Re: About metadata (long!)

[David Jeske <jeske home chat net>]

On Wed, Aug 19, 1998 at 10:51:37AM -0400, Christopher Curtis wrote:
> > So if a file has an attribute 'viewer', and every user on my system wants
> > to use a different 'viewer' for a particular file, we _won't_ store the
> > 'viewer' metadata in the extended attribute?
> 
> Not really true.  We will store a default (set of) viewer(s) in the file.

This makes no sense. There should be some sort of central database of
what filetypes are opened by what apps. If someone wants to get fancy
we could store the mime type of the file.

> > What _are_ we storing in the extended attributes?
> 
> Primarily non-mutable data.  This is stuff such as Copyright, which the
> owner wants to assign to a file, and give a "children of this file must
> inherit" flag (think like storing the GPL here).  Also, Author, presuming
> a file has only one Author - there would be a flag perhaps to reference
> this attribute in all children (file copies).  

Perhaps it's just me, but I don't see this as metadata, it's just
data. If you have an image, then the size of the image, or the author,
or whatever informaiton needs to stay with that image file should be
part of the file itself. Imagine having an image format which didn't
have it's size stored anywhere inside it (impossible). 

Metadata can be used as a standardized way to pull this data out of
the specific file format and publish it to the world in a standard
way. Eventually (long down the road, when metadata filesystems are
everywhere) I could see a day where everything is stored in structured
metadata fields, and there is no 'file format'. However, that day is
long from here, and that might not even be the right way to go.

> And thumbnails would be stored here, because this is specific to
> this data and we don't want each user to have to create their own
> thumbnail in thier personal library.  Basically, anything that is
> not user preference (that is system default) would be stored here,
> plus "metadata attributes", for what attributes can be assigned,
> inherited, (not)created, overriden, forced-on-copy (GPL),
> lost-on-edit (thumbnail), etc.

Thumbnails (IMO) are a perfect example of something which would be
well stored in metadata. It's recreatable from the original file, but
useful on it's own on a given system. It's a public export, in a
standard format, of information "about" the data (i.e. meta-data).

-- 
David Jeske (N9LCA) + http://www.chat.net/~jeske/ + jeske@chat.net