Re: Niches for the Hurd: evaluation method; was: DRM musings, capabilities and stuff

[Arne Babenhauserheide]

Am Dienstag 09 Dezember 2008 12:54:42 schrieb Michal Suchanek:
> The driver itself does not restrict the use of the system, it only
> identifies what system you are running (among other things).
>
> It probably would not be part of a GNU system but I do not see how
> adding it would violate any license.

The combination "you can't use our software with version X of the system, but 
you can use it with version Y, though both are completely API compatible" with 
"the system is licensed under the GPLv3" is a license violation, if using that 
software is part of the "normal operation" of that system. 

As I read it, shipping a media-player which builds on GPLv3 software but has a 
frontend which only works with a certain version of the GPLv3 software would 
be a license violation. 

If you don't ship the program on the system, but instead the user installs it 
himself at a later time, that is no license violation, since the user doesn't 
distribute the whole system. 

It might be that I read the GPLv3 too hard here, but deciding that is up to a 
judge to decide. 


Information: 

* What is tivoization? How does GPLv3 prevent it?
Some devices utilize free software that can be upgraded, but are designed so 
that users are not allowed to modify that software. There are lots of 
different ways to do this; for example, sometimes the hardware checksums the 
software that is installed, and shuts down if it doesn't match an expected 
signature. The manufacturers comply with GPLv2 by giving you the source code, 
but you still don't have the freedom to modify the software you're using. We 
call this practice tivoization.

When people distribute User Products that include software under GPLv3, 
section 6 requires that they provide you with information necessary to modify 
that software. User Products is a term specially defined in the license; 
examples of User Products include portable music players, digital video 
recorders, and home security systems.
- http://www.gnu.org/licenses/gpl-faq.html#Tivoization

* GPLv3, section 6: 
[...]
“Installation Information” for a User Product means any methods, procedures, 
authorization keys, or other information required to install and execute 
modified versions of a covered work in that User Product from a modified 
version of its Corresponding Source. The information must suffice to ensure 
that the continued functioning of the modified object code is in no case 
prevented or interfered with solely because modification has been made.

If you convey an object code work under this section in, or with, or 
specifically for use in, a User Product, and the conveying occurs as part of a 
transaction in which the right of possession and use of the User Product is 
transferred to the recipient in perpetuity or for a fixed term (regardless of 
how the transaction is characterized), the Corresponding Source conveyed under 
this section must be accompanied by the Installation Information. But this 
requirement does not apply if neither you nor any third party retains the 
ability to install modified object code on the User Product (for example, the 
work has been installed in ROM).
- http://www.gnu.org/licenses/gpl-3.0.html

In short: Any part under GPLv3 may not be hindered by other software only 
because it was modified. 

Best wishes, 
Arne
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