  Thus, you should be free to redistribute copies, either with or  
153  without modifications, either gratis or charging a fee for  <p>
154  distribution, to <A HREF="#exportcontrol">anyone anywhere</A>.  Being  A program is free software if it gives users adequately all of these
155  free to do these things means (among other things) that you do not  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
156  have to ask or pay for permission.  nonfree distribution schemes in terms of how far they fall short of
157    being free, we consider them all equally unethical.</p>
158    
159    <p>In any given scenario, these freedoms must apply to whatever code
160    we plan to make use of, or lead others to make use of.  For instance,
161    consider a program A which automatically launches a program B to
162    handle some cases.  If we plan to distribute A as it stands, that
163    implies users will need B, so we need to judge whether both A and B
164    are free.  However, if we plan to modify A so that it doesn't use B,
165    only A needs to be free; B is not pertinent to that plan.</p>
166    
167    
168    <h4 id="selling">Free software <em>can</em> be commercial</h4>
169    
170    <p>
171    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.
172    On the contrary, a free program must be available for commercial use,
173    commercial development, and commercial distribution.  This policy is
174    of fundamental importance&mdash;without this, free software could not
175    achieve its aims.
176    </p>
177    
178    <p>
179    We want to invite everyone to use the GNU system, including businesses
180    and their workers.  That requires allowing commercial use.  We hope
181    that free replacement programs will supplant comparable proprietary
182    programs, but they can't do that if businesses are forbidden to use
183    them.  We want commercial products that contain software to include
184    the GNU system, and that would constitute commercial distribution for
185    a price.  Commercial development of free software is no longer
186    unusual; such free commercial software is very important.  Paid,
187    professional support for free software fills an important need.
188    </p>
189    
190    <p>
191    Thus, to exclude commercial use, commercial development or commercial
192    distribution would hobble the free software community and obstruct its
193    path to success.  We must conclude that a program licensed with such
194    restrictions does not qualify as free software.
195    </p>
196    
197    <p>
198    A free program must offer the four freedoms to any would-be user that
199    obtains a copy of the software, who has complied thus far with the
200    conditions of the free license covering the software in any previous
201    distribution of it.  Putting some of the freedoms off limits to some
202    users, or requiring that users pay, in money or in kind, to exercise
203    them, is tantamount to not granting the freedoms in question, and thus
204    renders the program nonfree.
205    </p>
206    
207    
208    <h3 id="clarifying" class="subheader">Clarifying the Boundary Between Free and Nonfree</h3>
209    
210    <p>In the rest of this article we explain more precisely how far the
211    various freedoms need to extend, on various issues, in order for a
212    program to be free.</p>
213    
214    <h4 id="run-the-program">The freedom to run the program as you wish</h4>
215    
216    <p>
217    The freedom to run the program means the freedom for any kind of person
218    or organization to use it on any kind of computer system, for any kind of
219    overall job and purpose, without being required to communicate about it
220    with the developer or any other specific entity.  In this freedom, it is
221    the <em>user's</em> purpose that matters, not the <em>developer's</em>
222    purpose; you as a user are free to run the program for your purposes,
223    and if you distribute it to someone else, she is then free to run it
224    for her purposes, but you are not entitled to impose your purposes on her.
225    </p>
226    
227    <p>
228    The freedom to run the program as you wish means that you are not
229    forbidden or stopped from making it run.  This has nothing to do with what
230    functionality the program has, whether it is technically capable of
231    functioning in any given environment, or whether it is useful for any
232    particular computing activity.</p>
233    
234    <p>For example, if the code arbitrarily rejects certain meaningful
235    inputs&mdash;or even fails unconditionally&mdash;that may make the
236    program less useful, perhaps even totally useless, but it does not
237    deny users the freedom to run the program, so it does not conflict
238    with freedom 0.  If the program is free, the users can overcome the
239    loss of usefulness, because freedoms 1 and 3 permit users and
240    communities to make and distribute modified versions without the
241    arbitrary nuisance code.</p>
242    
243    <p>&ldquo;As you wish&rdquo; includes, optionally, &ldquo;not at
244    all&rdquo; if that is what you wish.  So there is no need for a
245    separate &ldquo;freedom not to run a program.&rdquo;</p>
246    
247    <h4 id="make-changes">The freedom to study the source code and make changes</h4>
248    
249    <p>
250    In order for freedoms 1 and 3 (the freedom to make changes and the
251    freedom to publish the changed versions) to be meaningful, you need to have
252    access to the source code of the program.  Therefore, accessibility of
253    source code is a necessary condition for free software.  Obfuscated
254    &ldquo;source code&rdquo; is not real source code and does not count
255    as source code.
256    </p>
257    
258    <p>
259    Freedom 1 includes the freedom to use your changed version in place of
260    the original.  If the program is delivered in a product designed to
261    run someone else's modified versions but refuse to run yours &mdash; a
262    practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
263    or (in its practitioners' perverse terminology) as &ldquo;secure
264    boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
265    practical reality.  These binaries are not free
266    software even if the source code they are compiled from is free.
267    </p>
268    
269    <p>
270    One important way to modify a program is by merging in available free
271    subroutines and modules.  If the program's license says that you
272    cannot merge in a suitably licensed existing module &mdash; for instance, if it
273    requires you to be the copyright holder of any code you add &mdash; then the
274    license is too restrictive to qualify as free.
275    </p>
276    
277    <p>
278    Whether a change constitutes an improvement is a subjective matter.
279    If your right to modify a program is limited, in substance, to changes that
280    someone else considers an improvement, that program is not free.
281    </p>
282    
283    <p>
284    One special case of freedom 1 is to delete the program's code so it
285    returns after doing nothing, or make it invoke some other program.
286    Thus, freedom 1 includes the &ldquo;freedom to delete the program.&rdquo;
287    </p>
288    
289    <h4 id="redistribute">The freedom to redistribute if you wish: basic
290    requirements</h4>
291    
292    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
293    redistribute copies, either with or without modifications, either
294    gratis or charging a fee for distribution, to
295    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
296    things means (among other things) that you do not have to ask or pay
297    for permission to do so.
298    </p>
299    
300  <P>  <p>
301  You should also have the freedom to make modifications and use them  You should also have the freedom to make modifications and use them
302  privately in your own work or play, without even mentioning that they  privately in your own work or play, without even mentioning that they
303  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
304  notify anyone in particular, or in any particular way.  notify anyone in particular, or in any particular way.
305    </p>
306    
307  <P>  <p>
308  The freedom to use a program means the freedom for any kind of person  Freedom 3 includes the freedom to release your modified versions
309  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
310  of overall job, and without being required to communicate subsequently  releasing them; in other words, it does not have to be
311  with the developer or any other specific entity.  a <a href="/licenses/copyleft.html">copyleft</a> license.  However, a
312    license that requires modified versions to be nonfree does not qualify
313    as a free license.
314    </p>
315    
316  <P>  <p>
317  The freedom to redistribute copies must include binary or executable  The freedom to redistribute copies must include binary or executable
318  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
319  unmodified versions.  (Distributing programs in runnable form is  unmodified versions.  (Distributing programs in runnable form is necessary
320  necessary for conveniently installable free operating systems.)  It is  for conveniently installable free operating systems.)  It is OK if there
321  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
322  certain program (since some languages don't support that feature), but  (since some languages don't support that feature), but you must have the
323  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
324  or develop a way to make them.  make them.
325    </p>
326  <P>  
327  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.  
328    
329  <P>  <p>
330  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
331  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
332  freedoms.  For example, copyleft (very simply stated) is the rule that  freedoms.  For example, <a href="/licenses/copyleft.html">copyleft</a>
333  when redistributing the program, you cannot add restrictions to deny  (very simply stated) is the rule that when redistributing the program,
334  other people the central freedoms.  This rule does not conflict with  you cannot add restrictions to deny other people the central freedoms.
335  the central freedoms; rather it protects them.  This rule does not conflict with the central freedoms; rather it
336    protects them.
337  <P>  </p>
338  Thus, you may have paid money to get copies of free software, or you  
339  may have obtained copies at no charge.  But regardless of how you got  <p>
340  your copies, you always have the freedom to copy and change the  In the GNU project, we use copyleft to protect the four freedoms
341  software, even to <A HREF="/philosophy/selling.html">sell copies</A>.  legally for everyone.  We believe there are important reasons why
342  <P>  <a href="/philosophy/pragmatic.html">it is better to use
343    copyleft</a>.  However,
344  ``Free software'' does not mean ``non-commercial''.  A free program  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
345  must be available for commercial use, commercial development, and  noncopylefted free software</a> is ethical
346  commercial distribution.  Commercial development of free software is  too.  See <a href="/philosophy/categories.html">Categories of Free
347  no longer unusual; such free commercial software is very important.  Software</a> for a description of how &ldquo;free software,&rdquo;
348    &ldquo;copylefted software&rdquo; and other categories of software
349  <P>  relate to each other.
350  Rules about how to package a modified version are acceptable, if they  </p>
351  don't effectively block your freedom to release modified versions.  
352  Rules that ``if you make the program available in this way, you must  <h4 id="packaging">Rules about packaging and distribution details</h4>
353  make it available in that way also'' can be acceptable too, on the  
354  same condition.  (Note that such a rule still leaves you the choice of  <p>
355  whether to publish the program or not.)  It is also acceptable for the  Rules about how to package a modified version are acceptable,
356  license to require that, if you have distributed a modified version  if they don't substantively limit your freedom to release modified
357  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.
358    Thus, it is acceptable for the license to require that you change the
359  <P>  name of the modified version, remove a logo, or identify your
360  In the GNU project, we use <A HREF="/copyleft/copyleft.html">  modifications as yours.  As long as these requirements are not so
361  ``copyleft''</A> to protect these freedoms legally for everyone.  But  burdensome that they effectively hamper you from releasing your
362  <A HREF="/philosophy/categories.html#Non-CopyleftedFreeSoftware">  changes, they are acceptable; you're already making other changes to
363  non-copylefted free software</A> also exists.  We believe there are  the program, so you won't have trouble making a few more.
364  important reasons why <A HREF="/philosophy/pragmatic.html"> it is  </p>
365  better to use copyleft</A>, but if your program is non-copylefted free  
366  software, we can still use it.  <p>
367    Rules that &ldquo;if you make your version available in this way, you
368  <P>  must make it available in that way also&rdquo; can be acceptable too,
369  See <A HREF="/philosophy/categories.html">Categories of Free Software  on the same condition.  An example of such an acceptable rule is one
370         (18k characters)</A>  saying that if you have distributed a
371  for a description of how ``free software,'' ``copylefted software'' and  modified version and a previous developer asks for a copy of it, you
372  other categories of software relate to each other.  must send one.  (Note that such a rule still leaves you the choice of
373    whether to distribute your version at all.)  Rules that require release
374  <P>  of source code to the users for versions that you put into public use
375  Sometimes government <A NAME="exportcontrol">export control  are also acceptable.
376  regulations</A> and trade sanctions can constrain your freedom to  </p>
377  distribute copies of programs internationally.  Software developers do  
378  not have the power to eliminate or override these restrictions, but  <p>
379  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
380  use of the program.  In this way, the restrictions will not affect  which the program will be invoked from other programs.  That
381  activities and people outside the jurisdictions of these governments.  effectively hampers you from releasing your changed version so that it
382    can replace the original when invoked by those other programs.  This
383  <P>  sort of requirement is acceptable only if there's a suitable aliasing
384  Most free software licenses are based on copyright, and there are  facility that allows you to specify the original program's name as an
385  limits on what kinds of requirements can be imposed through copyright.  alias for the modified version.</p>
386  If a copyright-based license respects freedom in the ways described  
387  above, it is unlikely to have some other sort of problem that we never  <h4 id="exportcontrol">Export regulations</h4>
388  anticipated (though this does happen occasionally).  However, some  
389  free software licenses are based on contracts, and contracts can  <p>
390  impose a much larger range of possible restrictions.  That means there  Sometimes government export control regulations
391  are many possible ways such a license could be unacceptably  and trade sanctions can constrain your freedom to distribute copies of
392  restrictive and non-free.  programs internationally.  Software developers do not have the power to
393  <P>  eliminate or override these restrictions, but what they can and must do
394  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
395  would be unacceptable.  If a contract-based license restricts the user  way, the restrictions will not affect activities and people outside the
396  in an unusual way that copyright-based licenses cannot, and which  jurisdictions of these governments.  Thus, free software licenses
397  isn't mentioned here as legitimate, we will have to think about it,  must not require obedience to any nontrivial export regulations as a
398  and we will probably decide it is non-free.  condition of exercising any of the essential freedoms.
399  <P>  </p>
400  When talking about free software, it is best to avoid using terms like  
401  ``give away'' or ``for free'', because those terms imply that the  <p>
402  issue is about price, not freedom.  Some common terms such as  Merely mentioning the existence of export regulations, without making
403  ``piracy'' embody opinions we hope you won't endorse.  See <A  them a condition of the license itself, is acceptable since it does
404  HREF="/philosophy/words-to-avoid.html">Confusing Words and Phrases  not restrict users.  If an export regulation is actually trivial for
405  that are Worth Avoiding</A> for a discussion of these terms.  free software, then requiring it as a condition is not an actual
406  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
407  of "free software"</A> into various languages.  export law could make the requirement nontrivial and thus render the
408    software nonfree.
409  <P>  </p>
410    
411  Finally, note that criteria such as those stated in this free software  <h4 id="legal-details">Legal considerations</h4>
412  definition require careful thought for their interpretation.  To  
413  decide whether a specific software license qualifies as a free  <p>
414  software license, we judge it based on these criteria to determine  In order for these freedoms to be real, they must be permanent and
415  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
416  license includes unconscionable restrictions, we reject it, even if we  software has the power to revoke the license, or retroactively add
417  did not anticipate the issue in these criteria.  Sometimes a license  restrictions to its terms, without your doing anything wrong to give
418  requirement raises an issue that calls for extensive thought,  cause, the software is not free.
419  including discussions with a lawyer, before we can decide if the  </p>
420  requirement is acceptable.  When we reach a conclusion about a new  
421  issue, we often update these criteria to make it easier to see why  <p>
422  certain licenses do or don't qualify.  A free license may not require compliance with the license of a
423    nonfree program.  Thus, for instance, if a license requires you to
424  <P>  comply with the licenses of &ldquo;all the programs you use&rdquo;, in
425    the case of a user that runs nonfree programs this would require
426  If you are interested in whether a specific license qualifies as a  compliance with the licenses of those nonfree programs; that makes the
427  free software license, see our <A  license nonfree.
428  HREF="/licenses/license-list.html">list of licenses</A>.  If the  </p>
429  license you are concerned with is not listed there, you can ask us  
430  about it by sending us email at <A  <p>
431  HREF="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</A>.  It is acceptable for a free license to specify which jurisdiction's
432    law applies, or where litigation must be done, or both.
433  <HR>  </p>
434    
435  <H4><A HREF="/philosophy/philosophy.html">Other Texts to Read</A></H4>  <h4 id="contracts">Contract-based licenses</h4>
436    
437  <P>  <p>
438  Another group has started using the term "open source" to mean  Most free software licenses are based on copyright, and there are limits
439  something close (but not identical) to "free software".  We prefer the  on what kinds of requirements can be imposed through copyright.  If a
440  term "free software" because, once you have heard it refers to freedom  copyright-based license respects freedom in the ways described above, it
441  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
442  to mind freedom</A>.  (though this does happen occasionally).  However, some free software
443    licenses are based on contracts, and contracts can impose a much larger
444  <HR>  range of possible restrictions.  That means there are many possible ways
445  [  such a license could be unacceptably restrictive and nonfree.
446  <!-- Please keep this list alphabetical -->  </p>
447  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  
448  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <p>
449  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  We can't possibly list all the ways that might happen.  If a
450  | <A HREF="/philosophy/free-sw.da.html">Danish</A>  contract-based license restricts the user in an unusual way that
451  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  copyright-based licenses cannot, and which isn't mentioned here as
452  | <A HREF="/philosophy/free-sw.html">English</A>  legitimate, we will have to think about it, and we will probably conclude
453  | <A HREF="/philosophy/free-sw.fr.html">French</A>  it is nonfree.
454  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  </p>
455  | <A HREF="/philosophy/free-sw.de.html">German</A>  
456  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <h3 id="in-practice" class="subheader">The Free Software Definition in Practice</h3>
457  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  
458  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  <h4 id="interpretation">How we interpret these criteria</h4>
459  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  
460  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  <p>
461  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  Note that criteria such as those stated in this free software
462  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  definition require careful thought for their interpretation.  To decide
463  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  whether a specific software license qualifies as a free software license,
464  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  we judge it based on these criteria to determine whether it fits their
465  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  spirit as well as the precise words.  If a license includes unconscionable
466  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>        restrictions, we reject it, even if we did not anticipate the issue
467  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  in these criteria.  Sometimes a license requirement raises an issue
468  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  that calls for extensive thought, including discussions with a lawyer,
469  <!-- Please keep this list alphabetical -->  before we can decide if the requirement is acceptable.  When we reach
470  <!-- 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
471  ]  it easier to see why certain licenses do or don't qualify.
472  <P>  </p>
473  Return to <A HREF="/home.html">GNU's home page</A>.  
474  <P>  <h4 id="get-help">Get help with free licenses</h4>
475    
476  Please send FSF &amp; GNU inquiries &amp; questions to  <p>
477    If you are interested in whether a specific license qualifies as a free
478  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  software license, see our <a href="/licenses/license-list.html">list
479  There are also <A HREF="/home.html#ContactInfo">other ways to  of licenses</a>.  If the license you are concerned with is not
480  contact</A> the FSF.  listed there, you can ask us about it by sending us email at
481  <P>  <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
482    </p>
483  Please send comments on these web pages to  
484    <p>
485  <A HREF="mailto:webmasters@gnu.org"><EM>webmasters@gnu.org</EM></A>,  If you are contemplating writing a new license, please contact the
486  send other questions to  Free Software Foundation first by writing to that address. The
487  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  proliferation of different free software licenses means increased work
488  <P>  for users in understanding the licenses; we may be able to help you
489  Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, Free  find an existing free software license that meets your needs.
490  Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  </p>
491  02111,  USA  
492  <P>  <p>
493  Verbatim copying and distribution of this entire article is  If that isn't possible, if you really need a new license, with our
494  permitted in any medium, provided this notice is preserved.  help you can ensure that the license really is a free software license
495  <P>  and avoid various practical problems.
496  Updated:  </p>
497    
498    <h4 id="terminology">Use the right words when talking about free software</h4>
499    
500    <p>
501    When talking about free software, it is best to avoid using terms
502    like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
503    the issue is about price, not freedom.  Some common terms such
504    as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
505    <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
506    are Worth Avoiding</a> for a discussion of these terms.  We also have
507    a list of proper <a href="/philosophy/fs-translations.html">translations of
508    &ldquo;free software&rdquo;</a> into various languages.
509    </p>
510    
511    <p id="open-source">
512    Another group uses the term &ldquo;open source&rdquo; to mean
513    something close (but not identical) to &ldquo;free software&rdquo;.  We
514    prefer the term &ldquo;free software&rdquo; because, once you have heard that
515    it refers to freedom rather than price, it calls to mind freedom.  The
516    word &ldquo;open&rdquo; never refers to freedom.
517    </p>
518    
519    <h3 id="beyond-software" class="subheader">Beyond Software</h3>
520    
521    <p>
522    <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
523    for the same reasons that software must be free, and because the
524    manuals are in effect part of the software.
525    </p>
526    
527    <p>
528    The same arguments also make sense for other kinds of works of
529    practical use &mdash; that is to say, works that embody useful knowledge,
530    such as educational works and reference
531    works.  <a href="https://wikipedia.org">Wikipedia</a> is the best-known
532    example.
533    </p>
534    
535    <p>
536    Any kind of work <em>can</em> be free, and the definition of free software
537    has been extended to a definition of <a href="http://freedomdefined.org/">
538    free cultural works</a> applicable to any kind of works.
539    </p>
540    <hr class="column-limit" />
541    </div>
542    
543    <h3 id="History">History</h3>
544    
545    <p>From time to time we revise this Free Software Definition.  Here is
546    the list of substantive changes, along with links to show exactly what
547    was changed.</p>
548    
549    <ul>
550    
551    <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
552    1.169</a>: Explain more clearly why the four freedoms must apply
553    to commercial activity.  Explain why the four freedoms imply the
554    freedom not to run the program and the freedom to delete it, so there
555    is no need to state those as separate requirements.</li>
556    
557    <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
558    1.165</a>: Clarify that arbitrary annoyances in the code do not
559    negate freedom 0, and that freedoms 1 and 3 enable users to remove them.</li>
560    
561    <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
562    1.153</a>: Clarify that freedom to run the program means nothing stops
563    you from making it run.</li>
564    
565    <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
566    1.141</a>: Clarify which code needs to be free.</li>
567    
568    <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
569    1.135</a>: Say each time that freedom 0 is the freedom to run the program
570    as you wish.</li>
571    
572    <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
573    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
574    
575    <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
576    1.131</a>: A free license may not require compliance with a nonfree license
577    of another program.</li>
578    
579    <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
580    1.129</a>: State explicitly that choice of law and choice of forum
581    specifications are allowed.  (This was always our policy.)</li>
582    
583    <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
584    1.122</a>: An export control requirement is a real problem if the
585    requirement is nontrivial; otherwise it is only a potential problem.</li>
586    
587    <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
588    1.118</a>: Clarification: the issue is limits on your right to modify,
589    not on what modifications you have made.  And modifications are not limited
590    to &ldquo;improvements&rdquo;</li>
591    
592    <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
593    1.111</a>: Clarify 1.77 by saying that only
594    retroactive <em>restrictions</em> are unacceptable.  The copyright
595    holders can always grant additional <em>permission</em> for use of the
596    work by releasing the work in another way in parallel.</li>
597    
598    <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
599    1.105</a>: Reflect, in the brief statement of freedom 1, the point
600    (already stated in version 1.80) that it includes really using your modified
601    version for your computing.</li>
602    
603    <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
604    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
605    
606    <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
607    1.90</a>: Clarify that freedom 3 means the right to distribute copies
608    of your own modified or improved version, not a right to participate
609    in someone else's development project.</li>
610    
611    <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
612    1.89</a>: Freedom 3 includes the right to release modified versions as
613    free software.</li>
614    
615    <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
616    1.80</a>: Freedom 1 must be practical, not just theoretical;
617    i.e., no tivoization.</li>
618    
619    <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
620    1.77</a>: Clarify that all retroactive changes to the license are
621    unacceptable, even if it's not described as a complete
622    replacement.</li>
623    
624    <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
625    1.74</a>: Four clarifications of points not explicit enough, or stated
626    in some places but not reflected everywhere:
627    <ul>
628    <li>"Improvements" does not mean the license can
629    substantively limit what kinds of modified versions you can release.
630    Freedom 3 includes distributing modified versions, not just changes.</li>
631    <li>The right to merge in existing modules
632    refers to those that are suitably licensed.</li>
633    <li>Explicitly state the conclusion of the point about export controls.</li>
634    <li>Imposing a license change constitutes revoking the old license.</li>
635    </ul>
636    </li>
637    
638    <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
639    1.57</a>: Add &quot;Beyond Software&quot; section.</li>
640    
641    <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
642    1.46</a>: Clarify whose purpose is significant in the freedom to run
643    the program for any purpose.</li>
644    
645    <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
646    1.41</a>: Clarify wording about contract-based licenses.</li>
647    
648    <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
649    1.40</a>: Explain that a free license must allow to you use other
650    available free software to create your modifications.</li>
651    
652    <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
653    1.39</a>: Note that it is acceptable for a license to require you to
654    provide source for versions of the software you put into public
655    use.</li>
656    
657    <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
658    1.31</a>: Note that it is acceptable for a license to require you to
659    identify yourself as the author of modifications.  Other minor
660    clarifications throughout the text.</li>
661    
662    <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
663    1.23</a>: Address potential problems related to contract-based
664    licenses.</li>
665    
666    <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
667    1.16</a>: Explain why distribution of binaries is important.</li>
668    
669    <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
670    1.11</a>: Note that a free license may require you to send a copy of
671    versions you distribute to previous developers on request.</li>
672    
673    </ul>
674    
675    <p>There are gaps in the version numbers shown above because there are
676    other changes in this page that do not affect the definition or its
677    interpretations.  For instance, the list does not include changes in
678    asides, formatting, spelling, punctuation, or other parts of the page.
679    You can review the complete list of changes to the page through
680    the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
681    interface</a>.</p>
682    <hr class="column-limit" />
683    
684    <h3 class="footnote">Footnote</h3>
685    <ol>
686    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
687    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
688    the freedom to run the program needed to be mentioned explicitly.
689    It was clearly more basic than the other three, so it properly should
690    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
691    </ol>
692    </div>
693    
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698    
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701    There are also <a href="/contact/">other ways to contact</a>
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704    
705    <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
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707    
708            We work hard and do our best to provide accurate, good quality
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