desktop vfs wiki page

[Alexander Larsson]

On Thu, 2005-03-03 at 14:40 -0500, Jeffrey Vaughan wrote:
> Sean Middleditch wrote:
> > http://freedesktop.org/wiki/Software/dvfs
> 
> Looks great, but I have one quibble:
> 
>  From the wiki:
> 
> It is noted that desktop apps often do access files besides the user's 
> documents. Your word processor might save configuration files, for 
> example, or a recently-used files list, and so on. The Desktop VFS is 
> not designed for these files. Those files are typically stored in the 
> user's home folder in a dot-directory. That is a local file system. 
> Applications can, and absolutely should, use the system's native file 
> API (POSIX) for these files.
> 
> I disagree with this understand this.  It would be hella cool for 
> applications to store settings using D-VFS.  For example, I would really 
> like to have my firefox bookmarks on a share of some sort that can i can 
> use from whatever host I want.  I think that chrome should be handled 
> (optionally) the same way. If a user wants her toolbar and bookmarks to 
> be consistent on different machines, she should absolutely be able to 
> specify a that bookmarks live on http://foo/... and that her chrome 
> settings are at smb://bar/...
> 
> However if the user doesn't want settings shared, she can always store 
> their configuration files at file://~/...

This is a bad idea. There are some things about posix that is very nice
when using files to implement internal behaviour. For instance, for
config files you really want the "atomically replacing renames" of
posix. When you replace a config file on disk you write it to a new
file, and when that is done you rename it over the old one. Doing this
means that posix guarantee that any read of the config file will either
read the whole old version or the whole new version, never a
half-written one.

On many backends for a desktop vfs there is no operation with guarantees
like that, so this is a piece of posix dvfs won't have. Thus, if you use
it for config settings (especially ones shared between apps) there is
risk of loosing config data.

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 Alexander Larsson                                            Red Hat, Inc 
                   alexl at redhat.com    alla at lysator.liu.se 
He's a gun-slinging guerilla romance novelist with a secret. She's an artistic 
communist museum curator married to the Mob. They fight crime!