XML Standards Update

December 6, 1999

Simon St. Laurent

Developers gathered at the XML '99 conference were treated to a somewhat more frank standards update than is typical at these conferences. Leading a series of presentations from consortia involved in XML development, Dan Connolly of the W3C took questions from the audience rather than presenting a static list of progress reports. Supported by a few W3C participants, Connolly took some hard questions about schemas, links, and namespaces. Other groups, including the GCA's new IDEAlliance, OASIS, and Microsoft (reporting on BizTalk) presented a more traditional update. All of the organizations seemed to share a common belief that their work would move XML ahead, despite several overlaps and potential competition.

Connolly took questions from cards filled in by the audience as well as a few live questions. Many questions revolved around whether the W3C was addressing particular fields and when it would deliver results, if in fact they were. Connolly warned developers that some fields --notably XML querying -- are only getting started, and that there were several proposals called 'XQL' out, among the many presented at a workshop earlier this year.

Schema and XLink timelines have both fallen behind original expectations. XML Schemas were supposed to be a Proposed Recommendation this December, but are still in Working Drafts. XLink lingered 16 months between drafts, and has fallen behind as XPath and XPointers received extra effort. A Last Call working draft of XPointer has emerged this week; XPath became a Recommendation last month. Asked whether XLink work should be continued, Connolly replied strongly that it should, and pointed to Scalable Vector Graphics (SVG) as an example of an XML application that uses XLink. Topic Maps, a recently approved ISO standard, seem to be considered a competitor or complement to the W3C's Resource Description Framework (RDF) project, not a tool which the W3C will include in future development efforts.

Despite the delays, schemas are starting to mature, Connolly said, and may achieve some key goals -- notably reconciliation between RDF and XML Schema data typing -- in the relatively near future. Asked about the W3C's position on copyrighting such schemas, Connolly pointed to the W3C's own approach to copyrighting and licensing its own developments, which strive to balance accessibility with the maintenance of 'clean' standards. Healso suggested that schemas could solve some issues involving binding data to both database structures and semantic meaning. Schemas will also probably go through a "candidate recommendation" process, in which the W3C posts a stable draft to collect implementation feedback.

As the debates about Simple Markup Language, a project to subset XML, continue to rage in XML-dev and other community forums, Connolly reaffirmed both that XML would remain itself a subset of SGML and preserve the current XML 1.0 feature set. Steven DeRose suggested that while everyone seemed to agree that XML itself could be trimmed, most developers have very different opinions about which parts to omit. Connolly also noted that Phase II of the XML Activity had studied just such a reduction, but hadn't been able to reach a consensus on requirements. When another questioner asked whether Extensible Style Language (XSL) might be ripe for a similar trim, Sharon Adler, XSL chair, suggested that while some subsetting might be possible, the complexity was merited and that tools for creating XSL were a better alternative for simplifying the style sheet design process.

Other organizations also presented updates on their work, though they didn't take questions. The Graphics Communication Association, hosts of the show, announced its IDEAlliance project, a framework for developing interchange standards. Focusing on interoperability, IDEAlliance will host work on Publishing Requirements for Industry Standard Metadata (PRISM), an XML initiative for the publishing industry, as well as Information and Content Exchange (ICE), an XML infrastructure for syndication and the Customer Profile Exchange Network, a "privacy enabled" infrastructure for exchanging information about business customers. IDEAlliance will also host the Independent Consultants Cooperative (ICC), an organization of SGML and XML consultants, and host XML events.

Norbert Mikula, CTO of OASIS

Norbert Mikula, CTO of OASIS, presented updates on their many projects, including its XML Conformance Technical Committee, which published a test suite earlier this year. He also spoke about the XML Tables Model group, which has published a standard based on the Open Exchange Table Model. The DocBook group is developing an XML version of the popular markup vocabulary, the Registry and Repository group is approaching a draft based on ISO 11179. CGM Open, an OASIS affiliate, is working on XML companion files for CGM files. The ebXML project, aimed at creating a framework for large-scale business interchange, is building on UN/CEFACT activity and is supporting 120 participants from 50 organizations.

Microsoft's Christopher Kurt

Christopher Kurt of Microsoft presented an update on BizTalk, discussing the framework, repository, and server as separate pieces of a puzzle that Microsoft hopes to use to bring businesses closer together. The BizTalk framework is available as specifications and a set of components. The BizTalk repository provides organizations -- not just Microsoft -- with a place to publish their schemas, providing developers with a place to share their them and find new ones. The final piece, the BizTalk server, is a software product, currently in alpha, that provides support for BizTalk framework and support for other industry standards, notably EDI technologies.

None of these last three speakers took questions from the crowd, leaving attendees to ponder the large set of acronyms they had heard without much give and take. Clarifying the relationships between the IDEAlliance's Customer Profile Exchange Network and the W3C's Platform for Privacy Preferences might have been worthwhile, as might a clearer statement of the relationship, or otherwise, between BizTalk and XML.org.