Computers are currently used in a variety of critical applications, including systems for nuclear reactor control, flight control (both aircraft and spacecraft), and air traffic control. Moreover, experience has shown that the dependability of such systems is particularly sensitive to that of its software components, both the system software of the embedded computers and the application software they support. Software Performability: From Concepts to Applications addresses the construction and solution of analytic performability models for critical-application software. The book includes a review of general performability concepts along with notions which are peculiar to software performability. Since fault tolerance is widely recognized as a viable means for improving the dependability of computer system (beyond what can be achieved by fault prevention), the examples considered are fault-tolerant software systems that incorporate particular methods of design diversity and fault recovery. Software Performability: From Concepts to Applications will be of direct benefit to both practitioners and researchers in the area of performance and dependability evaluation, fault-tolerant computing, and dependable systems for critical applications. For practitioners, it supplies a basis for defining combined performance-dependability criteria (in the form of objective functions) that can be used to enhance the performability (performance/dependability) of existing software designs. For those with research interests in model-based evaluation, the book provides an analytic framework and a variety of performability modeling examples in an application context of recognized importance. The material contained in this book will both stimulate future research on related topics and, for teaching purposes, serve as a reference text in courses on computer system evaluation, fault-tolerant computing, and dependable high-performance computer systems.

The International Working Conference on Dependable Computing for Critical Applications was the first conference organized by IFIP Working Group 10. 4 "Dependable Computing and Fault Tolerance," in cooperation with the Technical Committee on Fault-Tolerant Computing of the IEEE Computer Society, and the Technical Committee 7 on Systems Reliability, Safety and Security of EWlCS. The rationale for the Working Conference is best expressed by the aims of WG 10. 4: " Increasingly, individuals and organizations are developing or procuring sophisticated computing systems on whose services they need to place great reliance. In differing circumstances, the focus will be on differing properties of such services - e. g. continuity, performance, real-time response, ability to avoid catastrophic failures, prevention of deliberate privacy intrusions. The notion of dependability, defined as that property of a computing system which allows reliance to be justifiably placed on the service it delivers, enables these various concerns to be subsumed within a single conceptual framework. Dependability thus includes as special cases such attributes as reliability, availability, safety, security. The Working Group is aimed at identifying and integrating approaches, methods and techniques for specifying, designing, building, assessing, validating, operating and maintaining computer systems which should exhibit some or all of these attributes. " The concept of WG 10. 4 was formulated during the IFIP Working Conference on Reliable Computing and Fault Tolerance on September 27-29, 1979 in London, England, held in conjunction with the Europ-IFIP 79 Conference. Profs A. Avi ienis (UCLA, Los Angeles, USA) and A.

Computers are currently used in a variety of critical applications, including systems for nuclear reactor control, flight control (both aircraft and spacecraft), and air traffic control. Moreover, experience has shown that the dependability of such systems is particularly sensitive to that of its software components, both the system software of the embedded computers and the application software they support. Software Performability: From Concepts to Applications addresses the construction and solution of analytic performability models for critical-application software. The book includes a review of general performability concepts along with notions which are peculiar to software performability. Since fault tolerance is widely recognized as a viable means for improving the dependability of computer system (beyond what can be achieved by fault prevention), the examples considered are fault-tolerant software systems that incorporate particular methods of design diversity and fault recovery. Software Performability: From Concepts to Applications will be of direct benefit to both practitioners and researchers in the area of performance and dependability evaluation, fault-tolerant computing, and dependable systems for critical applications. For practitioners, it supplies a basis for defining combined performance-dependability criteria (in the form of objective functions) that can be used to enhance the performability (performance/dependability) of existing software designs. For those with research interests in model-based evaluation, the book provides an analytic framework and a variety of performability modeling examples in an application context of recognized importance. The material contained in this book will both stimulate future research on related topics and, for teaching purposes, serve as a reference text in courses on computer system evaluation, fault-tolerant computing, and dependable high-performance computer systems.