Re: reiser4 plugins

From: Kyle Moffett
Date: Tue Jun 28 2005 - 02:50:27 EST


On Jun 28, 2005, at 01:30:08, Hubert Chan wrote:
On Tue, 28 Jun 2005 00:38:38 -0400, Kyle Moffett <mrmacman_g4@xxxxxxx> said:
Ok. Those things should probably be divided up. Stuff like POSIX
extended attributes and such that have existing interfaces should use
those.

One of the claimed advantages of the '...' interface is that everything
is editable as a file. So if someone wanted to edit the description
extended attribute for foo.txt, he would just run
"[editor] foo.txt/.../description" (or
"[editor] /meta/fs/$(getattrpath foo.txt)/description"), instead of
needing to use some special purpose editor. It works well for things
like being able to use Gimp to edit a thumbnail or icon attribute.

I don't disagree with the thumbnail/icon/description, but things like
POSIX acls and extended attributes have _existing_ interfaces which
should be used. I don't deny them the right to add other interfaces
later, but such should be a secondary or tertiary patch, after the
rest of the stuff is in. In any case, if we were to provide an
interface by which one could $EDITOR the POSIX ACLs, it should be
done in the VFS where all filesystems can share it.

The inspiration, I think, was the MacOS X/NeXTSTEP bundle format. For
example, MacOS X/NeXTSTEP .app file is actually a directory that behaves
much like an executable file (double-clicking a .app file in the Finder
launches the application, instead of opening the directory). However,
it is in reality a directory that contains many things that could be
thought of as extended attributes (such as the application icon,
information about the application, etc.). Since the application icon is
a real file, it can be edited by normal graphics editors (not like
Windows programs, where you need a special icon editor). And since it's
inside the .app directory, it's attached to the application (not like
Linux, where the program is in /usr/bin, and the icon is in
/usr/share/pixmaps), so it makes package management easier (to delete an
application, just delete the .app file -- don't need to look in
/usr/share/pixmaps for the icon and delete it).

The key difference here is that Mac OS X does all of the bundle mess
in userspace where it belongs. :-D (I know, I use it daily) I think
that part of Reiser4 needs more review than it's been given at present.

Cheers,
Kyle Moffett

--
There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies.
-- C.A.R. Hoare

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