discuss: Would like to maintain Linux Networking Howto
Subject:
Re: [discuss] Would like to maintain Linux Networking Howto
From:
Rick Moen ####@####.####
Date:
24 Sep 2008 21:56:22 +0100
Message-Id: <20080924205620.GC13340@linuxmafia.com>
Quoting Jean-Daniel Dodin ####@####.####
> I'm always puzzled about dual licencing when some people say the
> licence are uncompatible. how can somebody say yes and no at the same
> time?
No problem. I'm glad to explain.
The notion of dual-licensing is to give the recipient the choice of
picking _either_ licence to accept the entire work under. In that
context, there's no reason why the licences in question cannot be wildly
different, and indeed so different that they would be completely
incompatible when specified for different parts of a single work.
For example, if you had a really fast, but obscure database engine, and
wanted to publicise it and show off its source code to the public but
didn't want to permit your software-industry competitors to incorporate
the engine into any of their commercial products, you could issue the
source code like this:
The MyEngine database source code is available under the
recipient's choice of either GPLv2 or, at the recipient's option,
the proprietary, pay-for-use licence posted at
http://myengine.example.com/licence/ .
Licence compatiblity becomes an issue where a single work includes code
under two licences, one of which does not permit inclusion of code under
the other in derivative works. Here's an example:
Back when I worked at VA Linux Systems in the late 1990s/early 2000s, my
friend Marc Merlin created RPMs of the Exim MTA with TLS extensions he
wrote that used OpenSSL libraries for cryptographic wrapping of SMTP.
He said he was going to put those out for public ftp.
I said, "Wait, Marc. Unfortunately, that would be copyright violation,
because OpenSSL is, in part, under the old BSD licence with the
advertising clause, whereas Exim is under GPLv2, such that the advertising
clause becomes a 'further restriction' making distribution of the
composite work a violation of Exim's licence." Marc swore fluently
about just how much licensing problems suck, and then just adopted my
suggestion of asking Exim author Phil Hazel to grant a licensing
exception permitting linking against OpenSSL, which he immediately gave.
End of problem.
> could there be any advantage to default LDP doc to dual licences
> (apart making lawyers rich?)
Of course there is.
First of all, the author giving people additional permissions cannot
possibly make any author rich. If you don't mind my saying so, your
question suggests you're confusing dual-licensing -- giving the
recipient the choice of two alternative licences -- with the use of two
incompatible licences within a single work. The latter (immediately)
creates problems. The former is often used to avoid them -- or to make
people like Rubini and Terry happy by letting recipients continue to
elect GPLv2 (which they know and trust) while also makign happy people
in LDP who for some reason like GFDL.
May I be really blunt for a moment? I have a strong suspicion that the
several people including yourself who've been pushing GFDL only, on this
mailing list, have no understanding of licensing and haven't actually
attempted to read and understand GFDL, either.
I could be wrong, of course, but I just have that suspicion.
