Category: Carl Rosenberger

Why Is This Project Successful?

Sean from Intel has sent me this link together with the comment "This is why I think you will succeed. I see a lot of similarities." Thanks Sean! rapid release scheduleYes, we release monthly. This is only possible because we always keep the code in our SVN in a state where it passes all regression tests. For big structural changes, like the one we just did, this may sound like a surplus in work, but it really isn't. Having a runnable state as a reference makes debugging so much easier when you wonder why new things don't work the way they should. We will be trying to engage our community to work with even more frequent versions than our monthly builds. For this purpose we are currently setting up a system for continous builds, to make a full set of all versions available every night. regression testsYes, we do have a lot of them. We make all tests available with our download so anyone is free to take a look at how we ensure quality. For every new bug that we discover or that gets sent in we immediately cr ...

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Performance progress

I really love performance tuning. Lately I did get a lot of opportunities to work on this favourite task, pairing with many of the members of our core development team. The first results are testable with the code in our CVS, if you know how to build db4o and how to turn the right switches: com.db4o.Debug.useOldClassIndex = false; com.db4o.Debug.useBTrees = true; com.db4o.marshall.MarshallerFamily.LEGACY = false; We have tried to document the latest progress by creating special circuits for the Poleposition open source database benchmark: (1) The new BTree architecture will really boost performance for bigger databases with object counts between 1 and 50 million: (2) The new String marshaller reduces one indirection for reading and writing strings: (3) We are still working on the new MarshallerFamily for untyped references, for arrays and collections. The step up in speed should be quite similar to the one for stri ...

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Company 2.0

Everybody is talking about web 2.0. I always thought that the "2.0" buzzword had something to do with web pages that become interactive. Can there be more to it, is "2.0" maybe a completely new culture?

Here is very nice post by Kathy Sierra that describes how 2.0 managers are supposed to be like: "Manager 2.0".

Looking at our company, I can add some further points to the list:


Native Query Paper published on DDJ

The Native Query paper is online in the February issue of Dr.Dobb's Journal. Thank you very much, William Cook! It was a great pleasure to have you as a guest at our company meeting.

Looking for an Open Source Developer Job?

Since we see a lot of interest from developers who want to join the core development team at our open source company db4objects as a paid developer, I would like to share some thoughts about how we and other open source companies hire. Most of the following is a re-iteration of the thoughts Brian Aker, director of architecture for MySQL AB, has outlined in NewsForge.We are always looking for smart, accomplished developers, no matter where in the world you are located – as long as you have a computer, a development environment, and hi-speed Internet access. Our selection criteria are based on open source skills, on excellent Java and/or .NET programming skills and we also like to see engagement for our product. As Aker puts it: "I'm not looking for someone who sends a resume to my mailbox and hasn't looked at our product," he says, "or who has a resume that has the all hottest current skills and every popular certification listed on it." What we look for are accomplishments rather than credential ...

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Achat and Acrobat

Our offsprings Achat and Acrobat are now 4 weeks old. Is there any nicer way to spend time than to watch kitten play?



I have been waiting for a dedicated portal on object databases ever since I started working on db4o. Finally ODBMS.ORG is online.

Thanks Roberto!

Leo Lenis Kittens

Zora and Occam proudly announce the birth of Achat and Acrobat. Both Somali kittens are ruddy coloured like their father Occam.

Manou and I have decided that the last name of our cats will be "Leo Lenis" (latin: gentle lion). Manou has started working on a webpage. So far it only shows a picture of Occam.


JavaOne was fun. Finally I had the chance to meet many people in person that I have only been communicating with virtually over the past years. A highlight for me after threads like this one: My first meeting with Craig Russell was very friendly. I sent Craig a db4objects T-Shirt and he reports he is wearing it.

Personal sympathy has little to do with opinions, jobs or emails. You only know when you meet face to face (but of course Craig's feeling could have been very different to mine).

Not everyone else I met at JavaOne is easy to get along with.

db4o Developer Conference in Bavaria

To be remembered:
  • A raft trip in a hailstorm. 4 degrees Celsius couldn't stop everyone from going swimming.
  • Playing fuzzy tabletennis with six people and two balls.
  • The card game with the "arbitrary semantics" card.
  • The bonfire ("Sonnwendfeuer").
  • Showing everyone around my hometown and my area.

Although the weather was terribly cold for the time of the year, we had a really great time and it wasn't a second of stress.

And yes, work was very productive too. We planned our roadmap for the release of db4o 5.0 in November. Klaus contributed the name "native queries" for our new query interface. Rodrigo wrote a brilliant implementation with .NET 2.0 predicates.

Jim Paterson's article on Prevayler popped into a design session and we (Carl, Klaus, Rodrigo) decided to send him the following picture immediately: