Rockley, Chapter 2 Summary - (Haupt)
This capability first become possible when Dr. Charles Goldfarb, an IBM researcher, invented Generalized Markup Language (GML) during the 1970s. Later morphed into a more advanced implementation of structured document markup as Standard Generalized Markup Language, this invention became one of the foundational technologies upon which the World Wide Web was built. Most people do not realize the HTML is merely a simplistic Document Type Definition (DTD) of SGML. An SGML document comprises of three parts, the Declaration (for example it can specify "Transitional" HTML, the Instance, and the DTD. In the World Wide Web the DTD is never transmitted. It is retained within the browser's code itself.
For the purposes of "reuse" we focus on the DTD. The DTD is a way to describe the logical hierarchy of a document. The logical structure of a document is separated from the typographical formatting of the document (formatting is contained in a Formatting Output Specification Instance - a FOSI). When the World Wide Web was invented SGML was found to be incompatible with it unless a browser plugin was used. Therefore, among other reasons, XML was created - a simplified and web-compatible version of SGML.
XML can be used with either a formal DTD (Yes, you can code your own XML DTDs!) or a valid schema. Either approach defines logical structure of a class of documents. In the world of technical communications XML data repositories are used that contain multiple DTDs/schemas. Authors don't write documents. They write elements. An element is simply an instance of a subset of a structured document defined by the DTD. The document elements are stored within the database and are available through a front-end editor such as Arbortext. Technical Writers are able to browse a library of elements and select the ones they wish to incorporate into their document. In the event that they can't find a suitable existing element they have the option to create a new element and write the content for it.
An XML-based content management system keeps track of the element reuse, version control, audit trails, records management, security, etc. and collects the elements at publishing time. Users can specify a wide variety of output formats including HTML, TROFF, RTP, PDF, and Java Help, etc.
Additionally, publishing outputs can be customized for individual readers - pulling a subset of reusable elements from the repository for each type of need - for example an "installation" view, a "training" view, or a "maintenance" view.
Rockley correctly identifies the benefits of an element reuse strategy: 1) Increased Consistency, 2) Reduced Development and Maintenance Costs, 3) Rapid Reconfiguration, and 4) Translation.
The concept of reuse has existed for a long time but is only recently gaining large-scale traction within industry. Software developers have long used reuse of code. A Class Library is simply a collection of previously used code that a developer can reuse for new applications under development. Technical Communicators are now seeing a plethora of solutions available to meet their element reuse needs. Rockley refers to element reuse as "single sourcing". Personally, I've never heard that term before in this context. This is probably because I have approached the problem from an engineering viewpoint instead of from the technical writer's viewpoint - hence I learned the jargon of documentation engineering and have used those terms to describe the environment Rockley describes.
Rockley correctly points out that reuse is not appropriate for every document. I am currently working with Astoria Software to implement a reuse solution within Wells Fargo. Astoria provides a three-pronged test to determine if a document is suitable for reuse: 1) document must be dynamic - constantly being updated, 2) document volume must be large to meet economies of scale, 3) document production processes need to be streamlined.
In conclusion, employing element reuse solutions represent an accelerating trend in technical communications. Learn to love it!