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Re: license learning

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On 2013-01-17 at 21:41, Daniel Pitts wrote:

> On 1/17/13 11:59 AM, bob wrote:
>> I certainly never learned them in college, and I doubt anyone else did either.

The students of my course did :-).  As a very superficial introduction, the
second part of this presentation of mine might be interesting to you:

http://ageinghacker.net/lipn-stuff/free-software-presentation--summer-2012.pdf

That was used in a French university, so the perspective may be somewhat
European.  As claimed in the first slides, I don't claim to be
impartial: I'm a free software advocate and a GNU maintainer.  I'm not a
lawyer, but a (French) lawyer checked my presentation slides.

Here I'm summing up the mains idea about free software licenses even
more synthetically.

According to copyright law, the author (or her employer in certain
conditions) *automatically* has a monopoly over the use, copy,
modification or redistribution of her work: such activities are
*forbitten* to everyone else, by default.  Notice that in order to
renounce to her copyright (or some approximation thereof, according to
the country) the copyright owner has to *explicitly* state so -- I
personally don't like that, but that's how it works.

For changing the default, the copyright owner may concede a license,
which is to say she can renounce to (part of) her monopoly by permitting
others to perform some of the activities above, at the conditions
specified by the license; such conditions depend on the specific
license, and may vary a lot: some licenses impose obnoxious
requirements, others permit to do most anything; most proprietary
licenses permit to *use* the software, but nothing more.

For some piece of software to be free software for some user, the user
must have *all* of the following rights:

0. use the software, for any purpose
1. study and change it for her own use
2. redistribute it
3. redistribute modified versions of it
These are Stallman's "four freedoms": http://www.gnu.org/philosophy/free-sw.html .

Points 1 and 3 in practice require access to the source code.

The Open Source initiative uses another definition for "Open Source
software", differently formulated because of philosophical differences,
but nearly equivalent to the above; so "free software" and "open source
software" is essentially the same set of software.  There are a couple
specific licenses that one side accepts and the other doesn't, but those
are very unusual cases you may ignore as a first approximation.

> Mostly, it is legalese, so for the finer points, a lawyer is recommended.

Indeed.

> For the general meaning, just read the licenses. It is pretty close
> the plain English. Also, I know some of these licenses have
> "annotated" version which describe the intent behind the wording. The
> danger there is that interpretation isn't a legally binding one
> compared to the actual wording.

This page contains a commentary on many common free software licenses.
As far as I know it's legally well-researched, even if political in
tone, written as it is from the point of view of somebody who cares
about free software: http://www.gnu.org/licenses/licenses.html

The GNU GPL, possible the most famous free software license, has a list
of Frequently-Asked Questions, which I recommend if you want to
understand some fine points or the need for fine points itself:

http://www.gnu.org/licenses/gpl-faq.html

As you can see some points are very technical, but that should cover a
lot of practical cases.

Even if the GPL is probably the most complex among the commonly-used
free software licenses, its complication comes from the need to
carefully prevent "workarounds" violating its spirit, which is actually
very simple: it's the idea is "copyleft"
(http://www.gnu.org/copyleft/copyleft.html), a condition requiring to
keep the same license in derived works (usually modified versions of the
program/library covered by the GPL, or programs linked to a library
covered by the GPL).

Some free software licenses such as the GNU LGPL are based on a weak
form of copyleft which does not force the user to use the same license
when just *linking* to a work covered by such a license (but it does in
case of modifications, on the modified software itself).

Of course there are no official laws about copyleft, which is not a
standard legal concept: so copyleft is "implemented" using copyright, as
a license condition: the license essentially says that *if* you want to
modify, redistribute or link the software, *then* you have to respect
some conditions, which force you to:
a) distribute the source code along with binary versions, so that study
and modifications are technically possible
b) keep the same license on derived works, so that the people
getting the software from you receive it as the same conditions,
particularly the four freedoms.

Other free software licenses such as the X11 license, the BSD licenses
or the Apache license are not based on copyleft at all.  Such licenses
tend to be much simpler, and *permit* the user to use a different
license on a derived work.  You might still be compelled to explicitly
identify your version as modified for example by changing the program
name, or to mention the original authors (which is always mandatory in
some countries recognizing "moral rights"), but that is usually trivial
in practice.

When joining two pieces of software covered by two licenses, you have to
respect them *both*: some licenses may have conflicting requirements,
and hence be incompatible with one another, which makes linking illegal.
Yes, it's complicated.  This is one more reason why inventing your own
licenses is a bad idea (the other reason is that a binding agreement
such as a license must be written very carefully, to express exactly
what you want in legally-correct terms).

Regards,

- -- 
Luca Saiu
Home page:   http://ageinghacker.net
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://marionnet.org
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license learning bob <bob@coolfone.comze.com> - 2013-01-17 11:59 -0800
  Re: license learning Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-01-17 12:41 -0800
  Re: license learning Luca Saiu <positron@gnu.org> - 2013-01-22 11:00 +0100

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