Example of Distance Learning System

Let us consider a (simplified) distance learning system. The distance learning materials are organized into a hypermedia structure. A student user can browse through these multimedia documents and follow the links to access related multimedia documents.

The following software components (modules) are specified:

Watcher: The watcher monitors individual documents or collection of documents to record in its local memory which user has accessed this (collection of) documents. It interacts with the prefetcher so that prefetcher can determine what to prefetch into the local store.

Prefetcher: The prefetcher would prefetch related multimedia documents into the local store so that when the user accesses them they are readily available. The way prefetcher works is that it will send messages to the watchers to find out what documents (pages) the user has already accessed. From this information, prefetcher estimates what documents will be accessed next, and starts to load them into the local store.