Mode switch for component-based multi-mode systems

University dissertation from Västerås : Mälardalen University

Abstract: Component-based software engineering is becoming a prominent solution to the development of complex embedded systems. Since it allows a system to be built by reusable and independently developed components, component-based development substantially facilitates the development of a complex embedded system and allows its complexity to be better managed. Meanwhile, partitioning system behavior into multiple operational modes is also an effective approach to reducing system complexity. Combining the component-based approach with the multi-mode approach, we get a component-based multi-mode system, for which a key issue is its mode switch handling. The mode switch of such a system corresponds to the joint mode switches of many hierarchically organized components. Such a mode switch is not trivial as it amounts to coordinate the mode switches of different components that are independently developed.Since most existing approaches to mode switch handling assume that mode switch is a global event of the entire system, they cannot be easily applied to component-based multi-mode systems where both the mode switch of the system and each individual component must be considered, and where components cannot be assumed to have global knowledge of the system. In this thesis, we present a mechanism---the Mode Switch Logic (MSL)---which provides an effective solution to mode switch in component-based multi-mode systems. MSL enables a multi-mode system to be developed in a component-based manner, including (1) a mode-aware component model proposed to suit the multi-mode context; (2) a mode mapping mechanism for the seamless composition of multi-mode components and their mode switch guidance; (3) a mode switch runtime mechanism which coordinates the mode switches of all related components so that the mode switch can be correctly and efficiently performed at the system level; and (4) a timing analysis for mode switches realized by MSL. All the essential elements of MSL are additionally demonstrated by a case study.