Re: A Proposal for Metadata

[Daniel Veillard <Daniel Veillard w3 org>]

> Anyway, I've written up my thoughts on what the metadata API should
> look like and how metadata ought to be implemented.  I've put it on
> the web:
> 
>       http://www.cygnus.com/~tromey/gnome/metadata.html
> 
> Please send any comments or suggestions back to the list.  I'm
> determined that this thread live forever.

  Ok, I won't let that thread stop either because there is more thought
needed before a good design still emerge. I tend to agree with your opinions
here, but I also tend to think that they are far too file oriented. My
reflexion comes from Web metadata (the one I'm most used to), and especially
the work done at W3C on metadata: http://www.w3.org/Metadata/
I may have a too "network oriented" vision, but I don't think that a file
oriented one will really fit the purpose of of a "Network Object Model" :-)
I beg of seamless access of remote data from my future Gnome desktop,
metadata handling included !

Metadata is "Data about Data", and this lead to a couple of direct remarks:
   - Metadata is Data, so to your question:
     "If the implementation represents metadata as a file associated 
      with the parent file, can that metadata file have metadata itself?"
     I would clearly answer yes !
   - Second the metadata is often far more useful than data (I guess in average
     we do more ls on files than we look at or edit their content).
   - The metadata is often not in the same physical space as the data itself
     since it's not generated by the same process/processus/person. Moreover
     for one given piece of data quite a lot of different metadata can be
     generated with various scope and usage (a thubnail may seem the most
     obvious for a viewver, but the Copyright info may be the more important
     for a publishing tool !).
   - One of the most important feature of metadata it that a program can
     discover them programatically, even if it doesn't really know how to
     handle them.

So could people assume in this thread that:
   - not only files need metadata, but rather the full scope of object
     manipulated on a desktop (files, URI, persistant objects, programs, ...).
   - metadata usually don't come with the data (otherwise they are integrated
     in the data format).
   - any given object can get metadata from various applications/persons,
     which doesn't necessarily understant each other metadata but should be
     able to discover them.

I agree that this makes things far less trivial, I believe that that makes
them far more useful too. I don't even give the slighliest idea about how
to actually implement this, but I guess that the debate need first to be
focused on what do we need, before jumping into implementation tricks.

  Feel free to flame me copiously since I wasn't specially kind on the
previous thread, but I really think that the debate has to be refocused.

  good night,

 Daniel
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