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Re: Microsoft's response to XML.com article

• From: "Steven R. Newcomb" <srn@t...>
• To: xml-dev@i...
• Date: Fri, 14 Jan 2000 11:16:54 -0600

[Jun Fujisawa <fujisawa@t...>:]

> On MSDN site, I found an article posted which addresses some of the
> issues raised by the David Brownell's XML.com review.

> <http://msdn.microsoft.com/xml/general/msxmlconform.asp>

> The article states that "you will see much better than 87 or 88
> percent of XML files exchanged between Msxml.dll and other parsers
> actually achieve interoperability".

  (Religion alert!  Below is a RANT from a person who believes Precise
  Communication Is A Good and Sacred Thing upon which the Lives and
  Livelihoods of All Civilized Human Beings Depend.)

I guess it depends on what is meant by "interoperability".
"Interoperability" means far more than "well-formedness" (parsability)
or even "validity" (conformance to a DTD or other schema).

An "interoperable" XML instance must provably conform, not only
lexically but also semantically, to a set of constraints such that any
application that relies upon an instance's conformance to that set of
constraints can successfully and fully interpret the instance
precisely in the manner intended by its creator.

  (Note: The widespread popular use of the term "XML file" is also
  imprecise and misleading.  I use the term "XML instance" because an
  "XML file" is not necessarily even well-formed, much less
  validatable, much less interoperable.  "XML instance" refers to the
  logical thing that is a complete XML expression.  "XML file" refers
  to a storage object that contains some data that has something to do
  with XML, but it does not imply that the contents of the file
  constitute a complete XML instance.  Therefore, while it is
  meaningful to speak of the "interoperability" of an "XML instance",
  it is not meaningful to speak of the "interoperability" of an "XML
  file".)

In the general case, there can be no such thing as "interoperability",
even for XML instances, unless the requirements of interoperability
have been exhaustively and precisely defined in writing -- most likely
using a natural language -- for a given class of XML instances.  Such
an "architecture definition document" (so-called in ISO/IEC
10744:1997) probably includes, but is not limited to, a DTD.  Yes, an
XML Schema might replace the DTD, but an XML Schema by itself cannot
be a definition of interoperability, any more than a DTD can.  This is
because no single parser, and no single schema language, regardless of
its level of sophistication, can be the arbiter of interoperability
for all types of instances.

Interoperability (regardless of what it is called after the word
"interoperability" has been rendered useless through widespread abuse)
is not yet a popular concept on the Web, but it will necessarily have
become popular by the time Web-based e-commerce has matured.  This is
because interoperable XML instances always make sense and always
perform as expected, even in multi-software-vendor, multi-application
contexts.  Business-to-business communications absolutely require that
level of reliability and precision, and business-to-business
communications very often occur in multi-software-vendor,
multi-application contexts.

Software vendors basically don't like information to be interoperable,
even though it serves the best interests of their customers.  One way
to attempt to stamp out the whole concept of interoperability is to
undermine the meaning of the word "interoperable", so that the concept
will afterwards not even have a name.  Even without a usable name,
though, the concept of real interoperability is not going to go away.
No amount of denial or FUD can change the basic business requirements.

-Steve

--
Steven R. Newcomb, President, TechnoTeacher, Inc.
srn@t...  http://www.techno.com  ftp.techno.com

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• References:
  • Microsoft's responce to XML.com article
    • From: Jun Fujisawa <fujisawa@t...>

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