Novel principles for developing and evaluating distributed safety critical systems

Safety-critical systems typically operate in unpredictable environments, Requirements for safety and reliability are in conflict with those for real-time responsiveness. Due to environmental needs there is no static trade-off between measures to accommodate the conflicting objectives, Instead, every feature or operating system service must be adaptive. MELODY was developed for supporting safety-critical applications under such constraints. This paper gives a brief survey of the different MELODY development phases by utilizing our heuristic design and evaluation methodology, Incremental Experimentation. A particular emphasis is laid on our novel adaptive concept of distributed task monitoring, plus its evaluation, regarding the total number of deadline failures as well as survivability.