Jon Bosak Opens XTech Conference

Jon Bosak, co-editor of the XML Specification, chair of the XML Coordination Group, and co-chair of GCA's new XTech conference provided this year's opening keynote. After welcoming all to GCA's newest technical conference, Bosak began with a discussion on the XML family of standards.

The XML Family

Bosak specified that although XML began as an individual standard, it is really the combined XML suite of standards that is required to move the Web to its next generation. This suite of standards includes:

• XML: a subset of ISO 8879, created for the Web
• XLL: (now XPointer and XLink) hypertext mechanisms for the Web built upon Hytime and the Text Encoding Initiative
• XSL: a transformation and style sheet language based on ISO/IEC 10719, Document Style Specification and Syntax Language (DSSSL) and Cascading Style Sheet Language (CSS)

XML, the Extensible Markup Language, is the standard upon which the syntax for the others is based. XML is different from SGML in that it is light enough for browsers to display, and designed to be truly international. Bosak described how the unicode implementations of XML have proven painful and are still highly debated. Although XML has its roots in documents, Bosak claims that XML has much wider application. In fact, XML gives us a system to develop languages to solve particular problems. However, rather than being the end of the road, the recommendation by W3C of XML 1.0 is just the beginning.

Finishing the Job

Today we know that there are a number of key standards that are required for the Web to work as envisioned. First, it is strengthening our ability to specify document constraints. Today we have XML DTDs to do that job. But DTDs do not support datatyping or complex inheritance models that we require. This work will be done via a new XML schema language.

Next we need industry-wide vocabularies, or standard tag sets. And we need a way to register tag sets. The Organization for the Advancement of Structured Information Standards (OASIS) has stepped up and plans to provide a registry for XML vocabularies as they are developed.

W3C Working Groups

The original W3C XML working group is now divided into five separate groups. These groups include:

• XML Linking
• XML Schema
• XML Fragment
• Infoset: XML objects
• XML Syntax

In addition there are a number of W3C working groups that are related to the work of these new XML working groups. These related working groups include:

• DOM (Document Object Model)
• XSL (Extensible Style Language)
• I18N: (Internationalization)
• RDF SYNTAX (generalized metadata)

The XML Coordination Group works to coordinate the activities of the 5 XML working groups. The XML Coordination Group:

• Schedules work of 5 XML working groups
• Serves as the point of liaison to DOM/XSL
• Participates in the XML Plenary Group (union set of all W3C XML-related working groups)

Jon Bosak serves as the chairperson of both the XML Coordination Group and the W3C Plenary. Bosak indicated that W3C is interested in opening the standards development process. Of course the best way to take part is to join the W3C or to join an organization that belongs to W3C. W3C uses membership dues to fund its activities. Therefore, those that pay dues to W3C have early access to both the process and content of developing standards. Another way to participate is for your organization to establish a formal liaison with the W3C. In addition, W3C now makes the requirements document for each new specification open to the public for comment. So you can participate by commenting on the requirements for each new standard, even if you are not a liaison or member of W3C.

XML and Documents

Bosak concluded his keynote by discussing the importance of XML and documents. Although XML has many other uses on the Web, to Bosak, documents are still a critical focus for XML. To demonstrate the importance of documents to us all, Bosak provided the audience with a historical perspective.

Documents began about 4000 BC. The first documents were inventories. About 3500 BC, inventories changed, in that it became important that each document/inventory was signed to show responsibility for the validity of the content. By 3000 BC, documents became more sophisticated. Not only were documents signed, but the numbers recorded in documents were labeled as to their type. So we now had not only inventories, but contracts and deeds.

Over the next 3000 years, the changes in documents were in media only. Documents that were once written on clay tablets were written on papyrus, and then on paper. The printing press was invented. But the typical document remained a business document. After all this time, it is still critical that a document can be exchanged, read, and a meaning derived.

The use of XML on the Web, follows this model. The first step was to create a language for the interchange of data (XML). The next step will be for us to develop technology to display/read the document. This role will be filled by XSL. And the next step will be to preserve the meaning of the data (XML schemas come into play here).

According to Bosak, solving the issue of display can be developed using a procedural approach or with a declarative approach. The procedural method is easy to develop by technical people and quick to process. However, the declarative approach can be more powerful, and is far more user friendly to the general user in the long run. PostScript can be used as an example of a procedural approach, while PDF is declarative. Scripts to display XML are procedural, and style sheets are declarative. Style sheets are harder to implement by programmers than scripts. However, they are easier for any user to develop and in the end can provide more powerful display capabilities.

Clearly implementing XML style sheet technology will be the next big hurdle for the Web. According to Bosak, we make a big mistake in continuing to believe that style for online presentation is a subset of print. In the near future, when we have display capabilities with DPI equaling what we have in print, it will become clear that just the opposite is true. Print will become a subset of online presentation capabilities. Online display will have advanced features, such as scrolling and hyperlinking behaviors that are simply not appropriate on paper.

To demonstrate some of the new display capabilities that will be enabled by XSL in the future, Bosak demonstrated an online newspaper with a number of different renderings. The data for each layout was identical, only the style sheet had changed. For this demonstration the different layouts and behaviors were created using Java (procedural). In the future, this same sort of layout sophistication can be specified using XSL style sheets.

The Sun/Adobe Challenge

Jon announced two grants that will be formally posted in April by Sun and Sun/Adobe. The first will be a grant to develop XSL rendering for online presentation. The second grant, given jointly by Sun and Adobe will be to develop in Java, an XSL batch pagination engine to output PDF. Sun and Adobe intend to make both sets of code publicly available to jump start new XSL-based display technologies. Look for more details in April! Demonstrations of each new technology will be scheduled during GCA's XML '99 Conference in Philadelphia.

Look for XTech Papers on the GCA Site in April!

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