We consider quad fault cases and show how a system can reconfigure from an error causing four faults at maximum. A system must be fault tolerant to decrease the failure rate and increase the reliability of it. Multiple faults can affect a system simultaneously and there is a trade-off between area overhead and number of faults tolerated. Fault tolerant architecture design for a ripple carry adder assuming quad faults.
Keywords: fault tolerant, Ripple carry adder, Test pattern generation.