>>>>> "A" == Andrew Morton <[EMAIL PROTECTED]> writes:
A> I'd be interested in seeing some expansion on why shared mem was
A> undesirable and why the NFS interface was not the way to go.
A> Particularly the latter, as people have been suggesting this
A> occasionally.
I'm curious, too!
IRIX (SGI's unix) has used NFS to implement user-mode filesystems
for many releases. It is simple to implement, and works acceptably
well for lightly used auxiliary filesystems (eg: FAT, HFS, ISO9660,
CDFS), especially for removable media. It is also used to implement
nsd, and there the limitations of using NFS shows up. It is an
essential service, and is not as reliable as desired. The worst
problems are associated with using NFS to implement the filesystem
interface to the user-mode process. There are performance,
reliability, and robustness issues attributable to NFS.
Statelessness is a problem in this case, as is the inability to use
shared memory or page-flipping (which Linux doesn't have yet) to
improve performance.
As part of project we are working on, I am tasked with developing a
user-mode filesystem for Linux and IRIX, with the same (or as close
as possible) interface in the user space. This is my first
experience inside the kernel (for both OSes), so the learning curve
is steep...
A> This was thrashed through a number of months back on the gnome list.
A> The debate concerned whether the exercise of unifying FTP/HTTP/etc with
A> filesystems should be done in user space or the OS. User space won out
A> (A VFS library, but limited to gnome apps only) because gnome is not
limitations can be som limiting...
A> just for linux.
Is this on the Gnome pages? If not, could you plese forward me a URL? thanks!
A> But the consensus was that if this were to be done in the OS, the NFS
A> hook should be the way because that gives the best shot at cross-Unix
A> portability.
A> Another comment on the web page: s/lession/lesson/ :-)
Haven't followed up on Jeremy's new web page yet...
--
Scott Henry <[EMAIL PROTECTED]> / Help! My disclaimer is missing!
IRIX MTS, / GIGO *really* means: Garbage in, Gospel Out
Silicon Graphics, Inc / http://reality.sgi.com/scotth/
