TWO FAULT INJECTION TECHNIQUES FOR TEST OF FAULT HANDLING MECHANISMS

Two fault injection techniques for experimental validation of fault handling mechanisms in computer systems are investigated and compared. One technique is based on irradiation of ICs with heavy-ion radiation from a 252Cf source. The other technique uses voltage sags injected in the power supply rails to ICs. Both techniques have been used for fault injection experiments with the MC6809E microprocessor. Most errors generated by the 252Cf method were seen first in the address bus, while the power supply disturbances most frequently affected the control signals. An error classification shows that both methods generate many control flow errors, while pure data errors are infrequent. Results from a simulation experiment show that that the low number data errors in the 252Cf experiments can be explained by the fact that many errors in data registers are overwritten owing to the normal program execution.