[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: GPLv3 comedy unfolding -- sheehantu: "Free Software Licenses in a Nu

From: Alexander Terekhov
Subject: Re: GPLv3 comedy unfolding -- sheehantu: "Free Software Licenses in a Nutshell"
Date: Sat, 30 Jun 2007 21:17:30 +0200

Free Software Licenses in a Nutshell

When I jumped into the Linux/open-source world I didn’t know nor care
about the different licenses software had attached with it. I guess I
was used to adhering to whatever license that was forced upon me by
Microsoft. Now I have a choice. There are many software licenses out
there - here are a few popular ones in a nutshell:


The General Public License is the foundation for many other licenses. It
is the most popular license in open-source and prevents copyleft -
restrictions on distributing copies and modified versions of a work for
others and requiring that the same freedoms be preserved in modified
versions. GPLv1 states that all binaries must have human readable source
code attached in the distribution. It also indicates that another
license that your software may carry cannot restrict clauses in the GPL.
Many software vendors will try and use that as a loophole to benefit
from open source while retaining their enhancements to themselves.


The major change in v2 is the Liberty or Death Clause in Section 7. This
states that if your software has some restriction where it violates
GPL-covered property, then it cannot be distributed. For example, if a
legal ruling states that they can only distribute the software in binary
form, they cannot distribute it at all. The Linux kernel is covered by
this license currently, and the license prevents others from just taking
the source, modifying it and not contributing back to the community that
founded it.


Known as the Lesser General Public License, its name is reflective of
its clauses - it has less restrictions. LGPL lets you distribute
modified work that is linked to free or proprietary software. For
example, if you write a media center application ontop of the MPlayer
library, under the LGPL you are allowed to distribute the software
regardless of the MPlayer library being open-source or binary. This was
instituted to give users more freedom.


This is license was just recently published and addresses the issues of
cross-patent licenses and anti-tivoization. Cross patent licenses for
example, the Novell-Microsoft agreement, under the GPLv3 indicates that
you cannot convey your product to a distributor who will charge their
customers for your work. The license is also meant to require Microsoft
to extend the patent licenses it grants to Novell customers for the use
of GPLv3 software to all users of that GPLv3 software; this is possible
only if Microsoft is legally a “conveyor” (distributor) of the GPLv3

Tivoization is the creation of a system that uses copyleft protected
software but includes hardware that restricts users from running
modified versions of the software on the hardware. It is named after
TiVo because it uses open-source software, however that software when
modified deems your TiVo device unusable, and is illegal under the the

BSD License

The GPL requires derivative work to be released according to the GPL
while the BSD license does not. Essentially, the BSD licence’s only
requirement is to acknowledge the original authors, and poses no
restrictions on how the source code may be used. As a result, BSD code
can find its way into proprietary software that only acknowledge the
source. For instance, the IP Stack in Microsoft Windows and Mac OS X are
derived from BSD-licensed software.

MPL License

Source code copied or changed under the MPL must stay under the MPL.
Unlike strong copyleft licenses, the code under the MPL may be combined
in a program with proprietary files which would otherwise be derivative
works of the MPL code. For example Netscape 6 and later releases were
proprietary versions of the Mozilla Application Suite. For these
Netscape releases, AOL was also exercising the exclusive rights to
proprietary versions that the another license provided to itself.

I have merely skimmed the surface of the purpose of licenses in the free
software world. I did not mention dual licensing, or compatability
between different licenses, or the myriad of other licenses available
for that matter, though I encourage you to do some extra reading if
you’re interested! Again, I am not a lawyer nor am I very familiar with
the technical aspects of the licenses, so please correct me if there is
a mistake or post a comment if you have anything to add!


"Mathematics is primarily a language for ensuring reliable results in
human social activity. "
                                  -- Columbia Professor Eben Moglen

reply via email to

[Prev in Thread] Current Thread [Next in Thread]