Debugging distributed implementations of modal process systems

From the perspective of performance and parts cost, distributed architectures are often superior to single processor architectures for embedded systems designs. Despite this, embedded system designers still tend to use single processors whenever possible. One of the main reasons for this is that the additional costs in design and maintenance of distributed systems can far outweigh the lower parts cost and lower power consumption that might result from a distributed implementation. This is largely because most distributed models are limited in the system level abstraction that can be derived. The modal process model [2] for embedded system design has been suggested as a way of addressing many of these issues. This model maps quite naturally to distributed implementations, while preserving unifying information from higher levels of abstraction. While this model provides numerous benefits as far as modularity and ease of composition, it also enhances the designers ability to debug such systems by enabling new debugging techniques. This paper discusses some debugging techniques enabled by the modal process model, and describes how these may be used.