General DITA Questions

Why is "Darwin" in the name of this architecture?

1. Darwin: it uses the principles of specialization and inheritance
2. Information Typing: it capitalizes on the semantics of topics (concept, task, reference) and of content (messages, typed phrases, semantic tables)
3. Architecture: it provides vertical headroom (new applications) and edgewise extension (specialization into new types) for information

This architecture supports the proper construction of specialized DTDs from any higher-level DTD or schema. The base DTD is ditabase DTD, which contains an archetype topic structure and three additional peer topics that are typed specializations from the basic topic: concept, task, and reftopic. The principles of specialization and inheritance resemble the principle of variation in species proposed by Charles Darwin. So the name reminds us of the key extensibility mechanism inherent in the architecture.

Where can I learn more about topic-oriented writing and user assistance?

1. Minimalism (John Carroll)
2. DITA: An XML-based Technical Documentation Authoring and Publishing Architecture
3. Asilomar Institute for Information Architecture (AIfIA)

Where can I learn more about using DITA?

Many good articles have been published about DITA covering such topics as experience reports, best practices, project planning, among others.

1. DITA coverpage, which contains links to resources such as:
   • Moving from Single Sourcing to Reuse with XML DITA by Lori Fisher (IBM)
   • DITA: An XML-based Technical Documentation Authoring and Publishing Architecture by Michael Priestley (IBM)
2. The OASIS Darwin Information Typing Architecture Technical Committee home page, which contains links to published materials and the submission materials, such as:
   • The DITA charter at OASIS site

How does DITA differ from DocBook?

It's important to recognize that DocBook and DITA take fundamentally different approaches.

DocBook was originally designed for a single, continuous technical narrative (where the narrative might be of article, book, or multi-volume length). Through transforms, DocBook can chunk this technical narrative into topics to provide support for Web sites and other information sets. Because the goal of the DocBook DTD is to handle all standard requirements for technical documentation, the usage model encourages customization to exclude elements that aren't local requirements. The usage model supports but discourages local extensions because of the potential for unknown new elements to break tool support and interoperability.

By contrast, DITA was designed for discrete technical topics. DITA collects topics into information sets, potentially using filtering criteria. The core DITA information types are not intended to cover all requirements but, instead, provide a base for meeting new requirements through extension. Extension is encouraged, but new elements must be recognizable as specializations of existing elements. Through generalization, DITA provides for tool reuse and interoperability.

Each approach has its strengths. DocBook would be the likely choice for a technical narrative. DITA would be the likely choice for large, complex collections of topics or for applications that require both extensibility and interoperability. Technical communications groups might want to experiment with both packages to determine which approach is better suited for their processes and outputs.

How will changes to the DTD be made and controlled?

The Darwin Information Typing Architecture was first introduced publicly by IBM in April 2001, and maintained through fixes and design updates through March 2004. IBM has contributed the design at the 1.1.3 level to OASIS (http://www.oasis-open.org) as a Technical Committee activity. The DITA TC will take over maintenance and formal specification of the architecture.

1. The OASIS DITA TC has a "Send a comment" link that you can use to send comments to the TC. The DITA TC members maintain a members mailing list that is publicly readable. You can use comments to inform the TC of issues. The Comments link and the members' list archives are both available from the DITA TC home page: OASIS Darwin Information Typing Architecture TC .
2. A DITA forum to discuss the use of the DITA DTDs and style sheets. The newsgroup-based forum will be actively monitored by DITA architects, Don Day and Michael Priestley, among others. Information about using this forum is at: developerWorks "DITA Forum".

Does DITA provide both Schemas and DTDs?

The basic concepts of DITA are not tied to implementation. Both schemas and DTDs can be used to define specializable DITA elements. The current demo package provides both DTDs and XML Schemas.

How many elements are in DITA?

Because DITA is an architecture, not just a DTD, you have to ask the question in terms of which infotype (concept, task, reference) you have in mind, and containing which domains. New specializations always increase the count because they introduce delta (or new) elements, but the new content models typically have more restricted content models (which sometimes helps limit the selection choices that writers might see in a validating XML editor}. The following count is based on version 1.1.3 of the DTDs in the dita13 toolkit on IBM's developerWorks XML Zone.

The unspecialized topic.dtd in DITA has 94 elements.

The 4 basic domains (software, programming, highlighting, UI) contribute 49 elements altogether, which brings the count for domain-specialized topic dtd to 143.

Since domain specialization inherits across all dtds derived from topic.dtd, 143 is the base count affecting the rest of the per-dtd totals that follow:

• Concept.dtd adds 2 elements for its single-dtd total of 145.
• Task.dtd adds 25 elements for its single-dtd total of 168.
• Reference.dtd add 12 elements for its single-dtd total of 155.
• Ditabase.dtd adds only 1 element but includes all the other infotypes, therefore it has a grand total of 183.

The delta elements added by any new specializations will affect the tag count in similar ways.