Paths: programming with system resources in support of real-time distributed applications

Real-time distributed applications often rely upon underlying communication services to provide different types of guarantees, such as forward progress and bounded delivery time. Providing such guarantees requires the careful management of several resources, including memory, CPU and network bandwidth. This paper describes how our Object-Oriented Communication Subsystem, CORDS, was enhanced to manage these resources. A new abstraction, the path, provides an end-to-end context for programmable control over system resources. Paths can be thought of as naming distinct virtual channels through a CORDS protocol graph. Although our work is motivated by hard real-time distributed applications (requiring deterministic guarantees), the new notion of "programming with system resources" also applies to scenarios outside the hard real-time realm. Preliminary empirical results demonstrate the effectiveness of CORDS' control over system resources.