Introduction to Darwin Information Typing Architecture

by Steve Kertesz

The following is a summary of the information that Michael Priestley of IBM Corporation presented at the November 1, 2005 general meeting.

What Is DITA?

Darwin Information Typing Architecture (DITA) is an XML-based architecture that IBM developed for authoring and producing technical documentation.

The architecture itself is comprised of a set of design principles for creating information typed modules. The fundamental unit of DITA is the topic. The topic is a unit of information that describes a single task, concept, or reference item.

Accompanying the topic is an XML Document Type Definition (DTD) called the “topic DTD”.

The Main Characteristics of DITA

Topic Orientation

The basic unit of structure is the topic. Any additional high-level structures, such as print organization, are part of the topical processing.

Topics have no internal hierarchical nesting. They rely on sections that define the topic for organization.

Topical Reuse

Since topics possess a non-nesting structure, a topic can be reused in any context.

Content Reuse

DITA implements a reuse technique, which provides each element with an attribute that can point to any base element. This ensures a fail safe structure is always part of the calling topic.

Specialization

Any DITA element can be extended into a new element. This is accomplished by adding the new element’s identifier to the class attribute through its DTD.

Specialization occurs on two levels: topic specialization and domain specialization.

Topic specialization is a way of extending the generic topic into new information types. These new information types can then be more specifically instantiated.

As a concept, domain specialization means that introducing elements that reflect a specific information domain served by the topics can extend the basic vocabulary within a generic topic. In other words, the generic topic can be extended to suit a specific usage.

Another characteristic of DITA is that the DITA model for metadata provides metadata and attributes used to process or filter the content of DITA topics for specific applications.

DITA also takes advantage of existing tags and tools by building on widely accepted sets of tags and can be used with standard XML tools.

Benefits of the DITA Architecture

The benefits of the DITA architecture include encapsulation and polymorphism.

Encapsulation

Through encapsulation, the designer of a topic needs to address only a specific manageable problem domain. Similarly, an author needs to learn only elements that are specific to the topic type, independent of other information.

Polymorphism

The concept of polymorphism, as it relates to DITA, means that specialized topic types can be treated as more generic topic types for common processing.

One additional benefit of DITA is that a topic may be generalized back to an earlier form at any time and, if class attributes are preserved, these topics may be re-specialized.

The chapter would like to thank Automation Tooling Systems (ATS) and Campana Systems Inc. for donating the door prizes for November. And, a belated thank you to ATS and Spicer Corporation for donating the door prizes for October!