Language support for the maruti real-time system

A time-driven approach for the design of hard real-time systems uses the time constraints of applications directly for their scheduling to ensure that their deadlines are met. The timedriven approach requires that the scheduler know the resource requirements, time constraints, and execution time of each application. Communication, precedence, and synchronization among processes affect the time constraints of applications, and must be taken into account while scheduling. Since these constraints and requirements are application specific, they need to be derived from application programs. Therefore, the programming language has to provide the programmer with features to express them. Maruti is a testbed for the design of time-driven hard real-time systems being designed at the University of Maryland. It uses the technique of pre-scheduling where the application is scheduled prior to execution and resources required by the application are reserved, in order to ensure that deadlines are met. This paper describes the features of MPL, a language for Maruti. MPL provides construts for expressing time constraints, precedence relations, and synchronization directly in the programs. The MPL features are designed to facilitate pre-scheduling.