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Abstract:
Aspects of Large World Wide Web Systems
J. Lennon
Department of Computer Science,
Private Bag 92019, Auckland, New Zealand - H. Maurer
Graz University of Technology,
Schießstattgasse 4a, A-8010 Graz, Austria
In this paper we consider some of the challenges associated with many World Wide Web systems, particularly in their
handling of large quantities of multimedia data, and ask whether we can look forward to better systems in the not too
distant future. In particular, we look at various aspects of hypermedia data models including new methods for link
management.
Introduction
The World Wide Web (WWW) must, on many counts, be rated a success: the number of servers, the number of users,
the amount of hype published daily all around the world. However, in this paper we look at some of the consequences of
using systems that have large numbers of unstructured nodes with considerable numbers of links [Conklin, 1987],
particularly on distributed systems such as WWW [Kappe, 1995]. Although hardware related problems such as
inadequate bandwidth obviously still exist, we concentrate on more fundamental data model issues, especially those
associated with link structures.
Internet Problems
It has, however, become quite apparent that a number of fundamental changes in Internet systems are necessary if they
are to continue to grow and to be used for large professional projects. We will begin by outlining just a few of the more
common problems experienced by users:
Dangling links. As we shall elaborate in Section 2, most of the commonly-used systems cannot guarantee any
degree of referential link integrity. All too often users are faced with some form of ``file doesn't exist" message.
It is particularly frustrating to discover that documents that were successfully accessed one day have disappeared
the next!
Loss of orientation. This well known problem of large systems is one consequence of the fact that links in many
WWW systems are unidirectional, have no type, and thus cannot support users by providing location cues such
as local area maps or tours.
Inappropriate user interfaces. Although browsers such as Netscape are suitable for many users, and a variety of
tasks, there are however notable exceptions. For example, specific interfaces need to be carefully designed for
systems such as public terminal viewers where novice users need guidance so that they can find the information
they want as efficiently as possible. On the other hand, experienced users also need better support. Currently,
developing HTML material is often a two screen process one screen running the editing application while the
other screen runs a specific browser.
Difficulty in finding specific material and knowing whether the found information is the ``best" available, and
whether there is more of interest.
Difficulty of gaining an overview of the material.
In the face of problems such as these, many new features for the next generation of hypermedia systems are needed, six
of which are discussed here in detail.
Link Management
Although in many respects link management is the crux of hypermedia system design it is, unfortunately, the weakest