brief notes on SGML Open entity management catalog for HTML spec

Paul Grosso (
Mon, 21 Nov 94 08:57:04 EST

As requested, here are some words about the SGML Open entity management
catalog to go into the HTML spec. Below I include the current content
of section 6.1.1 along with my added words.

[However, please note in other mail that I discuss that I do not feel
that the use of the public text display version field (the "//2.0"
after the "//EN") is appropriate. I also make some suggestions
regarding the use of ISOlat1.sgml as a file name.]

Note that the file name in the catalog entry may be optionally
surrounded by quotes. The full text of the Resolution is available
through SGML Open (contact; see also the
SGML Open home page at, the international
SGML Users Group (dpsl!, or through the Graphics
Communication Association (


Paul Grosso
VP Research Chief Technical Officer
ArborText, Inc. SGML Open


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6.1.1 SGML Open Style Entity Catalog for HTML

The SGML standard describes an "entity manager" as the portion or
component of an SGML system that maps SGML entities into the actual
storage model (e.g., the file system). The standard itself does not
define a particular mapping methodology or notation.

In order to assist the interoperability among various SGML tools
and systems, the SGML Open consortium has passed a technical resolution
that defines a format for an application-independent entity catalog that
maps external identifiers and/or entity names to file names.

Each entry in the catalog associates a storage object identifier (such
as a file name) with information about the external entity that appears
in the SGML document. In addition to entries that associate public
identifiers, a catalog entry can associate an entity name with a
storage object indentifier. For example, the following are possible
catalog entries:

PUBLIC "ISO 8879:1986//ENTITIES Added Latin 1//EN" "iso-lat1.gml"
PUBLIC "-//ACME DTD Writers//DTD General Report//EN" report.dtd
ENTITY "graph1" "graphics\graph1.cgm"

In particular, the following shows entries relevant to HTML.

-- catalog: SGML Open style entity catalog for HTML --
-- $Id: catalog,v 1.1 1994/10/07 21:35:07 connolly Exp $ --

-- Ways to refer to Level 2: most general to most specific --
PUBLIC "-//IETF//DTD HTML//EN" html.dtd
PUBLIC "-//IETF//DTD HTML//EN//2.0" html.dtd
PUBLIC "-//IETF//DTD HTML Level 2//EN" html.dtd
PUBLIC "-//IETF//DTD HTML Level 2//EN//2.0" html.dtd

-- Ways to refer to Level 1: most general to most
specific --
PUBLIC "-//IETF//DTD HTML Level 1//EN" html-1.dtd
PUBLIC "-//IETF//DTD HTML Level 1//EN//2.0" html-1.dtd

-- Ways to refer to Level 0: most general to most
specific --
PUBLIC "-//IETF//DTD HTML Level 0//EN" html-0.dtd
PUBLIC "-//IETF//DTD HTML Level 0//EN//2.0" html-0.dtd

-- ISO latin 1 entity set for HTML --
PUBLIC "-//IETF//ENTITIES Added Latin 1//EN" ISOlat1.sgml