Publications [#236031] of Robert Calderbank

Journal articles or Book chapters PUBLISHED

1. Calderbank, AR; Coffman, EG; Flatto, L, A Note Extending the Analysis of Two-Head Disk Systems to More General Seek-Time Characteristics, IEEE Transactions on Computers, vol. 38 no. 11 (January, 1989), pp. 1584-1586, Institute of Electrical and Electronics Engineers (IEEE) [doi]
   (last updated on 2026/01/18)

   Abstract:
   We analyze a model of a movable-head disk system with two read/write heads maintained a fixed distance d apart on each arm. Successive request-addresses are assumed to be independent random variables, uniformly distributed over the set of cylinders. The purpose of an earlier analysis was to find that value of d which minimizes the expected seek time per request, assuming that seek time varies linearly with the distance z traveled by the heads. In this note, we extend this analysis to more general seek-time characteristics which take into account nonlinear acceleration effects. Detailed results, combining both analysis and simulation experiments, are presented for seek times linear in zα 0  α  1. An unexpected result of the study was that the value of d which minimizes expected seek time is very nearly independent of α. © 1989 IEEE