US 11,899,968 B2
Magnetic disk apparatus and method
Masahisa Miyake, Ome Tokyo (JP); and Kazuya Takada, Chigasaki 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 Mar. 8, 2022, as Appl. No. 17/689,242.
Claims priority of application No. 2021-152184 (JP), filed on Sep. 17, 2021.
Prior Publication US 2023/0088609 A1, Mar. 23, 2023
Int. Cl. G06F 12/00 (2006.01); G06F 3/06 (2006.01); G11B 5/012 (2006.01); G11B 5/54 (2006.01); G11B 5/00 (2006.01)
CPC G06F 3/0656 (2013.01) [G06F 3/0619 (2013.01); G06F 3/0676 (2013.01); G11B 5/012 (2013.01); G11B 5/54 (2013.01); G11B 2005/001 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A magnetic disk apparatus comprising:
a magnetic disk having plural bands, each band serving as a storage area to which data is written by a Shingled Magnetic Recording (SMR) method;
a buffer memory; and
a control circuit configured to
receive a request of read from outside and,
when data requested to be subjected to the read is first data of an update target stored in a first band among the plural bands, read the first data from the first band, stores the first data in the buffer memory, update the first data in the buffer memory, transmit the first data in the buffer memory to the outside, and write the first data in the buffer memory to one of the plural bands, wherein
the magnetic disk apparatus further comprises plural actuator systems, each actuator system provided with a magnetic head at a distal end, wherein,
the control circuit is configured to,
when the data requested to be subjected to the read is the first data and second data of an update target, the second data being stored in a second band different from the first band among the plural bands,
write the first data in the buffer memory to one band among the plural bands by using a first actuator system that is one actuator system among the plural actuator systems, and,
in parallel to the write of the first data using the first actuator system, read the second data from the second band by using a second actuator system that is different from the first actuator system among the plural actuator systems and store the second data in the buffer memory, wherein
the buffer memory is provided with a first buffer area and a second buffer area; and
the control circuit is configured to copy the first data read from the first band to acquire two pieces of the first data, store third data serving as one of the two pieces of the first data in the first buffer area, store fourth data serving as another one of the two pieces of the first data in the second buffer area, transmit the third data in the first buffer area to the outside, and write the fourth data in the second buffer area to one band among the plural bands.