Feel free to add whatever occurs to you by finishing the sentence 'VFS needs ...'
VFS needs to support more of the core vfs functionality, specifically copy and rename. They are currently lacking, and so tcl's vfs core falls back to open/read/write/close for copy and copy/delete for rename.
vfs composition: the ability to stack vfs on top of one another, ala Plan 9. It's got it, Cache VFS - complete with write-back.
A component of this is 'vfs::add, which gives the ability to compose file systems functionally. -- 20040612 CMcC
A more featureful facility is offered by SEH's A collate/broadcast virtual filesystem
versioning vfs: write to a file, and the diffs are store and accessed by globbing the file as if it were a directory. People have got to realise that the distinction between file and directory is a purely arbitrary and not particularly useful constraint.
Implementation ideas: use CVS or metakit as a backing store? I'm tempted to use metakit with progressive diffs. I guess it ought really to be backend agnostic, but I'm not sure I want to go to the trouble. -- 20040612 CMcC
SEH Try a versioning virtual filesystem.