Automatic file compression?

[Dan Bernstein]

In article <5 at rdb1.UUCP> root at rdb1.UUCP (Robert Barrell) writes:
>      Is there any way, or any library of routines, which would automatically
> compress data when it is stored into a file, and uncompress it when it is
> retrieved?

It shouldn't be hard to stick this into any filesystem implemented
outside the kernel. You store all files with a compression type: either
no compression or a choice of available methods. You keep an MRU cache
of uncompressed files, including all the files open at the moment. You
might keep a priority queue of LRU files to switch from uncompressed to
compressed, or you might have all files compressed immediately upon
close().

Anyone want to try to stick this into RFS?

Note that making this sort of transparent change becomes very, very
difficult if the filesystem is hidden inside the kernel. comp.std.unix
readers know what I'm referring to.

---Dan