--- www/philosophy/free-sw.html 2011/09/20 08:15:37 1.106 +++ www/philosophy/free-sw.html 2018/04/23 17:57:32 1.159 @@ -1,44 +1,84 @@ - -The Free Software Definition - GNU Project - Free Software Foundation (FSF) + +What is free software? +- GNU Project - Free Software Foundation - - - + + +

What is free software?

-

The Free Software Definition

+

+Have a question about free software licensing not answered here? +See our other licensing resources, +and if necessary contact the FSF Compliance Lab +at licensing@fsf.org.

+
+ +

The Free Software Definition

+ +
+

+The free software definition presents the criteria for whether a +particular software program qualifies as free software. From time to +time we revise this definition, to clarify it or to resolve questions +about subtle issues. See the History section +below for a list of changes that affect the definition of free +software. +

-We maintain this free software definition to show clearly what must be -true about a particular software program for it to be considered free -software. From time to time we revise this definition to clarify it. -If you would like to review the changes we've made, please see -the History section below for more information. +“Open source” is something different: it has a very +different philosophy based on different values. Its practical +definition is different too, but nearly all open source programs are +in fact free. We explain the +difference in +Why “Open Source” misses the point of Free Software.

+

-“Free software” is a matter of liberty, not price. To understand -the concept, you should think of “free” as in “free speech,” -not as in “free beer.” +“Free software” means software that respects users' +freedom and community. Roughly, it means that the users have the +freedom to run, copy, distribute, study, change and improve the +software. Thus, “free software” is a matter of +liberty, not price. To understand the concept, you should think of +“free” as in “free speech,” not as in +“free beer”. We sometimes call it “libre +software,” borrowing the French or Spanish word for +“free” as in freedom, to show we do not mean the software +is gratis.

-Free software is a matter of the users' freedom to run, copy, distribute, -study, change and improve the software. More precisely, it means that the -program's users have the four essential freedoms: +We campaign for these freedoms because everyone deserves them. With +these freedoms, the users (both individually and collectively) control +the program and what it does for them. When users don't control the +program, we call it a “nonfree” or +“proprietary” program. The nonfree program controls the +users, and the developer controls the program; this makes the +program +an instrument of unjust power. +

+ +

The four essential freedoms

+ +

+A program is free software if the program's users have the +four essential freedoms: [1]

-A program is free software if users have all of these freedoms. Thus, -you should be free to redistribute copies, either with or without -modifications, either gratis or charging a fee for distribution, to -anyone anywhere. Being free to do these -things means (among other things) that you do not have to ask or pay -for permission to do so. -

+A program is free software if it gives users adequately all of these +freedoms. Otherwise, it is nonfree. While we can distinguish various +nonfree distribution schemes in terms of how far they fall short of +being free, we consider them all equally unethical.

+ +

In any given scenario, these freedoms must apply to whatever code +we plan to make use of, or lead others to make use of. For instance, +consider a program A which automatically launches a program B to +handle some cases. If we plan to distribute A as it stands, that +implies users will need B, so we need to judge whether both A and B +are free. However, if we plan to modify A so that it doesn't use B, +only A needs to be free; B is not pertinent to that plan.

-You should also have the freedom to make modifications and use them -privately in your own work or play, without even mentioning that they -exist. If you do publish your changes, you should not be required to -notify anyone in particular, or in any particular way. +“Free software” does not mean “noncommercial”. A free +program must be available for commercial use, commercial development, +and commercial distribution. Commercial development of free software +is no longer unusual; such free commercial software is very important. +You may have paid money to get copies of free software, or you may have +obtained copies at no charge. But regardless of how you got your copies, +you always have the freedom to copy and change the software, even to +sell copies.

+

The rest of this page clarifies certain points about what makes +specific freedoms adequate or not.

+ +

The freedom to run the program as you wish

+

The freedom to run the program means the freedom for any kind of person or organization to use it on any kind of computer system, for any kind of @@ -76,19 +130,17 @@

-The freedom to redistribute copies must include binary or executable -forms of the program, as well as source code, for both modified and -unmodified versions. (Distributing programs in runnable form is necessary -for conveniently installable free operating systems.) It is OK if there -is no way to produce a binary or executable form for a certain program -(since some languages don't support that feature), but you must have the -freedom to redistribute such forms should you find or develop a way to -make them. -

+The freedom to run the program as you wish means that you are not +forbidden or stopped from making it run. This has nothing to do with what +functionality the program has, whether it is technically capable of +functioning in any given environment, or whether it is useful for any +particular computing activity.

+ +

The freedom to study the source code and make changes

In order for freedoms 1 and 3 (the freedom to make changes and the -freedom to publish improved versions) to be meaningful, you must have +freedom to publish the changed versions) to be meaningful, you must have access to the source code of the program. Therefore, accessibility of source code is a necessary condition for free software. Obfuscated “source code” is not real source code and does not count @@ -101,10 +153,9 @@ run someone else's modified versions but refuse to run yours — a practice known as “tivoization” or “lockdown”, or (in its practitioners' perverse terminology) as “secure -boot” — freedom 1 becomes a theoretical fiction rather -than a practical freedom. This is not sufficient. In other words, -these binaries are not free software even if the source code they are -compiled from is free. +boot” — freedom 1 becomes an empty pretense rather than a +practical reality. These binaries are not free +software even if the source code they are compiled from is free.

@@ -116,6 +167,29 @@

+Whether a change constitutes an improvement is a subjective matter. +If your right to modify a program is limited, in substance, to changes that +someone else considers an improvement, that program is not free. +

+ +

The freedom to redistribute if you wish: basic requirements

+ +

Freedom to distribute (freedoms 2 and 3) means you are free to +redistribute copies, either with or without modifications, either +gratis or charging a fee for distribution, to +anyone anywhere. Being free to do these +things means (among other things) that you do not have to ask or pay +for permission to do so. +

+ +

+You should also have the freedom to make modifications and use them +privately in your own work or play, without even mentioning that they +exist. If you do publish your changes, you should not be required to +notify anyone in particular, or in any particular way. +

+ +

Freedom 3 includes the freedom to release your modified versions as free software. A free license may also permit other ways of releasing them; in other words, it does not have to be @@ -125,41 +199,45 @@

-In order for these freedoms to be real, they must be permanent and -irrevocable as long as you do nothing wrong; if the developer of the -software has the power to revoke the license, or retroactively change -its terms, without your doing anything wrong to give cause, the -software is not free. +The freedom to redistribute copies must include binary or executable +forms of the program, as well as source code, for both modified and +unmodified versions. (Distributing programs in runnable form is necessary +for conveniently installable free operating systems.) It is OK if there +is no way to produce a binary or executable form for a certain program +(since some languages don't support that feature), but you must have the +freedom to redistribute such forms should you find or develop a way to +make them.

+

Copyleft

+

-However, certain kinds of rules about the manner of distributing free +Certain kinds of rules about the manner of distributing free software are acceptable, when they don't conflict with the central -freedoms. For example, copyleft (very simply stated) is the rule that -when redistributing the program, you cannot add restrictions to deny -other people the central freedoms. This rule does not conflict with -the central freedoms; rather it protects them. +freedoms. For example, copyleft +(very simply stated) is the rule that when redistributing the program, +you cannot add restrictions to deny other people the central freedoms. +This rule does not conflict with the central freedoms; rather it +protects them.

-“Free software” does not mean “noncommercial.” A free -program must be available for commercial use, commercial development, -and commercial distribution. Commercial development of free software -is no longer unusual; such free commercial software is very important. -You may have paid money to get copies of free software, or you may have -obtained copies at no charge. But regardless of how you got your copies, -you always have the freedom to copy and change the software, even to -sell copies. +In the GNU project, we use copyleft to protect the four freedoms +legally for everyone. We believe there are important reasons why +it is better to use +copyleft. However, + +noncopylefted free software is ethical +too. See Categories of Free +Software for a description of how “free software,” +“copylefted software” and other categories of software +relate to each other.

-

-Whether a change constitutes an improvement is a subjective matter. -If your modifications are limited, in substance, to changes that -someone else considers an improvement, that is not freedom. -

+

Rules about packaging and distribution details

-However, rules about how to package a modified version are acceptable, +Rules about how to package a modified version are acceptable, if they don't substantively limit your freedom to release modified versions, or your freedom to make and use modified versions privately. Thus, it is acceptable for the license to require that you change the @@ -183,15 +261,15 @@

-In the GNU project, we use -copyleft -to protect these freedoms legally for everyone. But -noncopylefted -free software also exists. We believe there are important reasons why -it is better to use copyleft, -but if your program is noncopylefted free software, it is still basically -ethical. (See Categories of Free Software for a description of how “free software,” “copylefted software” and other categories of software relate to each other.) -

+A special issue arises when a license requires changing the name by +which the program will be invoked from other programs. That +effectively hampers you from releasing your changed version so that it +can replace the original when invoked by those other programs. This +sort of requirement is acceptable only if there's a suitable aliasing +facility that allows you to specify the original program's name as an +alias for the modified version.

+ +

Export regulations

Sometimes government export control regulations @@ -201,10 +279,46 @@ 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. Thus, free software licenses -must not require obedience to any export regulations as a condition of -any of the essential freedoms. +must not require obedience to any nontrivial export regulations as a +condition of exercising any of the essential freedoms. +

+ +

+Merely mentioning the existence of export regulations, without making +them a condition of the license itself, is acceptable since it does +not restrict users. If an export regulation is actually trivial for +free software, then requiring it as a condition is not an actual +problem; however, it is a potential problem, since a later change in +export law could make the requirement nontrivial and thus render the +software nonfree.

+

Legal considerations

+ +

+In order for these freedoms to be real, they must be permanent and +irrevocable as long as you do nothing wrong; if the developer of the +software has the power to revoke the license, or retroactively add +restrictions to its terms, without your doing anything wrong to give +cause, the software is not free. +

+ +

+A free license may not require compliance with the license of a +nonfree program. Thus, for instance, if a license requires you to +comply with the licenses of “all the programs you use”, in +the case of a user that runs nonfree programs this would require +compliance with the licenses of those nonfree programs; that makes the +license nonfree. +

+ +

+It is acceptable for a free license to specify which jurisdiction's +law applies, or where litigation must be done, or both. +

+ +

Contract-based licenses

+

Most free software licenses are based on copyright, and there are limits on what kinds of requirements can be imposed through copyright. If a @@ -224,6 +338,8 @@ it is nonfree.

+

Use the right words when talking about free software

+

When talking about free software, it is best to avoid using terms like “give away” or “for free,” because those terms imply that @@ -235,6 +351,8 @@ “free software” into various languages.

+

How we interpret these criteria

+

Finally, note that criteria such as those stated in this free software definition require careful thought for their interpretation. To decide @@ -249,6 +367,8 @@ it easier to see why certain licenses do or don't qualify.

+

Get help with free licenses

+

If you are interested in whether a specific license qualifies as a free software license, see our list @@ -271,7 +391,7 @@ and avoid various practical problems.

-

Beyond Software

+

Beyond Software

Software manuals must be free, @@ -293,28 +413,64 @@ free cultural works applicable to any kind of works.

-

Open Source?

+

Open Source?

-Another group has started using the term “open source” to mean -something close (but not identical) to “free software.” We +Another group uses the term “open source” to mean +something close (but not identical) to “free software”. We prefer the term “free software” because, once you have heard that it refers to freedom rather than price, it calls to mind freedom. The word “open” never refers to freedom.

-

History

+

History

-

From time to time we revise this Free Software Definition to -clarify it. Here we provide a list of those modifications, along with -links to illustrate exactly what changed, so that others can review -them if they like.

+

From time to time we revise this Free Software Definition. Here is +the list of substantive changes, along with links to show exactly what +was changed.

-

There are gaps in the version numbers because there are many other -changes that do not affect the substance of the definition at all. -Instead, they fix links, add translations, and so on. If you would -like to review the complete list of changes, you can do so on -our cvsweb +

There are gaps in the version numbers shown above because there are +other changes in this page that do not affect the definition or its +interpretations. For instance, the list does not include changes in +asides, formatting, spelling, punctuation, or other parts of the page. +You can review the complete list of changes to the page through +the cvsweb interface.

- +

Footnote

+
    +
  1. The reason they are numbered 0, 1, 2 and 3 is historical. Around +1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that +the freedom to run the program needed to be mentioned explicitly. +It was clearly more basic than the other three, so it properly should +precede them. Rather than renumber the others, we made it freedom 0.
  2. +
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