Ganger

Proceedings of the ACM Sigmetrics Conference, May 1995, pp. 146-156.

Bruce L. Worthington, Gregory R. Ganger, Yale N. Patt, and John Wilkes*

University of Michigan 1301 Beal Avenue, EECS Dept. Ann Arbor, MI 48109-­2122
*Hewlett­Packard Laboratories 1501 Page Mill Road, MS 1U13 Palo Alto, CA 9430-­1126  

Sophisticated disk scheduling algorithms require accurate and detailed disk drive specifications, including inormation on mechanical delays, on­board caching and prefetching algorithms, command processing and protocol overheads, and logical­to­physical block mappings. Comprehensive disk models used in storage subsystem design require similar levels of detail. This report describes a suite of general­purpose techniques and algorithms for acquiring the necessary data from SCSI disks via the ANSI­standard interface. The accuracy of the extracted information is demonstrated by comparing the behavior of a configurable disk simulator against actual disk drive activity. Detailed measurements extracted from several SCSI disk drives are provided.

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