Chapter 1: Semantics - A Trillion-Dollar Cottage Industry

Overview

The U.S. economy is perched precariously on top of some 200 billion lines of aging legacy mainframe code^[1] and a comparable amount of newer, but no less endangered, code on various flavors of servers and PCs. This represents a $3 trillion investment,^[2] most of which will need to be replaced over the next decade, at a price more likely to hit $10 trillion.

This is pretty much business a usual, except for two things:

• A large percentage of this cost, perhaps as much as half, is avoidable.

• The approach we take to this next round of replacement will determine how much of this investment really will be an "investment" that will carry forward to subsequent generations of technology.

And the technology on which the realization of these benefits hinges is not really a technology at all. It is a 2500-year-old branch of philosophy, made suddenly relevant by a confluence of developments: semantics.

Consider the following:

• The Mars Climate Observer crashed into the surface of Mars, a victim not of a technical problem, but of a semantic misunderstanding concerning the units of measure used to calculate the thrust.

• Between half and three quarters of the $300 billion spent annually on systems integration is spent resolving semantic issues.

• The entire Y2K adventure was two semantic problems piled on top of each other, the first being the simple problem of determining whether "01" meant "1901" or "2001," the second being that the stewards of many of the affected systems had no way to understand the applications in enough fidelity to predict what would happen to them if they were altered.

• The most promising technologies currently offered up to solve our application development and implementation problems—Enterprise Application Integration (EAI), XML, Business Rules, Web Services, Collaboration, and of course the Semantic Web—all share a foundational reliance on semantics.

Perhaps this is enough to whet your appetite, and maybe about now you are wondering: "Where can I buy some semantics?" or "How do I ‘do’ semantics?" or "Can I implement semantics in my organization?" But that's not the nature of semantics. Semantics is a discipline you apply, not a technology you buy.

Monsieur Jourdain, in Jean Baptiste Moli re's play The Bourgeois Gentleman:

• "And when one speaks, what is that?"

• "That is prose, Monsieur."

• "What! When I say, ‘Nicole, bring me my slippers, and give me my nightcap’; is that prose?"

• "Yes, Monsieur."

• "Well, well, well! To think that for more than forty years I have been speaking prose, and didn't know a thing about it. I am very much obliged to you for having taught me this."

Like Monsieur Jourdain in the accompanying sidebar, I trust most software developers will be quite pleased to find they have been applying semantics their entire career. Maybe you haven't been intentional or rigorous about it, but in order to get anything at all done in the world of software you have had to deal with semantics.

In this book, we look at every aspect of business systems anew. We also put semantics under the microscope and find out what it is composed of, and how that might guide our further investigations. And we look at our applications and our development technologies from the point of view of semantics, to see how that changes our perceptions.

Before we go any further, let's get this out of the way:

Semantics

Semantics is the study of meaning.

Semantics is often defined as the study of the meaning of words, but we are going to take the broader definition here, allowing for the possibility for meaning to reside in something other than just words. Ultimately, the relevance and success of our application systems rest on what the symbols that we are manipulating inside the computer really mean in the "real world." Of importance is not only what they mean—but do the people, and other computer programs, that deal with the presented information understand and agree with the meaning as implied by the system?

^[1]Rekha Balu, "(Re)Writing Code," Fast Company, April 2001, pp. 181–189.

^[2]Paul Strassman, "End Build-and-Junk," Computerworld, July 5, 1999. Available at http://www.strassmann.com/pubs/cw/end-junk.shtml.