Thursday, October 29, 2009


Every time when a new industry joins OSGi there is a lot of new people entering the specification work. These people, inevitably, bring their their own culture. Mixing cultures is not always without its problems. Having lived and worked in Holland, Sweden, and France I learned the hard way that moving to another culture can be a tricky thing; it does take some time before you realize that your absolute truth is not really shared by your new countrymen.

So the Enterprise experts bring their prevailing culture. With respect to standards, this culture is heavily influenced by JCP, specifically JEE, and the way things work in the open source world. This is not always aligned with the way OSGi has been run so far. Previous OSGi specs have always been rather rather thoroughly reviewed and picked apart. A running joke in the Alliance is that we start with a telegraph pole but we we end up with a tooth pick. But what a tooth pick!

One of the key things I always liked about the final OSGi specs is that they are complete. Virtually all service specifications and framework specification thoroughly specify edge cases, are fully introspective and provide relevant events to track what is happening inside the service. In JEE vendors have much more freedom. For example, in JEE the deployment aspects are left as an implementation detail. This completeness of OSGi specs is demonstrated by the fact that (so far) all our specs were able to run from a single test framework while only requiring vendors to have their to be tested bundles installed. It is possible to define do the test setup in the test case because the specifications are sufficiently complete. For example, we can deploy a bundle in a framework without having to know the vendor of that framework.

However, some of the EEG members complain we're too specific and do not allow enough space for implementations to do it their way. By giving more leeway to implementations, you allow more innovation and vendors can more easily fit existing products under a specification. These are not invalid arguments.

So I am struggling a bit with this issue. One of my primary roles in the OSGi Alliance is to guard the consistency between the specifications. This causes me sometimes to feel that I am fighting the whole group to guard this consistency. Despite the fact that I am really trying to run the fine line between being conservative and enabling new groups to do it their way. However, the hardest part is that I continuously have to challenge my own beliefs to try to see their point of view. Well, that is what mixing cultures does to you ...

Peter Kriens

Monday, October 19, 2009

OSGi on the Road

A few weeks ago I got a very nice thank you letter from Eric Gaignet, an employee of a regional bus company in the South-West of France called RDTL Voyages. A few years ago he asked me a few questions over email and I had replied him with some architectural advice of how to use OSGi in a vehicle. I remember that at the time I thought this was a wonderful application for OSGi. He reported now that this project had gone very smoothly.

RDTL is a small regional bus carrier (150 buses) with low overhead. A few years ago they realized that new regulations, the impact on the environment, the complexity of the many isolated black box solutions in the bus, and new business opportunities were being combined with an aging IT infra-structure in the bus. This created an interesting opportunity to design a new infra-structure virtually from the ground up, taking advantage of modern technology.

The number of IT solutions in a passenger bus is surprisingly large. Today, a bus interacts with the road systems, it provides up to date information to the electronic displays, it handles the ticketing issues, and reports about the state of the bus. Traditionally, different vendors provide their own isolated solutions.

Not so for RDTL. They started a collaboration with GeenSys, a French IT company specialized in embedded systems to create the e-nove architecture. The input was to create a system where an OSGi gateway in the bus would communicate with an OSGi server in the back office. The gateway connects all the equipment in the bus, provide local information to the driver and aggregates the information to the back-end. Instead of having a proprietary ticketing system, the OSGi gateway connects to a printer, reader, and a display. This all being controlled by OSGi bundles. In the past two years, this architecture was developed and implemented in a remarkably short time. Today, there are more than 30 buses equipped with OSGi gateways.

After I queried Eric for some more information how things had been going, he replied with the following quote:
The best positive experience we got is that we immediately needed an "small application" this summer. I asked a local software company to design this software. They spent 2 days training with Geensys engineers. Thanks to e-nove, they spent only 2 days to design this application. This is great because this was one of the key goals of the project. We can react, adapt and deploy bundles in a very short time.
The e-nove architecture is a very nice example of what you can do with OSGi. It has many of the use cases that drove the development of OSGi in the early years and it is wonderful that it not only has been developed, but it now also been proven to provide the expected advantages. Thanks Eric, for this update!

Peter Kriens

Friday, October 9, 2009

JavaBlend in Ljubljana and Belgrade

About 6 months ago Aleš Justin (JBoss/Redhat) asked me if I could come to Ljubljana for the JavaBlend conference. I told Aleš to talk to OSGi marketing and after some mail exchanges we agreed that if they paid the trip I would come. After this was agreed, I was informed it also included a presentation in Belgrade. Well, from a time perspective this wasn't too much of a difference so I agreed, under the condition I could fly back Friday from Belgrade and then forgot about it.

Normally a conference trip means flying in the night before, giving your presentation, talking to a few people and then trying to get back home as quickly as possible. However, this trip turned out to be quite different; it felt more like a 3 day adventure than work.

The Ljubljana JavaBlend day was very interesting with just very good speakers. Everything helped, the weather was good, the location was excellent (a very nice castle overlooking Ljubljana), and an intriguing number of very young fashion models.

Even my presentation went well. I was fortunate that the speaker before me, Juha Lindfors (OpenRemote), spoke about an open source project doing home automation. Exactly the area that got OSGi started! Though they had taken Tomcat as their platform, I obviously worked on him to move to OSGi. I could honestly say OSGi was made for exactly their purpose.

I learned about Yugoslavia in school and I followed the news about Tito's dead in 1980, the breakup, and the balkan wars. However, the whole geographic situation was a tad fuzzy to me. The first time in former Yugoslavia, the republic Slovenia definitely charmed me, especially because Aleš had taken me on a small sight-seeing tour. However, what I did not know was that Belgrade was more than 500 KM away from Ljubljana. We would do the trip with a bus. I had visions of a small executive bus with leather fauteuils and a lovely stewardess serving us coffee and snacks. Not too bad I thought.

The next day we would leave at 2pm so that would at least gave me some time to get some work done in the morning, which I decided to do in the bar, enjoying some latte. However, this plan was disrupted by Dalibor Topic (Sun) but he made more than up for that by providing a more than worthwhile discussion about JSR 294, the meaning of life, OSGi, and Sun. It is always nice to talk to Dalibor, whom I seem to meet on more conferences than pure chance would predict.

At 2pm we gathered in the lobby and we took a taxi to the Parsek (the conference sponsor), where the bus would leave. There my visions of spacious leather seats were rather rudely shattered. Even Michael O'Leary would've blushed about the available leg space. However, the lack of space turned out not to really matter that much because the trip went amazingly fast. In the bus I was sitting next to Manik Surtani (Redhat) and we had a long and intense discussion about lots of very interesting subjects. Manik was interested in OSGyifing his Infinispan (a data grid) project so I might have made another OSGi convert. Hey, I am the evangelist!

Though Tomaž Cerar had forgotten to bring the promised bottle of whiskey, the hosts kept us well entertained through the evening driving through Croatia. We were told scary stories about the Serbians specifically and Balkan politics in general, creating a nice suspense. The eerie mood was amplified by farmers burning their land all along the highway, supervised by a slowly rising large blood-red moon. The crossing of the Kroation-Serbian border was therefore almost a disappointment when it only took 10 minutes by civilized officers instead of the 2.5 hours and brutal interrogations we were promised. Though the very modern (well in 1971) 5-star (Serbian stars that is) hotel turned a bit scary when they insisted to take my passport and then pushed it through a hole in the wall. Fortunately, I got it back half an hour later, though it took some angry looks.

The next morning we had to travel through the middle of Belgrade to the conference hotel. I still remembered the scary stories of the night before, describing Serbian drivers and Belgrade traffic. Especially the queues over bridges were told to be notorious. Now, it was kind of important to me that we started in time because the plan was that I would be the first speaker, then hop in a taxi, and hopefully catch my flight back from Tesla Airport. After all the horror stories leaving at 7.30 sounded, well, not unimportant. However, the relaxed nature that seems to be part of of all ex-Yugoslavians made us leave well after 8. Traffic was not too bad but I am pretty sure we blatantly violated the rules of the bridges of Königsberg by crossing the same bridge multiple times. And I am sure it was the same Samsung building I saw after about 20 minutes. Thinking about my taxi ride, it was also a bit disconcerting that we seemed to move farther and farther away from the airport. We did arrive before nine, well just. Any hopes to also start at nine were shattered by two introductory speakers that took their time, and more. Then, half way through my presentation, I was told to stop because the taxi was waiting. I felt that I needed at least another 10 minutes to finish and take some questions, only to discover the taxi had disappeared when I came down! Some nerve wrecking 15 minutes later, and several organizers talking in their phones (still relaxed!), an also very relaxed taxi driver showed up. And actually they were right, the drive to the airport was a non-event, though I swear I have seen cars on those roads that I had last seen when I was 5.

Thanks Aleš for inviting me and all the others that made this a really trip wonderful!

Peter Kriens