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List:       kde-look
Subject:    Re: Moving away from app-centric mimetypes (e.g. kword)
From:       Dave Leigh <dave.leigh () cratchit ! org>
Date:       2002-05-15 12:30:34
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On Tuesday 14 May 2002 19:15, Steven D'Aprano wrote:
> Not pointing the finger, but various people have suggested that its
> easy to add metadata to XML-based files such as kword documents. This
> is true, but it misses the point of metadata:

As one who suggests this, I don't think it's missing the point at all. The 
point is, given that all non-filesystem solutions are hacks, you have to pick 
the best hack out of the pile. IMHO, using metadata that are already bound to 
the file is superior overall precisely because the metadata are not dependent 
on KDE. You can move your files using mc in a terminal without problem. It is 
a partial system that doesn't handle all files, but can never break. OTOH, 
KDE-only solutions might handle all files, but will constantly break. The 
system will spend a lot of time sweeping away broken metadata, and you won't 
be able to trust queries based on the metadata you DO have. Given a choice, 
I'd choose "never breaks."

> It should be applicable to any file, regardless of file format. It
> should be totally independent of the application used to generate it,
> or view it. It should be transparent to apps that don't understand it,
> but those apps should not break the link between data and metadata.
>
> This is why, ultimately, no metadata system without kernel support can
> ever be complete.

Uhm, not exactly. I agree with all of this except I think that no metadata 
system without FILESYSTEM support will ever be complete. We already have 
situations where metadata are lost when copying from one filesystem to 
another (such as permissions information lost when moving a file from ext3 to 
vfat even though the kernel supports both filesystems. That's why I also 
strongly advocate a virtual filesystem (pat on the back to Sven for bringing 
it up).

> *But* there are lots of things that you can do with metadata on the
> file level, that you may want to do to non-XML files such as text,
> source code, jpeg, etc etc etc. For instance, you might want to
> associate a general purpose Comment metadata field to *any* file. And a
> generic metadata system should allow users to create and use their own
> metadata fields, and not just be limited to the ones the app developer
> thinks you need.

This is another wonderful use for XML. Don't think in terms of fields. You 
can store all of your metadata in a single .kmetadata XML file and have all 
the ad-hoc extensibility you like. But as you point out already, it's a hack. 
And even as a hack it sucks. As mentioned, it breaks as soon as you *or 
another user* pull out something else. It's the "any other user" part that's 
scary, as you've got no control over that for shared files.

> To my way of thinking, metadata is a USEFUL thing, not an ESSENTIAL
> thing. So if we have to go through one or two less-than-perfect
> inelegant hacks in order to demonstrate the usefulness of the concept
> enough to get the kernel support needed for a perfect implementation,
> then so be it.

This isn't essential to casual or single users. But there are situations 
where it *can be* essential. The only reason it's NOT essential is because 
it's not available, if you catch my meaning.  Sort of like cooked food wasn't 
essential before fire was invented. I've already mentioned development and 
publishing. Data Warehousing comes to mind. Multimedia production. These 
would need something a bit more robust than a loosely associated text file, 
though... it's a given that many of the tools will not be KDE-aware

> Am I off-case here? If what I say is unreasonable, I'd like to hear
> your feed-back.

I don't think it's unreasonable, though my opinion differs.

-- 
Dave Leigh, Consulting Systems Analyst
Cratchit.org
  http://www.cratchit.org
  864-427-7008 (direct)
  AIM or Yahoo!: leighdf
  MSN: leighdf29379@hotmail.com
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Androphobia:
	Fear of men.

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