Comment by summerlight

This reminds me of WinFS, which was probably one of the most ambitious architectural project ever in the history of Windows yet failed to materialize. The vision was so attractive, encode all the semantic knowledge of file schema and metadata into relational filesystem. So you can programmatically query on whatever information about the filesystem and its content.

IIRC the problem was its performance. I don't have any insider knowledge so cannot pinpoint the culprit but I suppose that the performance issue was probably not something fundamental tradeoff (as this article suggests) but more of its immature implementation. The storage technologies got much better nowadays so many of its problem could be tackled differently. Of course the question it has to answer is also different; is it a still worth problem to solve?