Component based reliability assessment from UML models

Model based development and testing techniques have ventured diverse research directions to assure quality of the software product. Models developed during architecture and design phases are efficient tools to assess quality at an early development stage. However, testing the extra-functional or non-functional properties of software systems is not frequently practised eg. reliability. The motivation to our work is to model the context of execution which is significant in system reliability analysis. In this paper we visualize the components of complex software systems and their interactions in the form of Functional Flow Diagram (FFD). This notation specifies the dynamic aspect of system behavior as the context of execution. To further asses reliability, the FFD is translated into Reliability Block Diagram (RBD). The relative importance of the components in terms of reliability is evaluated and is associated with prioritization of the component. The model is simple but significant for system maintenance, improvisation and modification. This model supports analysis and testing through better understanding of the interacting components and their reliabilities.