Embedded Projects Journal

As it seems, for about one year there has been a new Embedded Projects Journal (in German). This magazine focuses entirely on FOSS embedded projects and open hardware. The idea is to have a magazine written by the community for the community. Plus, the magazine and all its articles are freely redistributable.

It's a pity that I've only noticed about this now. Let's hope more people learn about it, now that I'm mentioning it here.

If you want to contribute, feel free to contact the journal's makers.

FZ6 Fazer is beyond reasonable repair

As it seems, the cost of spare parts and labor to fix the engine of my recently bust FZ6 engine are well beyond EUR 4000, so there's no point in repairing it.

As it further turns out, the previous owner of the bike (I bought it in April last year) had forged some signatures in the service booklet, i.e. the motorbike has likely not seen the regular inspection and service like it should. Haven't yet decided whether to file any claims against that previous owner or not.

Now I've decided to buy a new one of the same model, and keep the old one for spare parts. At some point next week I should be the proud owner of a brand-new FZ6 Fazer. With three full years of Yamaha warranty. Hopefully this one will live longer than 17,000 kilometers.

Linux-Kongress date change - now longer collides with Linux Plumbers

As I have just received today, Linux Kongress 2009 has shifted its dates to October 27 through October 30 (and changed the Location from Hamburg to Dresden).

This is good news, since it no longer collides with Linux Plumbers Conference 2009 on September 23rd through 25th. I guess that many speakers and some attendees would otherwise have ran into scheduling problems - with many preferring Linux Plumbers.

Also, the Call for Papers is out, it runs until August 31st, i.e. you (yes you, the reader!) have more than four weeks of time to decide what kind of topic you want to talk about :)

OpenBSC talk at HAR2009

My talk about OpenBSC has been accepted at HAR2009 quite some time ago, I just thought I'd mention it here since the schedule now is public/online.

It's a pity though that HAR2009 is already sold out - but then better an early sold-out than an event where only half the available tickets are sold.

I'm looking forward to meeting up with other GSM hackers for improving the various projects such as OpenBSC, airprobe.org or other not-yet-public projects related to Free Software and GSM.

GSM test license for GSM900 at HAR2009

I have just received the news that today the Dutch regulatory authority sent us the final "ACK" for a GSM test license during HAR2009.

This means we can use four ARFCN in the GSM900 band, each with up to 100mW transmit power.

We also will be able to use certain GSM1800 channels, but then I expect almost nobody has equipment to make use of it.

I have created a GSM wiki page in the HAR2009 wiki for coordinating GSM related activities at the camp.

If you are a bit familiar with BS-11 and/or OpenBSC and you're at the camp, please let me know. We can use any help you might be able to provide.

Playing with the new airprobe.org GSM receiver

Within the airprobe.org community, Piotr has recently a new GSM receiver codebase that he has developed. It seems like the reception/decoding quality is significantly better than gsm-tvoid, at least from my experience. But it might just be me using gsm-tvoid in a suboptimal way.

Today, Piotr has managed to fix some of the bugs regarding certain BSIC configurations, and I can also decode Um traces that were captured from a nanoBTS running with OpenBSC.

Piotr also has already integrated my old gsmtap code that I was hacking on during FOSS.in/2008. As I've also received in e-mail today: The pcap data link type for the GSMTAP header has been assigned.

I'm spending a bit more time testing the entire stack, but I'm confident the GSMTAP wireshark dissector can be submitted soon - closing yet another gap for GSM protocol analysis.

However, there still remains a lot of work to do for airprobe.org. I am willing to put in some time to help the gsm-receiver along, particularly for the layer2/layer3 decoding, which will then feed the channel configuration and CCCH configuration back into the upper half of layer 1 that takes care of generating MAC blocks from the actual GSM bursts.

Legal dispute on OpenBTS has been resolved

There's only small message on David Burgess' blog, but according to it the legal dispute surrounding the OpenBTS software (the USRP+gnuradio based software defined radio "BTS+").

This is great news, I hope it makes it easier for OpenBTS folks to focus on their actual work rather than being distracted with fighting legal battles.

Launch of International FOSS Law Review

I'm a bit late with this, but the occasional reader of my blog might be interested to hear about the launch of ifosslr.org: International Free and Open Source Software Law Review, the only legal journal that focuses entirely on legal aspects of FOSS, which obviously includes license and specifically GPL related issues.

If you look at the editorial committee, you will realize many prominent names in this field.

It's very good to see this, as it means that more lawyers now have a resource for enhancing and sharing their knowledge about legal aspects of FOSS.

I have heard about this project from its beginning in the Legal Network of the FSFE Freedom Task Force. I know there has been a lot of (volunteer) work into the publication of this first edition/volume. Thanks to everyone involved, from authors to editors to people who took care of administrative issues.

Bad luck with motorbikes, episode 2342

Last night I was riding back to Hamburg (on my Fazer FZ-6) from a two-day visit to my home in Berlin. It was a pleasant ride, at least for about the first 210 kilometers. Suddenly at about 1am when I was riding at smooth 190kph (far away from full throttle), there was a sudden loss of engine power and the engine sounded as if it was running on 3 instead of four pistons. I immediately pulled over and used the conveniently placed highway exit. While I was getting slower I realized enormous amount of smoke (identified correctly engine oil that vaporized on the surface of the exhaust pipes). As soon as the clutch was pulled, the engine went off.

I then realized that a lot of oil had spilled to the rear wheel, including the tire. There was no other solution then having the bike transported to Hamburg in a van... Thinking about the possible cause, I thought of something along the lines of a blown cylinder head gasket. Arriving in Hamburg at roughly 4am in complete darkness, there was no way to dig any deeper into it.

This morning, in bright daylight I could clearly see the actual cause: An about 5x7cm wide hole in the engine case! WTF ?!?.

So it seems that suddenly, while travelling, the aluminum-cast engine case decided to blast a part off. Quite amazing. And that not at any particularly high rpm or under high load... let's see what the Yamaha mechanics will say about that.

So now I have a broken BMW F650 in Berlin and a Broken Yamaha Fazer FZ6 in Hamburg. And that in the best part of summer. *sigh*. The only remaining bike is in Taipei and not really of much use to me right now.

NerdAlert podcast / radio show

Today, I was invited for an interview with the German nerd alert podcast. The show was also broadcasted live via the free public FM radio station FSK Hamburg.

Much of the interview is about my work at gpl-violations.org, but we also covered quite a bit about Openmoko as well as OpenBSC. I had a good time in the more-than-one hour interview, despite it somehow being too short to cover more about the motivation and reasons behind each of the projects....

I'm not sure if the podcast is available yet, but I suppose it will be accessible from the homepage of todays show.

Wireshark packet dissector for GSM 12.21 (A-bis OML)

During the last weeks I've been spending some time to start a wireshark dissector plugin for GSM 12.21, which is the Organization and Maintenance protocol between BSC and BTS. Using this protocol, many aspects of a BTS are configured by the BSC.

I have already implemented the BSC side of 12.21 inside OpenBSC, and OpenBSC contains parsing code and debug logs about what is happening on this protocol. However, I think it is much better to remove most of that debug printing code from OpenBSC and move it into wireshark. Whoever needs per-message debugging, can start wireshark and look at the output - with the advantage of extensive filtering capabilities.

The protocol is quite complex and has many different messages with each their own set of attributes. So the current work is far from being complete, but it's already at a point where it is really useful.

I've put a specific focus on implementing the vendor-specific bits for ip.access, since those are hard to figure out and much more difficult to implement for anyone who hasn't spent as many weeks looking at hexdumps from their Abis-IP protocol as me. Parsing standard 12.21 messages is easy, just read the publicly-available spec and add wireshark code for it.

In case you're interested, the plugin is available from this path in the OpenBSC git tree

ip.accesss nanoBTS serial port CLI

As Dieter has recently discovered, the nanoBTS has an optional serial port. You need to solder two small bridges on your nanoBTS PCB and then you will get a RS232 port (at 3.3V) to the embedded PowerPC.

On this serial port, you can use an extensive command line interface (CLI) to display the status of the BTS, and for any kind of interactive debugging.

I only wish they had made that interface also available via TCP/IP :) Not many people will want to risk soldering their nanoBTS and thus loosing their warranty... it's not a cheap device, after all.

A description of the pin-out, including a picture for which solder bridges you have to set can be accessed in the OpenBSC wiki