In need of a virtual filesystem / archive

[Enigma Curry]

I need to store a large number of files in an archive. From Python, I
need to be able to create an archive, put files into it, modify files
that are already in it, and delete files already in it.

The easy solution would be to use a zip file or a tar file. Python has
good standard modules for accessing those types. However, I would tend
to think that modifying or deleting files in the archive would require
rewriting the entire archive.

Is there any archive format that can allow Python to modify a file in
the archive *in place*? That is to say if my archive is 2GB large and I
have a small text file in the archive I want to be able to modify that
small text file (or delete it) without having to rewrite the entire
archive to disk.

Does anything like this exist? If nothing exists for Python, is there
something written in C maybe that I could wrap (preferably you won't
suggest wrapping the ext2 filesystem driver..  ;) ?