Patent ID: 6145052
Filing Date: 2000-11-07
Classification: G06F,G11B

Abstract:
In a disk drive having an intelligent interface for communicating to a host, and a read/write head positioned by an actuator, where the disk drive receives a plurality of commands from the host, wherein each one of the plurality of commands has associated requested data with a data location on a disk, wherein the disk drive experiences a mechanical time delay when positioning the read/write head to the data location, and wherein the time a command was received from the host is recorded for each one of the plurality of commands, a method for selecting a next command to execute comprising the steps of:a) providing an execution threshold age;b) providing a pool threshold age;c) providing an age threshold age;d) calculating a mechanical time delay for each one of the plurality of commands based on the time required to position the read/write head over the data location requested in each command;e) calculating a command age for each one of the plurality of commands based on a current time and the time the command was received from the host;f) checking whether any command has aged beyond the execution threshold age and executing any command that has aged beyond the execution threshold age; andg) then checking, if no command has aged beyond the execution threshold age, if the oldest command has aged beyond the age threshold age; andif the oldest command has aged beyond the age threshold age, then executing the command that has both aged beyond the pool threshold age and has a smallest mechanical time delay; andif the oldest command has not aged beyond the age threshold age, then executing the command with the smallest mechanical time delay.