On Tuesday 20 February 2007 23:25:54 Mikkel Kamstrup Erlandsen wrote: > 2007/2/20, Jos van den Oever <[EMAIL PROTECTED]>: > > 2007/2/20, Joe Shaw <[EMAIL PROTECTED]>: > > > Hi, > > > > > > On Tue, 2007-02-20 at 20:52 +0100, Jos van den Oever wrote: > > > > But reading, writing and searching metadata fields is something that > > > > desktop applications will want to do more and more. Since there is, > > > > to my knowledge, also no standard for reading and writing metadata in > > > > fd.o, this is a good opportunity to come up with it. > > > > > > I agree. But it is something that should be kept conceptually separate > > > from desktop search. > > > > > > > Whereas we are talking about metadata that relates to files, they are > > > > working on a wider definition. > > > > > > Do you mean files in their strictest sense, or also things like emails, > > > addressbook contacts, etc? > > > > Yes, those too. Mails are clear, addressbook contacts is a bit > > slippery, but yes those too. So files and url-addressable parts of > > files. > > > > > > When you think of writing metadata, you can e.g. think of the > > > > properties dialog in Konqueror where you can write title and artist > > > > for mp3 files. For searching you want to name this field and for the > > > > read/write api you want to name it too, so you might as well use the > > > > same language for that. > > > > > > Indeed, and we should also use the same storage for it whenever > > > possible. I envision a three-tiered system for actually setting > > > metadata on files: > > > > > > 1. Store the metadata in the file itself whenever possible. Things > > > like id3 tags in MP3s or XMP metadata in jpegs. This is ideal because > > > it's in a standardized format that most tools can read, and the > > > metadata follows the file around no matter where it's sent. > > > > > > 2. Store metadata in extended attributes on the file in the file > > > system. This has the benefit in that the metadata follows the data > > > around within a single system, and our desktop applications can be > > > standardized around a schema for xattrs. Obviously this won't work for > > > non-file items or on file systems that don't support them. > > > > > > 3. Lastly, store metadata in some sort of centralized store, like a > > > sqlite database. Keeping metadata in sync with data is harder, but > > > fortunately most of the data that would require this mechanism wouldn't > > > have mostly unique URIs. I'm sure Jamie will disagree with me on this, > > > but I don't think this requires a constantly running daemon; a simply > > > library interface would probably suffice. > > > > Hehe, now _you_ are taking this spec further then intended. ;-) > > I'll not get into this. On the KDE side this is something for > > Sebastian Trueg (Nepomuk) to consider. > > Is it just Sebastian? I'm generally not keen on one-man-speccing.
Time to get into this discussion. Sorry for the delay. No, it is not me at all. I am just the portal to the open-source world. The metadata ontologies (Nepomuk defines complete ontologies here, see my other email) are defined by a task force within the Nepomuk project. I actually only try to communicate this to the outside world (apparently I did not that good a job so far ;) > I can't make up my mind. On one hand I think that the way metadata is > stored is an implementation detail, on the other hand it might be good to > standardize it. It could be a standard that is orthogonal to the other > parts of the metadata specs though. > > Cheers, > Mikkel _______________________________________________ xdg mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/xdg
