A common VFS and a Common conf-system (Was: namespacing)

[Avery Pennarun]

On Tue, Mar 01, 2005 at 11:43:58AM -0500, Sean Middleditch wrote:

> >> Unfortunately, it's Linux only, and has an incredibly brain-dead design
> >> where you have to utilize "round-trips" through the kernel for
> >> something that essentially happens entirely in user-space,
> >
> >This is not entirely true: thanks to some contributions by my company,
> >FUSE has extensions that allow the kernel to *cache* your stuff in the
> >normal page cache, so after the first access, files can be retrieved as
> >quickly as from a normal filesystem, even across processes, and with a
> >high level of reliability.  That's a very big advantage that you will
> >simply never achieve in a 100% userspace solution.
> 
> Why can't it be done in userspace?

For the same reasons that microkernels are slow.  I don't think I want to be
part of *that* famous argument, so I'll leave it at that :)

If all you're doing is opening a word document, I suppose nobody cares how
slow it is (which is why kioslave and gnome-vfs, both awfully slow systems
compared to the kernel, are accepted and useful).  But please don't ask me
to compile my openoffice source tree on such a filesystem.

Have fun,

Avery