MEFISTO-L: a VHDL-based fault injection tool for the experimental assessment of fault tolerance

The early assessment of the adequacy of fault tolerance mechanisms (FTMs), and the subsequent removal of fault tolerance deficiency faults (ftd-faults), are essential tasks in the design process of dependable computer systems. The paper is centered on the description and application of the features of MEFISTO-L, the fault injection tool for VHDL models, being developed at LAAS for supporting the strategy that we have proposed for testing FTMs. The paper first describes the overall testing framework in which MEFISTO-L is incorporated. The main guidelines for the design of MEFISTO-L and its objectives, attributes, implementation and use are then described. Special attention is given to the main original and innovative features: i) the embedded VHDL code analyzer, ii) the observation and injection mechanisms, iii) their synchronization, and iv) their automatic placement in the target VHDL model.