US 12,217,769 B1
Magnetic disk device and method
Sho Suzuki, Tokyo (JP); and Takeyori Hara, Kawasaki Kanagawa (JP)
Assigned to Kabushiki Kaisha Toshiba, Tokyo (JP); and Toshiba Electronic Devices & Storage Corporation, Tokyo (JP)
Filed by Kabushiki Kaisha Toshiba, Tokyo (JP); and Toshiba Electronic Devices & Storage Corporation, Tokyo (JP)
Filed on Jan. 31, 2024, as Appl. No. 18/428,274.
Claims priority of application No. 2023-158709 (JP), filed on Sep. 22, 2023.
Int. Cl. G11B 19/20 (2006.01); H02P 6/182 (2016.01); H02P 21/18 (2016.01)
CPC G11B 19/2081 (2013.01) [G11B 19/2009 (2013.01); H02P 6/182 (2013.01); H02P 21/18 (2016.02)] 20 Claims
OG exemplary drawing
 
1. 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.