Time-redundant recovery policy of TMR failures using rollback and roll-forward methods

A time-redundant approach is proposed by adopting a rollback and/or roll-fo rward technique to recover TMR failures producing incorrect majority output s in a TMR (structured) system that uses the simplest spatial redundancy Th is technique is apparently effective in recovering TMR failures primarily c aused by transient faults. The proposed policies carry out fewer reconfigur ations at the cost of (minimal) time overhead needed for applying those tim e-redundant schemes. Specifically, two methods are presented (flexibly used ) for the recovery policy to guarantee high reliability. The optimal checkp oint vectors are also derived for both methods by using the likelihoods of all possible failure states as well as the total execution time. Consequent ly, the effectiveness of the proposed policy is validated through certain n umerical examples and computer simulation.