Conformance testing of ARINC 653 compliance for a safety critical RTOS using UPPAAL model checker

Modern avionics systems have several safety critical control software that need to be accurate and provide deterministic response in real-time. Accuracy of such responses is determined by the real-time operating system (RTOS) on which the software applications run. Standards provide guidelines to ensure correctness with high assurance. The conformance of a RTOS to a standard can be achieved by executing a set of test cases against the properties listed in the standard. Conventional testing methodologies are inadequate for conformance testing due to cost and time constraints and lack of guarantees of correctness. We propose a formal methods based technique for conformance testing of a safety critical RTOS to the ARINC 653 standard. We model a space and time partitioned RTOS as a network of timed automata using UPPAAL model checker and verify conformance to functional and timing requirements. Our approach is illustrated in the context of HAL-OS, a proprietary RTOS used in avionics systems.