Fair distribution of concerns in design and evaluation of fault-tolerant distributed computer systems

Abstract

In literature dealing with fault-tolerant computer systems, the replaceable components are most often modeled as one of the two extreme types with respect to their faulty output behavior: the fail-silent unit (FSU) model at the simplest end and the malicious unit (MaU) model, also called the Byzantine unit model, at the other end. The basic weaknesses of these models for use in practical system design and evaluation are pointed out. It is also pointed out that the state of the art in analytic modeling and evaluation of fault-tolerant distributed computer systems has a vast weakly characterized region in the domain of conceivable component models enclosed by the two extreme models. The main constructive proposition made with respect to advancing the state of the art is to establish scientific procedures for fair distribution of concerns over possible occurrences of anomalous events during system design and validation. A direction for obtaining such a procedure relying on extensive probabilistic reasoning is proposed. >