2010/1/7 Robert Rohde rarohde@gmail.com:
The historical position has been that absolutely nothing goes into the WMF software pool unless it is open source. As I recall, the only recognized exception was the closed source firmware running the routers at the server farm. By that standard, even a freebie is not good enough if the system is closed source. However, my recollection is based on discussions years ago. On searching, I couldn't find any policy forbidding closed source software (is there one?). So, it is possible that closed source might be looked on as a more acceptable possibility for some functions now (though I wouldn't bet on it).
The reasoning is that having the data be free content is not enough - the systems you need to use the data need to be free software as well.
Lucene is free software, but was out for a while as Java wasn't free software then. I believe we used a rewritten version in C# for a while, in fact. A Java version of Lucene started being used again when Java was in the process of being freed up, I think we were using it before there was an entirely free software Java.
(corrections welcomed!)
- d.