RE: [xml-dev] RE: Caution using XML Schema backward- or forward-compatib

[Len Bullard <len.bullard@uai.com>]

I missed this one.

Conformance tests are provided by the Web3DC as part of the X3D standards
work.  Unless the standard includes some form of functional expression (eg,
the object model in X3D), conformance tests are bolted to definitions which
are, themselves, bolted on.  That's rough sledding regardless of the means
used to define the semantics.

X3D standards are client standards for implementation of the language.  I
don't think the lessons there apply to a web service.   The work on the
network sensor relies on the protocol standard being a separately defined
and testable artifact.   Interoperability is a much tougher problem.

When you say 'interoperability', you open a very deep can of system worms.
As has been asked many times on this list, what do you mean by
'interoperability'?  Last time I asked, the reply I got was something along
the lines of "well, Len, we ALL know what we mean by that; we don't have to
define it" but that sort of punt doesn't work in a standard and that
assumption is specious.   My reply is still, "Data is portable.  Systems
interoperate".  Without a systemic definition, a standard promising
"interoperability" is guaranteed to fail without out-of-band definitions.
Without consolidation into a process-mediated contract/standard/spec, the
drift is inevitable.  So now it comes down to the size of the system, its
role among systems of systems, and the different gaps emerging from
unforeseen applications of these.  

Try to do it all, we fail.  Try to do the minimal, we fail.   So you might
want to ask if QOS is a measure of errors or successes given ANY operation
attempted with or by the system version where that is a roll-up of other
versions.   IOW, the best declaration of a version is the system build
version and that is all you have for hanging a reliability number on.

len




From: Stephen Green [mailto:stephengreenubl@gmail.com] 

I wonder how much of all this will improve interoperability. Has anyone
tried
actually testing semantics as part of conformance testing? Is there any way
to test whether an implementation, say of a web service, properly
'understands'
the semantics behing the syntax and structure?

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