Approaches to Mechanization of the Conversation Scheme Based on Monitors

A basic problem in designing error detection and backward recovery capabilities into concurrent programs is to coordinate the detection and recovery activities of cooperating processes. As an aid to such design Randell proposed a language construct called conversation in an abstract form. Practical mechanization of the conversation scheme, i.e., selection of a well-structured syntax and associated semantics, is the issue dealt with in this paper. Four different mechanizations based on the monitor approach to interprocess communication are presented. They are presented as feasible extensions of Concurrent Pascal in order to enable visualization of their full implementation details in at least one type of concurrent programming environment. They are presented in the increasing order of the amount of efforts that they require for extending Concurrent Pascal. They offer different degrees of assistance to the programmer in proper structuring of recoverable process interactions.