The notion of encapsulations is introduced as the basic construct used to support optimistic make (a software tool). The authors describe the implementation of optimistic make in the V-System on a collection of SUN workstations. Statistics measured from this implementation are used to synthesize a workload for a discrete-event simulation, and to validate the simulation's results. The simulation shows a speedup distribution over pessimistic make with a median of 1.72 and a mean of 8.28. The speedup distribution is strongly dependent on the ratio between the target out-of-date times and the command execution times. With faster machines the median of the speedup distribution grows to 5.1, and then decreases again