PERFORMANCE EVALUATION OF ROLLBACK-RECOVERY TECHNIQUES IN COMPUTER-PROGRAMS

Rollback-recovery is a backward error-recovery technique used to recov er from temporary faults in database and process-control systems. Roll back in process-control systems is generally constrained by deadlines, thereby requiring a dynamic insertion of rollback points. This is in contrast with the rollback-recovery in database systems where rollback points are inserted at equidistant intervals. This paper develops a s imple model based on a semi-Markov process to study the performance of rollback-recovery strategies. Using this model, the mean program comp letion time is obtained for both database and process-control systems when rollback-recovery is implemented. The analytic results obtained b y the semi-Markov model are compared with the simulation results by me ans of extensive computer simulation.