Error Recovery in Systems of Communicating Processes

This paper deals with some of the relevant problems concerning the backward recovery of autonomous processes. The tools for the description of the past history of the system are formally defined, and an implementation is outlined. 1 Introduction The term "error recovery" is used for the activity which restores to a consistent state a system which is an inconsistent one. Thus, the notion of consistent state is essential to the definition of the methods and purposes of the error recovery. In this introduction we shall give an interpretation of the term "consistency" which should explain its use in different fields of computer science. The attribute of consistency is applied to the information stored in a system (the state of the system), and is strictly bound to the way in which this information is used (according with an algorithm or protocol to produce the expected behavior of the system (described in its specifications): we give the following informal description of consistent state..