Abstract: A disk controller and method which dynamically compensates for host command queue depth during the data rebuild process and thus maintains a predictable level of performance during data reconstruction operations. During non-idle periods, a rebuild task monitors the current host command queue depth generated by the host and submits additional rebuild requests accordingly. Rebuild requests are preferably sized based on the current rebuild queue depth and the user-selected performance allotment for rebuild operations to maintain a predictable level of performance degradation. Therefore, the rebuild task dynamically compensates for host command queue depth by queueing an appropriate number of rebuild requests of varying size so that neither requesting task dominates. This compensates for instances when the host queues requests deeply, such as during write cache flushing, while also preserving responsiveness when the host has one single thread of activity.

Abstract: When a fault occurs on a data communication processor that controls data communication between information processors, all information processors connected to the data communication processor are notified of the occurrence of the fault, upon which the information processors automatically reset the data communications processors. A fault detector is provided in an interface controller in a data communications processor 101, a crossbar switch 108, and an arbitration controller 109. When a fault occurs, the fault processor in the interface controller is notified of the occurrence and the failed location by means of a broadcast signal. The fault processor notifies the information processor of the fault by means of an interrupt signal. The notified information processor instructs the data communications processor to reset each controller of the data communication processor for fault recovery.