Re: SAX and delayed entity loading

John Cowan (cowan@locke.ccil.org)
Thu, 03 Dec 1998 15:50:08 -0500


Simon St.Laurent wrote:

> How is [a notation] any better than a MIME
> type, which does about the same thing? It is slightly more flexible - like
> a gun with a barrel that can rotate 90 degrees, right at your foot.

It also allows you to escape the dilemma "either private use only,
or published in the IANA registry". See below.

> So you'd like to use the Web as one giant registry? I suppose I could
> ponder this, but again, I have serious doubts as to its usefulness. If
> only on grounds of longevity - /X10/ could go dim in ten years, with no way
> to figure out what happened.

Very true. Hence the need for URNs, or URLs managed as URNs.
No formal property whatever *guarantees* persistence: persistence
is a property of how humans behave (in the case of MIME, how
Jon Postel behaved and how his successors are expected to behave).

> External X10 data could, however, change its
> identification without some lucky person or program tracking down every
> reference to it in documents to reflect the change.

Again, I believe notations (whether used directly, or mediated through
schemas/DTDs) are far more useful when governing elements than when
describing whole remote documents.

> Putting the notations
> in documents creates a maintenance headache that shouldn't be
> underestimated. Of course, it depends on whether its easier to change the
> documents or the server providing the extra resources. Right now, it's a
> lot easier to change the server.

Okay, I'm convinced now that we really need the MIME-types-as-notations
DTD fragment. Stand by.....

> >> Public registries and self-identifying documents seem like the only out of
> >> this mess to me, but so far that hasn't gone nearly far enough.
> >
> >The WWW *is* a public registry, or at least can encapsulate one
> >using PURLs and such.
>
> See above for longevity issues. Something safe and centralized, complete
> with version control, seems like the only way out of this nightmare.

Safe central registries can be *created* on top of the WWW (as
the PURL folks are doing) without sacrificing the utility of
ad-hoc-but-globally-accessible universal names for things.

-- 
John Cowan	http://www.ccil.org/~cowan		cowan@ccil.org
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)