Software Engineering Institute

Durra is a language designed to support PMS-level programming. PMS stands for Processor-Memory-Switch, the name of the highest level in the hierarchy of digital systems. An application or PMS-level program is written in Durra as a set of task descriptions and type declarations that prescribes a way to manage the resources of a heterogeneous machine network. The application describes the tasks to be instantiated and executed as concurrent processes, the types of data to be exchanged by the processes, and the intermediate queues required to store the data as they move from producer to consumer processes.

This report describes the Durra Runtime Environment. The environment consists of three active components: the application tasks, the Durra server, and the Durra scheduler. After compiling the type declarations, the component task descriptions, and the application description, the application can be executed by starting an instance of the server on each processor, starting an instance of the scheduler on one of the processors, and downloading the component task implementations (i.e., the programs) to the processors. The scheduler receives as an argument the name of the file containing the scheduler program generated by the compilation of the application description. This step initiates the execution of the application.