FITS - A Fault Injection Architecture for Time-Triggered Systems

Time-triggered systems require a very high degree of temporal accuracy at critical stages during run time. While many software fault injection environments exist today, none of these make provisions to meet the timing requirements of such systems.This paper introduces a fault injection environment for time-triggered systems. We describe the architecture of FITS and how it addresses the requirements of temporal accuracy in the time-triggered paradigm.An implementation of FITS was used to conduct fault injection experiments on a prototype implementation of a time-triggered communication protocol for safety-critical hard real-time applications. We describe the fault injection strategy that was used for these experiments to assess the dependability of this protocol.Through the white box fault injection experiments that were performed using FITS, a number of small design problems were found and subsequently corrected in the protocol. The results of the experiments also enabled an important quantitative assessment of the dependability measures for the protocol, which is vital for its inclusion into dependable systems. Together with the large quantity and variety of experiments this implementation of FITS was able to perform, these are important factors of evidence that demonstrate the viability and utility of the presented fault injection architecture.