HP Labs Technical Reports

On-Line Extraction of SCSI Disk Drive Parameters

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

HPL-97-02

Keyword(s): SCSI disk drives, parameters, automatic measurement

Abstract: Sophisticated disk scheduling algorithms require accurate and detailed disk drive specifications, including information on mechanical delays, on-board caching and prefetching algorithms, command processing and protocol overheads, and logical-to-physical block mappings. Comprehensive disk models used in storage subsystem design require similar levels of detail. This report describes a suite of general-purpose techniques and algorithms for acquiring the necessary data from SCSI disks via the ANSI-standard 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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