Lightweight firm real-time extensions for low memory profile Java systems

Abstract

This paper shows a novel approach to real-time extensions for Java running on low memory profile systems. Dynamic time-driven firm real-time scheduling is rendered possible by merely using regular Java threads. A three level scheduling scheme using earliest deadline first (EOF), fair-share and round-robin policies is integrated into a Java virtual machine kernel. The application programming interface (API) of this extension is elementary. Just one class representing deadlines must be added to the system library. Time critical code regions are encapsulated using standard synchronization techniques on deadline objects. They are applicable to oneshot, periodic and sporadic tasks. The underlying concepts of this technique are characterized in detail and applications are presented that already make use of these real-time capabilities. © Springer-Verlag 2004.