Abstract: The present invention provides a method and system for reporting disk utilization in a computer system. The method includes collecting at least one parameter pertaining to a disk array in a disk subsystem by a processor in the disk subsystem; transferring the at least one parameter from the processor to an open system host; and calculating disk utilization based upon the at least one parameter. The method and system is able to provide disk utilization which is understandable to the open system host. In a preferred embodiment, the disk utilization is provided by collecting the relevant parameters from the microcode in the processor of the disk subsystem, and then calculating the average disk utilization per disk based upon the parameters. Thus, an open system host is able to obtain a useful characteristic for determining the performance of the disk subsystem.

Abstract: A cache management system for dynamically switching between record caching and track caching. Statistics are collected within the cache management system to determine the type and amount of locality associated with a specific data set currently within the cache. Using these statistics, metrics of the actual hit ratio, whole-track hit ratio, and other-record-hit ratio are generated. The metrics are periodically reviewed for a given band, and the band is placed into one of three cache modes accordingly. The mode assignment determines what type of staging will be performed for data within the band in the event of a miss. The possible modes are: track mode for track-based staging, record mode for staging of a single record only, or uncached mode if no data is to be staged. If a band has been assigned to either record or track mode, the assignment is re-evaluated after for a predetermined number of I/O's (128).