1. Architecture and Real Time Systems Lab University of Massachusetts, Amherst An Application Driven Reliability Measures and Evaluation Tool for Fault Tolerant Real Time Systems I Koren and C M Krishna Electrical and Computer Engineering University of Massachusetts Amherst, MA 01003 Sponsored by Space and Naval Warfare Systems Command & Advanced Research Projects Agency ARPA order B855 under SPAWAR contract N00039-94-C-0165 (Please view the slides only through Power Point Slide Show. The show is automated)

2. Architecture and Real Time Systems Lab University of Massachusetts, Amherst * Provides Network Measures which quantify how network parameters including topology and routing techniques effect the reliability of a given system * Provides Computer Measures which quantify how parameters such as task allocation, scheduling, check pointing and fault recovery algorithms affect the system’s reliability * GUI part of simulator allows user to draw the topology and specify the task sets * Output of the simulator is presented in the form of graph between various parameters TRIDENT

3. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Calculating Computer Measures for Robotics Application Loading environment file for robotics application Simulator is running now Graphs indicating computer measures are produced

4. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Computer Measures for Robotics Application Minimum Deadline vs. Surge size for various number of processors Recovery Time vs. Surge size for various number of processors

5. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Computer Measures for Robotics Application System Recovery Time vs. Surge Orientation Processor for various number of processors Processor Recovery Time vs. Processor ID for various number of processors

6. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Calculating Network and Computer Measures for Avionics Application Loading environment file for Avionics application Simulator is running now Graphs indicating network measures are produced Simulator is running now to get computer measures Graphs indicating computer measures are produced

7. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Network Measures for Avionics Application Diameter vs. Link Failure Probability for various networks Probability of Disconnection vs. Link Failure Probability for various networks

8. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Network Measures for Avionics Application Node Pair Distance vs. Link Failure Probability for various networks Frequency of failure and component size vs. Link Failure Probability for various networks

9. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Minimum Deadline vs. Surge size for various Tasks sets Recovery Time vs. Surge size for various Tasks sets Computer Measures for Avionics Application

10. Architecture and Real Time Systems Lab University of Massachusetts, Amherst System Recovery Time vs. Surge Origination Processor for various Tasks sets Processor Recovery Time vs. Processor ID for various Tasks sets Computer Measures for Avionics Application

11. Architecture and Real Time Systems Lab University of Massachusetts, Amherst Summary The new measures can be used to evaluate the effect of * Task Allocation algorithms * Scheduling algorithms * Interconnection topologies * Communication protocols * Failure recovery mechanisms on real-time dependability Our tool, TRIDENT, calculates the new dependability measures and presents in graphical form