Architecture of hypertext system, reference model

A hypertext system is a complex piece of software, consisting of several parts which serve a very different purpose. In order to make systems open and also integrate hypertext functionality into the desktop, researchers have been working on various hypertext models and interchange standards.

As these models describe the possible conceptual elements in hypertext systems, no implementation exists for any of these models. Some systems have implemented parts of the HAM and the Dexter model.

Reference models

No model has been found that applies to all multimedia environments, because multimedia user communities are very diversity and also of the functions and processing approaches involved. Hence, many model of hypermedia exist, with a different scope for each model.

Some may focus on particular document sets or user communities, thus the models are detailed but not widely applicable. The other may focus on different sets of shared functions between community of users, thus providing common frameworks but not complete environments. Some also focus on details of the final presentation, while others define more general structure of documents that may be presented in a variety of different manners.

Because they give an abstract conceptual model of hypertext systems, hence the models are often called Reference Models. In general, there are quite some numbers of models available, however not all models will be discussed here.

The reference models are:

• HAM model
• Trellis model
• Dexter model
• Tower model
• Lange's basic data model
• WWW model
• CANTO data model
• Etc