Summary

The blackboard model supports concurrency. The concurrency is inherent in the structure of the blackboard and the relationship between the blackboard and the knowledge sources and between the knowledge sources and each other. The blackboard is a problem-solving model. The problem is divided up into knowledge-specific areas. Each area is assigned a knowledge source or problem solver. The knowledge sources and problem solvers are typically self-contained and require little interaction with the other knowledge sources. The communication that is necessary occurs through the blackboard. Therefore, the knowledge sources and problem solvers serve to modularize the processing within the program. These modules can be treated separately and they can execute concurrently without complex synchronization needs. The blackboard may be implemented using CORBA objects. When the blackboard is implemented as CORBA objects, the knowledge sources can be distributed across intranets or the Internet. The blackboard acts as a kind of shared distributed memory for tasks within a PVM-type environment. The blackboard model easily supports MPMD (MIMD) and the SPMD (SIMD) model. The concept of the blackboard motivates the designer to break down the work that a program needs to do along knowledge lines . This results in the program having a WBS of knowledge specialists. The blackboard will contain software models of the problem domain and the solution space. These software models help the designer and developer to discover any parallelism that is necessary within a program that will be implemented. Alongside of the classic client-server model of distributed programming the blackboard model is one of the most powerful models available for both distributed and parallel programming. The knowledge sources or problem solvers in the blackboard model are often implemented as agents . In the next chapter we will take a closer look at how to implement agents and how to deploy multiagent systems to achieve concurrency.