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This paper gives the main definitions relating to dependability, a generic concept including a special case of such attributes as reliability, availability, safety, integrity, maintainability, etc. Security brings in concerns for confidentiality, in addition to availability and integrity. Basic definitions are given first. They are then commented upon, and(More)
Dependability is the system property that integrates such attributes as reliability, availability, safety, security, survivability, maintainability. The aim of the presentation is to summarize the fundamental concepts of dependability. After a historical perspective, definitions of dependability are given. A structured view of dependability follows,(More)
The paper presents, and discusses the rationale behind, a method for structuring complex computing systems by the use of what we term “recovery blocks”, “conversations” and “fault-tolerant interfaces”. The aim is to facilitate the provision of dependable error detection and recovery facilities which can cope with errors(More)
A framework for the provision of fault tolerance in asynchronous systems is introduced. The proposal generalizes the form of simple recovery facilities supported by nested atomic actions in which the exception mechanisms only permit backward error recovery. It allows the construction of systems using both forward and backward error recovery and thus allows(More)
Dependability: ability to deliver service that can justifiably be trusted Service delivered by a system: its behavior as it is perceived by its user(s) User: another system that interacts with the former Function of a system: what the system is intended to do (Functional) Specification: description of the system function Correct service: when the delivered(More)
This paper surveys the various problems involved in achieving very high rehability from complex computing systems, and discusses the relatmnship between system structurmg techniques and techniques of fault tolerance. Topics covered mclude: 1) protective redundancy in hardware and software; 2) the use of atomic actmns to structure the activity of a system to(More)
This paper introduces the concept of a `structured occurrence net', which as its name indicates is based on that of anòccurrence net', a well-established formalism for an abstract record that represents causality and concurrency information concerning a single execution of a system. Structured occurrence nets consist of multiple occurrence nets, associated(More)