A thought to consider: Apple's Hierarchical File System (HFS) has a useful
notion: the "resource" fork. The best description I ever heard of it was as
"extensible meta-data." If you simply define a basic structure that those
meta-data aware programs can carry without parsing in an explicit way (e.g.
tar, cpio, pax, dump/restore, etc), then whatever meta-data other programs
need can be added to any file with non-resource-fork programs being none
the wiser.

Now, I don't want to get into a discussion of the merits (or distinct lack
thereof) of Apple's overall HFS design, or its implementation - I'm just
suggesting that the resource-fork as extensible meta-data notion be
pondered for a bit...

	Erik <fair@clock.org>