Re: MIRROR for external entity references in XML?

Paul Prescod (
Wed, 16 Apr 1997 09:47:56 -0400

Message-ID: <>
Date: Wed, 16 Apr 1997 09:47:56 -0400
From: Paul Prescod <>
Subject: Re: MIRROR for external entity references in XML?

Steven Champeon wrote:
> Assuming that Bob Metcalfe is right about the death of the Net,
> or at least its slow grinding descent into saturation, wouldn't
> it make sense to allow for unreachable hosts with a MIRROR alt
> for external refs?

I don't think that this problem is much worse than in HTML. The solution
should probably be part of the public identifier resolution mechanism.
XML doesn't currently specify a particular public identifier resolution
mechanism (and it was a long and painful debate that isn't likely to be
repeated!) but most likely a default mechanism will be specified in a
separate proposal to the W3C (separate from XML). It will most likely be
a catalog format that maps public identifiers (like URNs) to system
identifiers (URLs) while we wait for a robust, global, automatic URN
mechanism to come on-line. That catalog can allow multiple system
identifiers to be associated with a single public identifier.
 Paul Prescod