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 <title>Categories of Free and Nonfree Software
 - GNU Project - Free Software Foundation</title>
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 <h2>Categories of Free and Nonfree Software</h2>
 
 <!-- GNUN: localize URL /philosophy/category.png -->
 <div id="diagram" class="c" role="figure" aria-labelledby="caption">
 <img src="/philosophy/category.png" alt=" [Categories of software] " />
       <p id="caption">
       This diagram, originally by Chao-Kuei and updated by several
       others since, explains the different categories of software. It's
       available as a <a href="/philosophy/category.svg">Scalable Vector
       Graphic</a> and as an <a href="/philosophy/category.fig">XFig
       document</a>, under the terms of any of the GNU GPL v2 or later,
       the GNU FDL v1.2 or later, or the Creative Commons
       Attribution-Share Alike v2.0 or later.</p>
 </div>
 
 <div class="announcement" role="complementary">
 <p>Also see <a href="/philosophy/words-to-avoid.html">Confusing
 	Words which You Might Want to Avoid</a>.</p>
 </div>
 
 <h3 id="FreeSoftware">Free software</h3>
 
 	<p>Free software is software that comes with permission for
 	anyone to use, copy, and/or distribute, either verbatim or with
 	modifications, either gratis or for a fee. In particular, this
 	means that source code must be available. &ldquo;If it's not
 	source, it's not software.&rdquo; This is a simplified
 	description; see also
 	the <a href="/philosophy/free-sw.html">full
 	definition</a>.</p>
 
 	<p>If a program is free, then it can potentially be included
 	in a free operating system such as GNU, or free versions of
 	the <a href="/gnu/linux-and-gnu.html">GNU/Linux
 	system</a>.</p>
 
 	<p>There are many different ways to make a program free&mdash;many
 	questions of detail, which could be decided in more than one way
 	and still make the program free. Some of the possible variations
 	are described below. For information on specific free software
 	licenses, see the <a href="/licenses/license-list.html">license
 	list</a> page.</p>
 
 	<p>Free software is a matter of freedom, not price. But
 	proprietary software companies typically use the term
 	&ldquo;free software&rdquo; to refer to price. Sometimes they
 	mean that you can obtain a binary copy at no charge; sometimes
 	they mean that a copy is bundled with a computer that you are
 	buying, and the price includes both.  Either way, it has
 	nothing to do with what we mean by free software in the GNU
 	project.</p>
 
 	<p>Because of this potential confusion, when a software company
 	says its product is free software, always check the actual
 	distribution terms to see whether users really have all the
 	freedoms that free software implies. Sometimes it really is free
 	software; sometimes it isn't.</p>
 
 	<p>Many languages have two separate words for
 	&ldquo;free&rdquo; as in freedom and &ldquo;free&rdquo; as in
 	zero price. For example, French has &ldquo;libre&rdquo; and
 	&ldquo;gratuit.&rdquo; Not so English; there is a word
 	&ldquo;gratis&rdquo; that refers unambiguously to price, but
 	no common adjective that refers unambiguously to freedom. So
 	if you are speaking another language, we suggest you translate
 	&ldquo;free&rdquo; into your language to make it clearer. See
 	our list of <a href= "/philosophy/fs-translations.html">
 	translations of the term &ldquo;free software&rdquo;</a> into
 	various other languages.</p>
 
 	<p>Free software is often <a href="/software/reliability.html">more
 	reliable</a> than nonfree software.</p>
 
 <h3 id="OpenSource">Open source software</h3>
 
 	<p>
 	The term &ldquo;open source&rdquo; software is used by some
 	people to mean more or less the same category as free
 	software. It is not exactly the same class of software: they
 	accept some licenses that we consider too restrictive, and
 	there are free software licenses they have not
 	accepted. However, the differences in extension of the
 	category are small: we know of only a few cases of source code that
 	is open source but not free.  In principle it could happen
 	that some free programs are rejected as open source, but
 	we don't know if that has ever happened.</p>
 	<p>We prefer the term &ldquo;<a
         href="/philosophy/open-source-misses-the-point.html">free
 	software</a>&rdquo; because it refers to
 	freedom&mdash;something that the term &ldquo;open
 	source&ldquo; does not do.</p>
 
 <h3 id="PublicDomainSoftware">Public domain
 	software</h3>
 
 	<p>Public domain software is software that is not copyrighted. If
 	the source code is in the public domain, that is a special case of
 	<a href="#Non-CopyleftedFreeSoftware">noncopylefted free
 	software</a>, which means that some copies or modified versions
 	may not be free at all.</p>
 
 	<p>In some cases, an executable program can be in the public domain
 	but the source code is not available. This is not free software,
 	because free software requires accessibility of source code.
 	Meanwhile, most free software is not in the public domain; it is
 	copyrighted, and the copyright holders have legally given
 	permission for everyone to use it in freedom, using a free software
 	license.</p>
 
 	<p>Sometimes people use the term &ldquo;public domain&rdquo;
 	in a loose fashion to
 	mean <a href="#FreeSoftware">&ldquo;free&rdquo;</a> or
 	&ldquo;available gratis.&rdquo; However, &ldquo;public
 	domain&rdquo; is a legal term and means, precisely, &ldquo;not
 	copyrighted.&rdquo; For clarity, we recommend using
 	&ldquo;public domain&rdquo; for that meaning only, and using
 	other terms to convey the other meanings.</p>
 
 	<p>Under the Berne Convention, which most countries have
 	signed, anything written down is automatically
 	copyrighted. This includes programs. Therefore, if you want a
 	program you have written to be in the public domain, you must
 	take some legal steps to disclaim the copyright on it;
 	otherwise, the program is copyrighted.</p>
 
 <h3 id="CopyleftedSoftware">Copylefted software</h3>
 
 	<p>Copylefted software is free software whose distribution
 	terms ensure that all copies of all versions carry more or
 	less the same distribution terms.  This means, for instance,
 	that copyleft licenses generally disallow others to add
 	additional requirements to the software (though a limited set
 	of safe added requirements can be allowed) and require making
 	source code available.  This shields the program, and its
 	modified versions, from some of the common ways of making a
 	program proprietary.</p>
 
         <p>Some copyleft licenses, such as GPL version&nbsp;3, block
 	other means of turning software proprietary, such as <a
     href="/licenses/rms-why-gplv3.html">tivoization</a>.</p> 
 
 	<p>In the GNU Project, we copyleft almost all the software we
 	write, because our goal is to give <em>every</em> user the freedoms
 	implied by the term &ldquo;free software.&rdquo; See our <a
         href="/licenses/copyleft.html">copyleft article</a> for more explanation of
 	how copyleft works and why we use it.</p>
 
 	<p>Copyleft is a general concept; to copyleft an actual program,
 	you need to use a specific set of distribution terms. There are
 	many possible ways to write copyleft distribution terms, so in
 	principle there can be many copyleft free software licenses.
 	However, in actual practice nearly all copylefted software uses the
 	<a href="/licenses/gpl.html">GNU General Public
 	License</a>. Two different copyleft licenses are usually
 	&ldquo;incompatible,&rdquo; which means it is illegal to merge
 	the code using one license with the code using the other
 	license; therefore, it is good for the community if people use
 	a single copyleft license.</p>
 
 <h3 id="Non-CopyleftedFreeSoftware">Noncopylefted free software</h3>
 
 	<p>Noncopylefted free software comes from the author with
 	permission to redistribute and modify, and also to add additional
 	restrictions to it.</p>
 
 	<p>If a program is free but not copylefted, then some copies
 	or modified versions may not be free at all. A software
 	company can compile the program, with or without
 	modifications, and distribute the executable file as
 	a <a href="#ProprietarySoftware">proprietary</a> software
 	product.</p>
 
 	<p>The <a href="https://www.x.org/wiki/">X Window System</a>
 	illustrates this.  The X Consortium released X11 with
 	distribution terms that made it noncopylefted free
 	software, and subsequent developers have mostly followed the
 	same practice.   A copy which has those
 	distribution terms is free software.  However, there are nonfree
 	versions as well, and there are (or at least were) popular
 	workstations and PC graphics boards for which nonfree
 	versions are the only ones that work.  If you are using this
 	hardware, X11 is not free software for
 	you.  <a href="/philosophy/x.html">The developers of X11 even
 	made X11 nonfree</a> for a while; they were able to do this
 	because others had contributed their code under the same
 	noncopyleft license.</p>
 
 <h3 id="LaxPermissiveLicensedSoftware">Lax permissive licensed software</h3>
 
 	<p>Lax permissive licenses include the X11 license and the
 	<a href="/licenses/bsd.html">two BSD licenses</a>.  These licenses permit
 	almost any use of the code, including distributing proprietary
 	binaries with or without changing the source code.</p>
 
 <h3 id="GPL-CoveredSoftware">GPL-covered software</h3>
 
 	<p>The <a href="/licenses/gpl.html">GNU GPL (General Public
 	License)</a> is one specific set of distribution terms for
 	copylefting a program. The GNU Project uses it as the distribution
 	terms for most GNU software.</p>
 
 	<p>To equate free software with GPL-covered software is therefore
 	an error.</p>
 
 <h3 id="TheGNUsystem">The GNU operating system</h3>
 
 	<p>The <a href="/gnu/gnu-history.html">GNU operating system</a> is the
 	Unix-like operating system, which is entirely free software, that
 	we in the GNU Project have developed since 1984.</p>
 
 	<p>A Unix-like operating system consists of many programs. The
 	GNU system includes all of the <a href="#GNUsoftware">official
 	GNU packages</a>.  It also includes many other packages, such as
 	the X Window System and TeX, which are not GNU software.</p>
 
 	<p>The first test release of the complete GNU system was in
 	1996.  This includes the GNU Hurd, our kernel, developed since
 	1990.  In 2001 the GNU system (including the GNU Hurd) began
 	working fairly reliably, but the Hurd still lacks some
 	important features, so it is not widely used.  Meanwhile,
 	the <a href="/gnu/linux-and-gnu.html">GNU/Linux system</a>,
 	an offshoot of the GNU operating system which uses Linux as
 	the kernel instead of the GNU Hurd, has been a great success
 	since the 90s.  As this shows, the GNU system is not a single
         static set of programs; users and distributors may select
         different packages according to their needs and desires.  The
         result is still a variant of the GNU system.</p>
 
 	<p>Since the purpose of GNU is to be free, every single
 	component in the GNU operating system is free
 	software.  They don't all have to be copylefted, however; any
 	kind of free software is legally suitable to include if it
 	helps meet technical goals.</p>
 
 <h3 id="GNUprograms">GNU programs</h3>
 
 	<p>&ldquo;GNU programs&rdquo; is equivalent
 	to <a href="#GNUsoftware">GNU software.</a> A program Foo is a
 	GNU program if it is GNU software.  We also sometimes say it
 	is a &ldquo;GNU package.&rdquo;</p>
 
 <h3 id="GNUsoftware">GNU software</h3>
 
 	<p><a href="/software/software.html">GNU software</a> is
 	software that is released under the auspices of the <a
 	href="/gnu/gnu-history.html">GNU Project</a>. If a program is GNU
 	software, we also say that it is a GNU program or a GNU
 	package.  The README or manual of a GNU package should say it
 	is one; also, the <a href="/directory">Free Software
 	Directory</a> identifies all GNU packages.</p>
 
 	<p>Most GNU software is <a href=
 	"/licenses/copyleft.html">copylefted</a>, but not all; however,
 	all GNU software must be <a href="/philosophy/free-sw.html">free
 	software</a>.</p>
 
 	<p>Some GNU software was written by <a
 	href="https://www.fsf.org/about/staff/">staff</a> of
 	the <a href="https://www.fsf.org/">Free Software
 	Foundation</a>, but most GNU software comes from many
 	<a href="/people/people.html">volunteers</a>.  (Some of these
 	volunteers are paid by companies or universities, but they are
 	volunteers for us.)  Some contributed software is copyrighted
 	by the Free Software Foundation; some is copyrighted by the
 	contributors who wrote it.</p>
 
 <h3 id="FSF-CopyrightedGNUSoftware">FSF-copyrighted GNU software</h3>
 
         <p>The developers of GNU packages can transfer the copyright
         to the FSF, or they can keep it.  The choice is theirs.</p>
 
         <p>If they have transferred the copyright to the FSF, the program
 	is FSF-copyrighted GNU software, and the FSF can enforce
 	its license.  If they have kept the copyright, enforcing the license
 	is their responsibility.</p>
 	
 	<p>The FSF does not accept copyright assignments of software
 	that is not an official GNU package, as a rule.</p>
 
 <h3 id="non-freeSoftware">Nonfree software</h3>
 
 	<p>Nonfree software is any software that is not free.
 	Its use, redistribution or modification is prohibited, or
 	requires you to ask for permission, or is restricted so much
 	that you effectively can't do it freely.</p>
 
 <h3 id="ProprietarySoftware">Proprietary software</h3>
 
 	<p>Proprietary software is another name for nonfree software.
 	In the past we subdivided nonfree software into
 	&ldquo;semifree software,&rdquo; which could be modified and
 	redistributed noncommercially, and &ldquo;proprietary
 	software,&rdquo; which could not be.  But we have dropped that
 	distinction and now use &ldquo;proprietary software&rdquo; as
 	synonymous with nonfree software.</p>
 
 	<p>The Free Software Foundation follows the rule that we cannot
 	install any proprietary program on our computers except temporarily
 	for the specific purpose of writing a free replacement for that
 	very program. Aside from that, we feel there is no possible excuse
 	for installing a proprietary program.</p>
 
 	<p>For example, we felt justified in installing Unix on our
 	computer in the 1980s, because we were using it to write a free
 	replacement for Unix. Nowadays, since free operating systems are
 	available, the excuse is no longer applicable; we do not use any
 	nonfree operating systems, and any new computer we install
 	must run a completely free operating system.</p>
 
 	<p>We don't insist that users of GNU, or contributors to GNU, have
 	to live by this rule. It is a rule we made for ourselves. But we
 	hope you will follow it too, for your freedom's sake.</p>
 
 
 <h3 id="freeware">Freeware</h3>
 
 	<p>The term &ldquo;freeware&rdquo; has no clear accepted
 	definition, but it is commonly used for packages which permit
 	redistribution but not modification (and their source code is
 	not available). These packages are <em>not</em> free software,
 	so please don't use &ldquo;freeware&rdquo; to refer to free
 	software.</p>
 
 <h3 id="shareware">Shareware</h3>
 
 	<p>Shareware is software which comes with permission for people to
 	redistribute copies, but says that anyone who continues to use a
 	copy is <em>required</em> to pay a license fee.</p>
 
 	<p>Shareware is not free software, or even semifree. There are two
 	reasons it is not:</p>
 
 	<ul>
 	<li>For most shareware, source code is not available; thus, you
 	cannot modify the program at all.</li>
 	<li>Shareware does not come with permission to make a copy and
 	install it without paying a license fee, not even for individuals
 	engaging in nonprofit activity. (In practice, people often
 	disregard the distribution terms and do this anyway, but the terms
 	don't permit it.)</li>
 	</ul>
 
 <h3 id="PrivateSoftware">Private software</h3>
 	<p>Private or custom software is software developed for one user
 	(typically an organization or company). That user keeps it and uses
 	it, and does not release it to the public either as source code or
 	as binaries.</p>
 	<p>A private program is free software (in a somewhat trivial
 	sense) if its sole user has the four freedoms.  In particular,
 	if the user has full rights to the private program, the program is
 	free.  However, if the user distributes copies to others and does
 	not provide the four freedoms with those copies, those copies
 	are not free software.</p>
 
 	<p>Free software is a matter of freedom, not access.  In
 	general we do not believe it is wrong to develop a program and
 	not release it. There are occasions when a program is so
 	important that one might argue that withholding it from the
 	public is doing wrong to humanity.  However, such cases are
 	rare.  Most programs are not that important, and declining to
 	release them is not particularly wrong. Thus, there is no
 	conflict between the development of private or custom software
 	and the principles of the free software movement.</p>
 
 	<p>Nearly all employment for programmers is in development of
 	custom software; therefore most programming jobs are, or could be,
 	done in a way compatible with the free software movement.</p>
 
 <h3 id="commercialSoftware">Commercial software</h3>
 
 	<p> &ldquo;Commercial&rdquo; and &ldquo;proprietary&rdquo; are
 	not the same!  Commercial software is software developed by a
 	business as part of its business. Most commercial software
 	is <a href="#ProprietarySoftware">proprietary</a>, but there
 	is commercial free software, and there is noncommercial
 	nonfree software.</p>
 
 	<p>For example, GNU Ada is developed by a company.  It is always
 	distributed under the terms of the GNU GPL, and every copy is
 	free software; but its developers sell support contracts. When
 	their salesmen speak to prospective customers, sometimes the
 	customers say, &ldquo;We would feel safer with a commercial
 	compiler.&rdquo; The salesmen reply, &ldquo;GNU
 	Ada <em>is</em> a commercial compiler; it happens to be free
 	software.&rdquo;</p>
 	<p>For the GNU Project, the priorities are in the other order:
 	the important thing is that GNU Ada is free software; that
 	it is commercial is just a detail. However, the additional
 	development of GNU Ada that results from its being commercial
 	is definitely beneficial.</p>
 	<p>Please help spread the awareness that free commercial
 	software is possible. You can do this by making an effort not
 	to say &ldquo;commercial&rdquo; when you mean
 	&ldquo;proprietary.&rdquo;</p>
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