Disk drive for portable computer with adaptive demand-driven power management

Claim 1

A method of managing electrical power usage in a data recording disk drive that has a recording disk with data tracks, a plurality of electrically powered components, and a data controller that generates disk drive accesses for the reading and writing of data on the disk, the disk drive components including a spindle motor for rotating the disk, a head for writing data to or reading data from the disk, and an actuator connected to the head for moving the head to different tracks on the disk, the method comprising the steps of: determining the frequency of read or write accesses from the data controller while the spindle motor is rotating at its operating speed; storing a plurality of values representing a like plurality of previously determined access frequencies; computing, from the stored values of previously determined access frequencies, an access threshold frequency while the spindle motor is rotating at its operating speed; and reducing electrical power to at least one of the electrically powered components when the determined access frequency falls below the computed access threshold frequency.

Claim 2

A method of managing electrical power usage in a data recording disk drive that has a recording disk with data tracks, a plurality of electrically powered components, and a data controller that generates disk drive accesses for the reading and writing of data on the disk, the disk drive components including a spindle motor for rotating the disk, a head for writing data to or reading data from the disk, and an actuator connected to the head for moving the head to different tracks on the disk, the method comprising the steps of: determining the frequency of read or write accesses from the data controller while the spindle motor is rotating at its operating speed; storing a plurality of values representing a like plurality of previously determined access frequencies; computing, from the stored values of previously determined access frequencies, an access threshold frequency while the spindle motor is rotating at its operating speed; and reducing electrical power to at least one of the electrically powered components when the determined access frequency falls below the computed access threshold frequency.

Claim 8

A method of managing electrical power usage in a data recording disk drive having a recording disk with data tracks, a spindle motor for rotating the disk, a head for writing data to or reading data from the data tracks, a data controller that accesses the head to read and write data, a voice coil motor (VCM) actuator driven by a VCM driver and connected to the head for moving the head to different data tracks and to a nondata parking location, and servo control electronics coupled to the actuator for maintaining the head on a data track during reading or writing of data, the disk drive being capable of operating in a first power-save mode during which the spindle motor is rotating at its operating speed and a second power-save mode during which power to the spindle motor is reduced, the method comprising the steps of: determining the frequency of read or write accesses while the spindle motor is rotating at its operating speed; storing a values representing a like plurality of previously determined access frequencies; computing from the stored values of previously determined access frequencies a first access threshold frequency while the spindle motor is rotating at its operating speed; and when the read or write access frequency is less than the first threshold frequency, reducing power to the VCM driver and the servo control electronics; whereby the disk drive is caused to enter the first power-save mode of operation.

Claim 9

A method of managing electrical power usage in a data recording disk drive having a recording disk with data tracks, a spindle motor for rotating the disk, a head for writing data to or reading data from the data tracks, a data controller that accesses the head to read and write data, a voice coil motor (VCM) actuator driven by a VCM driver and connected to the head for moving the head to different data tracks and to a nondata parking location, and servo control electronics coupled to the actuator for maintaining the head on a data track during reading or writing of data, the disk drive being capable of operating in a first power-save mode during which the spindle motor is rotating at its operating speed and a second power-save mode during which power to the spindle motor is reduced, the method comprising the steps of: determining the frequency of read or write accesses while the spindle motor is rotating at its operating speed; storing a values representing a like plurality of previously determined access frequencies; computing from the stored values of previously determined access frequencies a first access threshold frequency while the spindle motor is rotating at its operating speed; and when the read or write access frequency is less than the first threshold frequency, reducing power to the VCM driver and the servo control electronics; whereby the disk drive is caused to enter the first power-save mode of operation.

Claim 16

A method of managing electrical power usage in a data recording disk drive having a recording disk with data tracks, a spindle motor for rotating the disk, a head for writing data to or reading data from the data tracks, a data controller that accesses the head to read and write data, an actuator connected to the head for moving the head to different data tracks and to a nondata parking location, and servo control electronics coupled to the actuator for maintaining the head on a data track during reading or writing of data, the disk drive being capable of entering and exiting a power-save mode of operation, the method comprising the steps of: determining the frequency of read or write accesses while the spindle motor is rotating; storing values of previously determined access frequencies; computing from the stored values of previously determined access frequencies a first access threshold frequency while the spindle motor is rotating; entering the power-save mode after the most recent access, the time to power-save mode entry being variable depending on the computed first access threshold frequency; selecting a performance factor having a range of values, one limit of the range representing maximum disk drive power savings and the other limit of the range representing maximum disk drive performance; and using the selected performance factor to modify the first access threshold frequency computation, whereby the power save mode entry behavior of the disk drive is adjusted by the selected performance factor.

Claim 17

A method of managing electrical power usage in a data recording disk drive having a recording disk with data tracks, a spindle motor for rotating the disk, a head for writing data to or reading data from the data tracks, a data controller that accesses the head to read and write data, an actuator connected to the head for moving the head to different data tracks and to a nondata parking location, and servo control electronics coupled to the actuator for maintaining the head on a data track during reading or writing of data, the disk drive being capable of entering and exiting a power-save mode of operation, the method comprising the steps of: determining the frequency of read or write accesses while the spindle motor is rotating; storing values of previously determined access frequencies; computing from the stored values of previously determined access frequencies a first access threshold frequency while the spindle motor is rotating; entering the power-save mode after the most recent access, the time to power-save mode entry being variable depending on the computed first access threshold frequency; selecting a performance factor having a range of values, one limit of the range representing maximum disk drive power savings and the other limit of the range representing maximum disk drive performance; and using the selected performance factor to modify the first access threshold frequency computation, whereby the power save mode entry behavior of the disk drive is adjusted by the selected performance factor.

Claim 25

A method of managing electrical power usage in a data recording disk drive having a recording disk with data tracks, a spindle motor for rotating the disk, a head for writing data to or reading data from the data tracks, a data controller that accesses the head to read and write data, an actuator connected to the head for moving the head to different data tracks and to a nondata parking location, and servo control electronics coupled to the actuator for maintaining the head on a data track during reading or writing of data, the disk drive being capable of entering and exiting a power-save mode of operation, the method comprising the steps of: determining the frequency of read or write accesses while the spindle motor is rotating at its operational speed; storing values of previously determined access frequencies; computing from the stored values of previously determined access frequencies an access threshold frequency while the spindle motor is rotating at its operational speed; when the read or write access frequency is less than the access threshold frequency, entering the power-save mode of operation; detecting the power-save mode entry and exit times; computing an energy penalty if a power-save mode duration from the detected mode entry and exit times is less than a predetermined energy break-even time, said break-even time being the power-save mode duration required for the disk drive energy savings to be generally equal to the disk drive energy required to exit the power-save mode; accumulating the computed energy penalties; and modifying the access threshold frequency when the accumulated energy penalties exceed a predetermined trip level, whereby the power-save mode entry behavior of the disk drive is dynamically adjusted from the history of energy penalties.

Claim 26

A method of managing electrical power usage in a data recording disk drive having a recording disk with data tracks, a spindle motor for rotating the disk, a head for writing data to or reading data from the data tracks, a data controller that accesses the head to read and write data, an actuator connected to the head for moving the head to different data tracks and to a nondata parking location, and servo control electronics coupled to the actuator for maintaining the head on a data track during reading or writing of data, the disk drive being capable of entering and exiting a power-save mode of operation, the method comprising the steps of: determining the frequency of read or write accesses while the spindle motor is rotating at its operational speed; storing values of previously determined access frequencies; computing from the stored values of previously determined access frequencies an access threshold frequency while the spindle motor is rotating at its operational speed; when the read or write access frequency is less than the access threshold frequency, entering the power-save mode of operation; detecting the power-save mode entry and exit times; computing an energy penalty if a power-save mode duration from the detected mode entry and exit times is less than a predetermined energy break-even time, said break-even time being the power-save mode duration required for the disk drive energy savings to be generally equal to the disk drive energy required to exit the power-save mode; accumulating the computed energy penalties; and modifying the access threshold frequency when the accumulated energy penalties exceed a predetermined trip level, whereby the power-save mode entry behavior of the disk drive is dynamically adjusted from the history of energy penalties.