Back from FOSDEM 2013

As (almost) every year, I attended the annual incarnation of FOSDEM. It is undoubtedly (one of?) the most remarkable events about Free Software in existence. No registration, no fees, 24 tracks in parallel, an estimated 5000 number of attendees. I also like that it brings together people from so many different communities, not _just_ the Linux or Gnome or KDE or Telephony or Legal people, but a good mixture of everything.

I have to congratulate the organizers, who manage to pull this off, year after year again. And as opposed to many other events, they do so quietly and without much recognition, I feel. I'd also like to thank the many volunteers working tirelessly before, at and after the event. Last, but not least, I'd like to thank the local university (ULB Solbosch) hosting the event.

What made me truly sad though, is the amount of littering that surprisingly many of the attendees did. This was particularly visible in the Cafeteria. Imagine an event run by volunteers, who put in a lot of time and effort. Imagine an event where food and drinks are sold by volunteers at such low prices that there can barely be any profit at all. And then imagine people eating there and leaving all their rubbish around, as if they were in some kind of restaurant where they are being served and where somebody is cleaning up after them. It really makes me feel very bitter to see this. Don't people realize that those very volunteers who are creating the event will then have to put in _their_ spare time just because those who just enjoyed their coffee or lunch didn't have the extra 30 seconds of bringing their trash to the trashcan? I feel ashamed for members of our community who behave this way. Please think next time before acting and show your respect to the people behind FOSDEM.

Talk Idea: How to write code to make later enforcement easy

During FOSDEM 2013, I spoke with some fellow Free Software developers about how my knowledge on copyright and specifically legal aspects of software copyright has influenced the way how I write code, and particularly how I design architecture of programs.

This made me realize that this would probably make a quite interesting talk at Free Software conferences: How to architect and write code in order to make later [GPL] enforcement easy.

Of course there are all the general and mostly well-known rules like keeping track of who owns which part of the copyright, having proper copyright claims and license headers, etc.

But I'm more thinking in the sense of: How do I write code in a way to make sure people extending it in some way with their own code will be forced to create a derivative work. If that is the case, they will have absolutely no choice but to also license that under GPL.

This is particularly important in the case of GPL licensed libraries. The common understanding in the community is that writing an executable program against a GPL licensed library will constitute a derivative work and thus the main program must be licensed under the GPL, if it is ever distributed.

However, in reality there is of course no precedent, and in some particular cases, the legal framework, depending on the jurisdiction, might come to different conclusions if it ever ended up in court. The claim of a 'derivative work' would be particularly weak if the main program is only using a set of standard function calls whose function declarations are the same in many versions of the GPL licensed library you link against. So let's assume there was a GPL licensed standard C library for stuff like open(), close(), printf() and the like. I think it would be very difficult to argue in court that a program written against those functions and linked against such a library would constitute a derivative work of the library. As in fact, there are many other implementations providing the exact same interface, under different licenses, and the API was not even drafted by the author of the GPL licensed implementation.

So I think there are some things that an author of an (intentionally) GPL licensed library can do while writing the code, which will later help him to establish that an executable program is a derived work.

The same is true to some extent for executable programs, too. I very intentionally did not introduce a plug-in interface for BTS drivers in OpenBSC, even though while technically it would have been possible. I _want_ somebody who adds code for a different BTS to touch the main code of the program instead of just writing an external plugin. The mere fact that he has to edit the main program in order to add a new BTS driver indicates that he is creating a derivative work.

So I'll probably try to submit a talk on this topic to some upcoming conference[s]. If you think this is an interesting topic and want me to talk about it at a FOSS related event, please feel free to send me an e-mail.