A few weeks back, I was whining that although Doctor Who was available on Amazon Prime streaming, I didn't have any way to watch it on my television. Thankfully, my friend Richard Servello pointed me to the bluecop repo for XBMC. Not only does bluecop support Amazon Prime streaming, but it also has add-ons for Hulu and countless other network-video-streaming collections. more>>

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Catalyst is the latest in the evolution of open-source Web development frameworks. Written in modern Perl and inspired by many of the projects that came before it, including Ruby on Rails, Catalyst is elegant, powerful and refined. It's a great choice for creating any Web-based application from the simple to the very complex. more>>

Nous invitons industriels, universitaires et chercheurs confrontés à la problématique des arcs et contacts électriques à participer à ce workshop.

Most people have heard of gold. Most people are familiar with dollars. For a handful of geeky folks, however, the currency they hope will become a global standard is digital. Whether it's a problem or not, the currency you use on a day-to-day basis is tied to the government. more>>

HTML5 lets you play music through compliant browsers—no "cloud" required. more>>

Rubies, Pythons and Perls!

It may sound like a new Indiana Jones movie or possibly a cheesy platform-style video game from the 1990s, but the title of this column actually refers to our focus this month—programming! Not that there's anything wrong with daring adventures in remote locations, it's just that all the red tape can be overwhelming. more>>

Multiprocessing, multithreading and evented I/O: the trade-offs in Web servers.

A Web server needs to support concurrency. The server should service clients in a timely, fair manner to ensure that no client starves because some other client causes the server to hang. Multiprocessing and multithreading, and hybrids of these, are traditional ways to achieve concurrency. Node.js represents another way, one based on system libraries for asynchronous I/O, such as epoll (Linux) and kqueue (FreeBSD). To highlight the trade-offs among the approaches, I have three echo servers written in close-to-the-metal C: a forking_server, a threading_server and a polling_server. more>>

Sometimes events and equipment conspire against you and your team to cause a problem. Occasionally, however, it's lack of understanding or foresight that can turn around and bite you. Unfortunately, this is a tale of where we failed to spot all the possible things that might go wrong. more>>

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 New products for April.

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This is the second Free Electrons newsletter for 2012. We are happy to share with you the latest news about our projects, training courses and contributions.

New “Android system development” training

As announced in our previous newsletter, we have created a new Android system development training course.

This course targets engineers who need to develop embedded systems with Google Android. In four days, through theory and practical labs, the course makes you familiar with compiling and booting Android, with adapting Android to support a new embedded board (assuming that it is already supported by the Linux kernel), and with building a real system through accessing specific hardware, customizing the filesystem and using debugging techniques. More details and the complete agenda.

The first public session of this training will take place on June 11-14 2012 in Toulouse, France (session taught in English). There are still seats available for this session. See cost and registration details.

We will start giving on-site sessions of this course in July 2012. Do not hesitate to contact us if you want to organize on-site sessions.

Opening our training materials source code

Since Free Electrons’ creation in 2004, we have been releasing our training materials under the Creative Commons Attribution Share-Alike license, a free license that allows anyone to share, improve and use our embedded Linux and Linux kernel training materials. Since that time, our training materials were available as PDF files, and as OpenDocument files for the source code, but we were only updating their online version from time to time.

Now, we are proud to announce that our training materials are being converted to the LaTeX language, and their latest version is available at any time from our public Git repository.

For the moment, our embedded Linux slides have been published (about 500 slides) in this Git repository, as well as the instructions for the practical sessions of our embedded Linux and Linux kernel courses. In the near future, we will also publish in LaTeX the slides of our Linux kernel training (which remain available under PDF and OpenDocument formats) as well as the materials of our new “Android system development” course.

The creation of this public Git repository is a strong sign of our commitment for open training materials.

The LaTeX format and the public Git repository now make it easy for everyone to follow updates on our materials, to keep one’s knowledge up to date, and even to teach a training session using our materials (commercial use of our materials is welcome, as it helps to spread knowledge about Free and Open Source Software for embedded systems).

Upcoming public training sessions

Our next public training sessions dates and locations are:

• Embedded Linux kernel and driver development
  June, 4-8 2012
  Toulouse, France
  Session given in French
  Details
• Android system development
  June, 11-14 2012
  Toulouse, France
  Session given in English
  Details
• Embedded Linux system development
  June, 18-22 2012
  Avignon, France
  Session given in French
  Details
• Embedded Linux kernel and driver development
  July 2-6, 2012
  Avignon, France
  Session given in French
  Details
• Embedded Linux kernel and driver development
  October, 8-12 2012
  Avignon, France
  Session given in English
  Details
• Embedded Linux system development
  October, 15-19 2012
  Toulouse, France
  Session given in French
  Details
• Embedded Linux system development
  December, 3-7 2012
  Avignon, France
  Session given in English
  Details
• Embedded Linux system development
  February, 4-8 2013
  Lyon, France
  Session given in French
  Details

Projects

Since the beginning of the year, we have been involved in the following projects for various customers:

• Boot time optimization and power management evaluation for a MIPS-based platform used in a payment terminal;
• Filesystem size optimization, embedded Linux build system integration, Ethernet PHY driver development for an AT91 ARM platform used in satellite video processing;
• Embedded Linux build system integration and generic embedded Linux debugging and support for an AT91 ARM platform used as a gateway between medical devices;
• Starting in April, we will be working with a major ARM SoC vendor to help mainlining support for their latest SoC in the official Linux kernel sources;
• Continued the creation of materials for our new “Android system development” course.
• Continued our work on the Linux kernel driver for the Analog-to-Digital converters of the AT91 ARM SoC (see ‘Contributions’, below);
• Continued our work on real-time Linux evaluation on AT91 ARM SoC (see ‘Contributions’, below.).

Career opportunities

Free Electrons is looking for a kernel developer in the the French Riviera, to be hired with a permanent contract. The job is open to English speaking people who do not speak French, but are ready to settle in the area of Nice, and be hired through a French contract. See details.

Conferences and contributions

Embedded Linux Conference and Android Builders Summit

Three engineers of Free Electrons attended the Embedded Linux Conference 2012 and Android Builders Summit 2012 in Redwood Shores, near San Francisco in California, on February. This strong participation of our engineers to technical conferences is a key factor to make sure we remain up to date on embedded Linux technologies and keep a close contact with the community.

During the conference, we have published daily reports about the various talks that we thought were interesting:

• First day at the Android Builders Summit
• Android Builders Summit: day 2, and Yocto Developer Day
• Embedded Linux Conference day 1
• Embedded Linux Conference day 2
• Embedded Linux Conference day 3

After the conference, we also posted videos of the talks:

• Android Builders Summit 2012 videos
• Embedded Linux Conference 2012 videos

Our scripts to encode videos to the royalty-free VP8 codec and add a title sequence to the videos are now available on on our public git server.

At this conference, our engineer Thomas Petazzoni has given a talk titled “Buildroot, a nice, simple and efficient embedded Linux build system”. Here are the slides and the video.

FOSDEM conference

Two of our engineers participated to the FOSDEM conference, a community-driven open-source conference, in early February.

Our engineer Maxime Ripard gave a talk on his work around the IIO kernel subsystem, which he used to write an ADC driver for the AT91 SoC. Here are the slides.

Our engineer Thomas Petazzoni gave a talk about “Using Qt for non-graphical applications”. Here are the slides.

AT91 Analog-to-Digital converter drivers

Details about the driver for the AT91 Analog-to-Digital converters driver written by Maxime Ripard from Free Electrons have been published on the Atmel Linux4Sam wiki. This driver relies on the IIO framework, and we are in the process of getting this driver merged upstream. See the Atmel Linux4Sam wiki page.

Real-time Linux benchmarks

A report of extensive real-time benchmarks conducted by Gregory Clement from Free Electrons on AT91 platforms has been published on the Atmel Linux4Sam Wiki. This report compares a vanilla Linux kernel, the PREEMPT-RT patches and the Xenomai co-kernel approach through timer-based and GPIO-based benchmarks. See the Atmel Linux4Sam wiki page.

Buildroot

Free Electrons’ involvement in Buildroot is still strong:

• Maxime Ripard and Thomas Petazzoni participated to the Buildroot Developer Day organized in Brussels before the FOSDEM conference. A report of this meeting, which gathered several other Buildroot developers, is available at the Buildroot mailing list archives.
• Since the beginning of the year, Thomas Petazzoni has contributed 64 patches that have been merged: support for the LTT-ng Linux tracing solution, support to represent host utilities in the menuconfig, many updates and fixes to external toolchain support and many other fixes.
• In the same time-frame, Maxime Ripard has contributed 13 patches that have been merged: support for systemd, improvements to the package infrastructure and various fixes.
• Thomas Petazzoni has implemented a Web interface that publicly shows the result of our random configuration builds, available at http://autobuild.buildroot.org. The Buildroot community is doing random configuration builds 24/7 on three machines, with various configurations. This Web interface collects the build results and sends a summary every day on the Buildroot mailing-list. This has already allowed to fix many build issues, and will help to improve Buildroot’s quality in the future.

Linux kernel course

Participants to our Embedded Linux kernel and driver development course have also started contributing to the Linux kernel sources during the course itself. Here are the patches which have been merged so far:

• https://lkml.org/lkml/2012/3/22/270
• https://lkml.org/lkml/2012/3/22/267

During our git lab, instead of asking people to make dummy code changes, we ask them to make real improvements to the Linux sources, and send them for real to the right maintainers and mailing lists. This way, people get a better understanding of how they can interact with the Linux kernel developers to merge their changes and contributions.

See our slides and practical lab instructions for our git lectures and lab.

Blog posts

Free Electrons has published several blog posts:

• Buildroot Developer Day, Brussels edition
• Announcing our Android system development training
• Free Electrons at FOSDEM: two talks and video recording
• Free Electrons at the Android Builders Summit and the Embedded Linux Conference: one talk and video recording
• HOWTO – Mailing lists with Mailman on Ubuntu 10.04
• Our blog posts on Android Builders Summit and Embedded Linux Conference listed previously
• Linux on ARM: xz kernel decompression benchmarks
• How to boot an uncompressed Linux kernel on ARM
• Android gdbclient command
• A new tool to ease kernel maintainer life
• Experiment with Yocto
• Report on extensive real-time Linux benchmarks on AT91
• Linux kernel engineer job in Nice

You can follow Free Electrons’ news by reading our blog and by following our quick news on Twitter.

By the way, the right column of the Free Electrons blog now lists the most popular posts and pages. This can help you to find useful content that you may have missed.

Free Electrons remains available to help you in your embedded Linux projects, either through its development and support services or through its training sessions. Do not hesitate to contact us!

Gregory, Maria, Maxime, Michael and Thomas – Free Electrons

Poorly implemented monitoring systems can drive an administrator crazy. At best, they are distracting. At worst, they'll keep whoever is on pager duty up for nights at a time. This article discusses the best practices for designing systems that will keep your systems up and stay quiet when nothing is wrong. more>>

See a detailed job description on our careers page.

For this particular job opening, we absolutely need someone with prior experience with kernel and driver development, and contributions to the official Linux kernel sources will be a strong advantage. This is because a customer of ours is looking for an engineer to develop new drivers and port the Linux kernel to pre-silicon and silicon platforms.

Once we find a candidate with the expected skills and profile, and once the customer agrees to contract this person for this initial project, the engineer will be hired by Free Electrons under a permanent contract, and will work on the customer site for at least 6 months.

Once the initial assignment is over, our engineer will continue to work on projects for other Free Electrons customers, and will also give embedded Linux and kernel training sessions to customers throughout the world.

Note that this position is open to people who do not speak French, but are ready to settle in the French Riviera and to be hired through a French contract.

If you are interested in this position, see our job description for details about how to apply.

Here are some figures associated to this work:

Voici le sujet du concours 2012 que nous avons le plaisir de lancer suite au succès du concours 2011. Il s’agit de développer un oscilloscope sur une carte FriendlyARM en prenant en compte les problématiques temps réel. Vous trouverez tous les détails ici : http://linuxembedded.fr/concours2012.

De nombreux lots sont à gagner et ce concours vous apprendra beaucoup. N’hésitez pas à utiliser les canaux de discussion mis à disposition : IRC (Freenode #linuxembedded), mailing list, mails aux organisateurs.

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In fact, Yocto is made of Poky (a build system based on OpenEmbedded), a few added build tools (swabber, pseudo, etc.), as well as a set of meta data allowing to create embedded distributions for a number of targets.

The strength but also the weakness of OpenEmbedded is that it a very flexible build system. It can make production root filesystems, but also a complete distribution with its ready to use package repository, and this for multiple hardware platforms. It makes it a difficult system to get started and get efficient with. Even two years ago, the OpenEmbedded documentation contributed to making it difficult to get started. Indeed, OpenEmbedded did supply some documentation, but which only started to make sense once you start mastering it. This is quite a paradox for a piece of documentation. It lacked the elements allowing developers to understand its operation well.

With Yocto, I was pleased to realize that substantial progress had been made on this side. The project comes with documentation that is much more exhaustive and above all much more accessible for beginners. Getting started with it is still not completely straightforward, but this time, this is rather because of the complexity and the rich features of the tool.

In a few hours, I managed to develop a minimalistic BSP (Board Support Package) for a given board (in this case a AT91SAM9G20-EK). The concept of layer allows to have a configuration layer specific to a given piece of hardware. You can even support multiple hardware platforms at once and add specific packages. A layer is indeed just a set of packages and configurations (or configuration overrides). The BSP is just a layer specific to one or several pieces of hardware.

As you can see, even to support a simple embedded board, there is already a number of concepts to deal with. There are also multiple ways of achieving the same result but which will be easier or more difficult to maintain. The concept of “BSP” for Yocto is therefore a kind of guideline to allow the Yocto community to have a common point of reference. I will try to illustrate the use of a BSP on the AT91SAMG20-EK board here and/or on my Google+ page.

Another significant progress is optimizing build time for a “minimalistic” target, which went down from more than three hours to just over one hour now. It remains a long time for a very simple target.

To build a filesystem image with only a few components, Buildroot remains much more appropriate. For systems that require a great number of components, more advanced functionality is then often needed, such as managing a package repository and supporting multiple hardware platforms at once for example. In this case, Yocto remains the best (the only?) option, all the more as this project addresses the traditional weaknesses of OpenEmbedded.