IBM developerWorks has published an article by Don R. Day, Michael Priestley, and Dave A. Schell on IBM's XML-based 'DITA' architecture for authoring, producing, and delivering technical information. DITA DTDs, style sheets, and sample documents are available online. The article surveys the development of DITA by a cross-company workgroup representing user assistance teams from IBM, Lotus, and Tivoli, and explains the decision not to simply convert IBMIDDoc, or to use an existing XML DTD such as DocBook, or TEI, or XHTML; after all, 'IBM, with millions of pages of documentation for its products, has its own very complex SGML DTD, IBMIDDoc, which has supported this documentation since the early 1990s'. In DITA, the 'topic' is the basic architectural unit: "a topic is a unit of information that describes a single task or concept or reference item. The information's category (concept, task, reference) is its information type. Typed topics are easily managed within content management systems as reusable, stand-alone units of information. The XML-based Darwin Information Typing Architecture (DITA) is an end-to-end architecture for creating and delivering modular technical information. The architecture consists of a set of design principles for creating information-typed topic modules, and for using that content in various ways, such as online help and product support portals on the Web. At the heart, the DITA is an XML document type definition (DTD) that expresses many of these design principles. The architecture, however, is the defining part of this proposal for technical information; the DTD, or any schema based on it, is just an instantiation of the design principles of the architecture. The IBM workgroup developed the architecture collaboratively during 2000 through postings to a database and weekly teleconferences; they are offering the architecture on IBM's developerWorks Web site as an alternative XML-based documentation system, designed to exploit XML as its encoding format."

[March 16, 2001] "Introduction to the Darwin Information Typing Architecture. Toward portable technical information." By Don R. Day, Michael Priestley, and Dave A. Schell. From IBM developerWorks. March 2001. The Darwin Information Typing Architecture (DITA) is an XML-based architecture for authoring, producing, and delivering technical information. This article introduces the architecture, which sets forth a set of design principles for creating information-typed modules at a topic level, and for using that content in delivery modes such as online help and product support portals on the Web. This article serves as a roadmap to the Darwin Information Typing Architecture: what it is and how it applies to technical documentation. The article links to representative source code."

Excerpts from the article:

The XML-based Darwin Information Typing Architecture (DITA) is an end-to-end architecture for creating and delivering modular technical information. The architecture consists of a set of design principles for creating information-typed topic modules, and for using that content in various ways, such as online help and product support portals on the Web. At the heart, the DITA is an XML document type definition (DTD) that expresses many of these design principles. The architecture, however, is the defining part of this proposal for technical information; the DTD, or any schema based on it, is just an instantiation of the design principles of the architecture.

The topic as the basic architectural unit: A topic is a unit of information that describes a single task or concept or reference item. The information's category (concept, task, reference) is its information type. Typed topics are easily managed within content management systems as reusable, stand-alone units of information. For example, selected topics can be gathered, arranged, and processed within a delivery context to provide a variety of deliverables, such as groups of recently updated topics for review, helpsets for building into a user-assistance application -- or even chapters or sections in a booklet, printed from user-selected search results or "shopping lists."

Specialization: A company that has specific information needs can define specialized topic types. For example, a product group might identify three main types of reference topic: messages, utilities, and APIs. By creating a specialized topic type for each type of content, the product architect can ensure that each type of topic has the appropriate content. In addition, the specialized topics make XML-aware search more useful, because users can make fine-grained distinctions. For example, a user could limit a search for xyz to messages only or to APIs only. A user could also search for xyz across reference topics in general. Rules govern how to specialize safely: each new information type must map to an existing one, and must be more restrictive in the content that it allows. With such specialization, new information types can use generic processing streams for translation, print, and Web publishing. Although a product group can override or extend these processes, they get the full range of existing processes by default, without any extra work or maintenance. A corporation can have a series of DTDs that represent a consistent set of information descriptions, each of which emphasizes the value of specialization for those new information types. [See the adjunct article by Michael Priestley, "Specialization in the Darwin Information Typing Architecture. Preparing topic-based DITA documents."]

Also: "Notes Help 5.0.3 in DITAbase XML." "[This document] Introduces users to Notes features, such as mail, scheduling, Calendar, and To Do. It also describes how to use Notes away from the office. This release of Notes Help is provided in XML using the DITAbase DTD, which is available on the IBM developerWorks site. The download includes style sheets for viewing the XML with Microsoft Internet Explorer 5.x, with the MSXML3 parser upgrade. We are providing this content solely as a proof-of-concept for the DITAbase DTD, and not with any explicit or implied statement of intention. Note that this release does not provide context-sensitive Help for Notes." [John Hunt]

Update 2001-11-01: "Introduction to the Darwin Information Typing Architecture: Toward Portable Technical Information." By Don R. Day, Michael Priestley, and David A. Schell (IBM Corporation). From IBM developerWorks. Updated October 2001. Original publication: March 2001. ['The Darwin Information Typing Architecture (DITA) is an XML-based architecture for authoring, producing, and delivering technical information. This article introduces the architecture, which sets forth a set of design principles for creating information-typed modules at a topic level, and for using that content in delivery modes such as online help and product support portals on the Web. This article serves as a roadmap to the Darwin Information Typing Architecture: what it is and how it applies to technical documentation. The article links to representative source code.'] "The XML-based Darwin Information Typing Architecture (DITA) is an end-to-end architecture for creating and delivering modular technical information. The architecture consists of a set of design principles for creating information-typed topic modules, and for using that content in various ways, such as online help and product support portals on the Web. At the heart, the DITA is an XML document type definition (DTD) that expresses many of these design principles. The architecture, however, is the defining part of this proposal for technical information; the DTD, or any schema based on it, is just an instantiation of the design principles of the architecture..." Note from Don Day, Lead DITA Architect: "After a round of bug fixes, evaluation of suggestions, and use in prototype projects, the DITA DTDs and tools are now available in a new update package on developerWorks. This version includes more examples of specialization and of topic reuse within example build frameworks. The DTD updates extend what can be done with semantics and domain-specific vocabularies built on a standard extensibility mechanism. For an introductory approach, follow the Resources link in any of the updated DITA articles. The article updates are relatively minor; the tools package is the major part of this update release. Or go directly to the package. Unzip the package to any handy directory; its contents will unpack within a "dita" top-level directory that will be created for you. Check out the README file in that directory to see what is in the package and what has been changed since the first release." See also: (1) the DITA FAQ set; (2) "Specialization in the Darwin Information Typing Architecture," a companion article which outlines how to implement DITA.

[Update: May 15, 2002]   IBM's Darwin Architecture Supports Enhancements for Domain Specialization, Content Reuse, and Linking Logic.    Communiqués from Don Day and Michael Priestley of IBM describe new features in the 2002-05 update of IBM's XML-Based Darwin Information Typing Architecture (DITA). The DITA XML-based architecture "provides a way for documentation authors and architects to create collections of typed topics that can be easily assembled into various delivery contexts. Topic specialization is the process by which authors and architects can define topic types, while maintaining compatibility with existing style sheets, transforms, and processes. The new topic types are defined as an extension, or delta, relative to an existing topic type, thereby reducing the work necessary to define and maintain the new type." Improving upon the original released of March 2001, DITA v1.0 features "a logical extension of specialization that has now been incorporated into DITA: the ability to extend existing content markup to represent domains of specialized markup that are common across particular sets of typed topics (hardware vs. software, for example)." The DITA design has a unified content reuse mechanism which enables one to combine several topics into a single document: "an element can replace itself with the content of a like element elsewhere, either in the current topic or in a separate topic that shares the same content models. The distinction between reusable content and reusing content, which is enshrined in the file entity scheme, disappears: any element with an ID, in any DITA topic, is reusable by 'conref' transclusion. The linking logic is also now supports type checking and takes advantage of the short description element to provide progressive disclosure." [Full context]