Vignettes: A distributed discrete event simulation system

The authors discuss Vignettes, a visual simulation programming system. Using Vignettes, a simulation analyst develops a simulation model in the form of extended queuing networks; Vignettes networks are constructed interactively on a graphics workstation. The authors begin by describing Vignettes, its icons and objects. They describe the implementation of Vignettes using a distributed discrete event simulation concept on a network of workstations. Specifically, they implement a form of D. R. Jefferson´s (1985) time warp concept called remote process execution (RPE). RPE is a form of dynamic process allocation. That is, in order to minimize rollback on n physical processors, the n lowest simulation times of the m logical processes (m>n) are scheduled on the n disjoint processors. In order to maintain this schedule dynamically, logical processes may have to be moved among the processors during simulation