On the road to real-time OSGi: extending OSGi with an admission control protocol

In previous work we motivated the need for using the OSGi Framework with the Real Time Specification for Java (RTSJ) to develop real-time systems. We found a number of issues with using these technologies together. One of the issues we discovered was unbounded dynamism caused by the absence of admission control. Components can be uninstalled, installed and updated without regulation. This means that it is impossible to guarantee resources to components. In this paper, we propose a solution to the unbounded dynamism problem by providing an admission control protocol for real-time OSGi (RT-OSGi). We also provide a priority assignment approach to support temporal isolation. The combination of admission control and temporal isolation ensure that it is safe to update components or install components into the system in terms of guaranteeing resources to components. We show the practicality of our admission control by discussing a case study application (chronic disease management) and its design an implementation using RT-OSGi. Finally, the admission control aspect of RT-OSGi (discussed in this paper) is evaluated through measuring its execution-time overhead in the context of the chronic disease management application.