Skytopia : Towards a single folder metadata (database) filesystem:
This article was written after much irritation with the present filesystem used in almost all computer operating systems today. Excluding Windows stuff, I currently have around 80,000 files on my hard drive - over half of which are sound files of various kinds and formats. After organizing such a vast collection with so many different file formats, it's clear that the present way of finding and storing files is much less efficient than a meta-tagged single folder filesystem (or database file system) for various reasons I have discussed below.
Microsoft and Apple have shown signs that the upcoming Windows Longhorn OS and Mac OS X will add some emphasis to file metadata, but I have my doubts that they will fully realize its potential, and utilize a single 'folder' for practically all files."