John Cowan cowan at
Fri Jul 10 00:45:30 BST 1998

Rick Jelliffe wrote:

> There are moves to extend urn syntax to encompass MIME types--I don't know
> the status, perhaps they already do.

Assuming they don't, then...
> Anyway there is a general expectation in XML that system identifiers should
> be URIs  and that public identifiers should be SGML FPIs.  However, until
> this is defined, there is no choice but to use MIME media types for SYSTEM
> identifiers. Even though MIME media types are, strictly speaking, public
> identifiers, they belong in the "WWW" slot not the "ISO" slot (i.e. the
> SYSTEM identifier not the PUBLIC identifier).

Not so.  In XML, system identifiers are URIs, period, and URIs are
URNs and URLs, period.  MIME types are not yet URNs and definitely
aren't URLs.
John Cowan		cowan at
	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)

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