Patent ID: 7567402

Claim:
A storage device having a ramp mechanism which shakes out a head onto a medium and holds said head by causing said head to evacuate from the medium, comprising: a command queuing processing unit which, after storing input/output commands in the order of command issuance by a host in accordance with a queuing protocol set forth in an interface having a command queuing function of connecting between the host and a storage device into a queue, executes the commands by arranging the commands in the increasing order of access time to the medium, and responds to the host with the command completion in the order of completion of execution; and an emergency evacuation processing unit which, upon receipt of an emergency evacuation command not set forth in said queuing protocol from said host during operation of said command queuing processing unit, discontinues operation of said command queuing processing unit, processes the command information queuing in said command queuing processing unit, and causes said head to evacuate from the medium into said ramp mechanism; wherein the procedure for selecting in advance by means of said emergency evacuation processing unit is: a first procedure of holding the discontinuance state upon discontinuing the command execution of said command queuing processing unit, and upon the completion of said emergency evacuation command, and releases the discontinuance state of command execution of said command queuing processing unit to resume command execution; or a second procedure of destroying all the command information queuing in said command queuing processing unit upon the completion of execution of said emergency evacuation command.