Interfacing GPSS/H with GKS

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Virginia Tech


This thesis report discusses the research that led to the interfacing of the latest version of GPSS, namely GPSS/H, and GKS, a graphics system which allows programs to support a wide variety of graphics devices.

The objective of the research was to represent the results of a syntactically and logically correct GPSS simulation model graphically.

A computer program to modify a running GPSS program to a form compatible for graphical emulation was developed. The modifier program identifies the event causing statements in the GPSS program and inserts CALL statements to invoke external subroutines to record these events. Further, it also adds CALL statements to record the statistics for the queues, facilities and storages in the model. The data recorded is in the form of data files. An animation program which takes as input, the data generated by the modified GPSS program was also developed. The GPSS programmer needs only to take care of the correct modeling of the system and know nothing at all about graphics and animation.