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

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

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1.165 - (show annotations) (download) (as text)
Mon Jul 29 21:25:25 2019 UTC (5 years ago) by rms
Branch: MAIN
Changes since 1.164: +7 -4 lines
File MIME type: text/html
Clean-up of structuere.

1 <!--#include virtual="/server/header.html" -->
2 <!-- Parent-Version: 1.86 -->
3 <title>What is free software?
4 - GNU Project - Free Software Foundation</title>
5 <style type="text/css" media="print,screen"><!--
6 .note { margin-left: 6%; margin-right: 6%; }
7 @media (min-width: 48em) {
8 .note { margin-top: .8em; }
9 }
10 --></style>
11 <meta http-equiv="Keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" />
12 <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." />
13
14 <!--#include virtual="/philosophy/po/free-sw.translist" -->
15 <!--#include virtual="/server/banner.html" -->
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 <h4>The freedom to study the source code and make changes</h4>
158
159 <p>
160 In order for freedoms 1 and 3 (the freedom to make changes and the
161 freedom to publish the changed versions) to be meaningful, you need to have
162 access to the source code of the program. Therefore, accessibility of
163 source code is a necessary condition for free software. Obfuscated
164 &ldquo;source code&rdquo; is not real source code and does not count
165 as source code.
166 </p>
167
168 <p>
169 Freedom 1 includes the freedom to use your changed version in place of
170 the original. If the program is delivered in a product designed to
171 run someone else's modified versions but refuse to run yours &mdash; a
172 practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown&rdquo;,
173 or (in its practitioners' perverse terminology) as &ldquo;secure
174 boot&rdquo; &mdash; freedom 1 becomes an empty pretense rather than a
175 practical reality. These binaries are not free
176 software even if the source code they are compiled from is free.
177 </p>
178
179 <p>
180 One important way to modify a program is by merging in available free
181 subroutines and modules. If the program's license says that you
182 cannot merge in a suitably licensed existing module &mdash; for instance, if it
183 requires you to be the copyright holder of any code you add &mdash; then the
184 license is too restrictive to qualify as free.
185 </p>
186
187 <p>
188 Whether a change constitutes an improvement is a subjective matter.
189 If your right to modify a program is limited, in substance, to changes that
190 someone else considers an improvement, that program is not free.
191 </p>
192
193 <h4>The freedom to redistribute if you wish: basic requirements</h4>
194
195 <p>Freedom to distribute (freedoms 2 and 3) means you are free to
196 redistribute copies, either with or without modifications, either
197 gratis or charging a fee for distribution, to
198 <a href="#exportcontrol">anyone anywhere</a>. Being free to do these
199 things means (among other things) that you do not have to ask or pay
200 for permission to do so.
201 </p>
202
203 <p>
204 You should also have the freedom to make modifications and use them
205 privately in your own work or play, without even mentioning that they
206 exist. If you do publish your changes, you should not be required to
207 notify anyone in particular, or in any particular way.
208 </p>
209
210 <p>
211 Freedom 3 includes the freedom to release your modified versions
212 as free software. A free license may also permit other ways of
213 releasing them; in other words, it does not have to be
214 a <a href="/copyleft/copyleft.html">copyleft</a> license. However, a
215 license that requires modified versions to be nonfree does not qualify
216 as a free license.
217 </p>
218
219 <p>
220 The freedom to redistribute copies must include binary or executable
221 forms of the program, as well as source code, for both modified and
222 unmodified versions. (Distributing programs in runnable form is necessary
223 for conveniently installable free operating systems.) It is OK if there
224 is no way to produce a binary or executable form for a certain program
225 (since some languages don't support that feature), but you must have the
226 freedom to redistribute such forms should you find or develop a way to
227 make them.
228 </p>
229
230 <h4>Copyleft</h4>
231
232 <p>
233 Certain kinds of rules about the manner of distributing free
234 software are acceptable, when they don't conflict with the central
235 freedoms. For example, <a href="/copyleft/copyleft.html">copyleft</a>
236 (very simply stated) is the rule that when redistributing the program,
237 you cannot add restrictions to deny other people the central freedoms.
238 This rule does not conflict with the central freedoms; rather it
239 protects them.
240 </p>
241
242 <p>
243 In the GNU project, we use copyleft to protect the four freedoms
244 legally for everyone. We believe there are important reasons why
245 <a href="/philosophy/pragmatic.html">it is better to use
246 copyleft</a>. However,
247 <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
248 noncopylefted free software</a> is ethical
249 too. See <a href="/philosophy/categories.html">Categories of Free
250 Software</a> for a description of how &ldquo;free software,&rdquo;
251 &ldquo;copylefted software&rdquo; and other categories of software
252 relate to each other.
253 </p>
254
255 <h4>Rules about packaging and distribution details</h4>
256
257 <p>
258 Rules about how to package a modified version are acceptable,
259 if they don't substantively limit your freedom to release modified
260 versions, or your freedom to make and use modified versions privately.
261 Thus, it is acceptable for the license to require that you change the
262 name of the modified version, remove a logo, or identify your
263 modifications as yours. As long as these requirements are not so
264 burdensome that they effectively hamper you from releasing your
265 changes, they are acceptable; you're already making other changes to
266 the program, so you won't have trouble making a few more.
267 </p>
268
269 <p>
270 Rules that &ldquo;if you make your version available in this way, you
271 must make it available in that way also&rdquo; can be acceptable too,
272 on the same condition. An example of such an acceptable rule is one
273 saying that if you have distributed a
274 modified version and a previous developer asks for a copy of it, you
275 must send one. (Note that such a rule still leaves you the choice of
276 whether to distribute your version at all.) Rules that require release
277 of source code to the users for versions that you put into public use
278 are also acceptable.
279 </p>
280
281 <p>
282 A special issue arises when a license requires changing the name by
283 which the program will be invoked from other programs. That
284 effectively hampers you from releasing your changed version so that it
285 can replace the original when invoked by those other programs. This
286 sort of requirement is acceptable only if there's a suitable aliasing
287 facility that allows you to specify the original program's name as an
288 alias for the modified version.</p>
289
290 <h4>Export regulations</h4>
291
292 <p>
293 Sometimes government <a id="exportcontrol">export control regulations</a>
294 and trade sanctions can constrain your freedom to distribute copies of
295 programs internationally. Software developers do not have the power to
296 eliminate or override these restrictions, but what they can and must do
297 is refuse to impose them as conditions of use of the program. In this
298 way, the restrictions will not affect activities and people outside the
299 jurisdictions of these governments. Thus, free software licenses
300 must not require obedience to any nontrivial export regulations as a
301 condition of exercising any of the essential freedoms.
302 </p>
303
304 <p>
305 Merely mentioning the existence of export regulations, without making
306 them a condition of the license itself, is acceptable since it does
307 not restrict users. If an export regulation is actually trivial for
308 free software, then requiring it as a condition is not an actual
309 problem; however, it is a potential problem, since a later change in
310 export law could make the requirement nontrivial and thus render the
311 software nonfree.
312 </p>
313
314 <h4>Legal considerations</h4>
315
316 <p>
317 In order for these freedoms to be real, they must be permanent and
318 irrevocable as long as you do nothing wrong; if the developer of the
319 software has the power to revoke the license, or retroactively add
320 restrictions to its terms, without your doing anything wrong to give
321 cause, the software is not free.
322 </p>
323
324 <p>
325 A free license may not require compliance with the license of a
326 nonfree program. Thus, for instance, if a license requires you to
327 comply with the licenses of &ldquo;all the programs you use&rdquo;, in
328 the case of a user that runs nonfree programs this would require
329 compliance with the licenses of those nonfree programs; that makes the
330 license nonfree.
331 </p>
332
333 <p>
334 It is acceptable for a free license to specify which jurisdiction's
335 law applies, or where litigation must be done, or both.
336 </p>
337
338 <h4>Contract-based licenses</h4>
339
340 <p>
341 Most free software licenses are based on copyright, and there are limits
342 on what kinds of requirements can be imposed through copyright. If a
343 copyright-based license respects freedom in the ways described above, it
344 is unlikely to have some other sort of problem that we never anticipated
345 (though this does happen occasionally). However, some free software
346 licenses are based on contracts, and contracts can impose a much larger
347 range of possible restrictions. That means there are many possible ways
348 such a license could be unacceptably restrictive and nonfree.
349 </p>
350
351 <p>
352 We can't possibly list all the ways that might happen. If a
353 contract-based license restricts the user in an unusual way that
354 copyright-based licenses cannot, and which isn't mentioned here as
355 legitimate, we will have to think about it, and we will probably conclude
356 it is nonfree.
357 </p>
358
359 <h4>Use the right words when talking about free software</h4>
360
361 <p>
362 When talking about free software, it is best to avoid using terms
363 like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
364 the issue is about price, not freedom. Some common terms such
365 as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse. See
366 <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
367 are Worth Avoiding</a> for a discussion of these terms. We also have
368 a list of proper <a href="/philosophy/fs-translations.html">translations of
369 &ldquo;free software&rdquo;</a> into various languages.
370 </p>
371
372 <h4>How we interpret these criteria</h4>
373
374 <p>
375 Finally, note that criteria such as those stated in this free software
376 definition require careful thought for their interpretation. To decide
377 whether a specific software license qualifies as a free software license,
378 we judge it based on these criteria to determine whether it fits their
379 spirit as well as the precise words. If a license includes unconscionable
380 restrictions, we reject it, even if we did not anticipate the issue
381 in these criteria. Sometimes a license requirement raises an issue
382 that calls for extensive thought, including discussions with a lawyer,
383 before we can decide if the requirement is acceptable. When we reach
384 a conclusion about a new issue, we often update these criteria to make
385 it easier to see why certain licenses do or don't qualify.
386 </p>
387
388 <h4>Get help with free licenses</h4>
389
390 <p>
391 If you are interested in whether a specific license qualifies as a free
392 software license, see our <a href="/licenses/license-list.html">list
393 of licenses</a>. If the license you are concerned with is not
394 listed there, you can ask us about it by sending us email at
395 <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
396 </p>
397
398 <p>
399 If you are contemplating writing a new license, please contact the
400 Free Software Foundation first by writing to that address. The
401 proliferation of different free software licenses means increased work
402 for users in understanding the licenses; we may be able to help you
403 find an existing free software license that meets your needs.
404 </p>
405
406 <p>
407 If that isn't possible, if you really need a new license, with our
408 help you can ensure that the license really is a free software license
409 and avoid various practical problems.
410 </p>
411
412 <h3 id="beyond-software">Beyond Software</h3>
413
414 <p>
415 <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
416 for the same reasons that software must be free, and because the
417 manuals are in effect part of the software.
418 </p>
419
420 <p>
421 The same arguments also make sense for other kinds of works of
422 practical use &mdash; that is to say, works that embody useful knowledge,
423 such as educational works and reference
424 works. <a href="http://wikipedia.org">Wikipedia</a> is the best-known
425 example.
426 </p>
427
428 <p>
429 Any kind of work <em>can</em> be free, and the definition of free software
430 has been extended to a definition of <a href="http://freedomdefined.org/">
431 free cultural works</a> applicable to any kind of works.
432 </p>
433
434 <h3 id="open-source">Open Source?</h3>
435
436 <p>
437 Another group uses the term &ldquo;open source&rdquo; to mean
438 something close (but not identical) to &ldquo;free software&rdquo;. We
439 prefer the term &ldquo;free software&rdquo; because, once you have heard that
440 it refers to freedom rather than price, it calls to mind freedom. The
441 word &ldquo;open&rdquo; <a href="/philosophy/open-source-misses-the-point.html">
442 never refers to freedom</a>.
443 </p>
444 </div>
445
446 <h3 id="History">History</h3>
447
448 <p>From time to time we revise this Free Software Definition. Here is
449 the list of substantive changes, along with links to show exactly what
450 was changed.</p>
451
452 <ul>
453
454 <li><a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.162&amp;r2=1.163">Version
455 1.163</a>: Clarify that the four freedoms apply to any and all users,
456 and that requiring users to pay to exercise some of these freedoms is
457 a way of denying them.</li>
458
459 <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
460 1.153</a>: Clarify that freedom to run the program means nothing stops
461 you from making it run.</li>
462
463 <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
464 1.141</a>: Clarify which code needs to be free.</li>
465
466 <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
467 1.135</a>: Say each time that freedom 0 is the freedom to run the program
468 as you wish.</li>
469
470 <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
471 1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
472
473 <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
474 1.131</a>: A free license may not require compliance with a nonfree license
475 of another program.</li>
476
477 <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
478 1.129</a>: State explicitly that choice of law and choice of forum
479 specifications are allowed. (This was always our policy.)</li>
480
481 <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
482 1.122</a>: An export control requirement is a real problem if the
483 requirement is nontrivial; otherwise it is only a potential problem.</li>
484
485 <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
486 1.118</a>: Clarification: the issue is limits on your right to modify,
487 not on what modifications you have made. And modifications are not limited
488 to &ldquo;improvements&rdquo;</li>
489
490 <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
491 1.111</a>: Clarify 1.77 by saying that only
492 retroactive <em>restrictions</em> are unacceptable. The copyright
493 holders can always grant additional <em>permission</em> for use of the
494 work by releasing the work in another way in parallel.</li>
495
496 <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
497 1.105</a>: Reflect, in the brief statement of freedom 1, the point
498 (already stated in version 1.80) that it includes really using your modified
499 version for your computing.</li>
500
501 <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
502 1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
503
504 <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
505 1.90</a>: Clarify that freedom 3 means the right to distribute copies
506 of your own modified or improved version, not a right to participate
507 in someone else's development project.</li>
508
509 <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
510 1.89</a>: Freedom 3 includes the right to release modified versions as
511 free software.</li>
512
513 <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
514 1.80</a>: Freedom 1 must be practical, not just theoretical;
515 i.e., no tivoization.</li>
516
517 <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
518 1.77</a>: Clarify that all retroactive changes to the license are
519 unacceptable, even if it's not described as a complete
520 replacement.</li>
521
522 <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
523 1.74</a>: Four clarifications of points not explicit enough, or stated
524 in some places but not reflected everywhere:
525 <ul>
526 <li>"Improvements" does not mean the license can
527 substantively limit what kinds of modified versions you can release.
528 Freedom 3 includes distributing modified versions, not just changes.</li>
529 <li>The right to merge in existing modules
530 refers to those that are suitably licensed.</li>
531 <li>Explicitly state the conclusion of the point about export controls.</li>
532 <li>Imposing a license change constitutes revoking the old license.</li>
533 </ul>
534 </li>
535
536 <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
537 1.57</a>: Add &quot;Beyond Software&quot; section.</li>
538
539 <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
540 1.46</a>: Clarify whose purpose is significant in the freedom to run
541 the program for any purpose.</li>
542
543 <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
544 1.41</a>: Clarify wording about contract-based licenses.</li>
545
546 <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
547 1.40</a>: Explain that a free license must allow to you use other
548 available free software to create your modifications.</li>
549
550 <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
551 1.39</a>: Note that it is acceptable for a license to require you to
552 provide source for versions of the software you put into public
553 use.</li>
554
555 <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
556 1.31</a>: Note that it is acceptable for a license to require you to
557 identify yourself as the author of modifications. Other minor
558 clarifications throughout the text.</li>
559
560 <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
561 1.23</a>: Address potential problems related to contract-based
562 licenses.</li>
563
564 <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
565 1.16</a>: Explain why distribution of binaries is important.</li>
566
567 <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
568 1.11</a>: Note that a free license may require you to send a copy of
569 versions you distribute to previous developers on request.</li>
570
571 </ul>
572
573 <p>There are gaps in the version numbers shown above because there are
574 other changes in this page that do not affect the definition or its
575 interpretations. For instance, the list does not include changes in
576 asides, formatting, spelling, punctuation, or other parts of the page.
577 You can review the complete list of changes to the page through
578 the <a href="http://web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
579 interface</a>.</p>
580
581 <h3 style="font-size:1em">Footnote</h3>
582 <ol>
583 <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
584 1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
585 the freedom to run the program needed to be mentioned explicitly.
586 It was clearly more basic than the other three, so it properly should
587 precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
588 </ol>
589
590 </div><!-- for id="content", starts in the include above -->
591 <!--#include virtual="/server/footer.html" -->
592 <div id="footer">
593 <div class="unprintable">
594
595 <p>Please send general FSF &amp; GNU inquiries to
596 <a href="mailto:gnu@gnu.org">&lt;gnu@gnu.org&gt;</a>.
597 There are also <a href="/contact/">other ways to contact</a>
598 the FSF. Broken links and other corrections or suggestions can be sent
599 to <a href="mailto:webmasters@gnu.org">&lt;webmasters@gnu.org&gt;</a>.</p>
600
601 <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
602 replace it with the translation of these two:
603
604 We work hard and do our best to provide accurate, good quality
605 translations. However, we are not exempt from imperfection.
606 Please send your comments and general suggestions in this regard
607 to <a href="mailto:web-translators@gnu.org">
608 &lt;web-translators@gnu.org&gt;</a>.</p>
609
610 <p>For information on coordinating and submitting translations of
611 our web pages, see <a
612 href="/server/standards/README.translations.html">Translations
613 README</a>. -->
614 Please see the <a
615 href="/server/standards/README.translations.html">Translations
616 README</a> for information on coordinating and submitting translations
617 of this article.</p>
618 </div>
619
620 <!-- Regarding copyright, in general, standalone pages (as opposed to
621 files generated as part of manuals) on the GNU web server should
622 be under CC BY-ND 4.0. Please do NOT change or remove this
623 without talking with the webmasters or licensing team first.
624 Please make sure the copyright date is consistent with the
625 document. For web pages, it is ok to list just the latest year the
626 document was modified, or published.
627
628 If you wish to list earlier years, that is ok too.
629 Either "2001, 2002, 2003" or "2001-2003" are ok for specifying
630 years, as long as each year in the range is in fact a copyrightable
631 year, i.e., a year in which the document was published (including
632 being publicly visible on the web or in a revision control system).
633
634 There is more detail about copyright years in the GNU Maintainers
635 Information document, www.gnu.org/prep/maintain. -->
636
637 <p>Copyright &copy; 1996, 2002, 2004-2007, 2009-2019
638 Free Software Foundation, Inc.</p>
639
640 <p>This page is licensed under a <a rel="license"
641 href="http://creativecommons.org/licenses/by-nd/4.0/">Creative
642 Commons Attribution-NoDerivatives 4.0 International License</a>.</p>
643
644 <!--#include virtual="/server/bottom-notes.html" -->
645
646 <p class="unprintable">Updated:
647 <!-- timestamp start -->
648 $Date: 2019/03/20 10:56:16 $
649 <!-- timestamp end -->
650 </p>
651 </div>
652 </div><!-- for class="inner", starts in the banner include -->
653 </body>
654 </html>

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