Page 27 - DCAP303_MULTIMEDIA_SYSTEMS

Unit 2: Text

2.4 Hypermedia and Hypertext notes

Both Hypermedia and hypertext refer to web pages and other kinds of on-screen content that
employ hyperlinks. Hyperlinks give us choices when we look for information, listen to music,
purchase products, and engage in similar activities. They take the form of buttons, underlined
words and phrases, and other “hot” areas on the screen.
Hypertext refers to the use of hyperlinks (or simply “links”) to present text and static graphics.
Many websites are entirely or largely hypertexts. Hypermedia refers to the presentation of
video, animation, and audio, which are often referred to as “dynamic” or “time based” content
or as “multimedia.” Non-web forms of hypertext and hypermedia include CD-ROM and DVD
encyclopaedias (such as Microsoft’s Encarta), e-books, and the online help systems that we find
in software products. It is common for people to use “hypertext” as a general term that includes
hypermedia. For example, when researchers talk about “hypertext theory,” they refer to theoretical
concepts that pertain to both static and multimedia content.
Starting in the 1940s, an important body of theory and research has evolved and many important
hypertext and hypermedia systems have been built. The history of hypertext begins with two visionary
thinkers: Vennevar Bush and Ted Nelson. Bush, writing in 1945, recognized the value of technologies
that would enable knowledge workers to link documents and share them with others. Nelson, starting
in the mid-1960s, spent decades trying to build a very ambitious global hypertext system (Xanadu)
and as part of this effort produced a rich (though idiosyncratic) body of theory.
2.4.1 Linear and non-linear Media

A “linear” communication medium is one, we typically experience straight through beginning
to end. There is little or no choosing as we go. Cinema is a linear medium. In the world of print,
novels are linear, but newspapers, magazines and encyclopaedias are somewhat non-linear.
They encourage a certain amount of jumping around. The web and other hypertextual media are
strongly non-linear. Indeed, the essence of hypertext and hypermedia is choice—the freedom to
decide what we will experience next. You can build a website, in which the hyperlinks take the
user on a single path from beginning to end, but this would be a strange website, and one can
question whether it is really hypertext.
2.4.2 nodes, Links and navigation
Web designers and others who are interested in hypertext often use the term “node” to refer to
chunks of content. Much of the time a “node” is simply a web page. But there are times when
we want to envision a cluster of closely related web pages as a single unit. Also, there are times
in which one physical web page really behaves like two or more separate chunks of content.
Furthermore, the “page” is not the fundamental unit of content in websites built with Flash (an
animation technology from Macromedia) and in many non-web hypertext systems. Therefore, we
do well to use the term “node” as the fundamental unit of hypertext content. Links (or hyperlinks)
are the pathways between nodes.
When we click links and thereby display a succession of web pages (nodes), we are in a sense
“navigating” the website. Navigation is only a metaphor; no one, of course, travels anywhere.
Navigation, however, is a very natural and useful metaphor because exploring a website (or a
non-web hypertext) is much like finding our way through a complex physical environment such
as a city. In both hypertext navigation and physical navigation, we choose the most promising
route and keep track of where we go. If we get lost, we may backtrack to familiar territory or even
return to our home base and start over. In the best case, we gain a mental picture of the overall
structure of the environment (a bird’s eye or map-like view).
At the same time, the concepts of nodes, links and navigation have limitations, and their
relevance and usefulness are being called into question due to the growing sophistication of web
technologies. If clicking a link plays an audio sequence, is the audio sequence then a node? Does
it matter whether the audio sequence is a single word or a 3-minute popular song? If clicking a
link on a web page begins a video sequence on a portion of that same page, how do we describe
what has happened? Is the video sequence a kind of sub-node embedded within the node that
is the page as a whole?

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