Experiments with the Sun Java Real-Time System -- Part 2
NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF COMPUTER SCIENCE
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In the authors first report on the Sun Java Real-Time System RTS, they concluded that it is preferable to use real-time Java threads that use heap memory rather than no-heap real-time threads NHRTTs for the Global Integrated Fire Control System GIFC due to the difficulty of writing correct Java programs using NHRTTs. However, they also found that such an architecture could not be implemented using RTS 1.0. Experiments with the RTS 2.0 alpha release August 2006 showed that it supports the real-time garbage collector RTGC, and they used it to explore viable software architectures for the GIFC software. Although the alpha version of RTS 2.0 incorporated a number of improvements over RTS 1.0, its RTGC fell short of their expectations and needs. In this second report, they describe the results of their study of the RTS 2.0 beta release December 2006, which includes a new RTGC. They performed a number of experiments to determine whether the improved RTGC would result in better software architecture for the GIFC -- a component of the C2BMC element of the Ballistic Missile Defense System BMDS. Their experiments showed that the new RTGC performed in a satisfactory manner and has met their expectations. They also found that it is possible to use only the real-time Java threads that use heap memory for the GIFC software. SUN RTJ 2.0 gives programmers more control over the priority of the garbage collection. The authors developed a real-time monitor design pattern to support the implementation of time-constrained computations that use heap memory, and a methodology to determine the RTS run-time parameters thread priorities, memory usage, process load, and task deadlines necessary for the timely execution of these time-constrained computations.
- Computer Programming and Software