Investigating rare-event failure tolerance: reductions in future uncertainty

At the 1995 Computer Assurance (COMPASS) conference, Voas and Miller (1995) presented a technique for assessing the failure tolerance of a program when the program was executing in unlikely modes (with respect to the expected operational profile). In that paper, several preliminary algorithms were presented for inverting operational profiles to more easily distinguish the unlikely modes of operation from the likely modes. This paper refines the original algorithms. It then demonstrates the new algorithms being used in conjunction with a failure tolerance assessment technique on two small programs.