Disk array system with controllers that prefetch and buffer ATA disk drive commands

摘要

A disk array system comprises a plurality of controllers, each of which preferably implements a host side of an ATA interface protocol within automated circuitry to control a respective ATA disk drive. Each controller includes a command buffer for storing disk drive commands to be executed by a respective ATA drive, and includes a circuit that prefetches such commands so that a next disk drive command will be available within the command buffer when the disk drive finishes executing a current disk drive command. A delay that commonly occurs when an ATA disk drive retrieves a next disk drive command is thereby reduced or avoided. The disk drive commands are preferably dispatched to the controllers by a microcontroller over a control bus that is separate from a bus used for input/output data transfers.