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Re: [xmlProfiles-29] TAG recommendation for work on subset of XML 1.1

From: Glenn A. Adams <glenn@xfsi.com>
Date: Sun, 16 Feb 2003 13:47:13 -0500
Message-ID: <7249D02C4D2DFD4D80F2E040E8CAF37C01FB9A@longxuyen.xfsi.com>
To: "Ian B. Jacobs" <ij@w3.org>
Cc: <www-tag@w3.org>

>Message-ID: <3E399D11.5060102@w3.org>
>Date: Thu, 30 Jan 2003 16:45:53 -0500
>From: "Ian B. Jacobs" <ij@w3.org>
>To: Liam Quin <liam@w3.org>
>CC: Paul Grosso <pgrosso@arbortext.com>, www-tag@w3.org, Michael Sperberg-McQueen <cmsmcq@w3.org>
>Subject: [xmlProfiles-29] TAG recommendation for work on subset of XML 1.1

>One clear requirement of the subset is that it must exclude
>internal and external subsets (no <!DOCTYPE declaration is
>allowed). This requirement effectively removes DTDs from XML and
>consequently removes entities and notations.

I want to point out the existence of a number of standards in
the television domain that:

(1) disallow internal declaration subsets;
(2) require standalone="no";
(3) require a document type declaration, with a specifically
    enumerated set of public FPIs to be supported;

These standards include:

(1) ATSC DTV Application Software Environment (DASE) [1]
(2) DVB Multimedia Home Processing (MHP) Version 1.1 [2]
(3) SMPTE 363M Declarative Data Essence Level 1 [3]

The rationale for the restrictions adopted by these standards include:

* inability to request external entities in a broadcast only
  transport environment coupled with inadequate bandwidth for
  broadcast of DTDs;

* unacceptable complexity in mandating DTD declaration parsing
  document validation in small footprint, embedded devices
  (set-top boxes and integrated receiver decoder devices);

* need to support specific, limited set of document types; while
  allowing (but not requiring) validation based on pre-compiled

* need to identify content as to specific document type against
  which optional validation and application specific processing
  may occur;

As a result of this usage, I would have to conclude that complete
elimination of document type declaration is overkill, as it removes
valuable (FPI) information requiredby these standards and the
systems which employ them.

Glenn Adams

[1] http://www.atsc.org/standards/ps_documents/PS-100-2.pdf
[2] http://pda.etsi.org/pda/home.asp?wki_id=13397
[3] http://www.smpte.org/shopping_cart/cart.cfm?function=add&productid=1481
Received on Sunday, 16 February 2003 13:47:18 UTC

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