Allocation and analysis of reliability: multiple levels: system, subsystem, and module

We model the reliability allocation and prediction process across a hierarchical software system comprised of modules, subsystems, and system. We experiment in modeling complex reliability software systems using several software reliability models to test the feasibility of the process and to evaluate the accuracy of the models for this application. This is a subject deserving research and experimentation because this type of system is implemented in safety-critical projects, such as National Aeronautics and Space Administration (NASA) flight software modules, that we use in our experiments. Given the reliability requirement of a software system in the software planning or design stage, we predict each module’s reliability and their relationships (e.g., reliability interactions among modules, subsystems, and system), Our critical interfaces and components are failure-mode sequences and the modules that comprise these sequences, respectively. In addition, we evaluate how sensitive the achievement of reliability goals is to predicted component reliabilities that do not meet expectations.