In "Advanced filesystems beyond metacrap" I proposed a way to remove hierarchy from file systems, without going all the way to database filesystems, retaining human-readable unique identifiers and possibly avoiding the metacrap associated with the latter. It turns out, that something rather similar already exists: LFS. A description can be found in this USENIX article. The code itself, unfortunately, seems a bit difficult to build. There should exist a FUSE module for convenient testing, however.

There are some differences to my proposal, however. Whereas I completely abandon "file names" in favour of a unique set of categories for identifying files, LFS actually retains file names, but replaces the directory name components of the path to a file with a boolean expression. It's only a superficial difference, though, but in my humble opinion, the LFS approach seems more complicated here than necessary (although, on the other hand, sometimes it might actually be useful to have a name for each file). But, indeed, at the implementation level the distinguished file name seems to disappear. A more important difference is that LFS allows both conjunctions and disjunctions as well as negations for looking up files, unlike my proposal.