A practical framework for eliciting and modeling system dependability requirements: Experience from the NASA high dependability computing project

The dependability of a system is contextually subjective and reflects the particular stakeholder’s needs. In different circumstances, the focus will be on different system properties, e.g., availability, real-time response, ability to avoid catastrophic failures, and prevention of deliberate intrusions, as well as different levels of adherence to such properties. Close involvement from stakeholders is thus crucial during the elicitation and definition of dependability requirements. In this paper, we suggest a practical framework for eliciting and modeling dependability requirements devised to support and improve stakeholders’ participation. The framework is designed around a basic modeling language that analysts and stakeholders can adopt as a common tool for discussing dependability, and adapt for precise (possibly measurable) requirements. An air traffic control system, adopted as testbed within the NASA High Dependability Computing Project, is used as a case study.