RE: cachefs on linux

From: Perez-Gonzalez, Inaky (
Date: Wed Jun 11 2003 - 16:01:20 EST

> From: []
> ...
> There are a lot of things we _could_ add to filesystems, E.G.:
> * Appending to a read-only filesystem on a separate volume

That can be done with a union fs.

> * File versioning

There was a thread one or two months ago regarding all this,
grep the archives.

> * Transparent, variable compression

There was a project to do this in ext2, but I don't remember
what happened to it - I think that at the end is simpler to
do that at the user level (think something like Gnome VFS or
KDE's KIOs).

> * Format conversion, (I.E. write a png file to a filesystem, and it is
> automatically visible as half a dozen other
> formats, without them actually existing on
> the disk)

Mr. Van Riel? Where are you?

> * Priorities, (E.G. temp files could have a bit to indicate that we
> don't really care how long they remain in
> write-cache, instead of flushing them along with
> other more-important-to-get-to-the-oxide data)

Having a tmpfs mounted in /tmp does the trick, more or less.
Then it is a matter of discipline: if a file is temporary,
stick it somewhere in /tmp.

> * WORM mode, (I.E. start at block 1 and use blocks sequentially, never
> re-using blocks - makes a tape somewhat usable as a
> block device)

What for? They are too slow; given the price of a gigabyte now,
and taking into account that IDE drives can store more than tapes,
it makes little sense (I would even say for long-term storage).
YMMV, though.


Iñaky Pérez-González -- Not speaking for Intel -- all opinions are my own
(and my fault)
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