293Special Topics
the rst of many tools for building models of industrial production. GSP
dealt with the tasks pertinent to most simulations: initialization of the model,
stepping through time, changing states of the system, consumption of
resources, andlogging and generating result reports. It enabled queues and
had machines that could be in one of various states: busy, idle, unavailable,
or failed.
Shortly afterward, in 1961, GSP was followed by the General Purpose
Simulation System (GPSS), created by Geoffrey Gordon (Schriber 1974) (see
Figure9.12for an example). There are still versions of GPSS being sold
and used for education and analyses. GPSS has been the foundation for
many of the modern simulation tools (Goldsman etal. 2010) like ...