Figure 2 shows the main components of the architecture. In the following list, the three components that were already present in an earlier version of the DIVA architecture (Schönhage & Eliëns, 1997; Schönhage & Eliëns, 1998), are listed first. The last three components in the list extend DIVA.
In a normal situation, one DIVA services directory and more than one of each of the other components could exist. A presentation component and a local collaboration component are present at the desktop of each participant. A short description is given for each of the components.
The generator embodies the primary model and generates all data needed for the visualization. Examples of generators are simulations of business processes. The generated raw data is transferred to the shared concept space.
The shared concept space stores information in an expressive and adaptive way. The information is contained in the form of concepts that are stored in a hierarchical manner. Each concept has one or more data properties that represent the information. The data properties are updated with data coming from the generator. The received data can be stored directly or can be used to compute and store derived information.
The presentation component actually visualizes concepts from the shared concept space. It makes use of gadgets, which are generic visualization primitives that present certain types of information. As an example, cone trees are primitives (gadgets) to visualize hierarchical information (Robertson et al., 1993).
Examples of gadgets are a rotating object which indicates a certain action or a histogram which displays data.
The DIVA services directory (DSD) is the central directory component. DIVA components (or services) can register here, identifying themselves and giving their location. Once they are registered, the DSD can inform other objects about the availability and whereabouts of these services.
The collaboration session manager (CSM) coordinates components. It deals with interaction protocols, which means it knows about the participants and their roles, sharing perspectives, user to user communication and consistency.
The local collaboration component is directly connected to the session manager. It is present at each participants desktop and handles interactions and information related to a collaborative session. It may for example display a list of participants and offer communication facilities.