Fault Injection for Software Certification

As software becomes more pervasive and complex, it's increasingly important to ensure that a system will be safe even in the presence of residual software faults (or bugs). Software fault injection consists of the deliberate introduction of software faults for assessing the impact of faulty software on a system and improving its fault tolerance. SFI has been included as a recommended practice in recent safety standards and has therefore gained interest among practitioners, but it's still unclear how it can be effectively used for certification purposes. In this article, the authors discuss the adoption of SFI in the context of safety certification, present a tool for the injection of realistic software faults, and show the usage of that tool in evaluating and improving the robustness of an operating system used in the avionic domain.