Magnetic disk device
View Patent ↗According to one embodiment, a magnetic disk device includes a disk, a write head, and a write processing unit. The write processing unit executes first write processing of writing data to a first segment of a first data sector in a first data track. The write processing unit then executes second write processing of writing data to a first segment of a second data sector in the first data track. The write processing unit then executes third write processing of writing data to a second segment of the first data sector in a second data track.
1. A magnetic disk device comprising:
a disk that includes a plurality of data tracks including a first data track and a second data track in a recording layer;
a write head that writes data to the recording layer of the disk; and
a write processing unit that is capable of executing write processing of writing data to the recording layer,
the write processing unit
executing first write processing of writing data to a first segment constituting a part of a first data sector in the first data track,
executing second write processing of writing data to the first segment constituting a part of a second data sector in the first data track after the first write processing is executed, and
executing third write processing of writing data to a second segment constituting a part of the first data sector in the second data track after the second write processing is executed.
2. The magnetic disk device according to claim 1 , wherein
the write head is used for writing data to the first data track and writing data to the second data track.
3. The magnetic disk device according to claim 2 , further comprising:
an arm that supports the write head; and
an actuator that moves the arm,
wherein
the write processing unit
drives the actuator and controls seek operation of seeking the write head,
moves the write head to a position facing the first data track by the seek operation when executing the first write processing,
maintains a state in which the write head faces the first data track when executing the second write processing, and
moves the write head to a position facing the second data track by the seek operation when executing the third write processing.
4. The magnetic disk device according to claim 1 , further comprising:
a write channel including a data processing unit that processes received data and a first memory that includes a first storage region and a second storage region and to which the data processed by the data processing unit is written; and
a second memory to which the data processed by the data processing unit is written,
wherein
the write processing unit
executes the first write processing after data corresponding to the first segment of the first data sector is written to the first storage region and data corresponding to the second segment of the first data sector is written to the second storage region, and
holds the data in the second storage region or moves the data from the second storage region to the second memory until the third write processing is executed after the data is written to the second storage region.
5. The magnetic disk device according to claim 4 , wherein
the first memory is a random access memory, and
the write processing unit
releases the first storage region of the first memory and permits overwriting to the first storage region after executing the first write processing,
prohibits overwriting to the second storage region in a case where the data is held in the second storage region, and
permits the overwriting to the second storage region in a case where the data is moved from the second storage region to the second memory.
6. The magnetic disk device according to claim 4 , wherein
the data processing unit executes processing of encoding the received data.
7. The magnetic disk device according to claim 1 , further comprising:
a write channel including a data processing unit that processes received data and a first memory to which the data processed by the data processing unit is written; and
a second memory that includes a first recording region and a second recording region and to which the data processed by the data processing unit is written,
wherein
the write processing unit
executes the first write processing after data corresponding to the first segment of the first data sector is written to the first recording region, data corresponding to the second segment of the first data sector is written to the second recording region, and the data is moved from the first recording region to the first memory, and
holds the data in the second recording region until the third write processing is executed after the data is written to the second recording region.
8. The magnetic disk device according to claim 7 , wherein
the second memory is a random access memory, and
the write processing unit
releases the first recording region of the second memory and permits overwriting to the first recording region after executing the first write processing, and
prohibits overwriting to the second recording region until the third write processing is executed after the data is written to the second recording region.
9. The magnetic disk device according to claim 1 , further comprising:
a write channel including a data processing unit that processes received data and a first memory to which the data processed by the data processing unit is written; and
a second memory that has recording capacity with which data corresponding to at least two data tracks of the data tracks are capable of being recorded and to which the data processed by the data processing unit is written,
wherein
the write processing unit
causes the write channel to process data corresponding to the first and second data tracks,
writes the data corresponding to the first and second data tracks, which are processed by the write channel, to the second memory, and
starts the data write processing on the first and second data tracks after the data corresponding to the first and second data tracks are stored in the second memory.
10. The magnetic disk device according to claim 9 , wherein
the write processing unit
moves the data corresponding to the first data track from the second memory to the first memory and executes first sequential write processing of sequentially writing the data corresponding to the first data track to a plurality of the first segments of the first data track after the data corresponding to the first and second data tracks are stored in the second memory,
the data corresponding to the first data track includes the data corresponding to the first segment of the first data sector and the data corresponding to the first segment of the second data sector,
each of the first segments constitutes a part of a corresponding data sector among a plurality of the data sectors, and
all the segments constituting the corresponding data sector are not allocated to the first data track.
11. The magnetic disk device according to claim 10 , wherein
the write processing unit
executes the first sequential write processing and then executes second sequential write processing of sequentially writing the data corresponding to the second data track to a plurality of the second segments of the second data track after moving the data corresponding to the first and second data tracks from the second memory to the first memory, the data corresponding to the second data track includes the data corresponding to the second segment of the first data sector and the data corresponding to the second segment constituting a part of the second data sector,
each of the second segments constitutes a part of the corresponding data sector, and
all the segments constituting the corresponding data sector are not allocated to the second data track.
12. The magnetic disk device according to claim 11 , wherein
each of the data sectors is divided into the first segment and the second segment.
13. The magnetic disk device according to claim 11 , wherein
the write processing unit
stores the data corresponding to the first data track in a plurality of regions to which a plurality of first addresses are allocated in the second memory and sequentially links the first addresses when storing the data corresponding to the first data track in the second memory,
stores the data corresponding to the second data track in a plurality of regions to which a plurality of second addresses are allocated in the second memory and sequentially links the second addresses when storing the data corresponding to the second data track in the second memory,
selects the first addresses in an order of the linked first addresses, sequentially moves data of the selected first addresses from the second memory to the first memory, and sequentially writes the data corresponding to the first data track to the first segments of the first data track in an order of moving the data from the second memory to the first memory when executing the first sequential write processing, and
selects the second addresses in an order of the linked second addresses, sequentially moves data of the selected second addresses from the second memory to the first memory, and sequentially writes the data corresponding to the second data track to the second segments of the second data track in an order of moving the data from the second memory to the first memory when executing the second sequential write processing.
14. The magnetic disk device according to claim 1 , further comprising
a write channel including a data processing unit that processes received data, a parity generation unit that performs an XOR operation on the data processed by the data processing unit, and a first memory that includes a third storage region and a fourth storage region and to which the data processed by the data processing unit and the data subjected to the XOR operation by the parity generation unit are written,
wherein
a plurality of sectors allocated across the first and second data tracks include a plurality of data sectors including the first data sector and the second data sector, and belonging to a group, and a parity sector in which a parity for recovering data of the data sectors belonging to the group is recorded, and each of the sectors is constituted by a first segment and a second segment,
the data processing unit processes the data corresponding to the data sectors belonging to the group and writes the processed data to the first memory, and
the parity generation unit
performs an XOR operation on data corresponding to a plurality of first segments belonging to the group among the data processed by the data processing unit, generates data corresponding to the first segment of the parity sector, and writes the data to the third storage region, and
performs the XOR operation on data corresponding to a plurality of second segments belonging to the group among the data processed by the data processing unit, generates data corresponding to the second segment of the parity sector, and writes the data to the fourth storage region.
15. The magnetic disk device according to claim 14 , wherein
when the parity generation unit generates data corresponding to the parity sector and writes the data to the first memory, after the data processing unit processes the data corresponding to the first data sector, the parity generation unit
performs the XOR operation on the data corresponding to the first segment of the first data sector, generates a part of data corresponding to the first segment of the parity sector, and writes the data to the third storage region, and
subsequently performs the XOR operation on the data corresponding to the second segment of the first data sector, generates a part of data corresponding to the second segment of the parity sector, and writes the data to the fourth storage region.
16. The magnetic disk device according to claim 14 , wherein
in a case where the data corresponding to the second segment of the parity sector is written to the first or second data track before the data corresponding to all the second segments belonging to the group are written to at least one of the first data track or the second data track, the parity generation unit performs the XOR operation on the data corresponding to all the second segments belonging to the group and completes the data corresponding to the second segment of the parity sector in advance.
17. The magnetic disk device according to claim 1 , wherein
the data tracks further include a third data track,
the first and second data tracks are provided in a first data region of the recording layer,
the third data track is provided in a second data region of the recording layer, the second data region being located to be shifted from the first data region in a radial direction, and
all of third data sectors are allocated to the third data track.
18. A magnetic disk device comprising:
a disk that includes a plurality of data tracks including a first data track and a second data track in a recording layer;
a first read head, a second read head, and a third read head that each reads data from the recording layer of the disk;
an arm that supports the first to third read heads;
an actuator that moves the arm; and
a read processing unit that is capable of executing read processing of reading data from the recording layer,
the first data track including a first segment constituting a part of a first data sector,
the second data track including a second segment that constitutes a part of the first data sector and being adjacent to the first segment in a radial direction, and
the read processing unit
driving the actuator and controlling seek operation of seeking the first to third read heads to move the first read head to a position facing the first data track,
selecting a first selection read head that is the first read head and a second selection read head that is a read head closest to the second data track of the second and third read heads according to a skew angle of the first read head, and
simultaneously reading data corresponding to the first segment of the first data track and data corresponding to the second segment of the second data track by using the first and second selection read heads.
19. The magnetic disk device according to claim 18 , further comprising
a read channel that includes a first two-dimensional FIR filter and a second two-dimensional FIR filter,
wherein
the first two-dimensional FIR filter performs first waveform equalization processing of equalizing a waveform of synthesis data obtained by synthesizing a first read signal read by the first selection read head and a second read signal read by the second selection read head such that an error rate of data written to the first data track is minimized, and outputs first waveform equalization data, and
the second two-dimensional FIR filter performs second waveform equalization processing of equalizing the waveform of the synthesis data such that an error rate of data written to the second data track is minimized, and outputs second waveform equalization data.
20. The magnetic disk device according to claim 19 , wherein
the read channel further includes a two-dimensional viterbi decoder that outputs decoding data obtained by simultaneously decoding the first waveform equalization data and the second waveform equalization data.