db4objects focuses on the embedded market because, according to Whittig, object databases are not the right choice for enterprise. "We target the range from embedded systems all the way to packaged software and real-time control systems," Whittig says. "Anything that is invisible to the end user, because there's huge growth there. It's a very interesting space."
db4o previously was available commercially, with site licenses running $1,000 per year and individual user licenses priced at $100 each. Curious potential customers could also download a free evaluation for non-commercial use, or fork over a minimum of $40,000 for access to the source code.
Now those customers can check out the code for free, and customize it for use in other free software or in-house projects. If they want to use db4o in a commercial product, however, they'll still have the option to purchase a commercial license for $1,000.
The commercial database is exactly the same as the free version, except that paying customers get technical support via a developer member network and a guaranteed response within 24 hours. Users of the free version receive no official product support but can still get their questions answered through community interaction. This licensing structure is identical to the one the MySQL database server project uses. db4o does not accept community contributions to its code base unless the developer signs over his rights to the code.
Whittig says open-sourcing db4o gives would-be purchasers an opportunity to evaluate the product and "get convinced" there are benefits. "We put the software out there to the community, we get a lot of eyeballs," says Whittig. "We get 400-plus downloads a day. It's zero revenue, but it's zero cost. A small subset of these people have a need to obtain a commercial license, so it's a highly qualified inbound sales lead. They are already convinced this is a good product."