Case Study I: Comparative Studies of Fault-Tolerant Software

Abstract

The types of computational redundancy employed by fault-tolerant software typically result in performance penalties, particularly with regard to computation delays. These, in turn, may have an adverse effect on system dependability, e.g., in real-time applications, an increased probability of failing to meet a deadline. More generally, such interactions and tradeoffs between performance and dependability affect the user-perceived benefits of a particular fault tolerance scheme. Hence, consideration of combined performance-dependability, via the concept of performability, appears to be a promising basis for assessing and improving the effectiveness of fault-tolerant software.