XML Information Set Requirements, W3C Note 18-February-1999
cbullard at hiwaay.net
Sat Feb 20 15:14:23 GMT 1999
Rick Jelliffe wrote:
> Do you mean "documents" (packages of structured information) or
> "electronic publishing"? I think you mean the latter.
I think they are hung up in the venerable "what is a document"
argument. The answer is, whatever you want it to be as long as
you stick to the markup standard. That's not hard.
> XML-like SGML has been used for years in applications other than
> publishing: someone told me that Xerox have used an XML-like syntax to
> deliver copier diagnostics to repairmens' PDAs for almost 10 years now.
> (Can anyone confirm this?)
I can confirm they used an SGML-like tagging language for a print
system. It was famous
for excluding attributes in the design. It was deployed at USA MICOM.
It was considered "that thing in the corner" because in not sticking
to the standard it presented it's owners with island of automation
Markup was adopted to integrate documentation production and
and to enable information lifecycles that were longer than
the lifecycles of the host systems. There has been over the years
many attempts to adopt a procedural/programming design in the
context of markup. That is another long story.
> HyTime was encouraged in part because of CIA interest in languages for
> orchestrating satellite movements, I have been told, too. Indeed, HyTime
> grew out of a desire to formally analyse performances of music.
That is close. HyTime had its origins in the desire to create a music
description language. That necessitated a timing model. It was
by several interested observers (from CIA, CALS vendors, and a fellow
from God's Brain (inside joke)) that a generalized timing model which
synchronization could be applied to managing very large and distributed
enterprise processes which included NASA launches, process/control
design for manufacturing (simulation), and so on. Indeed, for the
this was true.
HyTime had several areas of interest including defining the general
hyperlinking and addressing. Timing models for real time systems are
difficult to generalize because of issues like "continuous vs discrete",
what to do about race conditions, event fanout, etc. The VRML community
took these same issues up. It is very thorny across a network with
unpredictable delivery (eg, the WWW) for distributed simulations. To
summarize, the HyTime models could probably be used for documenting
historical performances, but might not work well for real-time control.
> Music performances, satellite movements, diagnostic data: these are not
> "publications" but they all can be "documents".
It may be that the reverse is the case. Given what markup does best,
it may be that it is indeed a publication. That begs the question of
"what is a document" but that question never gets answered outside the
parameters of what the standard defines. The point at which you take
the M out of XML, you are defining a different metalanguage for a
set of requirements, therefore, a different standard. This is not the
charter of the XML Information Set WG. They have a constained task
task which the HyTime efforts have proven is hard enough without more
Think long and hard. There are several interdependent efforts moving
in parallel and other language efforts outside the core XML standards
which depend on these (eg, X3D). If rabbit trails impact these
the decisions by the W3C and W3D consortia to close the WGs to members
and invited experts are justified.
xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1
To (un)subscribe, mailto:majordomo at ic.ac.uk the following message;
To subscribe to the digests, mailto:majordomo at ic.ac.uk the following message;
List coordinator, Henry Rzepa (mailto:rzepa at ic.ac.uk)
More information about the Xml-dev