I just ran across the patent application for what appears to be some rendition of the purportedly defunct Object Spaces.  At least, I hope that's what it is and not some attempt by Microsoft to patent the idea of entity mapping itself.  I didn't read the whole thing (who has that kind of time!?), but I can only assume (because patenting entity mapping itself would be preposterous) that it is a patent for their particular solution that they are working on for the WinFS timeframe.

In any case, I guess those who were trying to model their own entity mapping utilities off of object spaces need to be careful if/when MS gets the patent on it.  I'm not really sure I see what's to be gained by patenting their approach.  Microsoft will squash any competition in the space when they get something out there anyways...