Parallel data paths in two-headed disk systems

Analytic models on the expected seek distances for a set of k shadowed conventional disks with one read/write head per surface have been reported in the past. In the present paper we study the expected seek performance in the case of parallel disks having two heads per surface. Two-headed disks may have either two autonomous heads per surface or may have two heads moving concurrently at a fixed distance. The performance of both models is examined by assuming that successive seeks are either independent or dependent. Exact new formulae are derived for each of the aforementioned cases and generalized performance comparisons of all these disk configurations are made