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An important factor contributing to an operating systems ’ performance is the design and efficiency of the kernel code. This is especially true for microkernel based operating systems where the microkernel and kernel provides support for system servers. RHODOS is a microkernel based distributed operating system designed as a testbed for the study of the numerous research topics available in this area. The current version of RHODOS uses a single threaded microkernel, which fulfilled our requirements of providing a stable platform. A significant drawback of a single threaded architecture is the difficulty with which paging can be implemented. This report details the current state of the RHODOS single threaded microkernel and provides justification for the implementation of a mult

Message Passing and RPC-based Interprocess Communication Mechanisms in the RHODOS Microkernel

RHODOS is a microkernel based distributed operating system that has been designed with message passing as the primary communication mechanism. RHODOS provides efficient interprocess communication system by providing two methods of cross address space communications: internal buffering and virtual memory mapping. Both methods were implemented to reduce operating system overheads in communications. Integral to the success of the interprocess communications facility within RHODOS are the microkernel data structures: SNames, Operation Structures, and Berkeley Mbufs. These microkernel data structures provide the required modularity, flexibility, and simplicity in the design of interprocess communication mechanism necessary for both message passing and remote procedure call based communications for RHODOS. *This work was partly supported by the Australian Research Council under Grant A48831034, A49232429 and the Deakin University Research Grant 0504010151. RHODOS September 8, 1994 ii CON..