Part VIII
Becoming an Electronic Publisher

29  Understanding the Old Paradigm

30  Understanding the Information Revolution: The New Paradigm

31  Object-Oriented Development of SGML Applications

Chapter 29
Understanding the Old Paradigm

To appreciate the importance of SGML, you need to think about how information has been modeled until now. It all depended on how the information was delivered—through books. That has changed. Books are still important, but computers have created more possibilities. It is time to upgrade how information is organized.

In this chapter, you learn:

•  The components of information delivery

•  The ways of organizing knowledge

•  The implications of the linear organization of knowledge

•  The role of format

•  The role of structure and the new paradigm

The Components of Information Delivery

The basic components of delivering information are structure, content, and format. They apply to the ways in which information has been gathered until now. They fit the old paradigm.

Components besides structure, content, and format exist. They include the media for delivering information, such as a sheet of paper, a book, or computer network. Spoken languages, tribal dances, and stone tablets engraved with symbols all convey information. Fortune cookies, chalkboards, traffic lights, roadside milestones, and calculators and abacuses convey information, too. The components of information delivery are innumerable, but structure, content, and format are always necessary.

Even with a fortune cookie, the boundary of the medium defines the structure. In this case, a small slip of paper that fits inside the cookie defines the boundary. With a calculator—or even a cave wall—physical boundaries define the limits of the structure. Content must fit the limits of structure. Format is applied on top of that.

Information can now be delivered by more abstract methods; many physical limitations no longer apply. To convey information by means of cave paintings, for example, you are limited by the space available on the cave wall. If you communicate by speech alone, you are limited by memory and time—sooner or later your voice goes out. When you store information on paper, you are limited by the size of the page.

The Ways of Organizing Knowledge

You can organize knowledge in many ways, two of which are linear and modular. Linear means from first to last, from front to back, and from start to end. You know what the beginning and the end are because you know where to look for them. Modular means there is not necessarily a beginning or an end by virtue of the structure of the information. For example, the whole contents of a library are modular; you don’t go into a library and read the first book on the shelves and proceed systematically through to the last book. You read a book here and a book there—the modules are relevant to you. However, individual novels are intended to be read from beginning to end, in a linear fashion. Figure 29.1 illustrates the difference between these two approaches to organizing knowledge.

Fig. 29.1  The linear approach emphasizes the sequence of information, whereas modular approach emphasizes information modules.

As for an individual book, if you read the middle section first or the first chapter last, you are using modular information retrieval. It is modular because “first” and “last” do not apply to the way in which you deal with the information’s structure. Many problems arise because books are often regarded as always being linear rather than modular.

Linear Books

How books and information have been organized indicates how people have looked at information. The sequential, step-by-step way of organizing knowledge implies that:

•  You must read and understand Chapter 1 before you can understand Chapter 2.

•  Everything in Chapter 4 builds on the material in Chapters 1, 2, and 3.

•  If you read chapters out of sequence, they will not make sense.

•  It is physically impossible to place Chapter 3 after Chapter 7.

•  All types of information should be organized from beginning to end.

•  No one wants information to be organized in a modular way.

Many of these conclusions are no longer true. When books existed only on paper, it was physically impossible to put Chapter 3 after Chapter 7—the physical position of the chapters dictated their names. In other words, if you placed Chapter 3 immediately after Chapter 7, it would be called Chapter 8. With the advent of hypertext and hypermedia, all this has changed. The electronic age enables you—even forces you—to rethink how you structure information. It is no longer physically impossible to place Chapter 3 after Chapter 7. This idea is the crux of the information revolution. It is the reason why SGML is so important. Even reference books like this one are organized into information modules to facilitate random retrieval of information. Many books have turned from presenting information linearly to modularly, as shown in figure 29.2.

Fig. 29.2  Linear books and modular books structure information differently. Today, linear books are becoming like modular books.

SGML is the ultimate tool for making information modular. That’s because modular books must be highly structured books, and structure is what SGML defines in documents.