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Examines a method of determining a policy for efficient allocation and utilization of a set of disk drives with differing operational characteristics. Application of the standard queueing model; Formula representing service time of a disk drive; Minimization of the total response time of the set of disk models under varying load conditions; Indication that faster devices should have higher utilization factors.

Presents the methods for computing the equilibrium distribution of customers in closed queueing networks with exponential servers. Evaluation of expressions for various marginal distributions; Computational algorithms based on two-dimensional iterative techniques; Examination of the storage allocation strategies and order of evaluation.

The solution of separable closed queueing networks requires the evaluation of homogeneous multinomial expressions. The number of terms in those expressions grows combinatorially with the size of the network such that a direct summation may become impractical. An algorithm is given which does not show a combinatorial operation count. The algorithm is based on a generalization of Homer's rule for polynomials. It is also shown how mean queue size and throughput can be obtained at negligible extra cost once the normalization constant is evaluated. [ABSTRACT FROM AUTHOR]