Multiprocessor systems with reserves and preferences

Two models involving multiprocessor systems with two different groups of processors are examined. In the first model, the processors which are in use break down from time to time; one of the two groups is used only when the other one is entirely inoperative. In the second model, the breakdowns are replaced by a Poisson stream of jobs. Again, one group of processors is used in preference to the other one. In both cases, the analysis is based on finding a polynomial in two variables which satisfies a partial differential-functional equation. Exact solutions are obtained.