Magnetic disk device and method
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorsSho Suzuki, Takeyori Hara
Life of this patent
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Abstract
According to one embodiment, a controller of a magnetic disk device calculates a first power amount that is an amount of power required for an unload operation of a magnetic head based on a state of a VCM while the VCM is operating. The controller calculates a first set value based on the first power amount. When an amount of second data that is first data stored in a volatile memory and not yet written to a magnetic disk exceeds the first set value, the controller executes a first write operation of writing a part or all of the second data to the magnetic disk. When supply of power from outside is interrupted, the controller executes the unload operation and saving of the second data to a nonvolatile memory by using power generated by a back electromotive force of the second motor.
Claims20
A magnetic disk device comprising:
- a magnetic disk;
- a magnetic head configured to write to and read from the magnetic disk;
- a first motor configured to move the magnetic head relative to the magnetic disk in a radial direction;
- a second motor configured to rotate the magnetic disk;
- a nonvolatile memory;
- a volatile memory configured to store first data that is data received from a host device at least until the first data is written to the magnetic disk;
- and
- a controller configured to:
- calculate a first power amount that is an amount of power required for an unload operation of the magnetic head based on a first state of the first motor while the first motor is operating;
- calculate a first set value based on the first power amount;
- execute a first write operation of writing a part or all of second data to the magnetic disk when an amount of the second data exceeds the first set value, the second data being the first data that is stored in the volatile memory and has not yet been written to the magnetic disk;
- and
- execute the unload operation and saving of the second data to the nonvolatile memory by using power generated by a back electromotive force of the second motor when supply of power from outside is interrupted.
A magnetic disk device comprising:
- a magnetic disk;
- a magnetic head configured to write to and read from the magnetic disk;
- a motor configured to rotate the magnetic disk;
- a nonvolatile memory;
- a volatile memory configured to store first data that is data received from a host device at least until the first data is written to the magnetic disk;
- and
- a controller configured to:
- calculate a first resistance value that is a coil resistance value of the motor based on a state of the motor while the motor is operating;
- calculate a first power amount that is an amount of power generated by a back electromotive force of the motor based on the first resistance value;
- calculate a first set value based on the first power amount;
- execute a first write operation of writing a part or all of second data to the magnetic disk when an amount of the second data exceeds the first set value, the second data being the first data that is stored in the volatile memory and has not yet been written to the magnetic disk;
- and
- execute saving of the second data to the nonvolatile memory by using power generated by a back electromotive force of the motor when supply of power from outside is interrupted.
A method of controlling a magnetic disk device including a magnetic disk, a magnetic head, a first motor configured to move the magnetic head relative to the magnetic disk in a radial direction, a second motor configured to rotate the magnetic disk, a nonvolatile memory, and a volatile memory,
- the method comprising:
- storing first data that is data received from a host device in the volatile memory at least until the first data is written to the magnetic disk;
- calculating a first power amount that is an amount of power required for an unload operation of the magnetic head based on a first state of the first motor while the first motor is operating;
- calculating a first set value based on the first power amount;
- executing a first write operation of writing a part or all of second data to the magnetic disk when an amount of the second data exceeds the first set value, the second data being the first data that is stored in the volatile memory and has not yet been written to the magnetic disk;
- and
- executing the unload operation and saving of the second data to the nonvolatile memory by using power generated by a back electromotive force of the second motor when supply of power from outside is interrupted.
Dependencies are inferred from the claim text.