DocBook is a schema (available in several languages including RELAX NG, SGML and XML DTDs, and W3C XML Schema) maintained by the DocBook Technical Committee of OASIS. It is particularly well suited to books and papers about computer hardware and software (though it is by no means limited to these applications).
Because it is a large and robust schema, and because its main structures correspond to the general notion of what constitutes a “book,” DocBook has been adopted by a large and growing community of authors writing books of all kinds. DocBook is supported “out of the box” by a number of commercial tools, and there is rapidly expanding support for it in a number of free software environments. These features have combined to make DocBook a generally easy to understand, widely useful, and very popular schema. Dozens of organizations are using DocBook for millions of pages of documentation, in various print and online formats, worldwide.
The DocBook Technical Committee maintains both SGML and XML versions of the DocBook DTD and XML versions in several other languages. To the extent that it is practical, these DTDs are identical. There is no intentional difference between the DTDs, they are supposed to accept the same set of documents.
DocBook has been under development since 1991.
The DocBook DTD was originally designed and implemented by HaL Computer
Systems and O'Reilly & Associates around 1991. It was developed primarily
for the purpose of holding the results of
of UNIX documentation, so that the files could be interchanged. Its design
appears to have been based partly on input from SGML interchange projects
being conducted by the UNIX International and Open Software Foundation consortia.
When DocBook V1.1 was published, its revision and maintenance began being discussed in earnest in the Davenport Group, a forum created by O'Reilly for computer documentation producers. V1.2 was influenced strongly by Novell and Digital.
In 1994, the Davenport Group became an officially chartered entity responsible for DocBook's maintenance; DocBook V1.2.2 was published simultaneously. The founding sponsors of this incarnation of Davenport included the following:
Jon Bosak, Novell
Dale Dougherty, O'Reilly & Associates
Ralph Ferris, Fujitsu OSSI
Dave Hollander, Hewlett-Packard
Eve Maler, Digital Equipment Corporation
Murray Maloney, SCO
Conleth O'Connell, HaL Computer Systems
Nancy Paisner, Hitachi Computer Products
Mike Rogers, SunSoft
Jean Tappan, Unisys
Under the auspices of the Davenport Group, the DocBook DTD began to take on a larger scope: It was now being used by a much wider audience, and for new purposes, such as direct authoring with SGML-aware tools and publishing directly to paper. As the largest users of DocBook, Novell and Sun tended to have heavy influence on the design.
In order to help users manage change, the new Davenport charter established the following rules for DocBook releases:
Minor versions (“point releases,” such as V2.2)
could add to the markup model, but could not change it in a backwards-incompatible
way. For example, a new kind of list element could be added, but it would
not be acceptable for the existing itemized-list model to start requiring
two list items inside it instead of only one. Thus, any document conforming
n.0 would also conform to
Major versions (such as V3.0) could both add to the markup model and make backwards-incompatible changes. However, the changes had to have been announced in the previous major release.
Major-version introductions must be separated by at least a year.
V3.0 was released in January 1997. After that time, although DocBook's audience continued to grow, many of the stalwarts of the Davenport Group became involved in the XML effort, and development slowed dramatically. The idea of creating an official XML-compliant version of DocBook was discussed, but not implemented.
The sponsors wanted to close out Davenport in an orderly way, but ensure that DocBook users would be supported somehow. It was suggested that OASIS become DocBook's new home. An OASIS DocBook Technical Committee was formed in July, 1998, with Eduardo Gutentag of Sun as chair.
The DocBook Technical Committee of OASIS is undertaking new DocBook development, has published an XML-compliant version of DocBook and plans to develop an XML Schema for DocBook.