Developing a Software Architecture for Graceful Degradation in an Elevator Control System

Many embedded systems have high safety and dependability requirements, which makes ensuring software robustness a top priority in these systems. As embedded computer systems become more complex and incorporate increasing functionality, their software systems become increasingly more difficult to design, build, and maintain. One approach to achieving software robustness is graceful degradation. However, graceful degradation is a difficult property to define or construct. Traditional hardware redundancy is not enough to achieve software safety and dependability. The system's software architecture may be the key to building graceful degradation into a software system. This paper describes a proposal for a software architecture that may enhance graceful degradation for an example elevator control system, and discussion about implementing and evaluating the architecture.