Nonsequentiality and Concrete Activity Phases in Discrete-Event Simulation Languages

Abstract

The design of languages for programming complex discrete-event simulations, with a conventional global notion of simulation time, is considered.An example language is described in which the main objects dealt with are concrete manifestations of phases of activity conceptually underlying a simulation and in which programs have an extremely nonsequential mode of notional operation.A program in the language very directly specifies a certain type of formal simulation system which generates a unique maximal simulation history.This history is a sequence of time instants, each associated with the partially ordered set of events considered to occur at that instant.In contrast to the case of programs in existing discrete-event simulation languages, (1) the event orders achievable at instants can be partial and are not restricted in any way, and (2) phase objects are central and explicit in a program, being the main units describing overall structure, data, and control.Variants of the language could have uses other than simulation.