A network architecture capable of efficiently running fault-tolerant applications
José Miró-Julià · 1991
Fault-tolerant execution of programs is a desirable feature. Up to now the only way to obtain fault tolerance for a process was to run it on a specially designed fault-tolerant computer system. This dissertation will show how a Local Area Network can be used as a basic architecture to run hardware and software fault-tolerant applications based on the N-Version Programming paradigm. These applications would run in coexistence with normal (non-fault-tolerant) processes, with minimal disturbance. Software and hardware approaches of how this can be achieved are presented. With the help of an N-Version eXecutive Processor (NVXP), a small and simple co-processor to be added to each node of the network, and a duplicated Broadcast Network, it is possible to run fault-tolerant applications efficiently. The use of a scheduler using a dynamic priority concept will further enhance the performance to be obtained from the system. The performance to be expected for both N-Version and normal software is then evaluated by using a simulation program and a queueing network for the different solutions proposed and under varying environment conditions.