[microcolonel]

Cool, but isn't that just an embedded database that looks a bit like a filesystem? It's nothing all that new to use an mmapped embedded database in an application, and every major operating system with a GUI includes (or tends to be distributed with) a copy of sqlite.

Also, if the point is that you want to expose the filesystem to other applications, but have it local to your own, then why not expose it through FUSE, even if it's in your own process?