GPSS/H: a 23-year retrospective view

The discrete event simulation language, GPSS/H was first placed into commercial service in November, 1977. Over the ensuing 23 years, it has become well known for its speed and dependability. In GPSS/H, the process-interaction world view has been combined with many advanced features to make an extremely powerful and flexible tool, capable of handling large, complicated models with ease, yet still providing exceptionally high performance. The article provides an overview of GPSS/H and its process-interaction world view, a discussion of model-building interfaces including tradeoffs associated with graphical modeling environments, and a summary of advanced and recently-added GPSS/H features. Finally, the use of special-purpose simulators is discussed, along with features of GPSS/H which make it very well-suited for use as the engine in such simulators. The paper provides a retrospective look at the history of GPSS/H.