A framework for software reuse in safety-critical system-of-systems

We introduce a process-neutral framework for software reuse in safety-critical system-of-systems, and present a new model, called C⁵RA, to capture the relevant component information and to assist in reusable component specification matching that takes software safety into account. The framework consists of four elements: organizational factors, component attributes, component specification, and safety analysis. The paper also presents a set of software safety metrics for indicating the potential safety problems and risks in reusing the components. We illustrate the application of the framework with an example involving the reuse of a generic avionics software component. Our key findings and products are: congruence between all elements is required; software should posses a number of attributes with metrics that support a design for safety; software component information can be specified using C⁵RA; and a process was identified for a system-of-systems hazard analysis for software reuse.