Assessment of COTS microkernels by fault injection

This paper addresses the problem of using COTS microkernels in safety critical systems. As the behavior in the presence of faults of such basic components is seldom established, it is questionable whether they can be used to develop operating systems for critical applications. The approach proposed for the assessment of a COTS microkernel relies on fault injection as a means to obtain objective insights for the provision of upper layer services. A specific tool (MAFALDA) has been developed to implement this approach. We present and discuss the results obtained when applying the tool to the Chorus ClassiX r3 microkernel. Finally, some lessons learnt from these experiments and plans for future work are described.