> While at USENIX, I saw the _correct_ way to do a union FS. It was done
> as a pre-loaded shared library, and because of that it was a lot more
> flexible than any kernel implementation would ever be (it was not
> limited to the unix mount global state: it was used more like Plan-9's
> dynamic per-process mounting).
You mean by (effectively) wrapping the libc file I/O functions? This seems
feasible, but I wonder about coherency and race conditions with each process
doing it's own "inheritance", and how the information on inheriting mounts
would be disseminated. (I suppose a deamon using IPC could resolve a lot
> After having seen that, I don't think I necessarily would even want a
> kernel implementation. It simply was so much better done in user
If my guess is right, it sounds like it has it's own problems, but even so it
must be less painful then doing it in kernel space.
> The stuff had been done by Dave Korn (or Korn shell fame (and don't
> flame me if his first name isn't "Dave", my mind is going)) at AT&T.
> Damn, but I can't remember his email address..
-- Kenneth Albanowski (firstname.lastname@example.org, CIS: 70705,126)