/[www]/www/philosophy/free-sw.html
ViewVC logotype

Diff of /www/philosophy/free-sw.html

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 1.50 by johnsu01, Fri Oct 13 16:47:36 2006 UTC revision 1.185 by gnun, Sat May 20 08:56:24 2023 UTC
# Line 1  Line 1 
1  <?xml version="1.0" encoding="utf-8" ?>  <!--#include virtual="/server/header.html" -->
2  <?xml-stylesheet type="text/css" href="/gnu.css"?>  <!-- Parent-Version: 1.96 -->
3  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"  <!-- This page is derived from /server/standards/boilerplate.html -->
4      "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">  <!--#set var="TAGS" value="essays aboutfs principles" -->
5  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">  <!--#set var="DISABLE_TOP_ADDENDUM" value="yes" -->
6    <title>What is Free Software?
7  <head>  - GNU Project - Free Software Foundation</title>
8  <title>  <style type="text/css" media="print,screen"><!--
9  The Free Software Definition - GNU Project - Free Software Foundation (FSF)  .toc > ul > li { list-style-type: none; font-weight: bold; }
10  </title>  .toc ul { font-weight: normal; }
11  <link rev="made" href="mailto:webmasters@gnu.org" />  #History ~ p, #History ~ ul { font-size: 1rem; }
12  </head>  --></style>
13    <meta name="keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" />
14  <!-- This document is in XML and XHTML. -->  <meta name="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." />
15  <!-- Please ensure that your final document is -->  <!--#include virtual="/philosophy/po/free-sw.translist" -->
16  <!-- consistent with W3C XHTML and CSS standards -->  <!--#include virtual="/server/banner.html" -->
17  <!-- Also, see validator.w3.org -->  <!--#include virtual="/philosophy/ph-breadcrumb.html" -->
18    <!--GNUN: OUT-OF-DATE NOTICE-->
19  <body>  <!--#include virtual="/server/top-addendum.html" -->
20    <div class="article reduced-width">
21  <div id="header">  <h2>What is Free Software?</h2>
22    <a href="http://www.defectivebydesign.org/join/gnu">  <div class="thin"></div>
23      <img src="/graphics/dbd.png"  
24           alt="[Join the FSF Campaign to Eliminate DRM]" />  <div class="important">
25    </a>  <p>
26  </div>  &ldquo;Free software&rdquo; means software that respects users'
27    freedom and community.  Roughly, it means that <b>the users have the
28  <hr />  freedom to run, copy, distribute, study, change and improve the
29    software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
30  <p><a href="#translations">Translations</a> of this page</p>  liberty, not price.  To understand the concept, you should think of
31    &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
32    &ldquo;free beer.&rdquo;  We sometimes call it &ldquo;libre
33    software,&rdquo; borrowing the French or Spanish word for
34    &ldquo;free&rdquo; as in freedom, to show we do not mean the software
35    is gratis.
36    </p>
37    
 <h3>The Free Software Definition</h3>  
38  <p>  <p>
39  <a href="/graphics/philosophicalgnu.html">  You may have paid money to get copies of a free program, or you may
40    <img src="/graphics/philosophical-gnu-sm.jpg"  have obtained copies at no charge.  But regardless of how you got your
41         alt=" [image of a Philosophical Gnu] "  copies, you always have the freedom to copy and change the software,
42         width="160px"  even to <a href="/philosophy/selling.html">sell copies</a>.
        height="200px" />  
 </a>  
43  </p>  </p>
44    </div>
45    
46  <p>  <p>
47  We maintain this free software definition to show clearly what must  We campaign for these freedoms because everyone deserves them.  With
48  be true about a particular software program for it to be considered  these freedoms, the users (both individually and collectively) control
49  free software.  the program and what it does for them.  When users don't control the
50    program, we call it a &ldquo;nonfree&rdquo; or
51    &ldquo;proprietary&rdquo; program.  The nonfree program controls the
52    users, and the developer controls the program; this makes the
53    program <a href="/philosophy/free-software-even-more-important.html">
54    an instrument of unjust power</a>.
55  </p>  </p>
56    
57  <p>  <p>
58  <q>Free software</q> is a matter of liberty, not price.  To understand  &ldquo;Open source&rdquo; is something different: it has a very
59  the concept, you should think of <q>free</q> as in <q>free speech,</q>  different philosophy based on different values.  Its practical
60  not as in <q>free beer.</q>  definition is different too, but nearly all open source programs are
61    in fact free.  We explain the
62    difference in <a href="/philosophy/open-source-misses-the-point.html">
63    Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
64    </p>
65    
66    <div class="toc">
67    <hr class="no-display" />
68    <h3 class="no-display">Table of contents</h3>
69    <ul>
70     <li><a href="#fs-definition">The Free Software Definition</a>
71      <ul>
72       <li><a href="#four-freedoms">The four essential freedoms</a></li>
73       <li><a href="#selling">Free software <em>can</em> be commercial</a></li>
74      </ul>
75     </li>
76     <li><a href="#clarifying">Clarifying the Boundary Between Free and Nonfree</a>
77      <ul>
78       <li><a href="#run-the-program">The freedom to run the program as you
79         wish</a></li>
80       <li><a href="#make-changes">The freedom to study the source code and make
81         changes</a></li>
82       <li><a href="#redistribute">The freedom to redistribute if you wish:
83         basic requirements</a></li>
84       <li><a href="#copyleft">Copyleft</a></li>
85       <li><a href="#packaging">Rules about packaging and distribution
86         details</a></li>
87       <li><a href="#exportcontrol">Export regulations</a></li>
88       <li><a href="#legal-details">Legal considerations</a></li>
89       <li><a href="#contracts">Contract-based licenses</a></li>
90      </ul>
91     </li>
92     <li><a href="#in-practice">The Free Software Definition in Practice</a>
93      <ul>
94       <li><a href="#interpretation">How we interpret these criteria</a></li>
95       <li><a href="#get-help">Get help with free licenses</a></li>
96       <li><a href="#terminology">Use the right words when talking about free
97         software</a></li>
98      </ul>
99     </li>
100     <li><a href="#beyond-software">Beyond Software</a></li>
101     <li><a href="#History">History</a></li>
102    </ul>
103    </div>
104    
105    <div class="edu-note" id="fsf-licensing" role="complementary">
106    <p style="font-size:80%">
107    Have a question about free software licensing not answered here?
108    See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
109    and if necessary contact the FSF Compliance Lab
110    at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
111    <hr class="no-display" />
112    </div>
113    
114    
115    <h3 id="fs-definition">The Free Software Definition</h3>
116    
117    <p>
118    The free software definition presents the criteria for whether a
119    particular software program qualifies as free software.  From time to
120    time we revise this definition, to clarify it or to resolve questions
121    about subtle issues.  See the <a href="#History">History section</a>
122    below for a list of changes that affect the definition of free
123    software.
124  </p>  </p>
125    
126    <h4 id="four-freedoms">The four essential freedoms</h4>
127  <p>  <p>
128  Free software is a matter of the users' freedom to run, copy, distribute,  A program is free software if the program's users have the
129  study, change and improve the software.  More precisely, it refers to  four essential freedoms: <a href="#f1">[1]</a>
 four kinds of freedom, for the users of the software:  
130  </p>  </p>
131    
132  <ul>  <ul class="important">
133    <li>The freedom to run the program, for any purpose (freedom 0).</li>    <li>The freedom to run the program as you wish,
134    <li>The freedom to study how the program works, and adapt it to        for any purpose (freedom 0).</li>
135        your needs (freedom 1). Access to the source code is a precondition    <li>The freedom to study how the program works, and change it so it
136        for this.        does your computing as you wish (freedom 1). Access to the source
137          code is a precondition for this.
138    </li>    </li>
139    <li>The freedom to redistribute copies so you can help your neighbor    <li>The freedom to redistribute copies so you can help others
140        (freedom 2).        (freedom 2).
141    </li>    </li>
142    <li>The freedom to improve the program, and release your improvements    <li>The freedom to distribute copies of your modified versions
143        to the public, so that the whole community benefits (freedom 3).        to others (freedom 3).  By doing this you can give the whole
144          community a chance to benefit from your changes.
145        Access to the source code is a precondition for this.        Access to the source code is a precondition for this.
146    </li>    </li>
147  </ul>  </ul>
148    
149  <p>  <p>
150  A program is free software if users have all of these freedoms.  Thus,  A program is free software if it gives users adequately all of these
151  you should be free to redistribute copies, either with or without  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
152  modifications, either gratis or charging a fee for distribution, to  nonfree distribution schemes in terms of how far they fall short of
153    being free, we consider them all equally unethical.</p>
154    
155    <p>In any given scenario, these freedoms must apply to whatever code
156    we plan to make use of, or lead others to make use of.  For instance,
157    consider a program A which automatically launches a program B to
158    handle some cases.  If we plan to distribute A as it stands, that
159    implies users will need B, so we need to judge whether both A and B
160    are free.  However, if we plan to modify A so that it doesn't use B,
161    only A needs to be free; B is not pertinent to that plan.</p>
162    
163    
164    <h4 id="selling">Free software <em>can</em> be commercial</h4>
165    
166    <p>
167    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial.&rdquo;
168    On the contrary, a free program must be available for commercial use,
169    commercial development, and commercial distribution.  This policy is
170    of fundamental importance&mdash;without this, free software could not
171    achieve its aims.
172    </p>
173    
174    <p>
175    We want to invite everyone to use the GNU system, including businesses
176    and their workers.  That requires allowing commercial use.  We hope
177    that free replacement programs will supplant comparable proprietary
178    programs, but they can't do that if businesses are forbidden to use
179    them.  We want commercial products that contain software to include
180    the GNU system, and that would constitute commercial distribution for
181    a price.  Commercial development of free software is no longer
182    unusual; such free commercial software is very important.  Paid,
183    professional support for free software fills an important need.
184    </p>
185    
186    <p>
187    Thus, to exclude commercial use, commercial development or commercial
188    distribution would hobble the free software community and obstruct its
189    path to success.  We must conclude that a program licensed with such
190    restrictions does not qualify as free software.
191    </p>
192    
193    <p>
194    A free program must offer the four freedoms to any would-be user that
195    obtains a copy of the software, who has complied thus far with the
196    conditions of the free license covering the software in any previous
197    distribution of it.  Putting some of the freedoms off limits to some
198    users, or requiring that users pay, in money or in kind, to exercise
199    them, is tantamount to not granting the freedoms in question, and thus
200    renders the program nonfree.
201    </p>
202    
203    
204    <h3 id="clarifying">Clarifying the Boundary Between Free and Nonfree</h3>
205    
206    <p>In the rest of this article we explain more precisely how far the
207    various freedoms need to extend, on various issues, in order for a
208    program to be free.</p>
209    
210    <h4 id="run-the-program">The freedom to run the program as you wish</h4>
211    
212    <p>
213    The freedom to run the program means the freedom for any kind of person
214    or organization to use it on any kind of computer system, for any kind of
215    overall job and purpose, without being required to communicate about it
216    with the developer or any other specific entity.  In this freedom, it is
217    the <em>user's</em> purpose that matters, not the <em>developer's</em>
218    purpose; you as a user are free to run the program for your purposes,
219    and if you distribute it to other people, they are then free to run it for
220    their purposes, but you are not entitled to impose your purposes on them.
221    </p>
222    
223    <p>
224    The freedom to run the program as you wish means that you are not
225    forbidden or stopped from making it run.  This has nothing to do with what
226    functionality the program has, whether it is technically capable of
227    functioning in any given environment, or whether it is useful for any
228    particular computing activity.</p>
229    
230    <p>For example, if the code arbitrarily rejects certain meaningful
231    inputs&mdash;or even fails unconditionally&mdash;that may make the
232    program less useful, perhaps even totally useless, but it does not
233    deny users the freedom to run the program, so it does not conflict
234    with freedom 0.  If the program is free, the users can overcome the
235    loss of usefulness, because freedoms 1 and 3 permit users and
236    communities to make and distribute modified versions without the
237    arbitrary nuisance code.</p>
238    
239    <p>&ldquo;As you wish&rdquo; includes, optionally, &ldquo;not at
240    all&rdquo; if that is what you wish.  So there is no need for a
241    separate &ldquo;freedom not to run a program.&rdquo;</p>
242    
243    <h4 id="make-changes">The freedom to study the source code and make changes</h4>
244    
245    <p>
246    In order for freedoms 1 and 3 (the freedom to make changes and the
247    freedom to publish the changed versions) to be meaningful, you need to have
248    access to the source code of the program.  Therefore, accessibility of
249    source code is a necessary condition for free software.  Obfuscated
250    &ldquo;source code&rdquo; is not real source code and does not count
251    as source code.
252    </p>
253    
254    <p>
255    Source code is defined as the preferred form of the program for making
256    changes in.  Thus, whatever form a developer changes to develop
257    the program is the source code of that developer's version.
258    </p>
259    
260    <p>
261    Freedom 1 includes the freedom to use your changed version in place of
262    the original.  If the program is delivered in a product designed to
263    run someone else's modified versions but refuse to run yours&mdash;a
264    practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown,&rdquo;
265    or (in its practitioners' perverse terminology) as &ldquo;secure
266    boot&rdquo;&mdash;freedom 1 becomes an empty pretense rather than a
267    practical reality.  These binaries are not free
268    software even if the source code they are compiled from is free.
269    </p>
270    
271    <p>
272    One important way to modify a program is by merging in available free
273    subroutines and modules.  If the program's license says that you
274    cannot merge in a suitably licensed existing module&mdash;for instance, if it
275    requires you to be the copyright holder of any code you add&mdash;then the
276    license is too restrictive to qualify as free.
277    </p>
278    
279    <p>
280    Whether a change constitutes an improvement is a subjective matter.
281    If your right to modify a program is limited, in substance, to changes that
282    someone else considers an improvement, that program is not free.
283    </p>
284    
285    <p>
286    One special case of freedom 1 is to delete the program's code so it
287    returns after doing nothing, or make it invoke some other program.
288    Thus, freedom 1 includes the &ldquo;freedom to delete the program.&rdquo;
289    </p>
290    
291    <h4 id="redistribute">The freedom to redistribute if you wish: basic
292    requirements</h4>
293    
294    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
295    redistribute copies, either with or without modifications, either
296    gratis or charging a fee for distribution, to
297  <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these  <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
298  things means (among other things) that you do not have to ask or pay  things means (among other things) that you do not have to ask or pay
299  for permission.  for permission to do so.
300  </p>  </p>
301    
302  <p>  <p>
# Line 89  notify anyone in particular, or in any p Line 307  notify anyone in particular, or in any p
307  </p>  </p>
308    
309  <p>  <p>
310  The freedom to run the program means the freedom for any kind of person  Freedom 3 includes the freedom to release your modified versions
311  or organization to use it on any kind of computer system, for any kind of  as free software.  A free license may also permit other ways of
312  overall job and purpose, without being required to communicate about it  releasing them; in other words, it does not have to be
313  with the developer or any other specific entity.  In this freedom, it is  a <a href="/licenses/copyleft.html">copyleft</a> license.  However, a
314  the <em>user's</em> purpose that matters, not the <em>developer's</em>  license that requires modified versions to be nonfree does not qualify
315  purpose; you as a user are free to run a program for your purposes,  as a free license.
 and if you distribute it to someone else, she is then free to run it  
 for her purposes, but you are not entitled to impose your purposes on her.  
316  </p>  </p>
317    
318  <p>  <p>
319  The freedom to redistribute copies must include binary or executable  The freedom to redistribute copies must include binary or executable
320  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
321  unmodified versions.  (Distributing programs in runnable form is necessary  unmodified versions.  (Distributing programs in runnable form is necessary
322  for conveniently installable free operating systems.)  It is ok if there  for conveniently installable free operating systems.)  It is OK if there
323  is no way to produce a binary or executable form for a certain program  is no way to produce a binary or executable form for a certain program
324  (since some languages don't support that feature), but you must have the  (since some languages don't support that feature), but you must have the
325  freedom to redistribute such forms should you find or develop a way to  freedom to redistribute such forms should you find or develop a way to
326  make them.  make them.
327  </p>  </p>
328    
329    <h4 id="copyleft">Copyleft</h4>
330    
331  <p>  <p>
332  In order for the freedoms to make changes, and to publish improved  Certain kinds of rules about the manner of distributing free
333  versions, to be meaningful, you must have access to the source code of  software are acceptable, when they don't conflict with the central
334  the program.  Therefore, accessibility of source code is a necessary  freedoms.  For example, <a href="/licenses/copyleft.html">copyleft</a>
335  condition for free software.  (very simply stated) is the rule that when redistributing the program,
336    you cannot add restrictions to deny other people the central freedoms.
337    This rule does not conflict with the central freedoms; rather it
338    protects them.
339  </p>  </p>
340    
341  <p>  <p>
342  One important way to modify a program is by merging in available  In the GNU project, we use copyleft to protect the four freedoms
343  free subroutines and modules.  If the program's license says that you  legally for everyone.  We believe there are important reasons why
344  cannot merge in an existing module, such as if it requires you to be the  <a href="/philosophy/pragmatic.html">it is better to use
345  copyright holder of any code you add, then the license is too restrictive  copyleft</a>.  However,
346  to qualify as free.  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
347    noncopylefted free software</a> is ethical
348    too.  See <a href="/philosophy/categories.html">Categories of Free
349    Software</a> for a description of how &ldquo;free software,&rdquo;
350    &ldquo;copylefted software&rdquo; and other categories of software
351    relate to each other.
352  </p>  </p>
353    
354    <h4 id="packaging">Rules about packaging and distribution details</h4>
355    
356  <p>  <p>
357  In order for these freedoms to be real, they must be irrevocable as  Rules about how to package a modified version are acceptable,
358  long as you do nothing wrong; if the developer of the software has the  if they don't substantively limit your freedom to release modified
359  power to revoke the license, without your doing anything to give cause,  versions, or your freedom to make and use modified versions privately.
360  the software is not free.  Thus, it is acceptable for the license to require that you change the
361    name of the modified version, remove a logo, or identify your
362    modifications as yours.  As long as these requirements are not so
363    burdensome that they effectively hamper you from releasing your
364    changes, they are acceptable; you're already making other changes to
365    the program, so you won't have trouble making a few more.
366  </p>  </p>
367    
368  <p>  <p>
369  However, certain kinds of rules about the manner of distributing free  Rules that &ldquo;if you make your version available in this way, you
370  software are acceptable, when they don't conflict with the central  must make it available in that way also&rdquo; can be acceptable too,
371  freedoms.  For example, copyleft (very simply stated) is the rule that  on the same condition.  An example of such an acceptable rule is one
372  when redistributing the program, you cannot add restrictions to deny  saying that if you have distributed a
373  other people the central freedoms.  This rule does not conflict with  modified version and a previous developer asks for a copy of it, you
374  the central freedoms; rather it protects them.  must send one.  (Note that such a rule still leaves you the choice of
375    whether to distribute your version at all.)  Rules that require release
376    of source code to the users for versions that you put into public use
377    are also acceptable.
378  </p>  </p>
379    
380  <p>  <p>
381  You may have paid money to get copies of free software, or you may have  A special issue arises when a license requires changing the name by
382  obtained copies at no charge.  But regardless of how you got your copies,  which the program will be invoked from other programs.  That
383  you always have the freedom to copy and change the software, even to  effectively hampers you from releasing your changed version so that it
384  <a href="/philosophy/selling.html">sell copies</a>.  can replace the original when invoked by those other programs.  This
385  </p>  sort of requirement is acceptable only if there's a suitable aliasing
386    facility that allows you to specify the original program's name as an
387    alias for the modified version.</p>
388    
389    <h4 id="exportcontrol">Export regulations</h4>
390    
391  <p>  <p>
392  <q>Free software</q> does not mean <q>non-commercial.</q>  A free  Sometimes government export control regulations
393  program must be available for commercial use, commercial development,  and trade sanctions can constrain your freedom to distribute copies of
394  and commercial distribution.  Commercial development of free software  programs internationally.  Software developers do not have the power to
395  is no longer unusual; such free commercial software is very important.  eliminate or override these restrictions, but what they can and must do
396    is refuse to impose them as conditions of use of the program.  In this
397    way, the restrictions will not affect activities and people outside the
398    jurisdictions of these governments.  Thus, free software licenses
399    must not require obedience to any nontrivial export regulations as a
400    condition of exercising any of the essential freedoms.
401  </p>  </p>
402    
403  <p>  <p>
404  Rules about how to package a modified version are acceptable, if they  Merely mentioning the existence of export regulations, without making
405  don't substantively block your freedom to release modified versions, or  them a condition of the license itself, is acceptable since it does
406  your freedom to make and use modified versions privately.  Rules that <q>if  not restrict users.  If an export regulation is actually trivial for
407  you make your version available in this way, you must make it available in  free software, then requiring it as a condition is not an actual
408  that way also</q> can be acceptable too, on the same condition.  (Note that  problem; however, it is a potential problem, since a later change in
409  such a rule still leaves you the choice of whether to publish your version  export law could make the requirement nontrivial and thus render the
410  at all.)  Rules that require release of source code to the users for  software nonfree.
 versions that you put into public use are also acceptable.  It is also  
 acceptable for the license to require that, if you have distributed a  
 modified version and a previous developer asks for a copy of it, you  
 must send one, or that you identify yourself on your modifications.  
411  </p>  </p>
412    
413    <h4 id="legal-details">Legal considerations</h4>
414    
415  <p>  <p>
416  In the GNU project, we use  In order for these freedoms to be real, they must be permanent and
417  <q><a href="/copyleft/copyleft.html">copyleft</a></q>  irrevocable as long as you do nothing wrong; if the developer of the
418  to protect these freedoms legally for everyone.  But  software has the power to revoke the license, or retroactively add
419  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">non-copylefted  restrictions to its terms, without your doing anything wrong to give
420  free software</a> also exists.  We believe there are important reasons why  cause, the software is not free.
 <a href="/philosophy/pragmatic.html"> it is better to use copyleft</a>,  
 but if your program is non-copylefted free software, we can still  
 use it.  
421  </p>  </p>
422    
423  <p>  <p>
424  See <a href="/philosophy/categories.html">Categories of Free Software</a>  A free license may not require compliance with the license of a
425  for a description of how <q>free software,</q> <q>copylefted software</q>  nonfree program.  Thus, for instance, if a license requires you to
426  and other categories of software relate to each other.  comply with the licenses of &ldquo;all the programs you use,&rdquo; in
427    the case of a user that runs nonfree programs this would require
428    compliance with the licenses of those nonfree programs; that makes the
429    license nonfree.
430  </p>  </p>
431    
432  <p>  <p>
433  Sometimes government <a id="exportcontrol">export control regulations</a>  It is acceptable for a free license to specify which jurisdiction's
434  and trade sanctions can constrain your freedom to distribute copies of  law applies, or where litigation must be done, or both.
 programs internationally.  Software developers do not have the power to  
 eliminate or override these restrictions, but what they can and must do  
 is refuse to impose them as conditions of use of the program.  In this  
 way, the restrictions will not affect activities and people outside the  
 jurisdictions of these governments.  
435  </p>  </p>
436    
437    <h4 id="contracts">Contract-based licenses</h4>
438    
439  <p>  <p>
440  Most free software licenses are based on copyright, and there are limits  Most free software licenses are based on copyright, and there are limits
441  on what kinds of requirements can be imposed through copyright.  If a  on what kinds of requirements can be imposed through copyright.  If a
# Line 204  is unlikely to have some other sort of p Line 444  is unlikely to have some other sort of p
444  (though this does happen occasionally).  However, some free software  (though this does happen occasionally).  However, some free software
445  licenses are based on contracts, and contracts can impose a much larger  licenses are based on contracts, and contracts can impose a much larger
446  range of possible restrictions.  That means there are many possible ways  range of possible restrictions.  That means there are many possible ways
447  such a license could be unacceptably restrictive and non-free.  such a license could be unacceptably restrictive and nonfree.
448  </p>  </p>
449    
450  <p>  <p>
# Line 212  We can't possibly list all the ways that Line 452  We can't possibly list all the ways that
452  contract-based license restricts the user in an unusual way that  contract-based license restricts the user in an unusual way that
453  copyright-based licenses cannot, and which isn't mentioned here as  copyright-based licenses cannot, and which isn't mentioned here as
454  legitimate, we will have to think about it, and we will probably conclude  legitimate, we will have to think about it, and we will probably conclude
455  it is non-free.  it is nonfree.
456  </p>  </p>
457    
458  <p>  <h3 id="in-practice">The Free Software Definition in Practice</h3>
459  When talking about free software, it is best to avoid using terms  
460  like <q>give away</q> or <q>for free,</q> because those terms imply that  <h4 id="interpretation">How we interpret these criteria</h4>
 the issue is about price, not freedom.  Some common terms such  
 as <q>piracy</q> embody opinions we hope you won't endorse.  See  
 <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that  
 are Worth Avoiding</a> for a discussion of these terms.  We also have  
 a list of <a href="/philosophy/fs-translations.html">translations of  
 <q>free software</q></a> into various languages.  
 </p>  
461    
462  <p>  <p>
463  Finally, note that criteria such as those stated in this free software  Note that criteria such as those stated in this free software
464  definition require careful thought for their interpretation.  To decide  definition require careful thought for their interpretation.  To decide
465  whether a specific software license qualifies as a free software license,  whether a specific software license qualifies as a free software license,
466  we judge it based on these criteria to determine whether it fits their  we judge it based on these criteria to determine whether it fits their
# Line 240  a conclusion about a new issue, we often Line 473  a conclusion about a new issue, we often
473  it easier to see why certain licenses do or don't qualify.  it easier to see why certain licenses do or don't qualify.
474  </p>  </p>
475    
476    <h4 id="get-help">Get help with free licenses</h4>
477    
478  <p>  <p>
479  If you are interested in whether a specific license qualifies as a free  If you are interested in whether a specific license qualifies as a free
480  software license, see our <a href="/licenses/license-list.html">list  software license, see our <a href="/licenses/license-list.html">list
# Line 249  listed there, you can ask us about it by Line 484  listed there, you can ask us about it by
484  </p>  </p>
485    
486  <p>  <p>
487  If you are contemplating writing a new license, please contact the FSF  If you are contemplating writing a new license, please contact the
488  by writing to that address. The proliferation of different free software  Free Software Foundation first by writing to that address. The
489  licenses means increased work for users in understanding the licenses;  proliferation of different free software licenses means increased work
490  we may be able to help you find an existing Free Software license that  for users in understanding the licenses; we may be able to help you
491  meets your needs.  find an existing free software license that meets your needs.
492  </p>  </p>
493    
494  <p>  <p>
495  If that isn't possible, if you really need a new license, with our  If that isn't possible, if you really need a new license, with our
496  help you can ensure that the license really is a Free Software license  help you can ensure that the license really is a free software license
497  and avoid various practical problems.  and avoid various practical problems.
498  </p>  </p>
499    
500  <hr />  <h4 id="terminology">Use the right words when talking about free software</h4>
501    
502  <p>  <p>
503  Another group has started using the term <q>open source</q> to mean  When talking about free software, it is best to avoid using terms
504  something close (but not identical) to <q>free software.</q>  We prefer  like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
505  the term <q>free software</q> because, once you have heard it refers to  the issue is about price, not freedom.  Some common terms such
506  freedom rather than price, <a href="free-software-for-freedom.html">it  as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
507  calls to mind freedom</a>.  The word <q>open</q> never does that.  <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
508  </p>  are Worth Avoiding</a> for a discussion of these terms.  We also have
509    a list of proper <a href="/philosophy/fs-translations.html">translations of
510  <hr />  &ldquo;free software&rdquo;</a> into various languages.
   
 <h4><a href="/philosophy/philosophy.html">Other Texts to Read</a></h4>  
   
 <div class="translations">  
 <p><a id="translations"></a>  
 <b>Translations of this page</b>:<br />  
   
 <!-- Please keep this list alphabetical, and in the original -->  
 <!-- language if possible, otherwise default to English -->  
 <!-- If you do not have it English, please comment what the -->  
 <!-- English is.  If you add a new language here, please -->  
 <!-- advise web-translators@gnu.org and add it to -->  
 <!--    - in /home/www/bin/nightly-vars either TAGSLANG or WEBLANG -->  
 <!--    - in /home/www/html/server/standards/README.translations.html -->  
 <!--      one of the lists under the section "Translations Underway" -->  
 <!--    - if there is a translation team, you also have to add an alias -->  
 <!--      to mail.gnu.org:/com/mailer/aliases -->  
 <!-- Please also check you have the 2 letter language code right versus -->  
 <!--     http://www.w3.org/WAI/ER/IG/ert/iso639.htm -->  
 [  
   <a href="/philosophy/free-sw.ar.html">&#1575;&#1604;&#1593;&#1585;&#1576;&#1610;&#1577;</a> <!-- Arabic -->  
 | <a href="/philosophy/free-sw.bg.html">&#x431;&#x44A;&#x43B;&#x433;&#x430;&#x440;&#x441;&#x43A;&#x438;</a>  <!-- Bulgarian -->  
 | <a href="/philosophy/free-sw.ca.html">Catal&#x00e0;</a>       <!-- Catalan -->  
   
 <!-- Chinese (Simplified) -->  
 | <a href="/philosophy/free-sw.cn.html">&#x7b80;&#x4f53;&#x4e2d;&#x6587;</a>  
   
 <!-- Chinese (Traditional) -->  
 | <a href="/philosophy/free-sw.zh.html">&#x7e41;&#x9ad4;&#x4e2d;&#x6587;</a>  
   
 | <a href="/philosophy/free-sw.cs.html">&#x010c;esky</a>        <!-- Czech -->  
 | <a href="/philosophy/free-sw.da.html">Dansk</a>       <!-- Danish -->  
 | <a href="/philosophy/free-sw.de.html">Deutsch</a>     <!-- German -->  
 | <a href="/philosophy/free-sw.html">English</a>  
 | <a href="/philosophy/free-sw.el.html">Ελληνικά</a>  <!--Greek-->  
 | <a href="/philosophy/free-sw.es.html">Espa&#x00f1;ol</a>      <!-- Spanish -->  
 | <a href="/philosophy/free-sw.eo.html">Esperanto</a>  
   
 <!-- Persian/Farsi -->  
 | <a href="/philosophy/free-sw.fa.html">&#x0641;&#x0627;&#x0631;&#x0633;&#x06cc;</a>  
   
 | <a href="/philosophy/free-sw.fr.html">Fran&#x00e7;ais</a>     <!-- French -->  
 | <a href="/philosophy/free-sw.gl.html">Galego</a>      <!-- Galician -->  
 | <a href="/philosophy/free-sw.he.html">&#x05e2;&#x05d1;&#x05e8;&#x05d9;&#x05ea;</a>    <!-- Hebrew -->  
 | <a href="/philosophy/free-sw.hr.html">Hrvatski</a>    <!-- Croatian -->  
 | <a href="/philosophy/free-sw.id.html">Bahasa Indonesia</a>    <!-- Indonesian -->  
 | <a href="/philosophy/free-sw.it.html">Italiano</a>    <!-- Italian -->  
 | <a href="/philosophy/free-sw.ja.html">&#x65e5;&#x672c;&#x8a9e;</a>    <!-- Japanese -->  
 | <a href="/philosophy/free-sw.ko.html">&#xd55c;&#xad6d;&#xc5b4;</a>    <!-- Korean -->  
 | <a href="/philosophy/free-sw.hu.html">Magyar</a>      <!-- Hungarian -->  
 | <a href="/philosophy/free-sw.nl.html">Nederlands</a>  <!-- Dutch -->  
 | <a href="/philosophy/free-sw.no.html">Norsk</a>       <!-- Norwegian -->  
 | <a href="/philosophy/free-sw.pl.html">Polski</a>      <!-- Polish -->  
 | <a href="/philosophy/free-sw.pt.html">Portugu&#x0ea;s</a>     <!-- Portuguese -->  
 | <a href="/philosophy/free-sw.ro.html">Rom&#x00e2;n&#x0103;</a>        <!-- Romanian -->  
 | <a href="/philosophy/free-sw.ru.html">&#1056;&#1091;&#1089;&#1089;&#1082;&#1080;&#1081;</a> <!-- Russian -->  
 | <a href="/philosophy/free-sw.sl.html">Slovinsko</a>   <!--- Slovenian -->  
 | <a href="/philosophy/free-sw.sr.html">&#x0421;&#x0440;&#x043f;&#x0441;&#x043a;&#x0438;</a> <!-- Serbian -->  
 | <a href="/philosophy/free-sw.tl.html">Tagalog</a>     <!-- Tagalog -->  
 | <a href="/philosophy/free-sw.tr.html">T&#x00fc;rk&#x00e7;e</a>        <!-- Turkish -->  
 ]  
511  </p>  </p>
 </div>  
512    
513  <div class="copyright">  <p id="open-source">
514  <p>  Another group uses the term &ldquo;open source&rdquo; to mean
515  Return to the <a href="/home.html">GNU Project home page</a>.  something close (but not identical) to &ldquo;free software.&rdquo;  We
516    prefer the term &ldquo;free software&rdquo; because, once you have heard that
517    it refers to freedom rather than price, it calls to mind freedom.  The
518    word &ldquo;open&rdquo; never refers to freedom.
519  </p>  </p>
520    
521    <h3 id="beyond-software">Beyond Software</h3>
522    
523  <p>  <p>
524  Please send FSF &amp; GNU inquiries to  <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
525  <a href="mailto:gnu@gnu.org"><em>gnu@gnu.org</em></a>.  for the same reasons that software must be free, and because the
526  There are also <a href="/home.html#ContactInfo">other ways to contact</a>  manuals are in effect part of the software.
 the FSF.  
 <br />  
 Please send broken links and other corrections (or suggestions) to  
 <a href="mailto:webmasters@gnu.org"><em>webmasters@gnu.org</em></a>.  
527  </p>  </p>
528    
529  <p>  <p>
530  Please see the  The same arguments also make sense for other kinds of works of
531  <a href="/server/standards/README.translations.html">Translations  practical use&mdash;that is to say, works that embody useful knowledge,
532  README</a> for information on coordinating and submitting  such as educational works and reference
533  translations of this article.  works.  <a href="https://wikipedia.org">Wikipedia</a> is the best-known
534    example.
535  </p>  </p>
536    
537  <p>  <p>
538  Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free  Any kind of work <em>can</em> be free, and the definition of free software
539  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  has been extended to a definition of <a href="http://freedomdefined.org/">
540  02110,  USA  free cultural works</a> applicable to any kind of works.
 <br />  
 Verbatim copying and distribution of this entire article is  
 permitted in any medium without royalty provided this notice is  
 preserved.  
541  </p>  </p>
542    
543  <p>  <h3 id="History">History</h3>
544  Updated:  
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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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="//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>&ldquo;Improvements&rdquo; 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="//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 &ldquo;Beyond Software&rdquo; section.</li>
640    
641    <li><a href="//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="//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="//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="//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="//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="//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="//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="//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="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
681    interface</a>.</p>
682    <div class="column-limit"></div>
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    
694    </div><!-- for id="content", starts in the include above -->
695    <!--#include virtual="/server/footer.html" -->
696    <div id="footer" role="contentinfo">
697    <div class="unprintable">
698    
699    <p>Please send general FSF &amp; GNU inquiries to
700    <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
701    There are also <a href="/contact/">other ways to contact</a>
702    the FSF.  Broken links and other corrections or suggestions can be sent
703    to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
704    
705    <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
706            replace it with the translation of these two:
707    
708            We work hard and do our best to provide accurate, good quality
709            translations.  However, we are not exempt from imperfection.
710            Please send your comments and general suggestions in this regard
711            to <a href="mailto:web-translators@gnu.org">
712            &lt;web-translators@gnu.org&gt;</a>.</p>
713    
714            <p>For information on coordinating and contributing translations of
715            our web pages, see <a
716            href="/server/standards/README.translations.html">Translations
717            README</a>. -->
718    Please see the <a
719    href="/server/standards/README.translations.html">Translations
720    README</a> for information on coordinating and contributing translations
721    of this article.</p>
722    </div>
723    
724    <!-- Regarding copyright, in general, standalone pages (as opposed to
725         files generated as part of manuals) on the GNU web server should
726         be under CC BY-ND 4.0.  Please do NOT change or remove this
727         without talking with the webmasters or licensing team first.
728         Please make sure the copyright date is consistent with the
729         document.  For web pages, it is ok to list just the latest year the
730         document was modified, or published.
731        
732         If you wish to list earlier years, that is ok too.
733         Either "2001, 2002, 2003" or "2001-2003" are ok for specifying
734         years, as long as each year in the range is in fact a copyrightable
735         year, i.e., a year in which the document was published (including
736         being publicly visible on the web or in a revision control system).
737        
738         There is more detail about copyright years in the GNU Maintainers
739         Information document, www.gnu.org/prep/maintain. -->
740    
741    <p>Copyright &copy; 1996-2002, 2004-2019, 2021, 2022, 2023
742    Free Software Foundation, Inc.</p>
743    
744    <p>This page is licensed under a <a rel="license"
745    href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
746    Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
747    
748    <!--#include virtual="/server/bottom-notes.html" -->
749    
750    <p class="unprintable">Updated:
751  <!-- timestamp start -->  <!-- timestamp start -->
752  $Date$ $Author$  $Date$
753  <!-- timestamp end -->  <!-- timestamp end -->
754  </p>  </p>
755  </div>  </div>
756    </div><!-- for class="inner", starts in the banner include -->
757  </body>  </body>
758  </html>  </html>

Legend:
Removed from v.1.50  
changed lines
  Added in v.1.185

savannah-hackers-public@gnu.org
ViewVC Help
Powered by ViewVC 1.1.26