ELC Europe in Grenoble


Just a quick note after the announcement that has just been made at the Embedded Linux Conference (ELC) in San Francisco…

Tim Bird has just announced that the next European edition of ELC will be in Grenoble, France, on October 15-16. As the new conference home page says, it will be colocated with ESWEEK.

We are very excited about this news, as Grenoble is a not only a beautiful place, but also a very dynamic city full of universities and high-tech companies. We will do our best to incite people to attend the conference, and of course to speak about their projects and propose demos.

Bootlin at ELC

My colleague Thomas Petazzoni and I will participate to the Embedded Linux Conference on April 6-8 in San Francisco.

This is an exciting conference with a very interesting program, and we are proud to be part of it:Golden Gate Bridge

If participate to this conference too, and if you are interested in the above topics, or in topics we covered in this blog, don’t hesitate to come and chat with us. We will both arrive on Saturday afternoon, so we could even meet before the conference starts.

If you can’t make it to this conference, we will also shoot and share videos as usual, so at least you won’t miss the technical contents. You will just miss the beer together…

FOSDEM 2009 videos

As previously announced, I had the chance to attend the FOSDEM conference again this year. And once again, the famous Bootlin video camera was with me, and I could record a few talks. I’m pleased to make them available today.

FOSDEM, the Free and Open Source Software Developers' European Meeting

Here are the available videos, with my personal comments. Of course, except the talk about CMake, all of them come from the embedded devroom. Thanks to the speakers for sharing their knowledge and presenting their projects !

  • video captureWt, a C++ web toolkit, for rich web interfaces to embedded systems, by Pieter Libin (Noesis Solutions)
    Video (44 minutes, 124M)
    Presentation of a Web application generator, which generates a Web application including a web server from a C++ description. The C++ design is based on many ideas coming from Qt, which eases the creation of the graphical application. Certainly a very interesting tool for embedded systems.
  • Hacking with modular hardware: the BUG, by Ken Gilmer (Bug Labs)
    Video (43 minutes, 129M)
    The BUG is a set of hardware modules that can be combined together. A base module contains the CPU, memory and other basic components, while additional modules can provide GPS, Wifi, webcam, I/O lines and many others. Of course, it comes with a completely free software SDK. Can be an interesting starting point for prototyping or hobbyist embedded hacking, even though the hardware is quite expensive.
  • Building Embedded Linux Systems with PTXdist, by Robert Schwebel (Pengutronix)
    Video (68 minutes, 151M)
    A very good presentation on why system building tools are needed for Embedded Linux systems (cross-compiling issues, etc.), and how PTXdist fits this need. Even though I’m personally quite fan of Buildroot, PTXdist’s competitor, the presentation was very interesting.
  • video captureDevelopment on the OpenMoko with hackable:1, by Pierre Pronchery (Bearstech)
    Video (55 minutes, 189M)
    A hands-on lab on the OpenMoko, which unfortunately was too short to be really interesting, and restricted to only the 10-12 people at the front of the room. Interesting for the people who did it, probably not so interesting to watch afterwards.
  • Development and Certification of Linux-Based Fire Safety & Security Systems, by Baurzhan Ismagulov (Siemens)
    Video (47 minutes, 124M)
    The topic of the talk was really appealing, because the use of free software in environments where human life is in danger has always caused many debates and discussions. Unfortunately, the talk completely misses the point : the speaker spent the whole talk discussing Germany-specific rules and laws for the certification of fire safety and security systems, almost without saying a word on how Linux can match these rules.
  • Maemo on BeagleBoard, by Juha Kallionen (Nokia)
    Video (20 minutes, 51M)
    Good talk, but not a lot of content, outside of « Hey, we run Maemo on BeagleBoard, try it !». A kind of announcement talk, I would say.
  • video captureAdvanced power management for OMAP3, by Peter De Schrijver (Nokia)
    Video (49 minutes, 169M)
    A very interesting, in-depth, technical talk about the power management features of the OMAP3 CPU and how these features can be used by the Linux kernel.
  • Emdebian 1.0 release – small and super small Debian, by Neil Williams (Debian)
    Video (86 minutes, 257M)
    video captureAgain, another interesting talk about the status of Emdebian, which has just reached 1.0. Neil described both Emdebian Crush and Emdebian Grip, that are two different approaches for making Debian more suitable for embedded systems. Very good progress has been made, and Emdebian is certainly something that should now be considered as a distribution for embedded systems.
  • CMake – what can it do for your project, by Alexander Neundorf
    Video (45 minutes, 167M)
    A general introduction to CMake, with lots of examples and demonstrations. Very nice for those who never had the opportunity to look at CMake.

Program for Embedded Linux Conference 2009 announced

CELF penguinThe program for the Embedded Linux Conference 2009 has been announced a few days ago, and the registration is now open. For the record, the Embedded Linux Conference is probably the largest technical conference specifically dedicated to the use of Linux on embedded systems. Organized by the CE Linux Forum every year, this conference gathers a large audience and a wide range of very interesting talks.

The 2009 edition of ELC will take place from April 6th to April 8th, in downtown San Francisco, in the United States.

The program features :

  • Almost 50 talks, tutorials and keynotes. The topics go from multimedia, flash filesystems, system initialization, memory management, instrumentation and debugging tools, real-time, embedded distributions, system building,
  • An opening keynote by Dirk Hohndel from Intel
  • A keynote by David Woodhouse, one of the two embedded Linux maintainers
  • Other famous speakers such as Paul Mundt (maintainer of the Linux port to the SuperH architecture), Kate Alhola (from Maemo/Nokia), Dan Malek (from Embedded Alley), Mike Anderson (the PTR group, famous for his JTAG tutorial), Jake Edge (from LWN), Klaas van Gend (from Montavista), Frank Rowand (from Sony, famous for his real-time adventures talk), Jim Ready, Denis Oliver Kropp (DirectFB main developer)
  • A panel on The Linux Kernel, what’s next with Jonathan Corbet, Greg KH, Andrew Morton, Keith Packard and Ted Ts’o
  • And last but not least, a talk from Michael Opdenacker, Bootlin, on flash filesystems.

Of course, both Michael and I will attend the conference. Hope to meet you there!
Golden Gate Bridge

Call for presentations for the LSM embedded track

The Libre Software Meeting (LSM) is an annual event on free software taking place in july in France since 2000. The LSM meeting is organized this year in Nantes, France from 7th to 11th July. Amongst several tracks, the Libre Software Meeting will feature an « Embedded Systems and Open Hardware » track, for which the call for presentations has been released recently.

The purpose of the “Embedded Systems and Open Hardware” session is to give the state of the art of free software for embedded systems and Open Hardware. Technical topics of this session include but are not limited to:

  • Embedded OS Development kernel architecture, implementation and port for embedded systems
  • Embedded Development Tools: tool chains and project cases (tool chain projects, packaging for cross compilation, portability …)
  • Embedded Linux: µClinux…
  • Real-time extensions for Linux: RTLinux, RTAI…
  • Hard real-time kernels: eCos, RTEMS, ADEOS, Xenomai…
  • Soft Real-time kernels
  • Embedded Java
  • GUI for embedded systems: Gtk, Qt, Nano/X…
  • Linux and System on Chip (SoC)
  • Open Hardware, Open design, free IP modules (Intellectual Property) and softcores: opencores, OpenRISC, NIOS, Microblaze, LEONSparc, FPGA…

The conference will last 30 minutes, questions included. Round tables will be organized. Synthetic presentations are scheduled to last 20 minutes. PDF versions of the presentation are not mandatory but they will be greatly appreciated (with an online web access just after the LSM event, they are a very useful documentation source for the entire community).

If you plan to participate and to propose a presentation, please send a message as soon as possible to the following address: embarque@rmll.info with a summary of your presentation (and if you can, a summary in English too) no later than 15th march 2009. Feel free to forward this Call For Presentation to other places or to everyone you think could be interested.

Embedded Linux Conference Europe 2008 videos

Together with the announcement of our free mainlining offer in our Linux kernel and bsp development services, we are pleased to announce the availability of new conference videos.

The CELF Embedded Linux Conference Europe (ELCE) and the NLUUG Autumn Conference on Mobile Computing took place last November in Ede, in the Netherlands.

For those who don’t know them yet, the Embedded Linux Conference (ELC) and ELCE are in our opinion the most interesting conferences for embedded Linux system developers. They cover only interesting topics, such as power management, boot time, flash storage, security, graphics, mobile applications and many more.

This time, four people shot videos: Ruud Derwig (NXP), Tim Bird (Sony), Thomas Petazzoni and Michael Opdenacker (both from Bootlin). Then, Thomas took care of reading the tapes and DVDs, and encoding them to Ogg/Theora, all this in just a few minutes of manual intervention, thanks to his super automated scripts.

Here are all the videos:

Speakers were supposed to post their slides on the CELF Wiki, but some of them haven’t done it yet.

If you don’t know which video to start with, here are the talks that Thomas Petazzoni and I preferred:

Of course, these are just our personal recommendations, from the talks we managed to attend. We are sure that many other ones are worth recommending.

Bootlin at FOSDEM 2009

The Free and Open Source Developer European Meeting (FOSDEM) is a major event for open source developers in Europe. This two-days event takes place in Brussels since several years and attracts 2000-3000 people around conferences and development rooms. The program for the main tracks has been recently announced, but the program for the development rooms is not available at this time. However, I’ve been at FOSDEM the last two years and always found interesting talks and discussions.


Of course, I’ll be particularly interested by the Embedded Devroom, and will record videos of the talks that will be posted on Bootlin website after the conference, as usual.

If you happen to come to FOSDEM, I’ll be happy to meet you!

Choosing graphical libraries for embedded systems

The free software community offers many solutions to embedded system developers willing to add graphical applications to their project. This variety of choice, typical from the free software world, has the advantage of giving several solutions, which increases the chance of finding the solution that bests suits your need, but at the same time, might confuse to choose the right one.

I made experiments with the major graphical libraries available, and reported these experiments during the Embedded Linux Conference Europe event, which took place early November 2008 in Ede, The Nederland. My presentation « Choosing graphical libraries for embedded systems » discussed DirectFB, X.org and its Kdrive variant, SDL, Nano-X, Gtk, Qt, FLTK and WxEmbedded, detailing the features, specifities, size of each solution and suitability to various use cases.

The slides are available under the Creative Commons BY-SA license : graphical-libraries.pdf (PDF), graphical-libraries.odp (Open Document Format).

While experimenting with these graphical libraries, I made a few contributions to the Buildroot project, which was used to build root filesystems including these libraries. I hope to release soon several root filesystems allowing an easy testing of these solutions, through Qemu.

Update on flash filesystems

Reviewing new possibilities for flash filesystems – My slides at ELCE 2008

With the release of Linux 2.6.27, including the new UBIFS filesystem for MTD storage, embedded Linux system developers now have multiple choices for their flash storage devices. As far as it is concerned, JFFS2 has also been improved and now has support for LZO compression, which makes uncompressing faster. So, how to choose between JFFS2, YAFFS2, and UBIFS?

To help our customers and the community make the right decision, I measured how these filesystems compare in terms of mount time, access time, read and write speed, as well as CPU usage in several corner cases and with different flash chip sizes.

I showed the results during the Embedded Linux Conference Europe event. Besides sharing lessons learned from these experiments, my presentation also introduced each filesystem and its implementation. I also gave advice for flash based block storage (such as Compact Flash and Solid State disks), to reduce the number of writes and avoid damaging flash blocks.

As usual, Bootlin slides are available under the Creative Commons BY-SA license: flash-filesystems.pdf (PDF), flash-filesystems.odp (Open Document Format).

The main finding is that UBIFS outperforms both JFFS2 and YAFFS2 in almost all corner cases. As shown by the benchmarks, it has consistently good mount time, and read/write performance. If your products are using a recent kernel, and are still based on JFFS2, you should definitely try UBIFS and get significant performance benefits, in particular for boot time, as mounting a JFFS2 root filesystem can take several seconds!

The advent of UBIFS also questions the relevance of YAFFS2. YAFFS2 used to be a good alternative to JFFS2, but unlike UBIFS, it doesn’t support compression. Then, why choose YAFFS2, when a apparently superior alternative is available?

The only case in which JFFS2 can still make sense if when you have very small partitions, sizing just a few megabytes. In this case, the overhead from UBI, the erase-block management layer below UBIFS, is no longer negligible. You will be able to pack much less data than with JFFS2. In this case, you can still improve JFFS2’s performance by using some of its new features (more details in the presentation).

SquashFS is also another great alternative, as shown by my benchmarks. It’s true it is a block filesystem, but since it is read-only, and there is no problem to use it on a write-once mtdblock device. You should really consider it for the read-only parts in your system, though it is advisable to use it on top of UBI, to make its blocks participate to wear-leveling and bad block management. Again, you will find more details in my presentation.

The presentation also mentions LogFS, which is also a promising filesystem for flash storage. Unfortunately, LogFS is not available yet for recent kernels. Stay tuned and I will benchmark it as soon this situation changes.

OLS 2008 videos

30 videos from the Linux Symposium in Ottawa

We are pleased to release 29 videos that we took at the Linux Symposium in Ottawa, Canada, in July 2008:

  • Keynote: The Kernel: 10 Years in Review, by Matthew Wilcox (Intel)
    video (57 minutes, 175M)
  • Talk: Tux on the Air: State of Linux Wireless Networking, by John W. Linville (Red Hat)
    paper, video (52 minutes, 168M)
  • Talk: Suspend to RAM in Linux: State of the Union, by Len Brown and Rafael Wysocki (Intel)
    paper, video (52 minutes, 163M)
  • Talk: Real Time vs Real Fast: How To Choose?, by Paul E. McKenney (IBM)
    paper, video (45 minutes, 166M)
  • Tutorial: ftrace: latency tracer, by Steven Rostedt (Red Hat) video (98 minutes, 772M)
  • BOF: Embedded Linux, by Tim R. Bird (Sony)
    video (42 minutes, 200M)
  • BOF: Embedded Microcontroller Linux, by Michael Durrant (Arcturus Networks)
    video (42 minutes, 243M)
  • Talk: Energy-aware task and interrupt management, by Vaidyanathan Srinivasan (IBM)
    paper, video (52 minutes, 182M)
  • Talk: Application Testing Under Realtime Linux, by Luis Claudio R. Gonçalves (Red Hat)
    paper, slides, video (54 minutes, 297M)
  • Talk: Application Framework for Your Mobile Device, by Shreyas Srinivasan (Geodesic Information Systems)
    paper, video (25 minutes, 146M)
  • Keynote: The Making of OpenMoko Neo, by Werner Almesberger (OpenMoko)
    video (94 minutes, 463M)
  • BOF: U-Boot by Wolfgang Denk (Denx)
    video (54 minutes, 362M)
  • BOF: Linux Compiler, by Rob Landley (Impact Linux)
    video (100 minutes, 765M)
  • Tutorial: Practical Guide to Using Git, by James Bottomley (Hansen Partnership)
    video (61 minutes, 357M)
  • Talk: Advanced XIP File System, by Jared Hulbert (Numonyx)
    paper, video (49 minutes, 160M)
  • Talk: SELinux for Consumer Electronic Devices, by Yuichi Nakamura (Hitachi)
    paper, video (31 minutes, 113M)
  • Talk: Around the Linux File System World in 45 Minutes, by Steve French (IBM)
    paper, slides, video (49 minutes, 298M)
  • BOF: Linux The Easy Way with LTIB, by Stuart Hughes (Freescale)
    slides, video (25 minutes, 144M)
  • Keynote: The Joy of Synchronicity: Coordinating the Releases of Upstream and Distributions, by Mark Shuttleworth (Canonical)
    slides, video (76 minutes, 458M)
  • Talk: Smack in Embedded Computing, by Casey Schauffer
    paper, video (59 minutes, 211M)
  • Talk: Bazillions of Pages: The Future of Memory Management, by Christoph H. Lameter (SGI)
    paper, video (49 minutes, 258M)
  • Tutorial: Writing application fault handlers, by Gilad Ben-Yossef (Codefidence)
    video (49 minutes, 275M)
  • Talk: Linux, Open Source and System Bringup Tools, by Tim Hockin (Google)
    paper, video (51 minutes, 229M)
  • Talk: DCCP Reached Mobiles, by Leandro Melo Sales (Federal University of Campina Grande)
    paper, video (42 minutes, 193M)
  • Talk: Building a robust Linux kernel, by Subrata Modak (IBM)
    paper, slides, video (51 minutes, 249M)
  • CELF BOF presentation: Best of recent CELF Conferences, by Tim Bird (Sony)
    slides, video (10 minutes, 88M)
  • CELF BOF presentation: Developing Embedded Linux with Target Control, by Tim Bird (Sony)
    slides, video (17 minutes, 145M)
  • CELF BOF presentation: Embedded Building Tools – An Audience Survey, by Michael Opdenacker (Bootlin)
    slides, video (17 minutes, 127M)
  • CELF BOF presentation: GCC Tips and Tricks Highlights, by Gene Sally
    video (14 minutes, 62M)

See also all the papers, and a report from the CELF BOF.

We could only shoot the presentations we attended. You can see that our main interests are embedded systems and the Linux kernel wink smiley.