Overall Design

The Prototyping Environment (PE) consists of a central interface (CI) and subsystem interfaces (SSI). The tasks of the central interface are to:

• Maintain a global database of all the information needed for the design process.
• Communicate with the subsystems to update any changes in the system. This requires the central interface to know which subsystems need to know these changes and send messages to these subsystems informing them of the required changes.
• Receive messages and reports from the subsystems when any changes are required, or when any action has been taken (e.g., update complete).
• Transfer data between the subsystems upon request.
• Check constraints and apply some of the update rules.
• Maintain a design history containing the changes and actions that have been taken during each design process with date and time stamps.
• Deliver reports to the user with the current status and any changes in the system.

The subsystem interfaces are the interface layers between the CI and the subsystems. This makes the design more flexible and enables us to change any of the subsystems without much change in the CI -- only the corresponding SSI need to be changed. The role of the SSIs are:

• Report any changes to the CI.
• Receive messages from the CI with required updates.
• Perform the necessary updates in the actual files of the subsystem.
• Send acknowledgments or error messages to the CI.

The assumption is that there is a user at each subsystem (by a user here we mean one or more skilled persons who understand this subsystem), and there is a user operating the central interface as a general director and coordinator for the design process. In other words, the CI is to assist in the coordination of the job and to help communicate with all subsystems. Figure 31 shows an overall view of the suggested design.

 
Figure 31: Overall design of the prototyping environment.  

In the first phase of implementing the PE, the users have more work to do. The CI and SSIs maintain the information routing between the subsystems by sending messages to the corresponding user at each subsystem, then the action itself (e.g., update a file) is accomplished by the user. Later on, the system will be automated to perform most of these actions itself and the user will simply be informed of the actions taken.

• Communication Protocols
• Design Cycles and Infinite Loops
• Central Interface Design Options