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3  <HEAD>  <title>What is free software?
4  <TITLE>The Free Software Definition - GNU Project - Free Software Foundation (FSF)</TITLE>  - GNU Project - Free Software Foundation</title>
5  <LINK REV="made" HREF="mailto:webmasters@www.gnu.org">  
6  </HEAD>  <meta http-equiv="Keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" />
7  <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#1F00FF" ALINK="#FF0000" VLINK="#9900DD">  <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." />
8  <H3>The Free Software Definition</H3>  
9    <!--#include virtual="/philosophy/po/free-sw.translist" -->
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11     ALT=" [image of a Philosophical Gnu] "  
12     WIDTH="160" HEIGHT="200"></A>  <h2>What is free software?</h2>
13    
14  [  <blockquote class="note" id="fsf-licensing"><p style="font-size: 80%">
15    <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  Have a question about free software licensing not answered here?
16  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
17  | <A HREF="/philosophy/free-sw.html">English</A>  and if necessary contact the FSF Compliance Lab
18  | <A HREF="/philosophy/free-sw.fr.html">French</A>  at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
19  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  </blockquote>
20  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  
21  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  <h3>The Free Software Definition</h3>
22  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  
23  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  <blockquote>
24  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  <p>
25  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  The free software definition presents the criteria for whether a
26  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  particular software program qualifies as free software.  From time to
27  ]  time we revise this definition, to clarify it or to resolve questions
28  <P>  about subtle issues.  See the <a href="#History">History section</a>
29    below for a list of changes that affect the definition of free
30  We maintain this free software definition to show clearly what must be  software.
31  true about a particular software program for it to be considered  </p>
32  ``free software''.  
33    <p>
34  <P>  &ldquo;Open source&rdquo; is something different: it has a very
35    different philosophy based on different values.  Its practical
36  ``Free software'' is a matter of liberty, not price.  To understand the  definition is different too, but nearly all open source programs are
37  concept, you should think of ``free'' as in ``free speech,'' not as in  in fact free.  We explain the
38  ``free beer.''  difference in <a href="/philosophy/open-source-misses-the-point.html">
39  <P>  Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
40  ``Free software'' refers to the users' freedom to run, copy,  </p>
41  distribute, study, change and improve the software.  More precisely,  </blockquote>
42  it refers to four kinds of freedom, for the users of the software:  
43  <P>  <p>
44    &ldquo;Free software&rdquo; means software that respects users'
45  <UL>  freedom and community.  Roughly, it means that <b>the users have the
46    <LI>The freedom to run the program, for any purpose (freedom 0).  freedom to run, copy, distribute, study, change and improve the
47    <LI>The freedom to study how the program works, and adapt it to your needs  software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
48        (freedom 1).   Access to the source code is a precondition for this.  liberty, not price.  To understand the concept, you should think of
49    <LI>The freedom to redistribute copies so you can help your neighbor  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
50    &ldquo;free beer&rdquo;.  We sometimes call it &ldquo;libre
51    software,&rdquo; borrowing the French or Spanish word for
52    &ldquo;free&rdquo; as in freedom, to show we do not mean the software
53    is gratis.
54    </p>
55    
56    <p>
57    We campaign for these freedoms because everyone deserves them.  With
58    these freedoms, the users (both individually and collectively) control
59    the program and what it does for them.  When users don't control the
60    program, we call it a &ldquo;nonfree&rdquo; or
61    &ldquo;proprietary&rdquo; program.  The nonfree program controls the
62    users, and the developer controls the program; this makes the
63    program <a href="/philosophy/free-software-even-more-important.html">
64    an instrument of unjust power</a>.
65    </p>
66    
67    <h4> The four essential freedoms</h4>
68    
69    <p>
70    A program is free software if the program's users have the
71    four essential freedoms: <a href="#f1">[1]</a>
72    </p>
73    
74    <ul>
75      <li>The freedom to run the program as you wish,
76          for any purpose (freedom 0).</li>
77      <li>The freedom to study how the program works, and change it so it
78          does your computing as you wish (freedom 1). Access to the source
79          code is a precondition for this.
80      </li>
81      <li>The freedom to redistribute copies so you can help others
82        (freedom 2).        (freedom 2).
83    <LI>The freedom to improve the program, and release your improvements    </li>
84       to the public, so that the whole community benefits.    <li>The freedom to distribute copies of your modified versions
85        (freedom 3).   Access to the source code is a precondition for this.        to others (freedom 3).  By doing this you can give the whole
86  </UL>        community a chance to benefit from your changes.
87          Access to the source code is a precondition for this.
88  <P>    </li>
89  A program is free software if users have all of these freedoms.  </ul>
90  Thus, you should be free to redistribute copies, either with or  
91  without modifications, either gratis or charging a fee for  <p>
92  distribution, to <A HREF="#exportcontrol">anyone anywhere</A>.  Being  A program is free software if it gives users adequately all of these
93  free to do these things means (among other things) that you do not  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
94  have to ask or pay for permission.  nonfree distribution schemes in terms of how far they fall short of
95    being free, we consider them all equally unethical.</p>
96    
97    <p>In any given scenario, these freedoms must apply to whatever code
98    we plan to make use of, or lead others to make use of.  For instance,
99    consider a program A which automatically launches a program B to
100    handle some cases.  If we plan to distribute A as it stands, that
101    implies users will need B, so we need to judge whether both A and B
102    are free.  However, if we plan to modify A so that it doesn't use B,
103    only A needs to be free; B is not pertinent to that plan.</p>
104    
105    <p>
106    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;.  A free
107    program must be available for commercial use, commercial development,
108    and commercial distribution.  Commercial development of free software
109    is no longer unusual; such free commercial software is very important.
110    You may have paid money to get copies of free software, or you may have
111    obtained copies at no charge.  But regardless of how you got your copies,
112    you always have the freedom to copy and change the software, even to
113    <a href="/philosophy/selling.html">sell copies</a>.
114    </p>
115    
116    <p>The rest of this page clarifies certain points about what makes
117    specific freedoms adequate or not.</p>
118    
119    <h4>The freedom to run the program as you wish</h4>
120    
121    <p>
122    The freedom to run the program means the freedom for any kind of person
123    or organization to use it on any kind of computer system, for any kind of
124    overall job and purpose, without being required to communicate about it
125    with the developer or any other specific entity.  In this freedom, it is
126    the <em>user's</em> purpose that matters, not the <em>developer's</em>
127    purpose; you as a user are free to run the program for your purposes,
128    and if you distribute it to someone else, she is then free to run it
129    for her purposes, but you are not entitled to impose your purposes on her.
130    </p>
131    
132    <p>
133    The freedom to run the program as you wish means that you are not
134    forbidden or stopped from making it run.  This has nothing to do with what
135    functionality the program has, whether it is technically capable of
136    functioning in any given environment, or whether it is useful for any
137    particular computing activity.</p>
138    
139    <h4>The freedom to study the source code and make changes</h4>
140    
141    <p>
142    In order for freedoms 1 and 3 (the freedom to make changes and the
143    freedom to publish the changed versions) to be meaningful, you must have
144    access to the source code of the program.  Therefore, accessibility of
145    source code is a necessary condition for free software.  Obfuscated
146    &ldquo;source code&rdquo; is not real source code and does not count
147    as source code.
148    </p>
149    
150    <p>
151    Freedom 1 includes the freedom to use your changed version in place of
152    the original.  If the program is delivered in a product designed to
153    run someone else's modified versions but refuse to run yours &mdash; a
154    practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
155    or (in its practitioners' perverse terminology) as &ldquo;secure
156    boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
157    practical reality.  These binaries are not free
158    software even if the source code they are compiled from is free.
159    </p>
160    
161    <p>
162    One important way to modify a program is by merging in available free
163    subroutines and modules.  If the program's license says that you
164    cannot merge in a suitably licensed existing module &mdash; for instance, if it
165    requires you to be the copyright holder of any code you add &mdash; then the
166    license is too restrictive to qualify as free.
167    </p>
168    
169    <p>
170    Whether a change constitutes an improvement is a subjective matter.
171    If your right to modify a program is limited, in substance, to changes that
172    someone else considers an improvement, that program is not free.
173    </p>
174    
175    <h4>The freedom to redistribute if you wish: basic requirements</h4>
176    
177    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
178    redistribute copies, either with or without modifications, either
179    gratis or charging a fee for distribution, to
180    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
181    things means (among other things) that you do not have to ask or pay
182    for permission to do so.
183    </p>
184    
185  <P>  <p>
186  You should also have the freedom to make modifications and use them  You should also have the freedom to make modifications and use them
187  privately in your own work or play, without even mentioning that they  privately in your own work or play, without even mentioning that they
188  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
189  notify anyone in particular, or in any particular way.  notify anyone in particular, or in any particular way.
190    </p>
191    
192  <P>  <p>
193  The freedom to use a program means the freedom for any kind of person  Freedom 3 includes the freedom to release your modified versions
194  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
195  of overall job, and without being required to communicate subsequently  releasing them; in other words, it does not have to be
196  with the developer or any other specific entity.  a <a href="/copyleft/copyleft.html">copyleft</a> license.  However, a
197    license that requires modified versions to be nonfree does not qualify
198    as a free license.
199    </p>
200    
201  <P>  <p>
202  The freedom to redistribute copies must include binary or executable  The freedom to redistribute copies must include binary or executable
203  forms of the program, as well as source code.  (It is ok if there is  forms of the program, as well as source code, for both modified and
204  no way to produce a binary or executable form, but people must have  unmodified versions.  (Distributing programs in runnable form is necessary
205  the freedom to redistribute such forms should they find a way to make  for conveniently installable free operating systems.)  It is OK if there
206  them.)  is no way to produce a binary or executable form for a certain program
207    (since some languages don't support that feature), but you must have the
208  <P>  freedom to redistribute such forms should you find or develop a way to
209  In order for the freedoms to make changes, and to publish improved  make them.
210  versions, to be meaningful, you must have access to the source code of  </p>
211  the program.  Therefore, accessibility of source code is a necessary  
212  condition for free software.  <h4>Copyleft</h4>
   
 <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.  
213    
214  <P>  <p>
215  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
216  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
217  freedoms.  For example, copyleft (very simply stated) is the rule that  freedoms.  For example, <a href="/copyleft/copyleft.html">copyleft</a>
218  when redistributing the program, you cannot add restrictions to deny  (very simply stated) is the rule that when redistributing the program,
219  other people the central freedoms.  This rule does not conflict with  you cannot add restrictions to deny other people the central freedoms.
220  the central freedoms; rather it protects them.  This rule does not conflict with the central freedoms; rather it
221    protects them.
222  <P>  </p>
223  Thus, you may have paid money to get copies of GNU software, or you  
224  may have obtained copies at no charge.  But regardless of how you got  <p>
225  your copies, you always have the freedom to copy and change the  In the GNU project, we use copyleft to protect the four freedoms
226  software, even to <A HREF="/philosophy/selling.html">sell copies</A>.  legally for everyone.  We believe there are important reasons why
227    <a href="/philosophy/pragmatic.html">it is better to use
228  <P>  copyleft</a>.  However,
229  ``Free software'' does not mean ``non-commercial''.  A free program  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
230  must be available for commercial use.  Commercial development of free  noncopylefted free software</a> is ethical
231  software is no longer unusual; such programs are free commercial  too.  See <a href="/philosophy/categories.html">Categories of Free
232  software.  Software</a> for a description of how &ldquo;free software,&rdquo;
233    &ldquo;copylefted software&rdquo; and other categories of software
234    relate to each other.
235    </p>
236    
237    <h4>Rules about packaging and distribution details</h4>
238    
239    <p>
240    Rules about how to package a modified version are acceptable,
241    if they don't substantively limit your freedom to release modified
242    versions, or your freedom to make and use modified versions privately.
243    Thus, it is acceptable for the license to require that you change the
244    name of the modified version, remove a logo, or identify your
245    modifications as yours.  As long as these requirements are not so
246    burdensome that they effectively hamper you from releasing your
247    changes, they are acceptable; you're already making other changes to
248    the program, so you won't have trouble making a few more.
249    </p>
250    
251    <p>
252    Rules that &ldquo;if you make your version available in this way, you
253    must make it available in that way also&rdquo; can be acceptable too,
254    on the same condition.  An example of such an acceptable rule is one
255    saying that if you have distributed a
256    modified version and a previous developer asks for a copy of it, you
257    must send one.  (Note that such a rule still leaves you the choice of
258    whether to distribute your version at all.)  Rules that require release
259    of source code to the users for versions that you put into public use
260    are also acceptable.
261    </p>
262    
263    <p>
264    A special issue arises when a license requires changing the name by
265    which the program will be invoked from other programs.  That
266    effectively hampers you from releasing your changed version so that it
267    can replace the original when invoked by those other programs.  This
268    sort of requirement is acceptable only if there's a suitable aliasing
269    facility that allows you to specify the original program's name as an
270    alias for the modified version.</p>
271    
272    <h4>Export regulations</h4>
273    
274    <p>
275    Sometimes government <a id="exportcontrol">export control regulations</a>
276    and trade sanctions can constrain your freedom to distribute copies of
277    programs internationally.  Software developers do not have the power to
278    eliminate or override these restrictions, but what they can and must do
279    is refuse to impose them as conditions of use of the program.  In this
280    way, the restrictions will not affect activities and people outside the
281    jurisdictions of these governments.  Thus, free software licenses
282    must not require obedience to any nontrivial export regulations as a
283    condition of exercising any of the essential freedoms.
284    </p>
285    
286    <p>
287    Merely mentioning the existence of export regulations, without making
288    them a condition of the license itself, is acceptable since it does
289    not restrict users.  If an export regulation is actually trivial for
290    free software, then requiring it as a condition is not an actual
291    problem; however, it is a potential problem, since a later change in
292    export law could make the requirement nontrivial and thus render the
293    software nonfree.
294    </p>
295    
296    <h4>Legal considerations</h4>
297    
298    <p>
299    In order for these freedoms to be real, they must be permanent and
300    irrevocable as long as you do nothing wrong; if the developer of the
301    software has the power to revoke the license, or retroactively add
302    restrictions to its terms, without your doing anything wrong to give
303    cause, the software is not free.
304    </p>
305    
306  <P>  <p>
307  Rules about how to package a modified version are acceptable, if they  A free license may not require compliance with the license of a
308  don't effectively block your freedom to release modified versions.  nonfree program.  Thus, for instance, if a license requires you to
309  Rules that ``if you make the program available in this way, you must  comply with the licenses of &ldquo;all the programs you use&rdquo;, in
310  make it available in that way also'' can be acceptable too, on the  the case of a user that runs nonfree programs this would require
311  same condition.  (Note that such a rule still leaves you the choice of  compliance with the licenses of those nonfree programs; that makes the
312  whether to publish the program or not.)  license nonfree.
313    </p>
314  <P>  
315  In the GNU project, we use <A HREF="/copyleft/copyleft.html">  <p>
316  ``copyleft''</A> to protect these freedoms legally for everyone.  But  It is acceptable for a free license to specify which jurisdiction's
317  <A HREF="/philosophy/categories.html#Non-CopyleftedFreeSoftware">  law applies, or where litigation must be done, or both.
318  non-copylefted free software</A> also exists.  We believe there are  </p>
319  important reasons why <A HREF="/philosophy/pragmatic.html"> it is  
320  better to use copyleft</A>, but if your program is non-copylefted free  <h4>Contract-based licenses</h4>
321  software, we can still use it.  
322    <p>
323  <P>  Most free software licenses are based on copyright, and there are limits
324  See <A HREF="/philosophy/categories.html">Categories of Free Software  on what kinds of requirements can be imposed through copyright.  If a
325         (18k characters)</A>  copyright-based license respects freedom in the ways described above, it
326  for a description of how ``free software,'' ``copylefted software'' and  is unlikely to have some other sort of problem that we never anticipated
327  other categories of software relate to each other.  (though this does happen occasionally).  However, some free software
328    licenses are based on contracts, and contracts can impose a much larger
329  <P>  range of possible restrictions.  That means there are many possible ways
330  Sometimes government <A NAME="exportcontrol">export control  such a license could be unacceptably restrictive and nonfree.
331  regulations</A> and trade sanctions can constrain your freedom to  </p>
332  distribute copies of programs internationally.  Software developers do  
333  not have the power to eliminate or override these restrictions, but  <p>
334  what they can and must do is refuse to impose them as conditions of  We can't possibly list all the ways that might happen.  If a
335  use of the program.  In this way, the restrictions will not affect  contract-based license restricts the user in an unusual way that
336  activities and people outside the jurisdictions of these governments.  copyright-based licenses cannot, and which isn't mentioned here as
337    legitimate, we will have to think about it, and we will probably conclude
338  <P>  it is nonfree.
339  When talking about free software, it is best to avoid using terms like  </p>
340  ``give away'' or ``for free'', because those terms imply that the  
341  issue is about price, not freedom.  Some common terms such as  <h4>Use the right words when talking about free software</h4>
342  ``piracy'' embody opinions we hope you won't endorse.  See <A  
343  HREF="/philosophy/words-to-avoid.html">Confusing Words and Phrases  <p>
344  that are Worth Avoiding</A> for a discussion of these terms.  When talking about free software, it is best to avoid using terms
345  We also have a list of <A HREF="/philosophy/fs-translations.html">translations  like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
346  of "free software"</A> into various languages.  the issue is about price, not freedom.  Some common terms such
347    as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
348    <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
349    are Worth Avoiding</a> for a discussion of these terms.  We also have
350    a list of proper <a href="/philosophy/fs-translations.html">translations of
351    &ldquo;free software&rdquo;</a> into various languages.
352    </p>
353    
354  <P>  <h4>How we interpret these criteria</h4>
355    
356    <p>
357  Finally, note that criteria such as those stated in this free software  Finally, note that criteria such as those stated in this free software
358  definition require careful thought for their interpretation.  To  definition require careful thought for their interpretation.  To decide
359  decide whether a specific software license qualifies as a free  whether a specific software license qualifies as a free software license,
360  software license, we judge it based on these criteria to determine  we judge it based on these criteria to determine whether it fits their
361  whether it fits their spirit as well as the precise words.  If a  spirit as well as the precise words.  If a license includes unconscionable
362  license includes unconscionable restrictions, we reject it, even if we  restrictions, we reject it, even if we did not anticipate the issue
363  did not anticipate the issue in these criteria.  Sometimes a license  in these criteria.  Sometimes a license requirement raises an issue
364  requirement raises an issue that calls for extensive thought before we  that calls for extensive thought, including discussions with a lawyer,
365  can decide if the requirement is acceptable, including discussions  before we can decide if the requirement is acceptable.  When we reach
366  with a lawyer.  When we reach a conclusion, we sometimes update these  a conclusion about a new issue, we often update these criteria to make
367  criteria to make it easier to see why certain licenses do or don't  it easier to see why certain licenses do or don't qualify.
368  qualify.  </p>
369    
370  <P>  <h4>Get help with free licenses</h4>
371    
372  If you are interested in whether a specific license qualifies as a  <p>
373  free software license, see our <A  If you are interested in whether a specific license qualifies as a free
374  HREF="/philosophy/license-list.html"> list of licenses </A>.  If the  software license, see our <a href="/licenses/license-list.html">list
375  license you are concerned with is not listed there, you can ask us  of licenses</a>.  If the license you are concerned with is not
376  about it by sending us email at <A  listed there, you can ask us about it by sending us email at
377  HREF="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</A>.  <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
378    </p>
379  <HR>  
380    <p>
381  <H4><A HREF="/philosophy/philosophy.html">Other Texts to Read</A></H4>  If you are contemplating writing a new license, please contact the
382    Free Software Foundation first by writing to that address. The
383  <P>  proliferation of different free software licenses means increased work
384  Another group has started using the term <A  for users in understanding the licenses; we may be able to help you
385  HREF="free-software-for-freedom.html"> open source</A> to mean  find an existing free software license that meets your needs.
386  something close (but not identical) to "free software".  </p>
387    
388  <HR>  <p>
389    If that isn't possible, if you really need a new license, with our
390  Return to <A HREF="/home.html">GNU's home page</A>.  help you can ensure that the license really is a free software license
391  <P>  and avoid various practical problems.
392  FSF &amp; GNU inquiries &amp; questions to  </p>
393  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  
394  Other <A HREF="/home.html#ContactInfo">ways to contact</A> the FSF.  <h3 id="beyond-software">Beyond Software</h3>
395  <P>  
396  Comments on these web pages to  <p>
397  <A HREF="mailto:webmasters@www.gnu.org"><EM>webmasters@www.gnu.org</EM></A>,  <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
398  send other questions to  for the same reasons that software must be free, and because the
399  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  manuals are in effect part of the software.
400  <P>  </p>
401  Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.,  
402  59 Temple Place - Suite 330, Boston, MA  02111,  USA  <p>
403  <P>  The same arguments also make sense for other kinds of works of
404  Verbatim copying and distribution of this entire article is  practical use &mdash; that is to say, works that embody useful knowledge,
405  permitted in any medium, provided this notice is preserved.<P>  such as educational works and reference
406  Updated:  works.  <a href="http://wikipedia.org">Wikipedia</a> is the best-known
407    example.
408    </p>
409    
410    <p>
411    Any kind of work <em>can</em> be free, and the definition of free software
412    has been extended to a definition of <a href="http://freedomdefined.org/">
413    free cultural works</a> applicable to any kind of works.
414    </p>
415    
416    <h3 id="open-source">Open Source?</h3>
417    
418    <p>
419    Another group uses the term &ldquo;open source&rdquo; to mean
420    something close (but not identical) to &ldquo;free software&rdquo;.  We
421    prefer the term &ldquo;free software&rdquo; because, once you have heard that
422    it refers to freedom rather than price, it calls to mind freedom.  The
423    word &ldquo;open&rdquo; <a href="/philosophy/open-source-misses-the-point.html">
424    never refers to freedom</a>.
425    </p>
426    
427    <h3 id="History">History</h3>
428    
429    <p>From time to time we revise this Free Software Definition.  Here is
430    the list of substantive changes, along with links to show exactly what
431    was changed.</p>
432    
433    <ul>
434    
435    <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
436    1.153</a>: Clarify that freedom to run the program means nothing stops
437    you from making it run.</li>
438    
439    <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
440    1.141</a>: Clarify which code needs to be free.</li>
441    
442    <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
443    1.135</a>: Say each time that freedom 0 is the freedom to run the program
444    as you wish.</li>
445    
446    <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
447    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
448    
449    <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
450    1.131</a>: A free license may not require compliance with a nonfree license
451    of another program.</li>
452    
453    <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
454    1.129</a>: State explicitly that choice of law and choice of forum
455    specifications are allowed.  (This was always our policy.)</li>
456    
457    <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
458    1.122</a>: An export control requirement is a real problem if the
459    requirement is nontrivial; otherwise it is only a potential problem.</li>
460    
461    <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
462    1.118</a>: Clarification: the issue is limits on your right to modify,
463    not on what modifications you have made.  And modifications are not limited
464    to &ldquo;improvements&rdquo;</li>
465    
466    <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
467    1.111</a>: Clarify 1.77 by saying that only
468    retroactive <em>restrictions</em> are unacceptable.  The copyright
469    holders can always grant additional <em>permission</em> for use of the
470    work by releasing the work in another way in parallel.</li>
471    
472    <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
473    1.105</a>: Reflect, in the brief statement of freedom 1, the point
474    (already stated in version 1.80) that it includes really using your modified
475    version for your computing.</li>
476    
477    <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
478    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
479    
480    <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
481    1.90</a>: Clarify that freedom 3 means the right to distribute copies
482    of your own modified or improved version, not a right to participate
483    in someone else's development project.</li>
484    
485    <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
486    1.89</a>: Freedom 3 includes the right to release modified versions as
487    free software.</li>
488    
489    <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
490    1.80</a>: Freedom 1 must be practical, not just theoretical;
491    i.e., no tivoization.</li>
492    
493    <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
494    1.77</a>: Clarify that all retroactive changes to the license are
495    unacceptable, even if it's not described as a complete
496    replacement.</li>
497    
498    <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
499    1.74</a>: Four clarifications of points not explicit enough, or stated
500    in some places but not reflected everywhere:
501    <ul>
502    <li>"Improvements" does not mean the license can
503    substantively limit what kinds of modified versions you can release.
504    Freedom 3 includes distributing modified versions, not just changes.</li>
505    <li>The right to merge in existing modules
506    refers to those that are suitably licensed.</li>
507    <li>Explicitly state the conclusion of the point about export controls.</li>
508    <li>Imposing a license change constitutes revoking the old license.</li>
509    </ul>
510    </li>
511    
512    <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
513    1.57</a>: Add &quot;Beyond Software&quot; section.</li>
514    
515    <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
516    1.46</a>: Clarify whose purpose is significant in the freedom to run
517    the program for any purpose.</li>
518    
519    <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
520    1.41</a>: Clarify wording about contract-based licenses.</li>
521    
522    <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
523    1.40</a>: Explain that a free license must allow to you use other
524    available free software to create your modifications.</li>
525    
526    <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
527    1.39</a>: Note that it is acceptable for a license to require you to
528    provide source for versions of the software you put into public
529    use.</li>
530    
531    <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
532    1.31</a>: Note that it is acceptable for a license to require you to
533    identify yourself as the author of modifications.  Other minor
534    clarifications throughout the text.</li>
535    
536    <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
537    1.23</a>: Address potential problems related to contract-based
538    licenses.</li>
539    
540    <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
541    1.16</a>: Explain why distribution of binaries is important.</li>
542    
543    <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
544    1.11</a>: Note that a free license may require you to send a copy of
545    versions you distribute to previous developers on request.</li>
546    
547    </ul>
548    
549    <p>There are gaps in the version numbers shown above because there are
550    other changes in this page that do not affect the definition or its
551    interpretations.  For instance, the list does not include changes in
552    asides, formatting, spelling, punctuation, or other parts of the page.
553    You can review the complete list of changes to the page through
554    the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
555    interface</a>.</p>
556    
557    <h3 style="font-size:1em">Footnote</h3>
558    <ol>
559    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
560    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
561    the freedom to run the program needed to be mentioned explicitly.
562    It was clearly more basic than the other three, so it properly should
563    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
564    </ol>
565    
566    </div><!-- for id="content", starts in the include above -->
567    <!--#include virtual="/server/footer.html" -->
568    <div id="footer">
569    <div class="unprintable">
570    
571    <p>Please send general FSF &amp; GNU inquiries to
572    <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
573    There are also <a href="/contact/">other ways to contact</a>
574    the FSF.  Broken links and other corrections or suggestions can be sent
575    to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
576    
577    <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
578            replace it with the translation of these two:
579    
580            We work hard and do our best to provide accurate, good quality
581            translations.  However, we are not exempt from imperfection.
582            Please send your comments and general suggestions in this regard
583            to <a href="mailto:web-translators@gnu.org">
584            &lt;web-translators@gnu.org&gt;</a>.</p>
585    
586            <p>For information on coordinating and submitting translations of
587            our web pages, see <a
588            href="/server/standards/README.translations.html">Translations
589            README</a>. -->
590    Please see the <a
591    href="/server/standards/README.translations.html">Translations
592    README</a> for information on coordinating and submitting translations
593    of this article.</p>
594    </div>
595    
596    <!-- Regarding copyright, in general, standalone pages (as opposed to
597         files generated as part of manuals) on the GNU web server should
598         be under CC BY-ND 4.0.  Please do NOT change or remove this
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600         Please make sure the copyright date is consistent with the
601         document.  For web pages, it is ok to list just the latest year the
602         document was modified, or published.
603        
604         If you wish to list earlier years, that is ok too.
605         Either "2001, 2002, 2003" or "2001-2003" are ok for specifying
606         years, as long as each year in the range is in fact a copyrightable
607         year, i.e., a year in which the document was published (including
608         being publicly visible on the web or in a revision control system).
609        
610         There is more detail about copyright years in the GNU Maintainers
611         Information document, www.gnu.org/prep/maintain. -->
612    
613    <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2018
614    Free Software Foundation, Inc.</p>
615    
616    <p>This page is licensed under a <a rel="license"
617    href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
618    Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
619    
620    <!--#include virtual="/server/bottom-notes.html" -->
621    
622    <p class="unprintable">Updated:
623  <!-- timestamp start -->  <!-- timestamp start -->
624  $Date$ $Author$  $Date$
625  <!-- timestamp end -->  <!-- timestamp end -->
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630    </html>

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