Dependability evaluation using hybrid fault/error injection

This paper presents a new hybrid fault/error injection technique which overcomes the limitations of both software-based and hardware-based approaches. The logic for the hardware fault unit injection circuitry is implemented using field programmable gate arrays, and the software is an extension of FERRARI, the software-based fault injection system. The combination of these techniques allows the incorporation of new capabilities by the use of mechanisms to trigger and synchronize the injection of a fault or error with events in the system. Results of physical fault/error injection experiments on a SPARC1 system are presented. The injection was synchronized to the executing modes and load conditions of the system. These results show that the system behavior is very sensitive to the internal state and load. Therefore, in order to validate the dependability properties of a system, it is imperative to inject faults/errors while the system is in critical conditions and different execution modes