Discriminating fault rate and persistency to improve fault treatment

In this paper the consolidate identification of faults, distinguished as transient or permanent/intermittent, is approached. Transient faults discrimination has long been performed in commercial systems: threshold-based techniques have been practice for several years for this purpose. The present work aims to contribute to the usefulness of the count-and-threshold scheme, through the analysis of its behaviour and the exploration of its effects on the system. To this goal, the scheme is mechanized as a device named ?-count, endowed with a few controllable parameters. ?-count tries to balance between two conflicting requirements: to keep in the system those components that have experienced just transient faults; and to remove quickly those affected by permanent or intermittent faults. Analytical models are derived, allowing detailed study of ?-count's behaviour; the actual evaluation, in a range of configurations, is performed by standard tools, in terms of the delay in spotting faulty components and the probability of improperly blaming correct ones.