ABSTRACT
This chapter describes early and seminal works on reliability, availability, and dependability evaluation. It provides a summary of early work related to dependability and briefly describes some seminal efforts and the respective relations with current prevalent methods. The chapter presents several fundamental concepts, taxonomy, and quantitative measures for dependability The consequence of a failure may be ordered into severity levels. The severity levels are usually related to the acceptable probabilities of occurrence. The consequence of a minor failure is similar to the benefits provided by the correct service. The advantage of using phase-type distributions is the fact that they can approximate any non-negative distribution arbitrarily closely. The Weibull distribution is widely used in reliability and life data analysis due to its versatility. The normal distribution is certainly the most widely adopted general-purpose distribution. The relation between the loglogistic and logistic distribution is similar to the relation between normal and lognormal distributions.
