Analyzing Software Contribution to System Failures. PROBLEM. SOLUTION. Software causes many failures - significant mission risk Hard to quantify effects on system risk of: software defects software development practices software verification and validation.
Link factors affecting software quality to system failures modes by:
Predicting number of defects in software subsystems given software development and V&V decisions
Using a fault tree to link software defects to system failures, affecting their probabilities
Prototype implementation in the Eclipse software development environment of tool linking:
ODC COQUALMO - USC/Ames tool which predicts number of software defects and effectiveness of V&V tools
DDP - JPL tool calculates risks, costs and effect of mitigation strategies from user specification of links between system objectives, risks and mitigations
In this application, DDP represents system fault tree where some leaf nodes correspond to software defects. DDP derives information from ODC COQUALMO on software defect numbers, type and V&V effectiveness. DDP calculates system failure probability before and after selected V&V mitigations applied.
Credits: DARP spacecraft image slide 1: “An artist conception of the autonomous DART spacecraft as it approaches the MUBLCOM satellite. … Credit: NASAexplores “ from http://www.nasa.gov/missions/science/dart_into_space.html