Evaluating the Use of Reference Run Models in Fault Injection Analysis

Fault injection (FI) has been shown to be an effective approach to assessing the dependability of software systems. To determine the impact of faults injected during FI, a given oracle is needed. Oracles can take a variety of forms, including (i) specifications, (ii) error detection mechanisms and (iii) golden runs. Focusing on golden runs, in this paper we show that there are classes of software which a golden run based approach can not be used to analyse. Specifically, we demonstrate that a golden run based approach can not be used in the analysis of systems which employ a main control loop with an irregular period. Further, we show how a simple model, which has been refined using FI experiments, can be employed as an oracle in the analysis of such a system.