All the OS research here is based on the following premises Performance is critical. Quantitative measures are better than conceptual cuteness. Designs must be driven by applications.
Correctness depends on deterministic and transparent OS mechanisms.
Memory management, communications, file systems, and process control are among the areas that are critical here. RT is needed for control of machinery, for high speed communications, and for multimedia. MP , SMP, and clusters. SMP is mainly interesting because it is so available, but it is really a poor engineering approach driven by the low quality of the dominant operating systems. The most expensive and limiting component of SMP hardware is the cache coherency and the only purpose of cache coherency hardware is to compensate for MP unaware operating systems.