On-line extraction of SCSI disk drive parameters

Sophisticated disk scheduling algorithms require accurate, detailed disk drive specifications, including data about mechanical delays, on-board caching and prefetching algorithms, command and protocol overheads, and logical-to-physical block mappings. Comprehensive disk models used in storage subsystem design require similar levels of detail. We describe a suite of general-purpose algorithms and techniques for acquiring the necessary information from a SCSI disk drive. Using only the ANSI-standard interface, we demonstrate how the important parameter values of a modern SCSI drive can be determined accurately and efficiently.