Fault-tolerant servers for the RHODOS system

Providing reliable services is one of the primary goals in designing a distributed operating system. Nowadays, we have seen a trend in distributed operating system design to shift from large kernel architectures or even monolithic architectures to microkernel architectures supported by the client/server model. This means that a lot of services of an operating system originally provided by the monolithic kernel are moved out of the kernel, forming individual servers. It is then crucial to guarantee that these servers will provide reliable services. This article describes a design, based on a twin-servers model, of fault-tolerant servers for the microkernel-based RHODOS distributed operating system. A model that supports fault-tolerant services is designed. The performance of the model is simulated and analyzed. A design that implements the model in the RHODOS environment is also outlined.