The Xception approach
Use processor built-in debugging and performance monitoring features to inject faults by software with minimal interference (hybrid approach):
        Breakpoint registers - used to implement non-intrusive fault triggers
        Special counters - used to collect data on the target system behavior after the injection of a fault.

Xception Architecture

Papers on Xception

• "Xception: Software Fault Injection and Monitoring in Processor Functional Units", J. Carreira, H. Madeira, and J. G. Silva, proc. Fifth IFIP Working Conference on Dependable Computing for Critical Applications, DCCA-5, Urbana-Champaign, Illinois, EUA, Sept., 27 to 29, 1995.
• "Injection of faults in complex computers", H. Madeira, J. Carreira, and J. G. Silva, Fourth IEEE International Workshop on Evaluation Techniques for Dependable Systems, San Antonio, Texas, EUA, Oct., 2 to 3, 1995.
• “Xception: Software Fault Injection and Monitoring in Processor Functional Units",  João Carreira, Henrique Madeira e João Gabriel Silva,  IEEE Transactions on Software Engeenering, Vol.24, No.2, February 1998.

• "Fault Tolerance in Parallel Systems",  J. G. Silva, H. Madeira, J. Carreira, D. Costa and F. Moreira, IEEE 26th Fault Tolerant Computing Symposium, FTCS-26, Sendai, Japan, June, 25 to 27, 1996
• "Fault Injection Evaluation os Assigned Signatures in a RISC Processor", P. Furtado and H. Madeira 2nd European Dependable Computing Conference- EDCC-2, Taormina, Italy, Oct., 2 to 4, 1996.
• "Practical Issues in the Use of ABFT and a new Failure Model",  João Gabriel Silva, Paula Prata, Mário Rela and Henrique Madeira, proceedings of the 28th IEEE Annual International Symposium on Fault-Tolerant Computing Symposium, FTCS-28, Munich, Germany, June 1998.
• "Experimental Assessment of COTS DBMS Robustness under Transient Faults", Diamantino Costa and Henrique Madeira, PRDC'99, Pacific Rim Dependable Computing, Hong Kong, 1999.
• “Joint Evaluation of Performance and Robustness of a COTS DBMS Through Fault-Injection”,  Diamantino Costa, Tiago Rilho, and Henrique Madeira, IEEE/IFIP International Conference on Dependable Systems and Networks  – DSN (FTCS-30 e DCCA-8), New York, USA, June 25 - 28,  2000.

• “On the Emulation of Software Faults by Software Fault Injection”, Henrique Madeira, Marco Vieira and Diamantino Costa, IEEE/IFIP International Conference on Dependable Systems and Networks  – DSN (FTCS-30 e DCCA-8), New York, USA, June 25 - 28,  2000.
• “ESFFI - A novel technique for the Emulation of Software Faults in COTS Components”, Diamantino Costa, Tiago Rilho e Henrique Madeira, paper accepted for presentation at the 8th Ann. IEEE Int'l Conference on the Eng. of Computer-Based Systems, ECBS 2001, Washington, D.C., April 17-20, 20001.