FOSDEM 2007

Here’s some notes about my visit to FOSDEM, in no particular order. I caught a cold (shouldn’t that be cold caught me?) and also managed to destroy my notes the week after so if I sound more incomprehensible than usual that’s probably because I am.

Pre-FOSDEM beer event. *burp*

Keynotes. I was somewhat distracted (planning the rest of the weekend, buying chocolates, hacking) during the keynotes so I mostly missed them. Liberating Java wasn’t as much about Java as it was about Sun’s vision related to working commercially as well as with communities. The evolution of software distribution models (bundled, shrink wrapped, services) had some interesting points. Showing that Sun has contributed significant amount of the code in Debian came as a surprise, hadn’t though about it, but felt a bit tacky marketing.

X.

AIGLX is about accelerated indirect GLX rendering, needed for OpenGL based compositing. And direct rendering is evil anyways. Even if we did have OpenGL on mobile devices I wonder if we have the memory to do compositing this way.

X security framework idea is to compartmentalize your X applications so that you can work on multiple projects (trusted / untrusted) on the same computer without risking information leaks. Quite important for NSA and the like. Funny limitations in old framework. New framework more flexible, but has similar problems to SELinux. How do you configure it so that it doesn’t get in the way? If it doesn’t get in the way how do you know it’s secure? The mental model is too complicated for the users. Using two laptops is much more simple, both in implementation and mental model.

Video on dope was quite crazy demonstration of using 3D hardware acceleration to do colorspace conversion and smooth out artefacts in videos. Curious way to use textures.

Everything new in X land was said to be blocking on new memory manager.

Debian. Automated testing of Debian packages, pbuilder, lintian, linda, piuparts. Interesting trivia: OpenOffice takes about 7.5h to build, using 40 nodes can build the whole Debian archive in the same time.

Formal dependency management (EDOS Project) had some interesting tools tracking package installability over time and is able to explain why certain package is not installable (anymore.) This might be interesting for Sardine.

Development platforms.
gtk+ upstream meeting. I have a feeling the desktop distributions are content with gtk+ and are not investing in pushing it forwards, or even maintaining it much. The mobile players on the other hand are only getting started 😉 ABI break is an acute problem for maemo gtk due to our modifications (no free expansion slots left.) We need to fiture out where we want to go and whether API/ABI break can help us getting there. For example, gtk+ uses cairo/Xlib, but when you have OpenGL hardware you could use from the widgets (there’s experimental cairo/glitz backend) how do you mix the two?

Bling it up. Mmm, eye candy. You can do lots of nice effects with cairo. Now, how do we make it trivial to integrate those effects into applications?

OpenMockupOpenMoko (Sorry, couldn’t resist. I blame MDK for coming up with the term.) Starting to feel the performance, the processor is even slower than ours, no FPU of course. The pixbuf engine with its bilinear (floating points based) scaling is really hurting. Switching to sapwood should give noticeable performance increase with some tradeoffs.

The display on the device is even higher density (280ppi) than ours (250ppi) The text is physically smaller but still readable, at least for me. The widgets are rather small, especially the ones around screen edges are almost impossible to use without stylus. I couldn’t find a stylus holder on the casing – whoopsie.

Talking to Mickey made me think their approach to developing applications is appealing. Single implementation for the basic navigation saves a lot of effort while enforcing familiar behavior in places where differentiation doesn’t buy you much.

Qtopia. Spying around a bit. I think there’s quite a bit we could learn from them about producing development platforms.