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LC-36 (your comments on XML Schema last-call draft)

From: C. M. Sperberg-McQueen <cmsmcq@acm.org>
Date: Thu, 21 Sep 2000 12:02:48 -0600
Message-Id: <>
To: David RR Webber <Gnosis_@compuserve.com>
Cc: <www-xml-schema-comments@w3.org>
Dear Mr. Webber:

The W3C XML Schema Working Group has spent the last several months
working through the comments received from the public on the last-call
draft of the XML Schema specification.  We thank you for the comments
you made on our specification during our last-call comment period, and
want to make sure you know that all comments received during the
last-call comment period have been recorded in our last-call issues
list (http://www.w3.org/2000/05/12-xml-schema-lcissues).

Among other issues, you raised the points registered as issue LC-36,
which suggests several changes to the WG's design and to its plans for
its further work.  Specifically, you suggested that the work on XML
Schema be suspended for three months to allow a reconsideration of the
requirements and design goals for XML Schema in the light of ebXML and
other similar projects, that we adopt a three-tier design, that we
schedule six months of field testing before formal adoption, and that
a test suite be provided.

The WG, being acutely aware that the work on XML Schema has already
lasted longer than was originally expected, was concerned that
returning to the requirements phase of the project would delay the
appearance of XML Schema 1.0 beyond any acceptable date.  The
requirements recorded in our requirements document continue to be
matters of concern for users, even if some users have different
requirements or concerns.

The adoption of a multi-tier design does have a number of advantages;
the two-tier design of the current XML Schema spec, which
distinguishes resolutely between the abstract component level and the
transfer-syntax level, seems to us to be the best available compromise
between simplicity and flexibility.  We may be wrong, of course, but
on the whole the WG felt that moving to three tiers would add
complexity faster than it would add flexibility.

Field testing is already part of the normal process of developing W3C
Recommendations, in the form of a period during which specifications
are published as Candidate Recommendations.  Specifications leave the
Candidate Recommendation period and are published as Proposed
Recommendations when there is sufficient implementation experience to
demonstrate their implementability.  The length of the CR period may
vary; given the fairly extensive progress on implementation already
reported by various development teams, the majority of the WG is
currently leaning toward a CR period of something less than six

We agree that a test suite will be useful, and we expect to devote WG
resources during the CR period to encouraging the development and
collection of test suites for XML Schema.

It would be helpful to us to know whether you are satisfied with the
decision taken by the WG on this issue, or wish your dissent from the
WG's decision to be recorded for consideration by the Director.

With best wishes,

- C. M. Sperberg-McQueen
   Dave Hollander
   Co-chairs, W3C XML Schema WG
Received on Thursday, 21 September 2000 08:52:21 UTC

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