Command queuing in disk drives

摘要

A method and system for command queuing in disk drives may improve performance by queuing multiple commands and sequentially executing them automatically without firmware intervention. The method may use a number of queues, e.g., a staging queue for commands to be executed, an execution queue for commands currently being executed, and a holding queue for commands which have been executed but have not received a status report from a host. With the pipelined nature of queued commands, when data requested by one command are being sent to the host, the queue logic may already be fetching data for the next command. If an error occurs in the transmission, commands in the queues may backtrack and restart from the point where data were last known to have been successfully sent to the host.

主权项

1. A method comprising:
executing commands from a first queue, the commands for transferring data between a storage device and a host; and storing, in a second queue, at least one of the commands for transferring data between the storage device and the host, the storing performed after the one of the commands has executed effective to initiate a transfer of data between the storage device and the host but before a status report for the one of the commands is accessible.