A Configurable Fault Tolerant Architecture for Component-Based Systems

Component-based software engineering is an emerging paradigm for software development. Benefits of component-based development include significant reduction in the development cost, time and improvement in the dependability requirements. Commercial off-the-shelf (COTS) components are used without any code modification and inspection. When such components are integrated to build safety-critical systems, faults within individual COTS components or faults due to their collaboration may cause catastrophic failures. Therefore, for systems with high dependability requirements, it is essential to incorporate ways for tolerating the software faults at architectural level to deal with the faults that are not catered within the components. The existing component based fault tolerant architectures provide fault tolerance through either exception handling or design diversity. In this paper, we propose a fault tolerant architecture, which supports design diversity and exception handling fault tolerance strategies. The proposed fault tolerant component architecture employs special-purpose connectors called design diverse-multiple version connectors (DD-MVC). These connectors allow design diverse N-variants of COTS to run in parallel. Moreover, proposed architecture also has fault tolerant architectural level connector. The proposed architecture can be configured to adjust the tradeoff between dependability and efficiency and exhibits the ability to tolerate the anticipated and unanticipated faults effectively. The applicability of proposed architecture is demonstrated with a prototype implementation and a case study