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3 <title>What is free software?
4 - GNU Project - Free Software Foundation</title>
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16
17 <h2>What is free software?</h2>
18
19 <div class="article">
20 <h3>The Free Software Definition</h3>
21
22 <blockquote class="note" id="fsf-licensing"><p style="font-size: 80%">
23 Have a question about free software licensing not answered here?
24 See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
25 and if necessary contact the FSF Compliance Lab
26 at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
27 </blockquote>
28
29 <div class="comment">
30 <p>
31 The free software definition presents the criteria for whether a
32 particular software program qualifies as free software. From time to
33 time we revise this definition, to clarify it or to resolve questions
34 about subtle issues. See the <a href="#History">History section</a>
35 below for a list of changes that affect the definition of free
36 software.
37 </p>
38
39 <p>
40 &ldquo;Open source&rdquo; is something different: it has a very
41 different philosophy based on different values. Its practical
42 definition is different too, but nearly all open source programs are
43 in fact free. We explain the
44 difference in <a href="/philosophy/open-source-misses-the-point.html">
45 Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
46 </p>
47 </div>
48
49 <p>
50 &ldquo;Free software&rdquo; means software that respects users'
51 freedom and community. Roughly, it means that <b>the users have the
52 freedom to run, copy, distribute, study, change and improve the
53 software</b>. Thus, &ldquo;free software&rdquo; is a matter of
54 liberty, not price. To understand the concept, you should think of
55 &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
56 &ldquo;free beer&rdquo;. We sometimes call it &ldquo;libre
57 software,&rdquo; borrowing the French or Spanish word for
58 &ldquo;free&rdquo; as in freedom, to show we do not mean the software
59 is gratis.
60 </p>
61
62 <p>
63 We campaign for these freedoms because everyone deserves them. With
64 these freedoms, the users (both individually and collectively) control
65 the program and what it does for them. When users don't control the
66 program, we call it a &ldquo;nonfree&rdquo; or
67 &ldquo;proprietary&rdquo; program. The nonfree program controls the
68 users, and the developer controls the program; this makes the
69 program <a href="/philosophy/free-software-even-more-important.html">
70 an instrument of unjust power</a>.
71 </p>
72
73 <h4> The four essential freedoms</h4>
74
75 <p>
76 A program is free software if the program's users have the
77 four essential freedoms: <a href="#f1">[1]</a>
78 </p>
79
80 <ul class="important">
81 <li>The freedom to run the program as you wish,
82 for any purpose (freedom 0).</li>
83 <li>The freedom to study how the program works, and change it so it
84 does your computing as you wish (freedom 1). Access to the source
85 code is a precondition for this.
86 </li>
87 <li>The freedom to redistribute copies so you can help others
88 (freedom 2).
89 </li>
90 <li>The freedom to distribute copies of your modified versions
91 to others (freedom 3). By doing this you can give the whole
92 community a chance to benefit from your changes.
93 Access to the source code is a precondition for this.
94 </li>
95 </ul>
96
97 <p>
98 A program is free software if it gives users adequately all of these
99 freedoms. Otherwise, it is nonfree. While we can distinguish various
100 nonfree distribution schemes in terms of how far they fall short of
101 being free, we consider them all equally unethical.</p>
102
103 <p>In any given scenario, these freedoms must apply to whatever code
104 we plan to make use of, or lead others to make use of. For instance,
105 consider a program A which automatically launches a program B to
106 handle some cases. If we plan to distribute A as it stands, that
107 implies users will need B, so we need to judge whether both A and B
108 are free. However, if we plan to modify A so that it doesn't use B,
109 only A needs to be free; B is not pertinent to that plan.</p>
110
111 <p>
112 &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial&rdquo;. A free
113 program must be available for commercial use, commercial development,
114 and commercial distribution. Commercial development of free software
115 is no longer unusual; such free commercial software is very important.
116 You may have paid money to get copies of free software, or you may have
117 obtained copies at no charge. But regardless of how you got your copies,
118 you always have the freedom to copy and change the software, even to
119 <a href="/philosophy/selling.html">sell copies</a>.
120 </p>
121
122 <p>
123 A free program must offer the four freedoms to any user that obtains a
124 copy of the software, provided the user has complied thus far with the
125 conditions of the free license covering the software. Putting some of
126 the freedoms off limits to some users, or requiring that users pay, in
127 money or in kind, to exercise them, is tantamount to not granting the
128 freedoms in question, and thus renders the program nonfree.
129 </p>
130
131 <h3>Clarifying the line at various points</h3>
132
133 <p>In the rest of this article we expain more precisely how far the
134 various freedoms need to extend, on various issues, in order for a
135 program to be free.</p>
136
137 <h4>The freedom to run the program as you wish</h4>
138
139 <p>
140 The freedom to run the program means the freedom for any kind of person
141 or organization to use it on any kind of computer system, for any kind of
142 overall job and purpose, without being required to communicate about it
143 with the developer or any other specific entity. In this freedom, it is
144 the <em>user's</em> purpose that matters, not the <em>developer's</em>
145 purpose; you as a user are free to run the program for your purposes,
146 and if you distribute it to someone else, she is then free to run it
147 for her purposes, but you are not entitled to impose your purposes on her.
148 </p>
149
150 <p>
151 The freedom to run the program as you wish means that you are not
152 forbidden or stopped from making it run. This has nothing to do with what
153 functionality the program has, whether it is technically capable of
154 functioning in any given environment, or whether it is useful for any
155 particular computing activity.</p>
156
157 <p>For example, if the code arbitrarily rejects certain meaningful
158 inputs&mdash;or even fails unconditionally&mdash;that may make the
159 program less useful, perhaps even totally useless, but it does not
160 deny users the freedom to run the program, so it does not conflict
161 with freedom 0. If the program is free, the users can overcome the
162 loss of usefulness, because freedoms 1 and 3 permit users and
163 communities to make and distribute modified versions without the
164 arbitrary nuisance code.</p>
165
166 <h4>The freedom to study the source code and make changes</h4>
167
168 <p>
169 In order for freedoms 1 and 3 (the freedom to make changes and the
170 freedom to publish the changed versions) to be meaningful, you need to have
171 access to the source code of the program. Therefore, accessibility of
172 source code is a necessary condition for free software. Obfuscated
173 &ldquo;source code&rdquo; is not real source code and does not count
174 as source code.
175 </p>
176
177 <p>
178 Freedom 1 includes the freedom to use your changed version in place of
179 the original. If the program is delivered in a product designed to
180 run someone else's modified versions but refuse to run yours &mdash; a
181 practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
182 or (in its practitioners' perverse terminology) as &ldquo;secure
183 boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
184 practical reality. These binaries are not free
185 software even if the source code they are compiled from is free.
186 </p>
187
188 <p>
189 One important way to modify a program is by merging in available free
190 subroutines and modules. If the program's license says that you
191 cannot merge in a suitably licensed existing module &mdash; for instance, if it
192 requires you to be the copyright holder of any code you add &mdash; then the
193 license is too restrictive to qualify as free.
194 </p>
195
196 <p>
197 Whether a change constitutes an improvement is a subjective matter.
198 If your right to modify a program is limited, in substance, to changes that
199 someone else considers an improvement, that program is not free.
200 </p>
201
202 <h4>The freedom to redistribute if you wish: basic requirements</h4>
203
204 <p>Freedom to distribute (freedoms 2 and 3) means you are free to
205 redistribute copies, either with or without modifications, either
206 gratis or charging a fee for distribution, to
207 <a href="#exportcontrol">anyone anywhere</a>. Being free to do these
208 things means (among other things) that you do not have to ask or pay
209 for permission to do so.
210 </p>
211
212 <p>
213 You should also have the freedom to make modifications and use them
214 privately in your own work or play, without even mentioning that they
215 exist. If you do publish your changes, you should not be required to
216 notify anyone in particular, or in any particular way.
217 </p>
218
219 <p>
220 Freedom 3 includes the freedom to release your modified versions
221 as free software. A free license may also permit other ways of
222 releasing them; in other words, it does not have to be
223 a <a href="/copyleft/copyleft.html">copyleft</a> license. However, a
224 license that requires modified versions to be nonfree does not qualify
225 as a free license.
226 </p>
227
228 <p>
229 The freedom to redistribute copies must include binary or executable
230 forms of the program, as well as source code, for both modified and
231 unmodified versions. (Distributing programs in runnable form is necessary
232 for conveniently installable free operating systems.) It is OK if there
233 is no way to produce a binary or executable form for a certain program
234 (since some languages don't support that feature), but you must have the
235 freedom to redistribute such forms should you find or develop a way to
236 make them.
237 </p>
238
239 <h4>Copyleft</h4>
240
241 <p>
242 Certain kinds of rules about the manner of distributing free
243 software are acceptable, when they don't conflict with the central
244 freedoms. For example, <a href="/copyleft/copyleft.html">copyleft</a>
245 (very simply stated) is the rule that when redistributing the program,
246 you cannot add restrictions to deny other people the central freedoms.
247 This rule does not conflict with the central freedoms; rather it
248 protects them.
249 </p>
250
251 <p>
252 In the GNU project, we use copyleft to protect the four freedoms
253 legally for everyone. We believe there are important reasons why
254 <a href="/philosophy/pragmatic.html">it is better to use
255 copyleft</a>. However,
256 <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
257 noncopylefted free software</a> is ethical
258 too. See <a href="/philosophy/categories.html">Categories of Free
259 Software</a> for a description of how &ldquo;free software,&rdquo;
260 &ldquo;copylefted software&rdquo; and other categories of software
261 relate to each other.
262 </p>
263
264 <h4>Rules about packaging and distribution details</h4>
265
266 <p>
267 Rules about how to package a modified version are acceptable,
268 if they don't substantively limit your freedom to release modified
269 versions, or your freedom to make and use modified versions privately.
270 Thus, it is acceptable for the license to require that you change the
271 name of the modified version, remove a logo, or identify your
272 modifications as yours. As long as these requirements are not so
273 burdensome that they effectively hamper you from releasing your
274 changes, they are acceptable; you're already making other changes to
275 the program, so you won't have trouble making a few more.
276 </p>
277
278 <p>
279 Rules that &ldquo;if you make your version available in this way, you
280 must make it available in that way also&rdquo; can be acceptable too,
281 on the same condition. An example of such an acceptable rule is one
282 saying that if you have distributed a
283 modified version and a previous developer asks for a copy of it, you
284 must send one. (Note that such a rule still leaves you the choice of
285 whether to distribute your version at all.) Rules that require release
286 of source code to the users for versions that you put into public use
287 are also acceptable.
288 </p>
289
290 <p>
291 A special issue arises when a license requires changing the name by
292 which the program will be invoked from other programs. That
293 effectively hampers you from releasing your changed version so that it
294 can replace the original when invoked by those other programs. This
295 sort of requirement is acceptable only if there's a suitable aliasing
296 facility that allows you to specify the original program's name as an
297 alias for the modified version.</p>
298
299 <h4>Export regulations</h4>
300
301 <p>
302 Sometimes government <a id="exportcontrol">export control regulations</a>
303 and trade sanctions can constrain your freedom to distribute copies of
304 programs internationally. Software developers do not have the power to
305 eliminate or override these restrictions, but what they can and must do
306 is refuse to impose them as conditions of use of the program. In this
307 way, the restrictions will not affect activities and people outside the
308 jurisdictions of these governments. Thus, free software licenses
309 must not require obedience to any nontrivial export regulations as a
310 condition of exercising any of the essential freedoms.
311 </p>
312
313 <p>
314 Merely mentioning the existence of export regulations, without making
315 them a condition of the license itself, is acceptable since it does
316 not restrict users. If an export regulation is actually trivial for
317 free software, then requiring it as a condition is not an actual
318 problem; however, it is a potential problem, since a later change in
319 export law could make the requirement nontrivial and thus render the
320 software nonfree.
321 </p>
322
323 <h4>Legal considerations</h4>
324
325 <p>
326 In order for these freedoms to be real, they must be permanent and
327 irrevocable as long as you do nothing wrong; if the developer of the
328 software has the power to revoke the license, or retroactively add
329 restrictions to its terms, without your doing anything wrong to give
330 cause, the software is not free.
331 </p>
332
333 <p>
334 A free license may not require compliance with the license of a
335 nonfree program. Thus, for instance, if a license requires you to
336 comply with the licenses of &ldquo;all the programs you use&rdquo;, in
337 the case of a user that runs nonfree programs this would require
338 compliance with the licenses of those nonfree programs; that makes the
339 license nonfree.
340 </p>
341
342 <p>
343 It is acceptable for a free license to specify which jurisdiction's
344 law applies, or where litigation must be done, or both.
345 </p>
346
347 <h4>Contract-based licenses</h4>
348
349 <p>
350 Most free software licenses are based on copyright, and there are limits
351 on what kinds of requirements can be imposed through copyright. If a
352 copyright-based license respects freedom in the ways described above, it
353 is unlikely to have some other sort of problem that we never anticipated
354 (though this does happen occasionally). However, some free software
355 licenses are based on contracts, and contracts can impose a much larger
356 range of possible restrictions. That means there are many possible ways
357 such a license could be unacceptably restrictive and nonfree.
358 </p>
359
360 <p>
361 We can't possibly list all the ways that might happen. If a
362 contract-based license restricts the user in an unusual way that
363 copyright-based licenses cannot, and which isn't mentioned here as
364 legitimate, we will have to think about it, and we will probably conclude
365 it is nonfree.
366 </p>
367
368 <h4>Use the right words when talking about free software</h4>
369
370 <p>
371 When talking about free software, it is best to avoid using terms
372 like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
373 the issue is about price, not freedom. Some common terms such
374 as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse. See
375 <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
376 are Worth Avoiding</a> for a discussion of these terms. We also have
377 a list of proper <a href="/philosophy/fs-translations.html">translations of
378 &ldquo;free software&rdquo;</a> into various languages.
379 </p>
380
381 <h4>How we interpret these criteria</h4>
382
383 <p>
384 Finally, note that criteria such as those stated in this free software
385 definition require careful thought for their interpretation. To decide
386 whether a specific software license qualifies as a free software license,
387 we judge it based on these criteria to determine whether it fits their
388 spirit as well as the precise words. If a license includes unconscionable
389 restrictions, we reject it, even if we did not anticipate the issue
390 in these criteria. Sometimes a license requirement raises an issue
391 that calls for extensive thought, including discussions with a lawyer,
392 before we can decide if the requirement is acceptable. When we reach
393 a conclusion about a new issue, we often update these criteria to make
394 it easier to see why certain licenses do or don't qualify.
395 </p>
396
397 <h4>Get help with free licenses</h4>
398
399 <p>
400 If you are interested in whether a specific license qualifies as a free
401 software license, see our <a href="/licenses/license-list.html">list
402 of licenses</a>. If the license you are concerned with is not
403 listed there, you can ask us about it by sending us email at
404 <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
405 </p>
406
407 <p>
408 If you are contemplating writing a new license, please contact the
409 Free Software Foundation first by writing to that address. The
410 proliferation of different free software licenses means increased work
411 for users in understanding the licenses; we may be able to help you
412 find an existing free software license that meets your needs.
413 </p>
414
415 <p>
416 If that isn't possible, if you really need a new license, with our
417 help you can ensure that the license really is a free software license
418 and avoid various practical problems.
419 </p>
420
421 <h3 id="beyond-software">Beyond Software</h3>
422
423 <p>
424 <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
425 for the same reasons that software must be free, and because the
426 manuals are in effect part of the software.
427 </p>
428
429 <p>
430 The same arguments also make sense for other kinds of works of
431 practical use &mdash; that is to say, works that embody useful knowledge,
432 such as educational works and reference
433 works. <a href="http://wikipedia.org">Wikipedia</a> is the best-known
434 example.
435 </p>
436
437 <p>
438 Any kind of work <em>can</em> be free, and the definition of free software
439 has been extended to a definition of <a href="http://freedomdefined.org/">
440 free cultural works</a> applicable to any kind of works.
441 </p>
442
443 <h3 id="open-source">Open Source?</h3>
444
445 <p>
446 Another group uses the term &ldquo;open source&rdquo; to mean
447 something close (but not identical) to &ldquo;free software&rdquo;. We
448 prefer the term &ldquo;free software&rdquo; because, once you have heard that
449 it refers to freedom rather than price, it calls to mind freedom. The
450 word &ldquo;open&rdquo; <a href="/philosophy/open-source-misses-the-point.html">
451 never refers to freedom</a>.
452 </p>
453 </div>
454
455 <h3 id="History">History</h3>
456
457 <p>From time to time we revise this Free Software Definition. Here is
458 the list of substantive changes, along with links to show exactly what
459 was changed.</p>
460
461 <ul>
462
463 <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.164&amp;r2=1.165">Version
464 1.165</a>: Clarify that arbitrary annoyances in the code do not
465 negate freedom 0, and that freedoms 1 and 3 enable users to remove them.</li>
466
467 <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
468 1.153</a>: Clarify that freedom to run the program means nothing stops
469 you from making it run.</li>
470
471 <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
472 1.141</a>: Clarify which code needs to be free.</li>
473
474 <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
475 1.135</a>: Say each time that freedom 0 is the freedom to run the program
476 as you wish.</li>
477
478 <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
479 1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
480
481 <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
482 1.131</a>: A free license may not require compliance with a nonfree license
483 of another program.</li>
484
485 <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
486 1.129</a>: State explicitly that choice of law and choice of forum
487 specifications are allowed. (This was always our policy.)</li>
488
489 <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
490 1.122</a>: An export control requirement is a real problem if the
491 requirement is nontrivial; otherwise it is only a potential problem.</li>
492
493 <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
494 1.118</a>: Clarification: the issue is limits on your right to modify,
495 not on what modifications you have made. And modifications are not limited
496 to &ldquo;improvements&rdquo;</li>
497
498 <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
499 1.111</a>: Clarify 1.77 by saying that only
500 retroactive <em>restrictions</em> are unacceptable. The copyright
501 holders can always grant additional <em>permission</em> for use of the
502 work by releasing the work in another way in parallel.</li>
503
504 <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
505 1.105</a>: Reflect, in the brief statement of freedom 1, the point
506 (already stated in version 1.80) that it includes really using your modified
507 version for your computing.</li>
508
509 <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
510 1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
511
512 <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
513 1.90</a>: Clarify that freedom 3 means the right to distribute copies
514 of your own modified or improved version, not a right to participate
515 in someone else's development project.</li>
516
517 <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
518 1.89</a>: Freedom 3 includes the right to release modified versions as
519 free software.</li>
520
521 <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
522 1.80</a>: Freedom 1 must be practical, not just theoretical;
523 i.e., no tivoization.</li>
524
525 <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
526 1.77</a>: Clarify that all retroactive changes to the license are
527 unacceptable, even if it's not described as a complete
528 replacement.</li>
529
530 <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
531 1.74</a>: Four clarifications of points not explicit enough, or stated
532 in some places but not reflected everywhere:
533 <ul>
534 <li>"Improvements" does not mean the license can
535 substantively limit what kinds of modified versions you can release.
536 Freedom 3 includes distributing modified versions, not just changes.</li>
537 <li>The right to merge in existing modules
538 refers to those that are suitably licensed.</li>
539 <li>Explicitly state the conclusion of the point about export controls.</li>
540 <li>Imposing a license change constitutes revoking the old license.</li>
541 </ul>
542 </li>
543
544 <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
545 1.57</a>: Add &quot;Beyond Software&quot; section.</li>
546
547 <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
548 1.46</a>: Clarify whose purpose is significant in the freedom to run
549 the program for any purpose.</li>
550
551 <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
552 1.41</a>: Clarify wording about contract-based licenses.</li>
553
554 <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
555 1.40</a>: Explain that a free license must allow to you use other
556 available free software to create your modifications.</li>
557
558 <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
559 1.39</a>: Note that it is acceptable for a license to require you to
560 provide source for versions of the software you put into public
561 use.</li>
562
563 <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
564 1.31</a>: Note that it is acceptable for a license to require you to
565 identify yourself as the author of modifications. Other minor
566 clarifications throughout the text.</li>
567
568 <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
569 1.23</a>: Address potential problems related to contract-based
570 licenses.</li>
571
572 <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
573 1.16</a>: Explain why distribution of binaries is important.</li>
574
575 <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
576 1.11</a>: Note that a free license may require you to send a copy of
577 versions you distribute to previous developers on request.</li>
578
579 </ul>
580
581 <p>There are gaps in the version numbers shown above because there are
582 other changes in this page that do not affect the definition or its
583 interpretations. For instance, the list does not include changes in
584 asides, formatting, spelling, punctuation, or other parts of the page.
585 You can review the complete list of changes to the page through
586 the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
587 interface</a>.</p>
588
589 <h3 style="font-size:1em">Footnote</h3>
590 <ol>
591 <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
592 1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
593 the freedom to run the program needed to be mentioned explicitly.
594 It was clearly more basic than the other three, so it properly should
595 precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
596 </ol>
597
598 </div><!-- for id="content", starts in the include above -->
599 <!--#include virtual="/server/footer.html" -->
600 <div id="footer">
601 <div class="unprintable">
602
603 <p>Please send general FSF &amp; GNU inquiries to
604 <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
605 There are also <a href="/contact/">other ways to contact</a>
606 the FSF. Broken links and other corrections or suggestions can be sent
607 to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
608
609 <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
610 replace it with the translation of these two:
611
612 We work hard and do our best to provide accurate, good quality
613 translations. However, we are not exempt from imperfection.
614 Please send your comments and general suggestions in this regard
615 to <a href="mailto:web-translators@gnu.org">
616 &lt;web-translators@gnu.org&gt;</a>.</p>
617
618 <p>For information on coordinating and submitting translations of
619 our web pages, see <a
620 href="/server/standards/README.translations.html">Translations
621 README</a>. -->
622 Please see the <a
623 href="/server/standards/README.translations.html">Translations
624 README</a> for information on coordinating and submitting translations
625 of this article.</p>
626 </div>
627
628 <!-- Regarding copyright, in general, standalone pages (as opposed to
629 files generated as part of manuals) on the GNU web server should
630 be under CC BY-ND 4.0. Please do NOT change or remove this
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632 Please make sure the copyright date is consistent with the
633 document. For web pages, it is ok to list just the latest year the
634 document was modified, or published.
635
636 If you wish to list earlier years, that is ok too.
637 Either "2001, 2002, 2003" or "2001-2003" are ok for specifying
638 years, as long as each year in the range is in fact a copyrightable
639 year, i.e., a year in which the document was published (including
640 being publicly visible on the web or in a revision control system).
641
642 There is more detail about copyright years in the GNU Maintainers
643 Information document, www.gnu.org/prep/maintain. -->
644
645 <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2019
646 Free Software Foundation, Inc.</p>
647
648 <p>This page is licensed under a <a rel="license"
649 href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
650 Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
651
652 <!--#include virtual="/server/bottom-notes.html" -->
653
654 <p class="unprintable">Updated:
655 <!-- timestamp start -->
656 $Date: 2019/07/29 21:33:12 $
657 <!-- timestamp end -->
658 </p>
659 </div>
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