> 1) The flag bits method is not truly heirarchical.  It only allows a
>    2-level storage system.

Why not?   Let's say you have a three-layer storage scheme.   If the
file has been archived on layer 1, then you go to layer 2.   If it's
archived there, you go to layer 3.   The fact that you can't tell the
file is on layer three without going to layer two does not mean that
the system isn't hierarchical - it just means you have to do a bit of
extra work.   Personally, I think storing a layer number in each layer
is _less_ hierarchical - now when layer two decides to archive the
file, it has to somehow notify layer one.

> 2) The mod-time, size etc. information of the disk and background
>    storage can't both be presented as the same time.

Again, you'd have to go through the layers.   When you have to resort
to tape, I have to admit that this gets ugly.   What's your proposed
solution?

			       _MelloN_