419 lines
14 KiB
Markdown
419 lines
14 KiB
Markdown
% Brief Introduction to the GNU General Public License
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% Bradley M. Kuhn
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% Monday 24 March 2014
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# Audience Polls
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+ My goal here is to move faster or slower based on audience knowledge.
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+ There are folks in this audience who have worked with this stuff for years,
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and those who are completely new.
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+ We want these presentations to be valuable to all of you.
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+ Please, don't be embarrassed:
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+ Ever GPL expert in the world, including me, started as a student who
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knew none of this.
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# IANAL
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<cite>IANAL</cite>
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# My Affiliations
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+ Formerly had John's job, Executive Director of FSF, years ago.
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+ Currently: on Board of Directors of FSF.
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+ President of Software Freedom Conservancy.
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# How These Orgs Relate to GPL?
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+ FSF
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+ Invented copyleft.
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+ Authors & stewards of the GPL.
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+ Holder of copyrights on many key GNU programs …
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+ … and therefore enforcers of those copyrights.
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+ Software Freedom Conservancy
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+ Adviser on legal issues of copyright, etc. to Free Software projects.
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+ Holder of some copyrights on its member projects.
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+ Enforcer of GPL on behalf of many copyright holders in:
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+ BusyBox, Samba, Mercurial, and the kernel named Linux.
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# How this Hour Will Go?
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+ Materials presented will mix the simple & complex.
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+ We cannot possibly cover the entire GPL in one hour.
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+ Discuss: motivations, origins, then a few of GPL's sections.
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+ I understand the mix of backgrounds in the audience.
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# A Restaurant's Lawyer?
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+ Considering why you want to learn this.
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+ What if your client was a restaurant?
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+ What would you want to need to know?
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# Restaurant Lawyer: What'd You Study?
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+ If you were a restaurant's lawyer:
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+ Probably three areas of law you'd focus on:
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+ building codes.
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+ health and safety regulations.
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+ tax regulations.
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+ Who would want to hear from?
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# Restaurant Lawyer: What'd You Study?
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+ Figure out the motivations behind the building code:
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+ What parts are arcane and less important to inspectors?
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+ How do inspections work?
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+ What are the penalties?
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+ Figure out the same for health & safety:
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+ Who inspects, and when?
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+ What's the health code say, and what checklist do inspectors use?
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+ Likely Questions:
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+ Who's in charge of all this?
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+ What's purpose and intent of these regulations?
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+ Can I meet the inspectors?
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# Why Listen To Us?
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+ FSF: Understanding the purpose and intent of the GPL.
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+ Conservancy & FSF:
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+ both enforce the GPL.
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+ if your client violates, you will hear from one of us.
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+ Such access to drafters, interpreters, enforcers is highly unique.
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+ Someday, we may (or already have) sit across the table from you.
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+ Our transparency does make your job easier.
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# The Mindset of GPL
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+ GPL protects software freedom.
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+ Ultimate goal: make sure every user has the four freedoms.
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+ Freedom to run the software.
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+ Freedom to study and modify the software.
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+ Freedom to share the software.
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+ Freedom to distribute modified versions.
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+ Every clause in GPL was designed to uphold one of these freedoms.
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+ Or, it's a compromise of drafting in adoption vs. freedom debate.
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# Using Copyright
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+ GPL is primarily a copyright license.
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+ Software is copyrighted.
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+ License grants key freedoms.
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+ Requirement prohibit activities that take away freedoms.
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+ General concept: copyleft.
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+ Specific implementation: GPL.
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<hr/>
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<span class="fitonslide">
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> Copyright protection subsists … original works of authorship fixed in any tangible medium of expression … from which they can be perceived, reproduced, or otherwise communicated, either directly or with the aid of a machine or device.
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<p align=right>
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— <a href="http://www.law.cornell.edu/uscode/text/17/102">17 USC §102</a>
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</p>
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</span>
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# Conditional Permissions
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+ A copyleft license grants copyright permissions, conditionally.
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+ Think of the phrase: “provided that”
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+ “provided that”: appears (in some form) only
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+ 4 times in GPLv2
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+ 9 times in GPLv3.
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# Compare To Proprietary Licenses
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+ Yes, the GPL has its requirements.
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+ But *none* of these activities are ever permitted under proprietary
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licenses.
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+ If you don't like what the GPL requires you to do, then just tell your
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client to use the proprietary software instead.
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+ That way, they know the answer to every question is “no&;rdquo,
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+ rather than: “yes, but only as long as you …”
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# The Technical Gap
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+ Understanding GPL well requires a some software expertise & legal
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expertise.
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+ You don't have to be a professional on either side to grok it.
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+ but you're best off if you're a professional in one & an amateur
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in the other.
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+ Most important technical concepts you need:
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+ source code, binaries, methods of distribution.
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# Considering Sections of the GPL
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+ With the remaining time …
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+ in interest of the experts in the audience …
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+ let's dig into a few specific sections.
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+ GPL ♥ 17 USC§106(2) & 17 USC§106(3)
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+ Modification and distribution.
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# Why Permission to Modify?
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+ Your new copyrights are your copyrights:
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+ you are affixing it in a tangible medium.
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+ Exclusive right of copyright holders:
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+ Control on “preparation of derivative works”
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+ Distribution of the work.
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+ Note the combination of these.
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+ Again, see 17 USC§106
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+ N.B.: “derivative works” is USA-centric, modify is more international)
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# Modification As a Center Provision
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+ GPL's primary copyright hook is copyright controls on the right to modify.
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+ GPL's central tenant:
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+ You can make a modified version of various types privately as much as you'd like.
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+ When you distribute that modified version, you have requirements to meet.
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+ Technological considerations dictate necessity of more complex rules for
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certain types of modifications.
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# GPLv2 § 2(a-b)
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<span class="fitonslide">
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<p>[GPLv2§]2. You may modify your copy or copies of the Program or any
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portion of it, thus forming a work based on the Program, and copy and
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distribute such modifications or work under the terms of Section 1 above,
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provided that you also meet all of these conditions:
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<br/>
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<br/>
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a) You must cause the modified files to carry prominent notices stating
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that you changed the files and the date of any change.
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<br/>
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<br/>
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b) You must cause any work that you distribute or publish, that in
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whole or in part contains or is derived from the Program or any
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part thereof, to be licensed as a whole at no charge to all third
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parties under the terms of this License.
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</p>
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</span>
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# GPLv3§5(a-c)
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<span class="fitonslide">
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<p>
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You may convey a work based on the Program, or the modifications to
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produce it from the Program, in the form of source code under the
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terms of section 4, provided that you also meet all of these conditions:
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<br/>
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<br/>
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a) The work must carry prominent notices stating that you modified it, and
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giving a relevant date.
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<br/>
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<br/>
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b) The work must carry prominent notices stating that it is released under
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this License and any conditions added under section 7. This requirement
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modifies the requirement in section 4 to "keep intact all notices".
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<br/>
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<br/>
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c) You must license the entire work, as a whole, under this License to anyone
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who comes into possession of a copy. This License will therefore apply,
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along with any applicable section 7 additional terms, to the whole of the
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work, and all its parts, regardless of how they are packaged. This License
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gives no permission to license the work in any other way, but it does not
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invalidate such permission if you have separately received it.
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</p>
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</span>
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# GPLv2§2¶ ante-penultimate & penultimate
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<span class="fitonslide">
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<p>
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These requirements apply to the modified work as a whole. If
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identifiable sections of that work are not derived from the Program,
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and can be reasonably considered independent and separate works in
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themselves, then this License, and its terms, do not apply to those
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sections when you distribute them as separate works. But when you
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distribute the same sections as part of a whole which is a work based
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on the Program, the distribution of the whole must be on the terms of
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this License, whose permissions for other licensees extend to the
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entire whole, and thus to each and every part regardless of who wrote it.
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<br/>
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<br/>
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Thus, it is not the intent of this section to claim rights or contest
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your rights to work written entirely by you; rather, the intent is to
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exercise the right to control the distribution of derivative or
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collective works based on the Program.
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</p>
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</span>
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# GPLv3 §0 ¶1-5
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<span class="fitonslide">
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<p>
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"Copyright" also means copyright-like laws that apply to other kinds of
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works, such as semiconductor masks.
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<br/>
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<br/>
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"The Program" refers to any copyrightable work licensed under this
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License. Each licensee is addressed as "you". "Licensees" and
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"recipients" may be individuals or organizations.
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<br/>
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<br/>
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To "modify" a work means to copy from or adapt all or part of the work
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in a fashion requiring copyright permission, other than the making of an
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exact copy. The resulting work is called a "modified version" of the
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earlier work or a work "based on" the earlier work.
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<br/>
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<br/>
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A "covered work" means either the unmodified Program or a work based
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on the Program.
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</p>
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# Binaries (i.e., Object Code) are Modifications
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+ Software that the computer understands is different than software humans
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read.
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+ There is often a process required to modify (and/or translate) the software
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from human-readable
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+ This process can be done ahead of time.
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+ Separation of source and binary was the first way proprietary software
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companies discovered to subjugate users.
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+ GPL uses the fact that binaries are modifications (which are often
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distribution) to prevent that subjugation.
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# GPLv2 § 3(a-b)
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<span class="fitonslide">
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<p>
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<p>[GPLv2§]3. You may copy and distribute the Program (or a work based on it,
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under Section 2) in object code or executable form under the terms of
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Sections 1 and 2 above provided that you also do one of the following:
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<br/>
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<br/>
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a) Accompany it with the complete corresponding machine-readable
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source code, which must be distributed under the terms of Sections
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1 and 2 above on a medium customarily used for software interchange; or,
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<br/>
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<br/>
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b) Accompany it with a written offer, valid for at least three
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years, to give any third party, for a charge no more than your
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cost of physically performing source distribution, a complete
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machine-readable copy of the corresponding source code, to be
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distributed under the terms of Sections 1 and 2 above on a medium
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customarily used for software interchange;
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</p>
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</span>
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# GPLv3 § 6(a-b)
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<span class="fitonslide">
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<p>
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[GPLv3 § ] 6. Conveying Non-Source Forms.
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<br/>
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<br/>
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You may convey a covered work in object code form under the terms
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of sections 4 and 5, provided that you also convey the
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machine-readable Corresponding Source under the terms of this License,
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in one of these ways:
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<br/>
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<br/>
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a) Convey the object code in, or embodied in, a physical product
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(including a physical distribution medium), accompanied by the
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Corresponding Source fixed on a durable physical medium
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customarily used for software interchange.
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<br/>
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<br/>
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b) Convey the object code in, or embodied in, a physical product
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(including a physical distribution medium), accompanied by a
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written offer, valid for at least three years and valid for as
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long as you offer spare parts or customer support for that product
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model, to give anyone who possesses the object code either (1) a
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copy of the Corresponding Source for all the software in the
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product that is covered by this License, on a durable physical
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medium customarily used for software interchange, for a price no
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more than your reasonable cost of physically performing this
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conveying of source, or (2) access to copy the
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Corresponding Source from a network server at no charge.
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</p>
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</span>
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# GPLv3 § 1 ¶ 1, 4-6
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<span class="fitonslide">
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<p>
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The "source code" for a work means the preferred form of the work
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for making modifications to it. "Object code" means any non-source
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form of a work.
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<br/>
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<br/>
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The "Corresponding Source" for a work in object code form means all the
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source code needed to generate, install, and (for an executable work) run the
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object code and to modify the work, including scripts to control those
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activities. However, it does not include the work's System Libraries, or
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general-purpose tools or generally available free programs which are used
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unmodified in performing those activities but which are not part of the work.
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For example, Corresponding Source includes interface definition files
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associated with source files for the work, and the source code for shared
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libraries and dynamically linked subprograms that the work is specifically
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designed to require, such as by intimate data communication or control flow
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between those subprograms and other parts of the work.
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<br/>
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<br/>
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The Corresponding Source need not include anything that users
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can regenerate automatically from other parts of the Corresponding
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Source.
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<br/>
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<br/>
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The Corresponding Source for a work in source code form is that
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same work.
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</p>
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</span>
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# The GPL is a Complex Topic
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+ An in-depth seminar on GPL's provisions is a one-day course …
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+ … but the written materials discuss every section in depth.
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+ Keep in mind: every requirement has a carefully considered purpose to
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uphold freedom of users.
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+ Software freedom licenses have a moral perspective.
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+ This is probably the most difficult thing for lawyers to understand.
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