Re: About metadata (long!)

[Christopher Curtis <ccurtis ee fit edu>]

On Wed, 19 Aug 1998, David Jeske wrote:

> 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

You're right.  I realized it after I wrote it.  The next statement
(immutable data) makes more sense.  However, it would (could) contain
owner-assigned viewers.  I was simply trying to use the same example. 

> > > 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). 

Image size is already stored.  The point is you should be able to assign
any attribute to any file.  Be it copyright, author, thumbnail,
derivation, commentary, etc.  Imagine you have an image and you want to
remind yourself how you created it (what font the text is in, what effect
were used with what patterns, anyway...) - you'll either need to write it
down on a apiece of paper or find a file format that supports annotation?

> 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

Some metadata may be 'standard' in that it can be 'expected', but I
wouldn't rely on any metadata being present in a file.  If anyone has ever
used OS/2, please use this as a base reference.  I'm not familiar with
NeXT.  I would think that if you are joining an argument over what does
and does not comprise an Object Model Environment (Windoze don't count),
you (plural - not *you* specifically) would have some experience in one
that already exists.

> > 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).

Anything that annotates the file is meta-data.  Author, references,
copyright, etc.  And remember that there are other issues that should be
addressed as well (socio-politik (copyright), expandability, and meta-data
attributes, I think, being especially important).

And please don't take this message as a personal dig, it's not meant to
be.

--
Christopher Curtis               - http://www.ee.fit.edu/users/ccurtis
                                 - System Administrator, Programmer
Melbourne, Florida  USA          - http://www.lp.org/