As I understand it, Mt. Rainier became available as of the 2.4.19 kernel. Unfortunately, I don't think there are any CD writers that support it yet. I have read that some current ones will be able to use the Mt Rainier standard but will require a firmware upgrade that isn't yet available. I suspect that these companies have been asked to wait by MS before they release this stuff. MS would not like it known that linux is way ahead of the curve on this cool technology. Anyway, once this goes into effect we won't need UDF.