XML and STEP

Further to my presentation at WWW6 and the accompanying position paper,
which I circulated to you all, you might be interested in a report,
reproduced below, wich I presented today to the Management Committee of
EPISTLE (the European Process Industry STEP Technical Liaison
Executive).

You will see that I tell EPISTLE that the Working Group has formally
been asked the question as to whether XML will be able to meet the
requirements of STEP. In fact, this question was put in the form of my
presentation at WWW6 and the accompanying position paper, which I then
circulated to the WG.

I know of no more formal way of putting a question to the WG than to
post it to this list. In case in the flurry of e-mails the posing of the
question passed unnoticed, may I re-pose it through this e-mail. I'd be
happy to respond to any requests for further information, in order to
elucidate the nature of the requirements in question.

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STEP and SGML - Outline of current status
Report presented to the EPISTLE Management Committee meeting Haarlem, NL
on Friday, 25 April 1997

1) STEP-SGML harmonisation
At a meeting between TC184/SC4/WG3/T14, the Product Documentation group,
and TC184/SC4/WG10, the Architecture Working Group, at the Chester STEP
meetings in March 1997, it was agreed that a proposal be drafted, for
submission to ballot at San Diego in June 1997, for a Preliminary Work
Item on STEP-SGML harmonisation.

A number of ways in which STEP and SGML could work together to mutual
advantage have been mooted. The meeting identified four of these, but
recognised that there is some overlap between the four, and the list may
not be exhaustive. It was suggested that the proposal should be drafted
in such a way as to give those working on the Preliminary Work Item the
mandate to consider the various options which have been put forward, and
recommend which should be actively pursued.

The four options were, briefly, the following:
*	that an sgml_string data type be added to the EXPRESS language.
The scope of this option could be broadened to the inclusion within STEP
of a more generic mechanism for handling structured strings or
notations, including but not limited to SGML strings.
*	that a standard way be developed for SGML documents to reference
(and call into their content) data from STEP databases, possibly through
the use of HyTime links. (It was recognised that this option could also
have relevance to the issue of parameterisation.)
*	that an SGML-based interchange format for exchanging data
between STEP databases be developed
*	that a standard mechanism be developed for two-way mappings
between STEP schemas and SGML DTDs, and between STEP database contents
and SGML document instances.

2) The SGML family of standards
The SGML standard is evolving. ISO 8879 (SGML itself) is currently
undergoing its formal 10-year review. A technical corrigendum to the
HyTime standard (which extends SGML to accommodate "architectural forms"
- or meta-DTDs - and complex linking structures) has been drafted and is
being circulated for comment. The DSSSL standard (for specifying
formatting and transformation rules for SGML documents) is also under
review.

A new standard, known as XML (eXtensible Markup Language) is under
development. It aims to define a powerful but readily implementable
subset of SGML, HyTime and DSSSL, suited for delivery over the Web.
Microsoft has stated publicly that it will implement XML in future
versions of Internet Explorer. Netscape, after refusing to countenance
such support, has now stated that it is considering the possibility that
its future browsers will also support XML.

The good news is that the groups working on these standards are
coordinating their efforts, in order to ensure that the standards will
all be able to coexist and interoperate (both with each other, and with
HTML).

3) The business needs and opportunities
A number of industries are beginning to express an active interest in
the idea of STEP and SGML working together. These include major players
in the oil industry, the semiconductors industry and the aerospace
industry. The question has been formally put to the XML working group as
to whether XML will deliver sufficient functionality, and sufficient
rigour, to meet the needs of STEP. If XML is able to rise to this
challenge, then STEP-SGML harmonisation could in practice become
STEP-XML harmonisation, and the Web technology, through appropriate
Intranets, could be used to exchange data between STEP databases. If (as
some believe) XML, given its choice of simplicity of implementation over
full power, will be incapable of meeting the
needs of STEP, then full SGML and HyTime are likely to be involved in
any STEP-SGML harmonisation.

Discussions are currently under way with the aim of bringing together
industry players with an interest in seeing this work come to fruition,
into a consortium which will fund the necessary research and development
work in association with the ISO Preliminary Work Item.

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Daniel Rivers-Moore, Technical Director, RivCom, Lotmead Business
Village, Swindon SN4 0UY, UK
Tel: +44 (0)1793 790802 Fax: +44 (0)1793 790812 e-mail:
daniel.rivers-moore@rivcom.com

Received on Monday, 28 April 1997 05:12:54 UTC