Last week from 23-Oct to 28-Oct I was at 3 conferences in Prague, Czech Republic, together with Gustavo Barbieri, Gustavo Padovan and Ulisses Furquim: the ProFUSION crew in Prague.
Starting from Kernel Summit, I had the opportunity to join the Bluetooth Summit and participate in the discussions regarding this subsystem in Linux, both in kernel and user space. We had a lot of hot topics to discuss, including the upcoming BlueZ 5.0, Bluetooth 3.0 (high speed), Bluetooth 4.0 (low energy) and I could also demonstrate the work I’ve been doing with the AVRCP profile. I’m glad it received a good acceptance from other developers. Some of them I didn’t know personally such as Luiz von Dentz, Claudio Takahasi, Vinicius Gomes. Others I had the pleasure to meet again like Marcel Holtmann and Johan Hedberg.
(We didn’t discuss only bluetooth related things. We noticed that more than 1/3 of the people there, working in the core of Bluetooth in Linux, was Brazilian and soon we were discussing with Samuel Ortis - a French, maintainer of ConnMan - who is the best soccer player :-).)
Daniel Wagner from BMW also brought up some interesting scenarios of multiple devices connected through Bluetooth in car kits and helmets (like this one): HFP, A2DP, HSP (and maybe also AVRCP?). All of them interacting and working together at the same time. Since the gstreamer conference was also taking place at the same facility we could also discuss with PulseAudio developers. In the end, it seems BlueZ and PulseAudio are working pretty well together, though we still have to polish some rough edges for some use cases like this.
Being at Kernel Summit was a great time to meet developers of other parts of the kernel too, such as Steven Rostetd and Peter Zylstra, with whom I had more contact some time ago when I was working in the Linux scheduler.
When the Kernel Summit was over (on Tuesday), LinuxCon and ELCE were taking off. It was great to have once more these two conferences collocated and being able to attend talks on both of them. There were several talks I’d like to attend but some of them were overlapping. ~~I’m looking forward to see the recorded talks later this year~~. It would be too extensive to detail each one here, so I’m just detailing some of them that grabbed more attention from me.
Gustavo Barbieri and Sulamita Garcia talked about Demistifying HTML5 and how it can be used to develop Apps. Gustavo focused on the EFL port of WebKit (in which I’m one of the developers ;-)) and the underlying technologies. It seems like the mentality of “let’s do apps in a very high-level language” instead of “providing a native language in a sdk” is coming back. Differently from what happened some years ago, this time maybe it will work out. Only future will show us.
Since this year I got involved with Android and development of the platform, I went to several Android-related talks. Leveraging Android’s Linux Heritage was really good stuff, showing how to replace some parts of the Android platform: bash instead of the I-wanna-be-a-shell that comes with Android by default, putting gstreamer in, optimizing some parts of the code, etc. In the same tune there was another talk entitled Build Community Android Distribution and Ensure the Quality. Interesting (but not surprising) to see how hard is to contribute to AOSP and how Android is much different from other open source projects we are used to.
Another interrelated areas that I have interest in (maybe because I work for a company related to embedded systems :-)) are system initialization, fast boot and development boards (such as Pandaboard). Therefore I attended systemd Administration in the Enterprise and Integrating systemd: Booting Userspace in Less Than 1 Second. The former, given by Lennart and Kay, focused on detailing some systemd features for guys running enterprise servers while in the latter Koen told us about his experience reducing boot time by using systemd in a Pandaboard. In this last talk I also met Jean Christophe, one of the developers of barebox (a bootloader aiming to replace U-Boot). Last time I checked, pandaboard was not in the list of supported boards but I was greatly surprised that now it is. Barebox has the advantages of running with caches enabled, having an architecture much more beautiful and being much faster than u-boot. In summary, IMHO it’s a bootloader done right.
Other interesting talk was Tuning Linux For Embedded Systems: When Less is More, in which Darren Hart gave instructions to reduce boot time and image size in very resource constrained scenarios (he was aiming a rootfs of only 4MB and total boot time under a second). Some key things to know is how to investigate what is not important to the application, what can be removed from kernel/userspace in order to fit the requirements and when to replace, why to replace and what to replace. Last but not least, in Developing Embedded Linux Devices Using the Yocto Project and What’s new in 1.1 David Stewart gave a status quo of the Yocto project. Interesting how the project evolved over this year and next time someone doing embedded systems think about ruling out its own distro from scratch, it would be good to look at Yocto.
I met a lot of other people for whom I apologize not citing their name here. This post would be yet bigger than it already is. I had a really great time their and I hope to continue going to these conferences. And the next one is LinuxCon Brazil, in which I’ll talk about How to Become an Open Source Developer. I look forward to seeing all of you there.
I’d like to thank the Linux Foundation for organizing such a great event and ProFUSION to allowing and sponsoring me to be there.
Side note: the problem is that now I want to do a lot of things in different projects without having time to to: systemd, Linux kernel, BlueZ, pandaboard, barebox, Android, etc :-)
 UPDATE: videos have been published - http://free-electrons.com/blog/elce-2011-videos/