Chocolate: a reservation-based real-time Java environment on Windows/NT

The authors present Chocolate, a reservation based real time Java run-time environment that runs on Windows NT. We first present a brief overview of the emerging real time Java standard and the Resource Kernel (RK) approach to providing timely, guaranteed and enforced access to system resources. Chocolate is a real time Java Virtual Machine that interfaces the real time Java programming language with the abstractions of a resource kernel. It also supports memory regimes to control allocation time and a protocol to bound priority inversion. This version of Chocolate is implemented on top of NT/RK, an OS environment that includes a "portable resource kernel" within the NT kernel. Our detailed evaluation of Chocolate shows that the overhead introduced by NT/RK is acceptable. A real time Java audio package on Chocolate demonstrates significantly better performance than its non real time counterpart. However, our Hartstone benchmark evaluations also show that our NT/RK implementation does have its drawbacks due to the lack of hard real time capabilities within Windows NT.