Analysis of a Real-Time Computer System for GPSS

In this paper, the analysis of the dynamic characteristics of an on-line real-time software system is described. An on-line real-time computer system on some assumptions is proposed, and the relation between the message processing and the system performance is analyzed. The multi-thread method is introduced in the on-line system, where the disc device is mainly used. The message processing programs are controlled by the monitor, CCP (Communicaton Control Program), and an on-line control program. The message processed by the message processing program is classified into three types, i.e. the simple response message, the compound response message, and the branch response message. The model is simulated in detail by GPSS/60. The main objects of this paper are (1) to be helpful to the system construction, (2) to be applicable to the modification of the proposed model flexibly, and (3) to be applicable to many job scheduling methods. Therefore it is clear that we can assign the priority, the routine to be usable or to be reusable, and that we can decide the polling intervals and the overlay structure in this model. The simulation program was executed by FACOM 230-60,through which we have affirmed that the simulation is accurate and practical. Finally we found that the modeling of an on-line real-time computer system for GPSS/60 improved the system performance.