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3.4.2 The Hyperwave Server

In contrast to a WWW server, the Hyperwave server is capable of handling large quantities of data, which can be spread over multiple servers. Most maintenance work is done automatically by the server, such as link management, or removing expired documents (actually they are not removed, but are no longer visible to users). Documents as well as users are stored in a sophisticated object-oriented database. This allows for the storage of arbitrary types of documents, and the assignment of attributes to any object. Attributes provide useful meta information about objects (see Figure 3.2), such as:

  

Figure 3.2: Hyperwave's attributes of an HTML document.
\begin{figure} \begin{center} \leavevmode \psfig {file=attributes.ps} \end{center}\end{figure}

  • Type of document (MIME type);

  • Access rights (read and write);

  • Time of creation and modification;

  • Period of time that the document should be visible;

  • Author of the document

  • Search keywords

  • Cost of document

  • etc.

Authors are free to add their own attributes to their documents. Since users are treated in the same manner as other objects in Hyperwave, we added an attribute ``LectureStatus'' to every user object, which can be either ``Student'' or ``Teacher'' to automatically provide the appropriate user interface for our teleteaching project.

3.4.2 The Hyperwave Server

In contrast to a WWW server, the Hyperwave server is capable of handling large quantities of data, which can be spread over multiple servers. Most maintenance work is done automatically by the server, such as link management, or removing expired documents (actually they are not removed, but are no longer visible to users). Documents as well as users are stored in a sophisticated object-oriented database. This allows for the storage of arbitrary types of documents, and the assignment of attributes to any object. Attributes provide useful meta information about objects (see Figure 3.2), such as:

  

Figure 3.2: Hyperwave's attributes of an HTML document.
\begin{figure} \begin{center} \leavevmode \psfig {file=attributes.ps} \end{center}\end{figure}

  • Type of document (MIME type);

  • Access rights (read and write);

  • Time of creation and modification;

  • Period of time that the document should be visible;

  • Author of the document

  • Search keywords

  • Cost of document

  • etc.

Authors are free to add their own attributes to their documents. Since users are treated in the same manner as other objects in Hyperwave, we added an attribute ``LectureStatus'' to every user object, which can be either ``Student'' or ``Teacher'' to automatically provide the appropriate user interface for our teleteaching project.

3.4.2.1 Object IDs 3.4.2.1 Object IDs
3.4.2.1 Object IDs 3.4.2.1 Object IDs
3.4.2.2 The Hierarchical Structure of Hyperwave 3.4.2.2 The Hierarchical Structure of Hyperwave
3.4.2.2 The Hierarchical Structure of Hyperwave 3.4.2.2 The Hierarchical Structure of Hyperwave
3.4.2.3 Searching 3.4.2.3 Searching
3.4.2.3 Searching 3.4.2.3 Searching
3.4.2.4 Link Management 3.4.2.4 Link Management
3.4.2.4 Link Management 3.4.2.4 Link Management
3.4.2.5 Users - Groups - Access Rights 3.4.2.5 Users - Groups - Access Rights
3.4.2.5 Users - Groups - Access Rights 3.4.2.5 Users - Groups - Access Rights
3.4.2.6 Billing and Licensing 3.4.2.6 Billing and Licensing
3.4.2.6 Billing and Licensing 3.4.2.6 Billing and Licensing