U.S. patent application number 16/942657 was filed with the patent office on 2021-09-09 for magnetic disk device configured to write data according to normal recording and modified shingled recording formats.
The applicant listed for this patent is KABUSHIKI KAISHA TOSHIBA, TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION. Invention is credited to Kiyotaka FUKAWA.
Application Number | 20210280215 16/942657 |
Document ID | / |
Family ID | 1000005020950 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210280215 |
Kind Code |
A1 |
FUKAWA; Kiyotaka |
September 9, 2021 |
MAGNETIC DISK DEVICE CONFIGURED TO WRITE DATA ACCORDING TO NORMAL
RECORDING AND MODIFIED SHINGLED RECORDING FORMATS
Abstract
A magnetic disk device includes a disk including a plurality of
areas divided in a radial direction, a head, and a controller
configured to control the head to write data to a first area
including a plurality of tracks that are separated from each other,
and a second area including at least two adjacent tracks that
partially overlap. A first distance between track centers of said
two adjacent tracks in the radial direction is different from a
second distance between track centers of another two adjacent
tracks in the second area in the radial direction.
Inventors: |
FUKAWA; Kiyotaka; (Hiratsuka
Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOSHIBA
TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION |
Tokyo
Tokyo |
|
JP
JP |
|
|
Family ID: |
1000005020950 |
Appl. No.: |
16/942657 |
Filed: |
July 29, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G11B 5/596 20130101;
G11B 2020/1259 20130101; G11B 2020/183 20130101; G11B 20/1258
20130101; G11B 20/1816 20130101 |
International
Class: |
G11B 20/12 20060101
G11B020/12; G11B 20/18 20060101 G11B020/18; G11B 5/596 20060101
G11B005/596 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 6, 2020 |
JP |
2020-038796 |
Claims
1. A magnetic disk device, comprising: a disk including a plurality
of areas divided in a radial direction; a head; and a controller
configured to control the head to write data to a first area
according to a normal recording format such that a plurality of
tracks in the first area are separated from each other, and a
second area according to a modified shingled recording format such
that at least two adjacent tracks in the second area partially
overlap, wherein a first distance between track centers of said two
adjacent tracks in the radial direction is different from a second
distance between track centers of a first track in the second area
that is at one end of the second area in the radial direction and a
second track in the second area that is adjacent to the first track
in the radial direction.
2. The magnetic disk device according to claim 1, wherein the first
track is at an outermost end of the second area in the radial
direction.
3. The magnetic disk device according to claim 2, wherein said at
least two adjacent tracks include a third and a fourth track, each
of which is at neither the outermost end nor an innermost end of
the second area in the radial direction.
4. The magnetic disk device according to claim 3, wherein the
second area further includes a fifth track and a sixth track
adjacent to the fifth track, the sixth track being located at the
innermost end of the second area, and a track center of the fifth
track is separated from a track center of the sixth track by the
second distance in the radial direction.
5. The magnetic disk device according to claim 4, wherein the first
and the second track do not overlap.
6. The magnetic disk device according to claim 5, wherein the fifth
and the sixth track do not overlap.
7. The magnetic disk device according to claim 4, wherein a
distance between track centers of any two adjacent tracks between
the first and sixth tracks is identical with the first
distance.
8. The magnetic disk device according to claim 4, wherein the
controller is further configured to count a first number of write
retries for the first track and a second number of write retries
for the sixth track.
9. The magnetic disk device according to claim 8, wherein the
controller is further configured to rewrite data that has been
stored in the second area, when either the first number of write
retries or the second number of write retries exceeds a
threshold.
10. The magnetic disk device according to claim 1, wherein the
controller is further configured to control the head to write data
to a plurality of second areas according to the modified shingled
recording format and a distance between track centers of an
outermost track of each second area and a track adjacent thereto is
equal to a distance between track centers of an innermost track of
each second area and a track adjacent thereto, but is different
from a distance between track centers of any other adjacent tracks
other than the outermost and innermost tracks.
11. A method for writing data to a magnetic disk, the method
comprising: writing data to a first area of the magnetic disk
according to a normal recording format such that a plurality of
tracks are separated from each other; writing data to a second area
of the magnetic disk according to a modified shingled recording
format such that at least two adjacent tracks partially overlap,
wherein a first distance between track centers of said two adjacent
tracks in the radial direction is different from a second distance
between track centers of a first track in the second area that is
at one end of the second area in the radial direction and a second
track in the second area that is adjacent to the first track in the
radial direction.
12. The method according to claim 11, wherein the first track is at
an outermost end of the second area in the radial direction.
13. The method according to claim 12, wherein said at least two
adjacent tracks include a third and a fourth track, each of which
is at neither the outermost end nor an innermost end of the second
area in the radial direction.
14. The method according to claim 13, wherein the second area
further includes a fifth track and a sixth track adjacent to the
fifth track, the sixth track being at the innermost end of the
second area, and a track center of the fifth track is separated
from a track center of the sixth track by the second distance in
the radial direction.
15. The method according to claim 14, wherein the first and the
second track do not overlap.
16. The method according to claim 15, wherein the fifth and the
sixth track do not overlap.
17. The method according to claim 14, wherein a distance between
track centers of any two adjacent tracks between the first and
sixth tracks is identical with the first distance.
18. The method according to claim 14, further comprising: counting
a first number of write retries occurred in the first track and a
second number of write retries occurred in the sixth track.
19. The method according to claim 18, further comprising: rewriting
data that has been stored in the second area when either the first
number of write retries or the second number of write retries
exceeds a threshold.
20. The method according to claim 11, further comprising: writing
data to a plurality of second areas according to the modified
shingled recording format, wherein a distance between track centers
of an outermost track of each second area and a track adjacent
thereto is equal to a distance between track centers of an
innermost track of each second area and a track adjacent thereto,
but is different from a distance between track centers of any other
adjacent tracks other than the outermost and innermost tracks.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2020-038796, filed
Mar. 6, 2020, the entire contents of which are incorporated here by
reference.
FIELD
[0002] Embodiments described herein relate generally to a magnetic
disk device and a write processing method.
BACKGROUND
[0003] In recent years, techniques for increasing recording density
of magnetic disk drives have been developed. One of such techniques
is shingled write magnetic recording (SMR) or shingled write
recording (SWR) in which data is written such that tracks that are
adjacent in a radial direction of a disk partially overlap each
other. There is a known magnetic disk device that can switch
between a SMR-type recording and a conventional magnetic recording
(CMR) (a non-SMR-type) in which a plurality of tracks are written
at predetermined intervals along the radial direction of a
disk.
DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a block diagram illustrating a magnetic disk
device according to a first embodiment.
[0005] FIG. 2 is a schematic diagram illustrating a disk according
to a first embodiment.
[0006] FIG. 3 is a schematic diagram illustrating a normal
recording processing.
[0007] FIG. 4 is a schematic diagram illustrating shingled
recording processing in a shingled recording band area according to
a first embodiment.
[0008] FIG. 5 is a schematic diagram illustrating an arrangement of
a plurality of normal recording band areas arranged in a radial
direction.
[0009] FIG. 6 is a schematic diagram illustrating an arrangement of
a shingled recording band area and a normal recording band area
that are adjacent in the radial direction.
[0010] FIG. 7 is a schematic diagram illustrating an arrangement of
a plurality of shingled recording band areas arranged in the radial
direction.
[0011] FIG. 8 is a schematic diagram illustrating an arrangement of
a normal recording band area and a shingled recording band area
that are adjacent in the radial direction.
[0012] FIG. 9 is a flowchart of write processing according to a
first embodiment.
[0013] FIG. 10 is a flowchart of write processing according to a
first modification example.
[0014] FIG. 11 is a block diagram illustrating a magnetic disk
device according to a second embodiment.
[0015] FIG. 12 is a schematic diagram illustrating shingled
recording processing in a standard shingled recording band
area.
[0016] FIG. 13 is a schematic diagram illustrating an arrangement
of zones.
[0017] FIG. 14 is a diagram illustrating a table for storing the
number of retries according to the second embodiment.
[0018] FIG. 15 is a diagram illustrating a table for storing the
number of retries according to the second embodiment.
[0019] FIG. 16 is a flowchart of write processing according to a
second embodiment.
[0020] FIG. 17 is a flowchart of determination processing of
refresh processing according to a second embodiment.
[0021] FIG. 18 is a flowchart of processing of counting the number
of retries according to a second embodiment.
[0022] FIG. 19 is a flowchart illustrating refresh processing
according to a second embodiment.
[0023] FIG. 20 is a schematic diagram illustrating an arrangement
of zones.
[0024] FIG. 21 is a diagram illustrating a table TB2 for storing
the number of retries according to a third embodiment.
[0025] FIG. 22 is a diagram illustrating a table TB2 for storing
the number of retries according to a third embodiment.
[0026] FIG. 23 is a flowchart of processing of counting the number
of retries according to a third embodiment.
DETAILED DESCRIPTION
[0027] Embodiments provide a magnetic disk device and a write
processing method that is capable of improving reliability.
[0028] In general, according to one embodiment, a magnetic disk
device includes a disk including a plurality of areas divided in a
radial direction, a head, and a controller. The controller is
configured to control the head to write data to a first area
including a plurality of tracks that are separated from each other,
and a second area including at least two adjacent tracks that
partially overlap. A first distance between track centers of said
two adjacent tracks in the radial direction is different from a
second distance between track centers of another two adjacent
tracks in the second area in the radial direction.
[0029] Hereinafter, certain example embodiments will be described
with reference to drawings. The drawings are merely examples and do
not limit the scope of the present disclosure.
First Embodiment
[0030] FIG. 1 is a block diagram illustrating a magnetic disk
device 1 according to a first embodiment.
[0031] A magnetic disk device 1 includes a head disk assembly (HDA)
described later, a driver IC 20, a head amplifier integrated
circuit (hereinafter, referred to as a "head amplifier IC" or
"preamplifier") 30, a volatile memory 70, a nonvolatile memory 80,
a buffer memory (hereinafter, referred to as a "buffer") 90, and a
system controller 130 which is a one-chip integrated circuit. The
magnetic disk device 1 is connected to a host system (hereinafter,
simply referred to as a host) 100.
[0032] The HDA includes a magnetic disk (hereinafter, referred to
as a disk) 10, a spindle motor (SPM) 12, an arm 13 on which a head
15 is mounted, and a voice coil motor (VCM) 14. The disk 10 is
attached to the SPM 12 and is rotated by the SPM 12. The arm 13 and
the VCM 14 make up an actuator. The actuator controls the movement
of the head 15 mounted on the arm 13 to a particular position on
the disk 10 by driving the VCM 14. Two or more disks 10 and heads
15 may be provided.
[0033] The disk 10 includes a user data area 10a available for the
user, a media cache 10b (sometimes referred to as a media cache
area) that temporarily stores data (or commands) transferred from a
host or the like before writing the data in a particular area of
the user data area 10a, and a system area 10c for writing
information necessary for system management. A direction from the
inner circumference to the outer circumference of the disk 10, and
likewise a direction from the outer circumference to the inner
circumference of the disk 10, is referred to as a radial direction.
In this context, the (radial) direction from the inner
circumference to the outer circumference is referred to as an
outward direction, and a (radial) direction from the outer
circumference to the inner circumference is referred to as an
inward direction. The direction orthogonal to the radial direction
of the disk 10 is referred to a circumferential direction. The
circumferential direction corresponds to a direction along the
circumference of the disk 10. Further, a certain position along the
radial direction of the disk 10 may be referred to as a radial
position, and a certain position along the circumferential
direction of the disk 10 may be referred to as a circumferential
position. The radial position and the circumferential position may
be collectively referred to as a position.
[0034] The disk 10 is divided into a plurality of areas (which may
be referred to as zones or zone areas) for predetermined ranges in
the radial direction. A zone can be divided into a plurality of
sub-areas (which may be referred to as band areas) in the radial
direction. Each band area includes a plurality of tracks. A track
includes a plurality of sectors. Furthermore, an area obtained by
dividing the disk 10 in the radial direction may be referred to as
a radial area. Such a radial area includes a zone, a band area, a
track, and the like.
[0035] The term "track" is used in this disclosure to indicate the
following: one of a plurality of areas divided at points along the
radial direction of the disk 10, a path of the head 15 at a
predetermined radial position, data extending in the
circumferential direction of the disk 10, one round of data written
to a track at a certain radial position, data written to the track,
a part of data written to the track, and various other meanings.
The term "sector" is used in this disclosure to indicate one of a
plurality of areas obtained by dividing a track at points along the
circumferential direction, data written in a predetermined position
on the disk 10, data written in a sector, and various other
meanings.
[0036] The a "track written on the disk 10" may be referred to as a
"write track", and a "track read from the disk 10" may be referred
to as a "read track". A "write track" may be more simply referred
to as a "track", a "read track" may be more simply referred to as a
"track". A "write track" and a "read track" may both be referred to
as a "track". A "width of a track in the radial direction" may be
referred to as a "track width". A "width of the write track in the
radial direction" may be referred to as a "write track width", and
a "width of the read track in the radial direction" may be referred
to as a "read track width". The "write track width" may be more
simply referred to as a "track width", the "read track width" may
be more simply referred to as a "track width". The "write track
width" and "read track width" may be both referred to as a "track
width".
[0037] A "path passing through the center position of a track width
in a predetermined track" is referred to as a "track center". A
"path passing through the center position of a write track width in
a predetermined write track" may be referred to as a "write track
center", and the "path passing through the center position of a
read track width of a read track" may be referred to as a "read
track center". The "write track center" may be more simply referred
to as a "track center", the "read track center" may be more simply
referred to as a "track center", and both the "write track center"
and "read track center" may be referred to as a "track center".
[0038] The head 15 has a slider and includes a write head 15W and a
read head 15R mounted on the slider. The write head 15W writes data
to the disk 10. The read head 15R reads data from the disk 10. The
"write head 15W" may be simply referred to as the "head 15", the
"read head 15R" may be simply referred to as the "head 15", and the
"write head 15W and read head 15R" may be collectively referred to
as the "head 15". The "central part of the head 15" may be referred
to as the "head 15", the "central part of the write head 15W" may
be referred to as the "write head 15W", and the "central part of
the read head 15R" may be referred to as the "read head 15R". The
"central part of the write head 15W" may be simply referred to as
the "head 15", and the "central part of the read head 15R" may be
simply referred to as the "head 15". "Positioning the central part
of the head 15 at the track center of a predetermined track" may be
expressed as "positioning the head 15 on a particular track",
"placing the head 15 on a particular track", or "positioning the
head 15 on a particular track".
[0039] FIG. 2 is a schematic diagram illustrating the disk 10
according to the present embodiment. As illustrated in FIG. 2, the
direction in which the disk 10 rotates in the circumferential
direction is referred to as a rotation direction. In the example
illustrated in FIG. 2, the rotation direction is counterclockwise,
but may be reverse (e.g., clockwise). In FIG. 2, the disk 10 is
divided into an inner circumferential area IR located inward, an
outer circumferential area OR located outward, and a middle
circumferential area MR located between the inner circumferential
area IR and the outer circumferential area OR. For example, the
inner circumferential area IR corresponds to a radial area from the
innermost circumferential position of the disk 10 to a
circumferential position separated from the innermost
circumferential position by a predetermined distance outward. For
example, the outer circumferential area OR corresponds to a radial
area from the outermost circumferential position of the disk to a
circumferential position separated from the outermost
circumferential position by a predetermined distance inward.
[0040] FIG. 2 illustrates the media cache 10b. In FIG. 2, the media
cache 10b and the system area 10c are located in the outer
circumferential area OR. In the example illustrated in FIG. 2, the
system area 10c is located at the outermost circumference of the
disk 10. The media cache 10b is arranged adjacent to the inside of
the system area 10c. Here, "adjacent" includes not only data,
objects, areas, spaces, and the like being arranged side by side
but also being arranged at certain intervals. The user data area
10a is arranged adjacent to the media cache 10b in the inward
direction. The media cache 10b may be located in the inner
circumferential area IR or the middle circumferential area MR.
Further, the media cache 10b may be located dispersedly in the
outer circumferential area OR, the middle circumferential area MR,
and the inner circumferential area IR.
[0041] The user data area 10a of the disk 10 includes an area
(hereinafter, may be referred to as a normal recording area) for
writing data in a normal recording (CMR) format in which tracks
adjacent to a particular track (hereinafter, may be referred to as
adjacent tracks) are written at predetermined intervals in the
radial direction from the particular track. Additionally, the user
data area 10a includes an area (hereinafter, may be referred to as
a shingled recording area) for writing data in a shingled recording
(SMR or SWR) format in which a track to be written next overlaps a
part of an adjacent track in the radial direction.
[0042] Hereinafter, "writing data in a normal recording type" may
be simply referred to as "normal recording" or "normal recording
processing", and "writing data in a shingled recording type" may be
simply referred to as "shingled recording" or "shingled recording
processing". Further, "write processing other than the normal
recording processing" may be referred to as "shingled recording
processing". In the user data area 10a, at least one shingled
recording area may be arranged between a plurality of normal
recording areas arranged at intervals in the radial direction, or
at least one normal recording area may be arranged between a
plurality of shingled recording areas arranged at intervals in the
radial direction. The entire area of the user data area 10a may be
a normal recording area, or the entire area of the user data area
10a may be a shingled recording area.
[0043] Each of the normal recording area and the shingled recording
area includes at least one band area. Hereinafter, the "band area
in a normal recording area" may be referred to as a "normal
recording band area", and the "band area in a shingled recording
area" may be referred to as a "shingled recording band area".
Hereinafter, the "normal recording band area" is simply referred to
as a "band area", the "shingled recording band area" is simply
referred to as a "band area", and the "normal recording band area"
and the "shingled recording band area" are collectively referred to
as a "band area." Further, the "normal recording band area" may be
referred to as a "normal recording area", and the "shingled
recording band area" may be referred to as a "shingled recording
area". In the example illustrated in FIG. 2, a normal recording
band area CBA and a shingled recording band area SBA are arranged
in the user data area 10a. In the user data area 10a, at least one
shingled recording band area SBA may be arranged between a
plurality of normal recording band areas CBA arranged at intervals
in the radial direction, or at least one normal recording area CBA
may be arranged between a plurality of shingled recording areas SBA
arranged at intervals in the radial direction. The entire area of
the user data area 10a may be the normal recording band area CBA or
the shingled recording band area SBA.
[0044] The normal recording band area CBA includes a plurality of
tracks written in normal recording. The normal recording band area
CBA may include only one track. The shingled recording band area
SBA includes a plurality of overlapping tracks in shingled
recording. The shingled recording band area SBA may include at
least one track written in normal recording. The shingled recording
band area SBA may include only one track.
[0045] The driver IC 20 drives the SPM 12 and the VCM 14 under the
control of the system controller 130 (or an MPU 60 described later
in detail).
[0046] The head amplifier IC (or the preamplifier) 30 includes a
read amplifier, a write driver, and the like. The read amplifier
amplifies a read signal read from the disk 10 and outputs the
amplified signal to the system controller 130 (specifically, a
read/write (R/W) channel 50 described later). The write driver
outputs a write current corresponding to the signal output from the
R/W channel 50 to the head 15.
[0047] The volatile memory 70 is a semiconductor memory in which
stored data is lost when power supply is cut off. The volatile
memory 70 stores data and the like necessary for processing in each
unit of the magnetic disk device 1. The volatile memory 70 is, for
example, a dynamic random access memory (DRAM) or a synchronous
dynamic random access memory (SDRAM).
[0048] The nonvolatile memory 80 is a semiconductor memory that
maintains data even when power supply is cut off. The nonvolatile
memory 80 is, for example, a NOR or NAND flash read only memory
(FROM).
[0049] The buffer memory 90 is a semiconductor memory for
temporarily storing data and the like transmitted and received
between the magnetic disk device 1 and the host 100. The buffer
memory 90 may be configured integrally with the volatile memory 70.
The buffer memory 90 is, for example, a DRAM, static random access
memory (SRAM), SDRAM, ferroelectric random access memory (FeRAM),
magnetoresistive random access memory (MRAM), or the like.
[0050] The system controller 130 is, for example, a large-scale
integrated circuit (LSI) called a system-on-a-chip (SoC) in which a
plurality of elements are integrated on a single chip. The system
controller 130 includes a hard disk controller (HDC) 40, the
read/write (R/W) channel 50, and a microprocessor or a
micro-processing unit (MPU) 60. The HDC 40, the R/W channel 50, and
the MPU 60 are electrically connected to each other. The system
controller 130 is electrically connected to, for example, the
driver IC 20, the head amplifier IC 30, the volatile memory 70, the
nonvolatile memory 80, the buffer memory 90, the host system 100,
and the like.
[0051] The HDC 40 controls data transfer between the host 100 and
the R/W channel 50 according to an instruction from the MPU 60
described later. The HDC 40 is electrically connected to, for
example, the volatile memory 70, the nonvolatile memory 80, the
buffer memory 90, and the like.
[0052] The R/W channel 50 executes signal processing of read data
and write data according to an instruction from the MPU 60. The R/W
channel 50 has a circuit or function for modulating write data. The
R/W channel 50 has a circuit or a function for measuring the signal
quality of the read data. The R/W channel 50 is electrically
connected to, for example, the head amplifier IC 30 or the
like.
[0053] The MPU 60 is a main controller that controls each unit of
the magnetic disk device 1. The MPU 60 controls the VCM 14 via the
driver IC 20 to execute positioning of the head 15. The MPU 60
controls an operation of writing data to the disk 10 and selects a
storage destination of the write data transferred from the host
100. The MPU 60 controls an operation of reading data from the disk
10 and controls the processing of read data transferred from the
disk 10 to the host 100. The MPU 60 manages an area for recording
data. The MPU 60 is connected to each unit of the magnetic disk
device 1. The MPU 60 is electrically connected to, for example, the
driver IC 20, the HDC 40, the R/W channel 50, and the like.
[0054] The MPU 60 operates as a read/write control unit 610 and a
recording area management unit 620. For example, the MPU 60
executes firmware to perform functions of the read/write control
unit 610 and the recording area management unit 620. Alternatively,
one or more of those functions may be performed by one or more
circuits.
[0055] The read/write control unit 610 controls data read
processing and data write processing according to a command or the
like from the host 100. The read/write control unit 610 controls
the VCM 14 via the driver IC 20, sets the head at a particular
radial position on the disk 10, and executes read processing or
write processing. Hereinafter, "write processing" and "read
processing" may be collectively expressed by the term "access" or
"access processing".
[0056] The read/write control unit 610 selects and executes normal
recording processing and shingled recording processing according to
a command from the host 100 or the like. In other words, the
read/write control unit 610 selectively executes normal recording
processing or shingled recording processing according to a command
from the host 100 or the like. The read/write control unit 610
writes data randomly or sequentially in the normal recording
processing. The read/write control unit 610 sequentially writes
data in the shingled recording processing. The read/write control
unit 610 may execute only the normal recording processing, or may
execute only the shingled recording processing. The read/write
control unit 610 writes data at a different recording density, for
example, bit per inch (BPI) according to the radial position. For
example, the read/write control unit 610 writes data by adjusting
the BPI for each zone.
[0057] The read/write control unit 610 executes normal recording
processing in a normal recording area. In the normal recording band
area CBA of the normal recording area, the read/write control unit
610 executes normal recording of data at a track pitch
(hereinafter, may be referred to as a normal recording track pitch)
at which a current track is written so as not to overlap an
adjacent track. In other words, the read/write control unit 610
sets a normal recording track pitch in the normal recording band
area CBA of the normal recording area as a track pitch at the time
of the write processing and executes normal recording of data at
the normal recording track pitch. The track pitch corresponds to,
for example, a radial distance between track centers of two
adjacent tracks in the radial direction. The read/write control
unit 610 may execute the shingled recording processing in the
normal recording band area CBA of the normal recording area.
Further, the read/write control unit 610 may write data at a
plurality of different track pitches in the normal recording band
area CBA of the normal recording area.
[0058] The read/write control unit 610 executes write processing in
the shingled recording area. The read/write control unit 610 writes
data at a plurality of different track pitches in the shingled
recording band area SBA of the shingled recording area. In other
words, the read/write control unit 610 sets a plurality of
different track pitches as a track pitch at the time of the write
processing in the shingled recording band area SBA of the shingled
recording area and writes data at the plurality of different track
pitches. That is, the read/write control unit 610 can change the
track pitch for each radial area in the write processing in the
shingled recording band area SBA.
[0059] In the shingled recording band area SBA, the read/write
control unit 610 writes data at different track pitches in a radial
area (hereinafter may be referred to as a band boundary area)
adjacent to the boundary (hereinafter, may be referred to as a band
boundary) of the shingled recording band area SBA in the radial
direction and an area (hereinafter, may be referred to as a
non-band boundary area) other than the band boundary area.
[0060] In a band boundary area adjacent to an outer boundary of the
shingled recording band area SBA, that is, an outermost band
boundary area (hereinafter, may be referred to as an outermost band
boundary area or a band boundary area), the read/write control unit
610 writes data at a predetermined track pitch (hereinafter, may be
referred to as an outer boundary track pitch or a boundary track
pitch). Hereinafter, the "outer boundary of the band area" or the
"outer end of the band area" may be referred to as an "outer band
end", an "outer band boundary", or a "band boundary".
[0061] In a band boundary area adjacent to an inner boundary of the
shingled recording band area SBA, that is, an innermost band
boundary area (hereinafter, may be referred to as an innermost band
boundary area or a boundary area), the read/write control unit 610
writes data at a predetermined track pitch (hereinafter, may be
referred to as an inner boundary track pitch or a boundary track
pitch). Hereinafter, "the inner end of the band area" or "the inner
boundary of the band area" may be referred to as an "inner band
end", "inner band boundary", or "band boundary".
[0062] The read/write control unit 610 executes shingled recording
of data at a track pitch (hereinafter, may be referred to as a
shingled recording track pitch) at which a current track overlaps
an adjacent track in a non-band boundary area of the shingled
recording band area SBA. The boundary track pitch (outer boundary
track pitch and inner boundary track pitch) is, for example, larger
than the shingled recording track pitch. The boundary track pitch
(that is, the outer boundary track pitch and the inner boundary
track pitch) is, for example, the same as the normal recording
track pitch. Terms such as "same", "identical", "match", and
"equivalent" include not only the meaning of exactly the same, but
also the meaning of being different enough to be considered
substantially the same. The read/write control unit 610 may execute
shingled recording of data at only one track pitch, for example,
only the shingled recording track pitch, in the shingled recording
band area SBA.
[0063] For example, in the outermost band boundary area (referred
to as the band boundary area) of the shingled recording band area
SBA of the shingled recording area, the read/write control unit 610
writes a track closest to the outer band boundary (hereinafter,
this track may be referred to as an outermost band track, a
boundary band track, an outermost band boundary area, or a band
boundary area), that is, the outermost track. In the outermost band
boundary area of the shingled recording band area SBA, the
read/write control unit 610 writes a predetermined track
(hereinafter, may be referred to as a first outer boundary area
band track, a first boundary area band track, an outermost band
boundary area, or a band boundary area.) at the outer boundary
track pitch (which may also be referred to as a boundary track
pitch) in a forward direction (the inward direction in this
context) from the outermost band track. In this disclosure, a
direction in which data is sequentially written and read in the
radial direction is referred to as the forward direction.
[0064] In the outermost band boundary area of the shingled
recording band area SBA, the read/write control unit 610 first
writes at least one track (here also referred to as an outer
boundary area band track, a boundary area band track, an outermost
band boundary area or a band boundary area) from the first outer
boundary area band track to a predetermined track (here also
referred to as a last outer boundary area band track, a last
boundary area band track, an outermost band boundary area, or a
band boundary area) in the forward direction at the outer boundary
track pitch.
[0065] In the non-band boundary area of the shingled recording band
area SBA, the read/write control unit 610 writes a predetermined
track (hereinafter, referred to as a start track, or a non-band
boundary area) at the outer boundary track pitch in the forward
direction from the last outer boundary area band track. In the
non-band boundary area of the shingled recording band area SBA, the
read/write control unit 610 executes shingled recording of a
plurality of tracks in the forward direction from a start track to
a predetermined track (hereinafter, may be referred to as a last
track or a non-band boundary area) at the shingled recording track
pitch.
[0066] In the innermost band boundary area of the shingled
recording band area SBA, the read/write control unit 610 writes a
predetermined track (hereinafter, may also be referred to as a
first inner boundary area band track, a first boundary area band
track, an innermost band boundary area, or a boundary area) at the
inner boundary track pitch (boundary track pitch) in the forward
direction from the last track. In the innermost band boundary area
of the shingled recording band area SBA, the read/write control
unit 610 writes at least one track (here referred to as an inner
boundary area band track, a boundary area band track, an innermost
band boundary area, or a band boundary area) from the first inner
boundary area band track to a predetermined track (hereinafter, may
be referred to as a last inner boundary area band track or a last
boundary area band track) in the forward direction at the inner
boundary track pitch. In the innermost band boundary area of the
shingled recording band area SBA, the read/write control unit 610
writes a track (hereinafter, may be referred to as an innermost
band track, a boundary band track, an innermost band boundary area,
or a band boundary area) closest to the inner band boundary, that
is, the innermost track, at the inner boundary track pitch in the
forward direction from the last inner boundary area band track.
[0067] For example, the read/write control unit 610 writes the
outermost band track (also referred to as the boundary band track,
outermost band boundary area, or band boundary area) in the
outermost band boundary area of the shingled recording band area
SBA of the shingled recording area. The read/write control unit 610
writes a start track at the outer boundary track pitch in the
forward direction from the outermost band track in the outermost
band boundary area of the shingled recording band area SBA. The
read/write control unit 610 executes shingled recording of a
plurality of tracks in the non-band boundary area from the start
track to the last track in the non-band boundary area of the
shingled recording band area SBA at the shingled recording track
pitch in the forward direction. The read/write control unit 610
writes the innermost band track (here also referred to as the
boundary band track, innermost band boundary area, or band boundary
area) in the innermost band boundary area of the shingled recording
band area SBA at the inner boundary track pitch in the forward
direction from the last track.
[0068] For example, the read/write control unit 610 writes the
innermost band track in the innermost band boundary area of the
shingled recording band area SBA of the shingled recording area.
The read/write control unit 610 writes a first inner boundary area
band track in the innermost band boundary area of the shingled
recording band area SBA at the inner boundary track pitch in the
forward direction (in this context, the outward direction) from the
innermost band track. In the innermost band boundary area of the
shingled recording band area SBA, the read/write control unit 610
writes at least one inner boundary area band track from the first
inner boundary area band track to the last inner boundary area band
track at the inner boundary track pitch in the forward
direction.
[0069] In the non-band boundary area of the shingled recording band
area SBA, the read/write control unit 610 writes the start track at
the inner boundary track pitch in the forward direction from the
last inner boundary area band track. In the non-band boundary area
of the shingled recording band area SBA, the read/write control
unit 610 executes shingled recording of a plurality of tracks in
the forward direction from the start track to the last track at the
shingled recording track pitch.
[0070] In the outermost band boundary area of the shingled
recording band area SBA, the read/write control unit 610 writes a
first outer boundary area band track at the outer boundary track
pitch in the forward direction from the last track. In the
outermost band boundary area of the shingled recording band area
SBA, the read/write control unit 610 writes at least one outer
boundary area band track from the first outer boundary area band
track to the last outer boundary area band track at the outer
boundary track pitch in the forward direction. In the outermost
band boundary area of the shingled recording band area SBA, the
read/write control unit 610 writes the track closest to the outer
boundary, that is, the outermost band track positioned at the outer
boundary track pitch from the last outer boundary area band
track.
[0071] For example, the read/write control unit 610 writes the
innermost band track in the innermost band boundary area of the
shingled recording band area SBA of the shingled recording area. In
the non-band boundary area of the shingled recording band area SBA,
the read/write control unit 610 writes the start track at the inner
boundary track pitch in the forward direction from the innermost
band track. In the non-band boundary area of the shingled recording
band area SBA, the read/write control unit 610 executes shingled
recording of a plurality of tracks in the forward direction from
the start track to the last track at the shingled recording track
pitch in the forward direction In the outermost band boundary area
of the shingled recording band area SBA, the read/write control
unit 610 writes the outermost band track at the outer boundary
track pitch in the forward direction from the last track.
[0072] FIG. 3 is a schematic diagram illustrating the normal
recording processing. FIG. 3 illustrates the normal recording band
area CBA. FIG. 3 illustrates an outer band boundary OCE of the
normal recording band area CBA and an inner band boundary ICE of
the normal recording band area CBA. In FIG. 3, the forward
direction is the inward direction. However, the forward direction
may be the outward direction. As illustrated in FIG. 3, a direction
in which the head 15 advances with respect to the disk 10 in the
circumferential direction, that is, a direction in which
reading/writing is executed, may be referred to as a traveling
direction.
[0073] In the example illustrated in FIG. 3, the normal recording
band area CBA includes a track CTR0, a track CTR1, a track CTR2, .
. . , a track CTRn-2, a track CTRn-1, and a track CTRn. In FIG. 3,
the tracks CTR0 to CTRn are arranged in the stated order along the
inward direction. In FIG. 3, the track CTR0 closest to the outer
band boundary OCE of the normal recording band area CBA, that is,
the outermost track CTR0 in the normal recording band area CBA,
corresponds to the outermost band track CTR0, and the track CTRn
closest to the inner band boundary ICE of the normal recording band
area CBA, that is, the innermost track CTRn in the normal recording
band area CBA, corresponds to the innermost band track CTRn.
[0074] FIG. 3 illustrates a track center CTC0 of the track CTR0
having a track width TRW, a track center CTC1 of the track CTR1
having the track width TRW, a track center CTC2 of the track CTR2
having the track width TRW, . . . , a track center CTCn-2 of the
track CTRn-2 having the track width TRW, a track center CTCn-1 of
the track CTRn-1 having the track width TRW, and a track center
CTCn of the track CTRn having the track width TRW. The tracks CTR0
to CTRn may have different track widths.
[0075] In the example illustrated in FIG. 3, the tracks CTR0 to
CTRn are each arranged at a normal recording track pitch CTP in the
radial direction. For example, the track center CTC0 of the track
CTR0 and the track center CTC1 of the track CTR1 are separated from
each other at the normal recording track pitch CTP in the radial
direction, and the track center CTC1 of the track CTR1 and the
track center CTC2 of the track CTR2 are separated at the normal
recording track pitch CTP in the radial direction. Further, for
example, the track center CTCn-2 of the track CTRn-2 and the track
center CTCn-1 of the track CTRn-1 are separated at the normal
recording track pitch CTP in the radial direction, and the track
center CTCn-1 of the track CTRn-1 and the track center CTCn of the
track CTRn are separated at the normal recording track pitch CTP in
the radial direction. The tracks CTR0 to CTRn may be arranged at
different track pitches in the radial direction.
[0076] In the example illustrated in FIG. 3, the tracks CTR0 to
CTRn are arranged with a gap CGP in the radial direction. For
example, the track CTR0 and the track CTR1 are separated with the
gap CGP in the radial direction, and the track CTR1 and the track
CTR2 are separated with the gap CGP in the radial direction. The
track CTRn-2 and the track CTRn-1 are separated by the gap CGP in
the radial direction, and the track CTRn-1 and the track CTRn are
separated with the gap CGP in the radial direction. The tracks CTR0
to CTRn may be arranged with different gaps.
[0077] In FIG. 3, for convenience of description, each track is
illustrated as a rectangular shape extending in the circumferential
direction with a predetermined track width, but is actually curved
along the circumferential direction. Further, each track may have a
wavy shape that varies in the radial direction and extends in the
circumferential direction.
[0078] In the example illustrated in FIG. 3, the read/write control
unit 610 positions the head 15 at the track center CTC0 in the
normal recording band area CBA of the user data area 10a and
executes normal recording of the track CTR0. In the normal
recording band area CBA, the read/write control unit 610 positions
the head 15 at the track center CTC1 which is separated from the
track center CTC0 of the track CTR0 inward at the normal recording
track pitch CTP and executes normal recording of the track CTR1. In
the normal recording band area CBA, the read/write control unit 610
positions the head 15 at the track center CTC2 which is separated
from the track center CTC1 of the track CTR1 inward at the normal
recording track pitch CTP and executes normal recording of the
track CTR2.
[0079] In the example illustrated in FIG. 3, in the normal
recording band area CBA, the read/write control unit 610 positions
the head 15 at the track center CTCn-1 which is separated from the
track center CTCn-2 of the track CTRn-2 inward at the normal
recording track pitch CTP and executes normal recording of the
track CTRn-1. In the normal recording band area CBA, the read/write
control unit 610 positions the head 15 at the track center CTCn
which is separated at the normal recording track pitch CTP inward
from the track center CTCn-1 of the track CTRn-1 and executes
normal recording of the track CTRn.
[0080] In the example illustrated in FIG. 3, in the normal
recording band area CBA, the read/write control unit 610 may
sequentially execute normal recording on sectors of the tracks
CTR0, CTR1, CTR2, . . . , CTRn-2, CTRn-1, and CTRn, or may randomly
execute normal recording on sectors of the tracks CTR0, CTR1, CTR2,
. . . , CTRn-2, CTRn-1, and CTRn.
[0081] FIG. 4 is a schematic diagram illustrating shingled
recording processing in a shingled recording band area according to
the present embodiment. FIG. 4 illustrates the shingled recording
band area SBA. FIG. 4 illustrates an outer band boundary OSE of the
shingled recording band area SBA and an inner band boundary ISE of
the shingled recording band area SBA. In the example illustrated in
FIG. 4, the shingled recording band area SBA includes tracks STR0,
STR1, STR2, . . . , STRn-2, STRn-1, and STRn. In FIG. 4, the tracks
STR0 to STRn are arranged in the stated order in the inward
direction. In FIG. 4, the tracks STR1 to STRn-1 overlap adjacent
tracks in the forward direction. In FIG. 4, the track STR0 closest
to the outer band boundary OSE of the shingled recording band area
SBA, that is, the outermost track STR0 in the shingled recording
band area SBA corresponds to the outermost band track STR0, and the
track STRn closest to the inner band boundary ISE of the shingled
recording band area SBA, that is, the innermost track STRn in the
shingled recording band area SBA corresponds to the innermost band
track STRn. In FIG. 4, the track STR1 of the plurality of
overlapping tracks STR1 to STRn-1 corresponds to the start track
STR1, and the track STRn-1 of the plurality of overlapping tracks
STR1 to STRn-1 corresponds to the last track STRn-1.
[0082] FIG. 4 illustrates a radial area OGR (hereinafter, may be
referred to as an outer guard area or a guard area) from the outer
band boundary OSE to the outer end 0E1 of the start track STR1, and
a radial area IGR (hereinafter, may be referred to as an inner
guard area or a guard area) from the inner band boundary ISE to the
inner end IEn-1 of the last track STRn-1. In FIG. 4, the outer
guard area OGR corresponds to an outermost band boundary area, and
the inner guard area IGR corresponds to an innermost band boundary
area. Each guard area (that is, the outer guard area OGR and the
inner guard area IGR) corresponds to an area in which at least one
guard cylinder or guard track for reducing the influence of leakage
magnetic flux (e.g., Adjacent Track Interference: ATI) or the like
generated from the head 15 is arranged, for example, when writing a
track in a shingled recording band area adjacent to a particular
shingled recording band area in the radial direction. FIG. 4
illustrates a width 0GW (hereinafter, may be referred to as an
outer guard area width or a guard area width) of the outer guard
area OGR in the radial direction and a width IGW of the inner guard
area IGR (hereinafter, may be referred to as an inner guard area
width or a guard area width) in the radial direction. For example,
the outer guard area width 0GW is identical with the inner guard
area width IGW. The outer guard area width 0GW and the inner guard
area width IGW may be different. FIG. 4 illustrates a high
recording density area HDR other than each guard area (that is,
outer guard area OGR and the inner guard area IGR) of the shingled
recording band area SBA. In FIG. 4, the high recording density area
HDR corresponds to a non-band boundary area.
[0083] In FIG. 4, the outermost band track STR0 having a track
width STW0 is arranged in the outer guard area OGR. For example,
the track center STC0 of the outermost band track STR0 overlaps the
center position of the outer guard area width 0GW of the outer
guard area OGR. The track center STC0 of the outermost band track
STR0 may be shifted from the center position of the outer guard
area width 0GW of the outer guard area OGR. The outer guard area
width OGW of the outer guard area OGR is larger than the track
width STW0. In FIG. 4, the outer guard area width 0GW corresponds
to a width in the radial direction in which one outermost band
track STR0 having the track width STW0 can be arranged.
[0084] In FIG. 4, the innermost band track STRn having a track
width STWn is arranged in the inner guard area IGR. For example,
the track center STRn of the innermost band track STRn overlaps the
center position of the inner guard area width IGW of the inner
guard area IGR. The track center STCn of the innermost band track
STRn may be shifted from the center position of the inner guard
area width IGW of the inner guard area IGR. The inner guard area
width IGW of the inner guard area IGR is larger than track width
STWn. In FIG. 4, the inner guard area width IGW corresponds to a
width in the radial direction in which one innermost band track
STRn having the track width STWn can be arranged.
[0085] For example, the track width STW0 may be identical with the
track width STWn. Further, for example, the track width STW0 and
the track width STWn are identical with the track width TRW of the
normally recorded track illustrated in FIG. 3.
[0086] The outer guard area width 0GW may be a width in which a
plurality of tracks can be arranged, and the inner guard area width
IGW may be a width in which a plurality of tracks can be arranged.
In the outer guard area OGR and the inner guard area IGR, the same
number of tracks having the same width in the radial direction may
be arranged, or different numbers of tracks having the same width
in the radial direction may be arranged. In the outer guard area
OGR and the inner guard area IGR, the same number of tracks having
different widths in the radial direction may be arranged, or
different numbers of tracks having different widths in the radial
direction may be arranged. The track width STW0 and the track width
STWn may be different. Further, the track width STW0 and the track
width STWn may be different from the track width TRW.
[0087] In FIG. 4, in a plurality of overlapping tracks STR1 to
STRn-1, the track STR1 written on the disk 10 by the write head 15W
is referred to as a write track WT1, the track STR2 written on the
disk 10 by the write head 15W is referred to as a write track WT2,
the track STR3 written on the disk 10 by the write head 15W is
referred to as a write track WT3, the track STRn-2 written to the
disk 10 by the write head 15W is referred to as a write track
WTn-2, and the track STRn-1 written to the disk 10 by the write
head 15W is referred to as a write track WTn-1.
[0088] FIG. 4 illustrates a track center STC1 of the write track
WT1 (track STR1) having a write track width WTW, a track center
STC2 of the write track WT2 (track STR2) having the write track
width WTW, and a track center STC3 of the write track WT3 (track
STR3) having the write track width WTW, . . . , a track center
STCn-2 of the write track WTn-2 (track STRn-2) having the write
track width WTW, and a track center STCn-1 of the write track WTn-1
(track STRn-1) having the write track width WTW. The write tracks
WT1 to WTn-1 may have different write track widths. The write track
width WTW is, for example, the same as the track width STW0 of the
outermost band track STR0 and the track width STWn of the innermost
band track STRn. Further, the write track width WTW may be
different from the track width STW0 of the outermost band track
STR0 and the track width STWn of the innermost band track STRn.
[0089] In the example illustrated in FIG. 4, the write track WT1 is
separated from the outermost band track STR0 inward at an outer
boundary track pitch OTP. For example, the track center STC0 of the
outermost band track STR0 and the track center STC1 of the write
track WT1 are separated at the outer boundary track pitch OTP in
the radial direction. Further, the write track WTn-1 is separated
from the innermost band track STRn outward at an inner boundary
track pitch ITP. Further, for example, the track center STCn of the
innermost band track STRn and the track center STCn-1 of the write
track WTn-1 are separated at the inner boundary track pitch ITP in
the radial direction. The outer boundary track pitch OTP and the
inner boundary track pitch ITP are, for example, the same. The
outer boundary track pitch OTP and the inner boundary track pitch
ITP are, for example, the same as the normal recording track pitch
CTP. The outer boundary track pitch OTP and the inner boundary
track pitch ITP may be different. Further, the outer boundary track
pitch OTP and the inner boundary track pitch ITP may be different
from the normal recording track pitch CTP.
[0090] In the example illustrated in FIG. 4, the write tracks WT1
(track STR1) to WTn-1 (STRn-1) are each arranged at the shingled
recording track pitch WTP in the radial direction. The shingled
recording track pitch WTP is smaller than the normal recording
track pitch CTP, for example. For example, the track center STC1 of
the write track WT1 and the track center STC2 of the write track
WT2 are separated at the shingled recording track pitch WTP in the
radial direction. For example, the track center STC2 of the write
track WT2 and the track center STC3 of the write track WT3 are
separated at the shingled recording track pitch WTP in the radial
direction. Further, for example, the track center STCn-2 of the
write track WTn-2 and the track STCn-1 of the write track WTn-1 are
separated at the shingled recording track pitch WTP in the radial
direction. The write tracks WT1 (track STR1) to WTn-1 (track
STRn-1) may be arranged at different track pitches in the radial
direction.
[0091] Further, the write tracks WT1 (track STR1) to WTn-1 (track
STRn-1) each overlap adjacent write tracks in the forward
direction. The area of the remaining write track WT1 other than the
area where the write track WT2 overlaps is referred to as a read
track RT1 (track STR1), and the area of the remaining write track
WT2 other than the area where the write track WT3 overlaps is
referred to as a read track RT2 (track STR2), the area of the
remaining write track WTn-2 other than the area where the write
track WTn-1 overlaps is referred to as a read track RTn-2 (track
STRn-2). When the data is sequentially written in the forward
direction in the shingled recording band area SBA, the write track
WTn-1 (last track STRn-1) which is written last and does not
overlap with other write tracks may be referred to as a read track
WTn-1 (last track STRn-1). FIG. 4 illustrates a read track width
RTW1 of the read tracks RT1 to RTn-2. In FIG. 4, the read track
width RTW2 of the read track RTn-1 is the same as the write track
width WTW of the write track WTn-1. The read track width RTW1 is
smaller than the write track width WTW. The read tracks RT1 to
RTn-2 may have different read track widths.
[0092] In FIG. 4, for convenience of description, each track is
illustrated as a rectangular shape extending in the circumferential
direction with a predetermined track width, but is actually curved
along the circumferential direction. Further, each track may have a
wavy shape that varies in the radial direction and extends in the
circumferential direction.
[0093] In the example illustrated in FIG. 4, the read/write control
unit 610 positions the head 15 at the track center STC0 in the
outer guard area OGR of the shingled recording band area SBA of the
user data area 10a, and writes (for example, normal recording) the
outermost band track STR0.
[0094] In the example illustrated in FIG. 4, in the high recording
density area HDR of the shingled recording band area SBA of the
user data area 10a, the read/write control unit 610 sequentially
executes shingled recording of the write track WT1, the write track
WT2, the write track WT3, . . . , the write track WTWn-2, and the
write track WTWn-1 in the stated order in the forward direction. In
other words, the read/write control unit 610 writes the track STR1
(write track WT1), the track STR2 (write track WT2), the track STR3
(write track WT3), . . . , the track STRn-2 (write track WTn-2),
and the track STRn-1 (write track WTn-1) in the shingled recording
band area SBA of the user data area 10a such that each track
overlaps adjacent tracks in the forward direction in the stated
order.
[0095] In the example illustrated in FIG. 4, in the high recording
density area HDR of the shingled recording band area SBA of the
user data area 10a, the read/write control unit 610 positions the
head 15 at the track center STC1 that is separated from the track
center STC0 of the outermost band track STR0 at the track pitch OTP
in the forward direction, and writes the write track WT1 (start
track STR1). In other words, the read/write control unit 610 writes
the start track STR1 at a distance in the radial direction so as
not to overlap the outermost band track STR0 in the high recording
density area HDR. The read/write control unit 610 positions the
head 15 at the track center STC2 which is separated from the track
center STC1 of the write track WT1 (start track STR1) at the track
pitch WTP in the forward direction in the high recording density
area HDR, and executes shingled recording of the write track WT2 on
the write track WT1. The read/write control unit 610 positions the
head 15 at the track center STC3 which is separated from the track
center STC2 of the write track WT2 at the track pitch WTP in the
forward direction in the high recording density area HDR and
executes shingled recording of the write track WT3 on the write
track WT2. The read/write control unit 610 positions the head 15 at
the track center STCn-1 which is separated from the track center
STCn-2 of the write track WTn-2 at the track pitch WTP in the
forward direction in the high recording density area HDR, and
executes shingled recording of the write track WTn-1 (last track
STRn-1) on the write track WTn-2.
[0096] In the example illustrated in FIG. 4, in the inner guard
area IGR of the shingled recording band area SBA of the user data
area 10a, the read/write control unit 610 positions the head 15 at
the track center STCn which is separated from the track center
STCn-1 of the last track STRn-1 (write track WTn-1) at the track
pitch ITP in the forward direction, and writes the innermost band
track STRn. In other words, the read/write control unit 610 writes
the innermost band track STRn in the inner guard area IGR at a
distance in the radial direction so as not to overlap the last
track STRn-1 (for example, normal recording).
[0097] The recording area management unit 620 manages recording
areas of the disk 10 (hereinafter, also simply referred to as the
disk 10) according to an instruction from the host 100 or the like.
The recording area management unit 620 sets a normal recording area
and a shingled recording area in the user data area 10a of the disk
10 according to an instruction from the host 100 or the like. The
recording area management unit 620 sets a normal recording area for
each normal recording band area CBA in the user data area 10a, for
example. In other words, the recording area management unit 620
sets, for example, the normal recording band area CBA in the user
data area 10a.
[0098] Additionally, the recording area management unit 620 sets a
shingled recording area for each shingled recording band area SBA
in the user data area 10a, for example. In other words, the
recording area management unit 620 sets, for example, the shingled
recording band area SBA in the user data area 10a.
[0099] The recording area management unit 620 can change the normal
recording band area CBA to the shingled recording band area SBA
according to an instruction from the host 100 or the like. Further,
the recording area management unit 620 can change the shingled
recording band area SBA to the normal recording band area CBA
according to an instruction from the host 100 or the like.
Hereinafter, "changing the normal recording band area CBA to the
shingled recording band area SBA" and "changing the shingled
recording band area SBA to the normal recording band area CBA" may
be referred to as "media conversion".
[0100] The recording area management unit 620 may record
information on the set normal recording band area CBA and
information on the set shingled recording band area SBA in a table
stored in a predetermined recording area, for example, the system
area 10c of the disk 10, the nonvolatile memory 80, or the like.
The recording area management unit 620 may set the entire area of
the user data area 10a of the disk 10 as the normal recording band
area CBA, or may set the entire area of the user data area 10a of
the disk 10 as the shingled recording band area SBA.
[0101] For example, when the recording area management unit 620
arranges a plurality of normal recording band areas CBA that are
continuous in the radial direction, the read/write control unit 610
executes predetermined processing, for example, writes a boundary
band track in the target normal recording band area CBA at a
predetermined track pitch (hereinafter, may be referred to as a
track pitch between bands) in the radial direction from the
boundary band track of the normal recording band area CBA which is
radially adjacent to the normal recording band area CBA to be
accessed or the like (hereinafter, may be referred to as a target
normal recording band area). The read/write control unit 610
executes normal recording of a plurality of tracks at the normal
recording track pitch CTP in the target normal recording band area
CBA, as illustrated in FIG. 3. Hereinafter, the "track pitch
between bands of the boundary band track between two normal
recording band areas CBA adjacent in the radial direction" may be
referred to as a "track pitch between normal recording bands".
[0102] For example, when the recording area management unit 620
arranges a plurality of shingled recording band areas SBA that are
continuous in the radial direction, the read/write control unit 610
executes predetermined processing, for example, writes a boundary
band track in the guard area of the target shingled recording band
area SBA at the track pitch between bands in the radial direction
from the boundary band track of the normal recording band area SBA
which is adjacent to the shingled recording band area SBA to be
accessed or the like (hereinafter, may be referred to as a target
shingled recording band area) in the radial direction. As
illustrated in FIG. 4, the read/write control unit 610 executes
shingled recording of a plurality of tracks in the high recording
density area HDR of the target shingled recording band area SBA at
the shingled recording track pitch WTP in the forward direction.
Hereinafter, the "track pitch between bands of the boundary band
track between two shingled recording band areas SBA adjacent in the
radial direction" may be referred to as a "track pitch between
shingled recording bands".
[0103] For example, when the recording area management unit 620
changes one of the plurality of shingled recording band areas SBA
that are continuous in the radial direction to the normal recording
band area CBA (media conversion), the read/write control unit 610
writes a boundary band track in the normal recording band area CBA
at the track pitch between bands from the boundary band track of
the shingled recording band area SBA adjacent to the normal
recording band area CBA in the radial direction. The read/write
control unit 610 executes normal recording of a plurality of tracks
at the normal recording track pitch CTP in the normal recording
band area CBA, as illustrated in FIG. 3. In other words, when the
recording area management unit 620 arranges the normal recording
band area CBA so as to be adjacent to the shingled recording band
area SBA in the radial direction, the read/write control unit 610
writes a boundary band track in the normal recording band area CBA
at the track pitch between bands from the boundary band track of
the shingled recording band area SBA adjacent to the normal
recording band area CBA in the radial direction. The read/write
control unit 610 executes normal recording of a plurality of tracks
at the normal recording track pitch CTP in the normal recording
band area CBA, as illustrated in FIG. 3. Hereinafter, the "track
pitch between bands of the boundary band track of the shingled
recording band area SBA and the boundary band track of the normal
recording band area CBA that are adjacent in the radial direction"
may be referred to as a "track pitch between shingled/normal
recording bands".
[0104] For example, when the recording area management unit 620
changes one of a plurality of normal recording areas CBA that are
continuous in the radial direction to the shingled recording band
area SBA (media conversion), the read/write control unit 610 writes
a boundary band track in the guard area of the shingled recording
band area SBA at the track pitch between shingled/normal recording
bands in the radial direction from the boundary band track of the
normal recording area CBA adjacent in the radial direction. As
illustrated in FIG. 4, the read/write control unit 610 executes
shingled recording of a plurality of tracks in the high recording
density area HDR of the shingled recording band area SBA at the
shingled recording track pitch WTP in the forward direction. In
other words, when the recording area management unit 620 arranges
the shingled recording band area SBA so as to be adjacent to the
normal recording band area CBA in the radial direction, the
read/write control unit 610 writes a boundary band track in the
guard area of the shingled recording band area SBA at the track
pitch between shingled/normal recording bands from the boundary
band track of the normal recording band area CBA adjacent to the
shingled recording band area SBA in the radial direction. As
illustrated in FIG. 4, the read/write control unit 610 executes
shingled recording of a plurality of tracks in the high recording
density area HDR of the shingled recording band area SBA at the
shingled recording track pitch WTP in the forward direction.
[0105] The track pitch between bands is, for example, the same as
the normal recording track pitch. The track pitch between bands may
be different from the normal recording track pitch. The track pitch
between normal recording bands, the track pitch between shingled
recording bands, and the track pitch between shingled/normal
recording bands are the same, for example. The track pitch between
normal recording bands, the track pitch between shingled recording
bands, and the track pitch between shingled/normal recording bands
may be different.
[0106] FIG. 5 is a schematic diagram illustrating an arrangement of
a plurality of normal recording band areas CBA arranged in the
radial direction. In FIG. 5, the normal recording band area CBA
includes two normal recording band areas CBAa and two normal
recording band areas CBAb that are adjacent in the radial
direction. FIG. 5 illustrates a boundary BB between the normal
recording band area CBAa and the normal recording band area CBAb
(hereinafter, also referred to as a boundary between normal
recording bands CBB). Hereinafter, the "boundary between two
adjacent band areas" may be referred to as an "inter-band
boundary". The configuration of the normal recording band areas
CBAa and CBAb is the same as that of the normal recording band area
CBA illustrated in FIG. 3.
[0107] In the example illustrated in FIG. 5, the normal recording
band area CBAa includes a track CTRa0, a track CTRa1, . . . , a
track CTRa(n-1), and a track CTRan. In FIG. 5, the tracks CTRa0 to
CTRan are arranged in the stated order in the inward direction. In
FIG. 5, the track CTRa0 corresponds to the outermost band track
CTRa0, and the track CTRan corresponds to the innermost band track
CTRan.
[0108] FIG. 5 illustrates a track center CTCa0 of the track CTRa0,
a track center CTCa1 of the track CTRa1, . . . , a track center
CTCa(n-1) of the track CTRa(n-1), and a track center CTCan of the
track CTRan. In the example illustrated in FIG. 5, the tracks CTRa0
to CTRan are each arranged at the normal recording track pitch CTP
in the radial direction. For example, the track center CTCa0 of the
track CTRa0 and the track center CTCa1 of the track CTRa1 are
separated at the normal recording track pitch CTP in the radial
direction. For example, the track center CTCa(n-1) of the track
CTRa(n-1) and the track center CTCan of the track CTRan are
separated from at the normal recording track pitch CTP in the
radial direction. The tracks CTRa0 to CTRan may be arranged at
different track pitches in the radial direction.
[0109] In the example illustrated in FIG. 5, the normal recording
band area CBAb includes a track CTRb0, a track CTRb1, . . . , a
track CTRb(n-1), and a track CTRbn. In FIG. 5, the tracks CTRb0 to
CTRbn are arranged in the stated order in the inward direction. In
FIG. 5, the track CTRb0 corresponds to the outermost band track
CTRb0, and the track CTRbn corresponds to the innermost band track
CTRbn.
[0110] FIG. 5 illustrates a track center CTCb0 of the track CTRb0,
a track center CTCb1 of the track CTRb1, . . . , a track center
CTCb(n-1) of the track CTRb(n-1), and a track center CTCbn of the
track CTRbn. In the example illustrated in FIG. 5, the tracks CTRb0
to CTRbn are each arranged at the normal recording track pitch CTP
in the radial direction. For example, the track center CTCb0 of the
track CTRb0 and the track center CTCb1 of the track CTRb1 are
separated at the normal recording track pitch CTP in the radial
direction. For example, the track center CTCb(n-1) of the track
CTRb(n-1) and the track center CTCbn of the track CTRbn are
separated at the normal recording track pitch CTP in the radial
direction. In FIG. 5, the track center CTCb0 of the outermost band
track CTRb0 and the track center CTCan of the innermost band track
CTRan are separated at a track pitch BTP between normal recording
bands in the radial direction. The tracks CTRb0 to CTRbn may be
arranged at different track pitches in the radial direction. In
FIG. 5, for convenience of description, the normal recording band
area CBA and the shingled recording band area SBA are illustrated
in a rectangular shape extending in the circumferential direction,
but actually, are curved along the circumferential direction.
[0111] In the example illustrated in FIG. 5, when the recording
area management unit 620 arranges two normal recording band areas
CBAa and CBAb that are adjacent in the radial direction, the
read/write control unit 610 writes the innermost band track CTRan
in the normal recording band area CBAa at the track pitch BTP
between normal recording bands outward from the outermost band
track CTRb0 in the normal recording band area CBAb.
[0112] In the example illustrated in FIG. 5, when arranging two
normal recording band areas CBAa and CBAb that are adjacent in the
radial direction, the recording area management unit 620 writes the
outermost band track CTRbn in the normal recording band area CBAb
at the track pitch BTP between normal recording bands inward from
the innermost band track CTRan of the normal recording band area
CBAa via the read/write control unit 610.
[0113] FIG. 6 is a schematic diagram illustrating an arrangement of
the shingled recording band area SBA and the normal recording band
area CBA that are adjacent in the radial direction. In FIG. 6, the
shingled recording band area SBA includes a shingled recording band
area SBAa. In FIG. 6, the shingled recording band area SBAa and the
normal recording band area CBAb are adjacent to each other in the
radial direction. FIG. 6 illustrates an inter-band boundary BB
between the shingled recording band area SBAa and the normal
recording band area CBAb (hereinafter, may be referred to as a
shingled/normal recording band boundary SCBB). The configuration of
the shingled recording band area SBAa is the same as that of the
shingled recording band area SBA illustrated in FIG. 4.
[0114] In the example illustrated in FIG. 6, the normal recording
band area SBAa includes a track STRa0, a track STRa1, a track
STRa2, a track STRa(n-2), a track STRa(n-1), and a track STRan. In
FIG. 6, the tracks STRa0 to STRan are arranged in the stated order
in the inward direction. In FIG. 6, the tracks STRa1 to STRa(n-1)
overlap in the forward direction. In FIG. 6, the track STRa0
corresponds to the outermost band track STRa0, and the track STRan
corresponds to the innermost band track STRan. In FIG. 6, the track
STRa1 of a plurality of overlapping tracks STRa1 to STRa(n-1)
corresponds to the start track STRa1, and the track STRa(n-1) of a
plurality of overlapping tracks STRa1 to STRa(n-1) corresponds to
the last track STRa(n-1).
[0115] In FIG. 6, the shingled recording band area SBAa includes an
outer guard area OGR (OGRa), an inner guard area IGR (IGRa), and a
high recording density area HDR (HDRa) between the outer guard area
OGRa and the inner guard area IGRa. In FIG. 6, the outermost band
track STRa0 is arranged in the outer guard area OGRa. In FIG. 6,
the innermost band track STRan is arranged in the inner guard area
IGRa.
[0116] In FIG. 6, a track center STCa0 of the track STRa0, a track
center STRa1 of the track STRa1, a track center STCa2 of the track
STRa2, . . . , a track center STCa(n-2) of the track STRa(n-2), a
track center STCa(n-1) of the track STRa(n-1), and a track center
STCan of the track STRan are illustrated. For example, the track
center STCa0 of the track STRa0 is separated from the track center
STRa1 of the track STRa1 at the outer boundary track pitch OTP in
the radial direction. For example, the track center STRa1 of the
track STRa1 and the track center STCa2 of the track STRa2 are
separated at the shingled recording track pitch WTP in the radial
direction. For example, the track center STCa(n-2) of the track
STRa(n-2) and the track center STCa(n-1) of the track STRa(n-1) are
separated at the shingled recording track pitch WTP in the radial
direction. The track center STCa(n-1) of the track STRa(n-1) and
the track center STCan of the track STRan are separated at the
inner boundary track pitch ITP in the radial direction. In FIG. 6,
the track center STCan of the innermost band track STRan and the
track center CTCb0 of the outermost band track CTRb0 are separated
at the track pitch between shingled/normal recording bands BTP in
the radial direction. In FIG. 6, for convenience of description,
the normal recording band area CBA and the shingled recording band
area SBA are illustrated in a rectangular shape extending in the
circumferential direction, but actually, are curved along the
circumferential direction.
[0117] In the example illustrated in FIG. 6, when the recording
area management unit 620 arranges the shingled recording band area
SBAa and the normal recording band area CBAb that are adjacent in
the radial direction, the read/write control unit 610 writes the
outermost band track STRa0 in the outer guard area OGRa of the
shingled recording band area SBAa. The read/write control unit 610
writes the start track STRa1 in the high recording density area
HDRa at the outer boundary track pitch OTP in the forward direction
from the outermost band track STRa0.
[0118] The read/write control unit 610 executes shingled recording
of a plurality of tracks STRa1 to STRa(n-1) from the start track
STRa1 to the last track STRa(n-1) in the high recording density
area HDRa in the forward direction at the shingled recording track
pitch WTP. The read/write control unit 610 writes the innermost
band track STRan in the inner guard area IGRa of the shingled
recording band area SBAa at the inner boundary track pitch ITP in
the forward direction from the last track STRa(n-1) and at the
track pitch BTP between shingled/normal recording bands outward
(that is, in a direction opposite to the forward direction) from
the outermost band track CTRb0 of the normal recording band area
CBAb.
[0119] In the example illustrated in FIG. 6, when the recording
area management unit 620 arranges the shingled recording band area
SBAa and the normal recording band area CBAb that are adjacent in
the radial direction, the read/write control unit 610 writes the
outermost band track CTRbn in the normal recording band area CBAb
at the track pitch BTP between shingled/normal recording bands
inward from the innermost band track STRan in the shingled
recording band area SBAa.
[0120] FIG. 7 is a schematic diagram illustrating an arrangement of
a plurality of shingled recording band areas SBA arranged in the
radial direction. In FIG. 7, the shingled recording band area SBA
includes two shingled recording band areas SBAa and shingled
recording band areas SBAb that are adjacent in the radial
direction. FIG. 7 illustrates the inter-band boundary BB between
the shingled recording band area SBAa and the shingled recording
band area SBAb (hereinafter, may be referred to as a shingled
recording band boundary SBB). The configuration of the shingled
recording band area SBAa is the same as that of the shingled
recording band area SBA illustrated in FIG. 4.
[0121] In the example illustrated in FIG. 7, the shingled recording
band area SBAb includes a track STRb0, a track STRb1, a track
STRb2, . . . , a track STRb(n-2), a track STRb(n-1), and a track
STRbn. In FIG. 7, the tracks STRb0 to STRbn are arranged in the
stated order in the inward direction. In FIG. 7, tracks STRb1 to
STRb(n-1) overlap in the forward direction. In FIG. 7, the track
STRb0 corresponds to the outermost band track STRb0, and the track
STRbn corresponds to the innermost band track STRbn. In FIG. 7, the
track STRb1 of a plurality of overlapping tracks STRb1 to STRb(n-1)
corresponds to the start track STRb1, and the track STRb(n-1) of a
plurality of overlapping tracks STRb1 to STRb(n-1) corresponds to
the last track STRb(n-1).
[0122] In FIG. 7, the shingled recording band area SBAb includes an
outer guard area OGR (OGRb), an inner guard area IGR (IGRb), and a
high recording density area HDR (HDRb) between the outer guard area
OGRb and the inner guard area IGRb. In FIG. 7, the outermost band
track STRb0 is arranged in the outer guard area OGRb. In FIG. 7,
the innermost band track STRbn is arranged in the inner guard area
IGRb.
[0123] In FIG. 7, a track center STCb0 of the track STRb0, a track
center STCb1 of the track STRb1, a track center STCb2 of the track
STRb2, . . . , a track center STCb(n-2) of the track STRb(n-2), a
track center STCb(n-1) of the track STRb(n-1), and a track center
STCbn of the track STRbn are illustrated. For example, the track
center STCb0 of the track STRb0 and the track center STCb1 of the
track STRb1 are separated at the outer boundary track pitch OTP in
the radial direction. For example, the track center STCb1 of the
track STRb1 and the track center STCb2 of the track STRb2 are
separated at the shingled recording track pitch WTP in the radial
direction. For example, the track center STCb(n-2) of the track
STRb(n-2) and the track center STCb(n-1) of the track STRb(n-1) are
separated at the shingled recording track pitch WTP in the radial
direction. The track center STCb(n-1) of the track STRb(n-1) and
the track center STCbn of the track STRbn are separated at the
inner boundary track pitch ITP in the radial direction.
[0124] In FIG. 7, the track center STCan of the innermost band
track STRan and the track center STCb0 of the outermost band track
STRb0 are separated at the track pitch between shingled recording
bands BTP in the radial direction. In FIG. 7, for convenience of
description, the normal recording band area CBA and the shingled
recording band area SBA are illustrated in a rectangular shape
extending in the circumferential direction, but actually, are
curved along the circumferential direction.
[0125] In the example illustrated in FIG. 7, when the recording
area management unit 620 arranges two shingled recording band areas
SBAa and SBAb that are adjacent in the radial direction, the
read/write control unit 610 writes the innermost band track STRan
in the inner guard area IGRa of the shingled recording band area
SBAa at the inner boundary track pitch ITP in the forward direction
from the last track STRa(n-1).
[0126] In the example illustrated in FIG. 7, when the recording
area management unit 620 arranges two shingled recording band areas
SBAa and SBAb that are adjacent in the radial direction, the
read/write control unit 610 writes the outermost band track STRb0
in the outer guard area OGRb of the shingled recording band area
SBAb at the track pitch BTP between shingled recording bands in the
forward direction (here, the inward direction) from the innermost
band track STRan of the shingled recording band area SBAa.
[0127] The read/write control unit 610 writes the start track STRb1
in the high recording density area HDRa at the outer boundary track
pitch OTP in the forward direction from the outermost band track
STRb0. The read/write control unit 610 executes shingled recording
of the plurality of tracks STRb1 to STRb(n-1) from the start track
STRb1 to the last track STRb(n-1) in the high recording density
area HDRb at the shingled recording track pitch WTP in the forward
direction. The read/write control unit 610 writes the innermost
band track STRbn in the inner guard area IGRb of the shingled
recording band area SBAb at the inner boundary track pitch ITP in
the forward direction from the last track STRa(n-1).
[0128] FIG. 8 is a schematic diagram illustrating an arrangement of
the normal recording band area CBA and the shingled recording band
area SBA that are adjacent in the radial direction. In FIG. 8, the
normal recording band area CBAa and the shingled recording band
area SBAb are adjacent to each other in the radial direction. FIG.
8 illustrates the inter-band boundary BB between the normal
recording band area CBAa and the shingled recording band area SBAb
(hereinafter, may be referred to as a shingled/normal recording
band boundary CSBB). In FIG. 8, for convenience of description, the
normal recording band area CBA and the shingled recording band area
SBA are illustrated in a rectangular shape extending in the
circumferential direction, but actually, are curved along the
circumferential direction.
[0129] In the example illustrated in FIG. 8, when the recording
area management unit 620 arranges the normal recording band area
CBAa and the shingled recording band area SBAb that are adjacent in
the radial direction, the read/write control unit 610 writes the
outermost band track STRb0 in the outer guard area OGRb of the
shingled recording band area SBAb at the track pitch BTP between
shingled/normal recording bands in the forward direction (here, the
inward direction) from the innermost band track CTRan of the normal
recording band area CBAa.
[0130] FIG. 9 is a flowchart of write processing according to the
present embodiment.
[0131] Initially, the MPU 60 determines whether a band area to be
accessed or the like (hereinafter, referred to as a target band
area) is the shingled recording band area SBA (B901). In other
words, the MPU 60 determines whether the target band area is the
shingled recording band area SBA or the normal recording band area
CBA. When it is determined that the target band area is not the
shingled recording band area SBA, that is, the target band area is
the normal recording band area CBA (NO in B901), the MPU 60 writes
data in the normal band area CBA at the normal recording track
pitch (B902) and ends the processing.
[0132] When it is determined that the target band area is the
shingled recording band area SBA (YES in B901), the MPU 60
determines whether an area to be accessed or the like (hereinafter,
may be referred to as a target area) is a guard area or a non-guard
area (B903). In other words, the MPU 60 determines whether the
target area is a guard area (that is, a band boundary area) of the
shingled recording band area SBA or a high recording density area
HDR (that is, a non-band boundary area) of the shingled recording
band area SBA. When it is determined that the target area is a
guard area(YES in B903), the MPU 60 writes data in the guard area
of the shingled recording band area SBA, for example, a band
boundary at the normal recording track pitch (B902) and ends the
processing. When it is determined that the target area is not a
guard area, that is, the target area is the high recording density
area HDR (NO in B903), the MPU 60 executes shingled recording of
data in the high recording density area HDR of the shingled
recording band area SBA at the shingled recording track pitch
(B904) and ends the processing.
[0133] According to the present embodiment, the magnetic disk
device 1 selectively executes normal recording processing and
shingled recording processing. The magnetic disk device 1 executes
normal recording of a plurality of tracks at the normal recording
track pitch in the normal recording band area CBA. In the band
boundary area of the shingled recording band area SBA, the magnetic
disk device 1 writes a boundary band track at the track pitch
between bands, for example, the normal recording track pitch, from
a boundary band track of a band area adjacent in the radial
direction. The magnetic disk device 1 writes a start track at a
predetermined distance in the forward direction from the boundary
band track in the non-band boundary area of the shingled recording
band area SBA. The magnetic disk device 1 executes shingled
recording of a plurality of tracks from the start track to the last
track in the non-band boundary area of the shingled recording band
area SBA in the forward direction at the shingled recording track
pitch. The magnetic disk device 1 writes a boundary band track at a
predetermined distance in the forward direction from the last track
in the band boundary area of the shingled recording band area SBA.
Even if the normal recording band area CBA and the shingled
recording band area SBA are arranged adjacent to each other in the
radial direction, the magnetic disk device 1 can equalize ATI and
the like occurring in the mutual band areas. Therefore, the
magnetic disk device 1 can evaluate the influence of ATI or the
like occurring in the band areas adjacent in the radial direction
without depending on whether the area is the normal recording band
area CBA or the shingled recording band area SBA. That is, the
magnetic disk device 1 can simplify management of the influence of
ATI or the like occurring between a plurality of band areas
adjacent in the radial direction. Therefore, the magnetic disk
device 1 can improve reliability.
[0134] Next, magnetic disk devices according to other embodiments
and other modification examples will be described. In other
embodiments and other modification examples, the same parts as
those in the above-described embodiment are denoted by the same
reference numerals, and detailed description thereof will be
omitted.
MODIFICATION EXAMPLE
[0135] The magnetic disk device 1 of a modification example differs
from the magnetic disk device 1 of the first embodiment in a write
processing method.
[0136] FIG. 10 is a flowchart of write processing according to the
modification example.
[0137] The MPU 60 determines whether a target band area is the
shingled recording band area SBA or the normal recording band area
CBA (B901). When it is determined that the target band area is the
shingled recording area SBA (YES in B901), the MPU 60 determines
whether the target area is a guard area or a high recording density
area HDR (B903). When it is determined that the target area is a
guard area (B903), the MPU 60 writes data in the guard area of the
shingled recording band area SBA at the boundary track pitch
(B1001) and ends the processing. In other words, when it is
determined that the target area is a band boundary area, the MPU 60
writes data in the band boundary area of the shingled recording
band area SBA at the boundary track pitch and ends the
processing.
[0138] According to the modification example, the magnetic disk
device 1 writes the start track at the boundary track pitch in the
forward direction from the boundary band track in the non-band
boundary area of the shingled recording band area SBA. The magnetic
disk device 1 executes shingled recording of a plurality of tracks
from the start track to the last track in the non-band boundary
area of the shingled recording band area SBA in the forward
direction at the shingled recording track pitch. Even if the normal
recording band area CBA and the shingled recording band area SBA
are arranged adjacent to each other in the radial direction, the
magnetic disk device 1 can prevent ATI and the like from occurring
in the mutual band areas. Therefore, the magnetic disk device 1 can
improve reliability.
Second Embodiment
[0139] The configuration of the magnetic disk device 1 of a second
embodiment is different from that of the magnetic disk device 1 of
the first embodiment.
[0140] FIG. 11 is a block diagram illustrating the magnetic disk
device 1 according to the second embodiment.
[0141] The MPU 60 operates as a read/write control unit 610, a
recording area management unit 620, a write retry counter 630, and
a refresh control unit 640. For example, the MPU 60 executes
firmware to perform functions of the read/write control unit 610,
the recording area management unit 620, the write retry counter
630, the refresh control unit 640, and the like. Alternatively, one
or more of those functions may be performed by one or more
circuits.
[0142] In a predetermined zone, the read/write control unit 610
writes the boundary band track closest to the boundary of this zone
(hereinafter, may be referred to as a zone boundary), that is, in
the band boundary area of the shingled recording band area SBA
(hereinafter, may be referred to as a boundary shingled recording
band area) arranged at both ends of the predetermined zone. The
read/write control unit 610 writes the first boundary area band
track at a boundary track pitch in the forward direction from the
boundary band track in the band boundary area of the boundary
shingled recording band area SBA. The read/write control unit 610
writes at least one boundary area band track from the first
boundary area band track to the last boundary area band track at
the boundary track pitch in the forward direction in the band
boundary area of the boundary shingled recording band area SBA. The
read/write control unit 610 writes the start track at a boundary
track pitch in the forward direction from the last boundary area
band track in the non-band boundary area of the boundary shingled
recording band area SBA. The read/write control unit 610 executes
shingled recording of a plurality of tracks from the start track to
the last track at the shingled recording track pitch in the forward
direction in the non-band boundary area of the boundary shingled
recording band area SBA. The read/write control unit 610 writes the
first boundary area band track at a boundary track pitch in the
forward direction from the last track in the band boundary area of
the boundary shingled recording band area SBA. The read/write
control unit 610 writes at least one boundary area band track from
the first boundary area band track to the last boundary area band
track at the boundary track pitch in the forward direction in the
band boundary area of the boundary shingled recording band area
SBA. The read/write control unit 610 writes a boundary band track
at a boundary track pitch in the forward direction from the last
boundary area band track in the band boundary area of the boundary
shingled recording band area SBA.
[0143] The read/write control unit 610 writes a boundary band track
in a band boundary area of the boundary shingled recording band
area SBA in a predetermined zone. The read/write control unit 610
writes the start track at a boundary track pitch in the forward
direction from the boundary band track in the non-band boundary
area of the boundary shingled recording band area SBA. The
read/write control unit 610 executes shingled recording of a
plurality of tracks from the start track to the last track at the
shingled recording track pitch in the forward direction in the
non-band boundary area of the boundary shingled recording band area
SBA. The read/write control unit 610 writes a boundary band track
at the boundary track pitch from the last track in the band
boundary area of the boundary shingled recording band area SBA.
[0144] In a predetermined zone, in a shingled recording band area
other than the boundary shingled recording band area SBA
(hereinafter, may be referred to as a standard shingled recording
band area), the read/write control unit 610 executes shingled
recording of a plurality of tracks in the forward direction from
the start track to the last track at a shingled recording track
pitch.
[0145] For example, the read/write control unit 610 writes the
outermost band track in a predetermined zone, in the outermost band
boundary area between the boundary closest to the outer zone
boundary (hereinafter, may be referred to as an outer zone
boundary) of this zone, that is, the outermost boundary shingled
recording band area SBA (hereinafter, may be referred to as an
outer boundary shingled recording band area or boundary shingled
recording band area) and the boundary closest to the inner zone
boundary (hereinafter, may be referred to as an inner zone
boundary) of this zone, that is, the innermost boundary shingled
recording band area SBA (hereinafter, may be referred to as an
inner boundary shingled recording band area or boundary shingled
recording band area).
[0146] In the outermost band boundary area of the outer boundary
shingled recording band area SBA and the inner boundary shingled
recording band area SBA, the read/write control unit 610 writes the
first outer boundary area band track at a boundary track pitch in
the forward direction (here, the inward direction) from the
outermost band track. In the outermost band boundary area of the
outer boundary shingled recording band area SBA and the inner
boundary shingled recording band area SBA, the read/write control
unit 610 writes at least one boundary area band track from the
first outer boundary area band track to the last outer boundary
area band track at the boundary track pitch in the forward
direction.
[0147] In the non-band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the start
track at the boundary track pitch in the forward direction from the
last outer boundary area band track. In the non-band boundary area
of the outer boundary shingled recording band area SBA and the
inner boundary shingled recording band area SBA, the read/write
control unit 610 executes shingled recording of a plurality of
tracks from the start track to the last track at a shingled
recording track pitch in the forward direction.
[0148] In the innermost band boundary area of the outer boundary
shingled recording band area SBA and the inner boundary shingled
recording band area SBA, the read/write control unit 610 writes the
first inner boundary area band track at the boundary track pitch in
the forward direction from the last track. In the innermost band
boundary area of the outer boundary shingled recording band area
SBA and the inner boundary shingled recording band area SBA, the
read/write control unit 610 writes at least one boundary area band
track from the first inner boundary area band track to the last
inner boundary area band track at the boundary track pitch in the
forward direction. In the innermost band boundary area of the outer
boundary shingled recording band area SBA and the inner boundary
shingled recording band area SBA, the read/write control unit 610
writes the innermost band track at a boundary track pitch in the
forward direction from the last inner boundary area band track.
[0149] For example, the read/write control unit 610 writes the
innermost band track in the innermost band boundary area of the
outer boundary shingled recording band area SBA and the inner
boundary shingled recording band area SBA in a predetermined zone.
In the innermost band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the first
outer boundary area band track at a boundary track pitch in the
forward direction (here, the outward direction) from the innermost
band track. In the innermost band boundary area of the outer
boundary shingled recording band area SBA and the inner boundary
shingled recording band area SBA, the read/write control unit 610
writes at least one boundary area band track from the first outer
boundary area band track to the last outer boundary area band track
at the boundary track pitch in the forward direction.
[0150] In the non-band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the start
track at the boundary track pitch in the forward direction from the
last inner boundary area band track. In the non-band boundary area
of the outer boundary shingled recording band area SBA and the
inner boundary shingled recording band area SBA, the read/write
control unit 610 executes shingled recording of a plurality of
tracks from the start track to the last track at a shingled
recording track pitch in a forward direction.
[0151] In the outermost band boundary area of the outer boundary
shingled recording band area SBA and the inner boundary shingled
recording band area SBA, the read/write control unit 610 writes the
first outer boundary area band track at the boundary track pitch in
the forward direction from the last track. In the outmost band
boundary area of the outer boundary shingled recording band area
SBA and the inner boundary shingled recording band area SBA, the
read/write control unit 610 writes at least one boundary area band
track from the first outer boundary area band track to the last
outer boundary area band track at the boundary track pitch in the
forward direction (here, the outward direction). In the outermost
band boundary area of the outer boundary shingled recording band
area SBA, the read/write control unit 610 writes the outermost band
track at the boundary track pitch in the forward direction (here,
the outward direction) from the last outer boundary area band
track.
[0152] For example, the read/write control unit 610 writes the
outermost band track in the outermost band boundary area of the
outer boundary shingled recording band area SBA and the inner
boundary shingled recording band area SBA in a predetermined zone.
In the non-band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the start
track at the boundary track pitch in the forward direction (here,
the inward direction) from the outermost band track. In the
non-band boundary area of the outer boundary shingled recording
band area SBA and the inner boundary shingled recording band area
SBA, the read/write control unit 610 executes recording of a
plurality of tracks from the start track to the last track at a
shingled recording track pitch in the forward direction. In the
innermost band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the innermost
band track at a boundary track pitch in the forward direction
(here, the inward direction) from the last track.
[0153] For example, the read/write control unit 610 writes the
innermost band track in the innermost band boundary area of the
outer boundary shingled recording band area SBA and the inner
boundary shingled recording band area SBA in a predetermined zone.
In the non-band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the start
track at the boundary track pitch in the forward direction (here,
the outward direction) from the innermost band track. In the
non-band boundary area of the outer boundary shingled recording
band area SBA and the inner boundary shingled recording band area
SBA, the read/write control unit 610 executes recording of a
plurality of tracks from the start track to the last track at a
shingled recording track pitch in a forward direction. In the
outermost band boundary area of the outer boundary shingled
recording band area SBA and the inner boundary shingled recording
band area SBA, the read/write control unit 610 writes the outermost
band track at a boundary track pitch in the forward direction
(here, the outward direction) from the last track.
[0154] FIG. 12 is a schematic diagram illustrating shingled
recording processing in a standard shingled recording band area
SBA. The shingled recording band area SBA includes, for example, a
standard shingled recording band area CSBA. In the example
illustrated in FIG. 12, the write track WT1 is separated from the
outer band boundary OSE of the shingled recording band area SBA by
a predetermined distance OGD (hereinafter, may be referred to as an
outer guard distance OGD) in the forward direction (here, the
inward direction). For example, the outer band boundary OSE and the
track center STC1 of the write track WT1 are separated by the outer
guard distance OGD in the radial direction. The outer guard
distance OGD is larger than the outer guard area width OGW, for
example. For example, the outer guard distance OGD corresponds to a
distance equal to or longer than the distance obtained by adding
one-half of the write track width WTW to the outer guard area width
OGW. The write track WTn-1 is separated from the inner band
boundary ISE of the shingled recording band area by a predetermined
distance IGD (hereinafter, may be referred to as an inner guard
distance IGD) in a direction opposite to the forward direction
(here, the outward direction). For example, the inner band boundary
ISE and the track center STCn-1 of the write track WTn-1 are
separated by the inner guard distance IGD in the radial direction.
The inner guard distance IGD is larger than the inner guard area
width IGW, for example. For example, the inner guard distance IGD
corresponds to a distance equal to or longer than the distance
obtained by adding one-half of the write track width WTW to the
inner guard area width IGW.
[0155] In the example illustrated in FIG. 12, the read/write
control unit 610 writes the track STR1 (write track WT1), the track
STR2 (write track WT2), the track STR3 (write track WT3), . . . ,
the track STRn-2 (Write track WTn-2), and the track STRn-1 (write
track WTn-1) in the shingled recording band area SBA of the user
data area 10a in the forward direction in the stated order in an
overlapping manner.
[0156] In the example illustrated in FIG. 12, in the high recording
density area HDR of the standard shingled recording band area CSBA
(SBA) of the user data area 10a, the read/write control unit 610
positions the head 15 at the track center STC1 separated from the
outer band boundary OSE by the outer guard distance OGD in the
forward direction (here, the inward direction) and writes the write
track WT1 (here, start track STR1).
[0157] In the example illustrated in FIG. 12, the read/write
control unit 610 positions the head 15 at the track center STC2
which is separated from the track center STC1 of the write track
WT1 at the track pitch WTP in the forward direction (here, the
inward direction) in the high recording density area HDR of the
standard shingled recording band area CSBA, and executes shingled
recording of the write track WT2 on the write track WT1 in an
overlapping manner. The read/write control unit 610 positions the
head 15 at the track center STC3 which is separated from the track
center STC2 of the write track WT2 at the track pitch WTP in the
forward direction in the high recording density area HDR of the
standard shingled recording band area CSBA, and executes shingled
recording of the write track WT3 on the write track WT2 in an
overlapping manner.
[0158] In the example illustrated in FIG. 12, in the high recording
density area HDR of the standard shingled recording band area CSBA,
the read/write control unit 610 positions the head 15 at the track
center STCn-1 which is separated from the track center STCn-2 of
the write track WTn-2 at the track pitch WTP in the forward
direction and is separated from the inner band boundary ISE by the
inner guard distance IGD in the direction (here, the outward
direction) opposite to the forward direction (here, the inward
direction), and executes shingled recording of the write track
WTn-1 (last track STRn-1) on the write track WTn-2 in an
overlapping manner.
[0159] In other words, in the standard shingled recording band area
CSBA, the read/write control unit 610 executes shingled recording
of a plurality of tracks in the forward direction from the write
track WT1 (start track STR0) to the write track WTn-1 (last track
STRn-1) in the high recording density area HDR without writing data
in the guard areas (that is, outer guard area OGR and inner guard
area IGR).
[0160] The write retry counter 630 counts the number of times
(retries) the processing of writing the same data to the same area
again has been executed/retried. The write retry counter 630 counts
the number of retries for each predetermined area, for example, for
each track, each band area, or each zone.
[0161] The write retry counter 630 counts the number of retries in
a predetermined area and the number of retries in an area where an
ATI or the like occurs when write is performed in this area. The
write retry counter 630 counts the number of retries in a band
boundary area of a predetermined band area and the number of
retries in a band boundary area adjacent to the band boundary
area.
[0162] For example, the write retry counter 630 counts the number
of retries of the outermost band track in a predetermined band area
and the number of retries of the innermost band track in a band
area adjacent to the outside of this band area. For example, the
write retry counter 630 counts the number of retries of the
innermost band track in a predetermined band area and the number of
retries of the outermost band track in a band area adjacent to the
inside of this band area. The write retry counter 630 may record
the number of retries in a predetermined area, for example, for
each track, as a table in a predetermined recording area, for
example, the system area 10c of the disk 10, the nonvolatile memory
80, or the like.
[0163] For example, the write retry counter 630 counts the number
of retries of a boundary band track closest to a zone boundary in a
predetermined zone, that is, a band area (hereinafter, may be
referred to as a zone boundary band area) arranged at both ends of
the predetermined zone. In other words, the write retry counter 630
counts the number of retries of the boundary band track in two
adjacent zone boundary band areas with the zone boundary of two
zones that are adjacent in the radial direction interposed
therebetween.
[0164] When a command (e.g., reset write pointer) for returning a
pointer indicating the position of the write processing to the
initial position of the band area in a predetermined band area is
received, or when the change of the predetermined band area (e.g.,
media conversion) is executed, since there is no valid data in the
predetermined band area, the write retry counter 630 resets the
number of retries in this band area, for example, to 0. Here, the
reset write pointer corresponds to a command specified by the
standard.
[0165] When the number of retries in a predetermined area exceeds a
threshold corresponding to this area (hereinafter, may be referred
to as a refresh threshold), the write retry counter 630 may set a
flag for executing refresh processing in this area.
[0166] In a predetermined area, when the number of retries exceeds
a refresh threshold corresponding to this area, the refresh control
unit 640 executes processing of reading data written in this area
and rewriting the same in the same area (hereinafter, may be
referred to as refresh processing). If the flag is set in the
predetermined area, the refresh control unit 640 determines that
the number of retries in this area exceeds a refresh threshold
corresponding to this area and sets this area as an area where
refresh processing is to be executed (hereinafter, may be referred
to as a refresh area). The refresh control unit 640 saves the data
written in the refresh area to a predetermined recording area, for
example, the system area 10c, the volatile memory 70, the
nonvolatile memory 80, the buffer memory 90, or the like. After
saving the data written in this area to the predetermined recording
area, the refresh control unit 640 performs the refresh processing
on this area at a timing when the refresh processing can be
executed, for example, at the time of idling. The refresh control
unit 640 clears the flag after executing the refresh processing on
this area.
[0167] For example, in the normal recording band area CBA, when the
number of retries in a predetermined area exceeds a refresh
threshold (hereinafter, may be referred to as a normal recording
band threshold) set in the normal recording band area CBA, the
refresh control unit 640 executes refresh processing in the entire
area (or all tracks) of the normal recording band area CBA. In the
normal recording band area CBA, when the number of retries in a
predetermined area exceeds a refresh threshold set in the
predetermined area, the refresh control unit 640 may execute
refresh processing on a predetermined radial area including the
predetermined area.
[0168] For example, in the shingled recording band area SBA, when
the number of retries in a predetermined area exceeds a refresh
threshold set in the shingled recording band area SBA (hereinafter,
may be referred to as a shingled recording band threshold), the
refresh control unit 640 executes refresh processing on the entire
area (or all tracks) of the shingled recording band area SBA. In
the shingled recording band area SBA, when the number of retries in
a predetermined area exceeds a shingled recording band threshold,
the refresh control unit 640 may execute refresh processing on a
predetermined radial area including the predetermined area.
[0169] FIG. 13 is a schematic diagram illustrating an arrangement
of zones. FIG. 13 illustrates zones Z0, Z1, and Z2 continuously
arranged in the radial direction. In FIG. 13, the zones Z0 and Z1
are adjacent in the radial direction, and the zones Z1 and Z2 are
adjacent in the radial direction. FIG. 13 illustrates a zone
boundary ZB0 between the zones Z0 and Z1, and a zone boundary ZB1
between the zones Z1 and Z2. The zone Z0 includes band areas BA00,
BA01, . . . , BA0(n-1), and BA0n. The band areas BA00, BA01, . . .
, BA0(n-1), and BA0n are arranged in the stated order from the
outside to the inside. For example, in the zone Z0, the band BA0n
corresponds to the inner boundary shingled recording band area BA0n
(SBA).
[0170] For example, in the zone Z0, the band areas BA00 to BA0(n-1)
correspond to the standard shingled recording band area CSBA or the
normal recording band area CBA. The zone Z1 includes band areas
BA10, BA11, . . . , BA1(n-1), and BA1n. The band areas BA10, BA11,
. . . , BA1(n-1), and BA1n are arranged in the stated order in the
inward direction. For example, in the zone Z1, the band BA10
corresponds to the outer boundary shingled recording band area BA10
(SBA), and the band area BA1n corresponds to the inner boundary
shingled recording band area BA1n (SBA). Further, for example, in
the zone Z1, the band areas BA11 to BA1(n-1) correspond to the
standard shingled recording band area CSBA or the normal recording
band area CBA. The zone Z2 includes band areas BA20, BA21, . . . ,
BA2(n-1), and BA2n. The band areas BA20, BA21, . . . , BA2(n-1),
and BA2n are arranged in the stated order from the outward
direction to the inward direction. For example, in zone 2, the band
BA20 corresponds to the outer boundary shingled recording band area
BA20 (SBA). Further, for example, in the zone Z2, the band areas
BA21 to BA2n correspond to the standard shingled recording band
area CSBA or the normal recording band area CBA.
[0171] In the example illustrated in FIG. 13, the read/write
control unit 610 writes each track as illustrated in FIG. 4 in the
inner boundary shingled recording band area BA0n closest to the
zone boundary ZB0 in the zone Z0, that is, arranged at the end in
the inward direction. The read/write control unit 610 writes each
track as illustrated in FIG. 4 in the outer boundary shingled
recording band area BA10 closest to the zone boundary ZB0 in the
zone Z1, that is, arranged at the end in the outward direction. The
read/write control unit 610 writes each track as illustrated in
FIG. 4 in the inner boundary shingled recording band area BA1n
closest to the zone boundary ZB1 in the zone Z1, that is, arranged
at the end in the inward direction. The read/write control unit 610
writes each track as illustrated in FIG. 4 in the outer boundary
shingled recording band area BA20 closest to the zone boundary ZB1
in the zone Z2, that is, arranged at the end in the outward
direction.
[0172] FIG. 14 is a diagram illustrating a table TB1 for storing
the number of retries according to the second embodiment. The table
TB1 illustrated in FIG. 14 corresponds to, for example, FIG. 13. In
FIG. 14, the table TB1 includes a zone boundary, a zone, a band
area, and the number of retries. In the table TB1, the number of
retries in the band area BA0n corresponds to, for example, the
number of retries of the innermost band track in the boundary
shingled recording band area BA0n. The number of retries in the
band area BA0n may correspond to, for example, the number of
retries of some tracks in the zone boundary ZB0 side of the inner
boundary shingled recording band area BA0n. In the table TB1, the
number of retries in the outer boundary shingled recording band
area BA10 corresponds to, for example, the number of retries of the
outermost band track in the outer boundary shingled recording band
area BA10. The number of retries in the band area BA10 may
correspond to, for example, the number of retries of some tracks in
the zone boundary ZB0 side of the outer boundary shingled recording
band area BA10. In the table TB1, the number of retries in the
boundary shingled recording band area BA1n corresponds to, for
example, the number of retries of the innermost band track in the
inner boundary shingled recording band area BA1n. The number of
retries in the band area BA1n may correspond to, for example, the
number of retries of some tracks in the zone boundary ZB1 side of
the inner boundary shingled recording band area BA1n. In the table
TB1, the number of retries in the boundary shingled recording band
area BA20 corresponds to, for example, the number of retries of the
outermost band track in the outer boundary shingled recording band
area BA20. The number of retries in the band area BA20 may
correspond to, for example, the number of retries of some tracks in
the zone boundary ZB1 side of the outer boundary shingled recording
band area BA20.
[0173] In the example illustrated in FIG. 14, when write retry
processing is executed a predetermined number of times, for
example, 10 times, on the innermost band track of the inner
boundary shingled recording band area BA0n, the write retry counter
630 increases the number of retries in the inner boundary shingled
recording band area BA0n and the number of retries in the outer
boundary shingled recording band area BA10 of the table TB1 by
ten.
[0174] In the example illustrated in FIG. 14, when the number of
retries in the boundary shingled recording band area BA0n exceeds a
refresh threshold for the inner boundary shingled recording band
area BA0n, the refresh control unit 640 executes refresh processing
in the inner boundary shingled recording band area BA0n and resets
the number of retries in the inner boundary shingled recording band
area BA0n, for example, to 0.
[0175] In the example illustrated in FIG. 14, when write retry
processing is executed a predetermined number of times in the
outermost band track of the outer boundary shingled recording band
area BA10, the write retry counter 630 increases the number of
retries in the outer boundary shingled recording band area BA10 and
the number of retries in the inner boundary shingled recording band
area BA0n of the table TB1 by the predetermined number.
[0176] In the example illustrated in FIG. 14, when the number of
retries in the outer boundary shingled recording band area BA10
exceeds a refresh threshold for the outer boundary shingled
recording band area BA10, the refresh control unit 640 executes
refresh processing in the outer boundary shingled recording band
area BA10 and resets the number of retries corresponding to the
outer boundary shingled recording band area BA10, for example, to
0.
[0177] In the example illustrated in FIG. 14, when the write retry
processing is executed a predetermined number of times in the
innermost band track of the inner boundary shingled recording band
area BA1n, the write retry counter 630 increases the number of
retries in the inner boundary shingled recording band area BA1n and
the number of retries in the outer boundary shingled recording band
area BA20 of the table TB1 by the predetermined number.
[0178] In the example illustrated in FIG. 14, when the number of
retries in the outer boundary shingled recording band area BA1n
exceeds a refresh threshold for the outer boundary shingled
recording band area BA1n, the refresh control unit 640 executes
refresh processing on the outer boundary shingled recording band
area BA1n and resets the number of retries in the outer boundary
shingled recording band area BA1n, for example, to 0.
[0179] In the example illustrated in FIG. 14, when write retry
processing is executed a predetermined number of times in the
outermost band track of the outer boundary shingled recording band
area BA20, the write retry counter 630 increases the number of
retries in the outer boundary shingled recording band area BA20 and
the number of retries in the inner boundary shingled recording band
area BA1n of the table TB1 by the predetermined number.
[0180] In the example illustrated in FIG. 14, when the number of
retries in the outer boundary shingled recording band area BA20
exceeds a refresh threshold for the outer boundary shingled
recording band area BA20, the refresh control unit 640 executes
refresh processing in the outer boundary shingled recording band
area BA20 and resets the number of retries in the outer boundary
shingled recording band area BA20, for example, to 0.
[0181] FIG. 15 is a schematic diagram illustrating the table TB1
when a reset write pointer is received or a media conversion is
executed.
[0182] In the example illustrated in FIG. 15, when a reset write
pointer is received for the inner boundary shingled recording band
area BA0n or when a media conversion is performed, the write retry
counter 630 resets the number of retries in the inner boundary
shingled recording band area BA0n, for example, to 0.
[0183] FIG. 16 is a flowchart of write processing according to the
second embodiment.
[0184] The MPU 60 determines whether predetermined processing, for
example, a band area to be accessed or the like (hereinafter, may
be referred to as a target band area) is a shingled recording band
area SBA or a normal recording band area CBA (B901). When it is
determined that the target band area is the shingled recording band
area SBA (YES in B901), the MPU 60 determines whether the target
band area is a zone boundary band area (B1601). When it is
determined that the target band area is not the zone boundary band
area (NO in B1601), the MPU 60 executes shingled recording of data
in the high recording density area HDR at the shingled recording
track pitch (B904), and ends the processing.
[0185] When it is determined that the target band area is a zone
boundary band area (YES in B1601), the MPU 60 determines whether
the target area is a guard area or a high recording density area
HDR (B903). When it is determined that the target area is a guard
area (YES in B903), the MPU 60 writes data in the guard area (a
band boundary area) of the shingled recording band area SBA at the
normal recording track pitch (B902), and ends the processing. When
it is determined that the target area is the high recording density
area HDR (NO in B903), the MPU 60 writes data in the high recording
density area HDR of the shingled recording band area SBA at the
shingled recording track pitch (B904), and ends the processing.
[0186] FIG. 17 is a flowchart illustrating determination processing
of refresh processing according to the second embodiment.
[0187] The MPU 60 determines whether the number of retries in the
target area is greater than a refresh threshold (B1701). When it is
determined that the number of retries in the target area is equal
to or less than the refresh threshold (NO in B1701), the MPU 60
proceeds to the processing of B1703. When it is determined that the
number of retries in the target area has exceeded the refresh
threshold (YES in B1701), the MPU 60 sets a flag for executing the
refresh processing in the target area (B1702), and executes write
processing in the target area (B1703). The MPU 60 determines
whether a write retry has occurred in the target area (B1704). When
it is determined that a write retry has not occurred (NO in B1704),
the MPU 60 ends the processing. When it is determined that a write
retry has occurred (NO in B1705), the MPU 60 executes processing of
counting the number of retries in the area where the write retry
has occurred (B1705), and ends the processing.
[0188] FIG. 18 is a flowchart of processing of counting the number
of retries according to the second embodiment.
[0189] The MPU 60 determines whether the area where a write retry
has occurred is a zone boundary band area (B1801). When it is
determined that the area where a write retry has occurred is not
the zone boundary band area (NO in B1801), the MPU 60 ends the
processing. When it is determined that the area where a write retry
has occurred is the zone boundary band area (YES in B1801), the MPU
60 counts up the number of retries in the area where the write
retry has occurred, for example, increments the number of retries
in the area where the write retry has occurred (B1802), and ends
the processing.
[0190] FIG. 19 is a flowchart of refresh processing according to
the second embodiment.
[0191] The MPU 60 sets a predetermined radial area for which a flag
has been set as a refresh area (B1901). The MPU 60 saves the data
written in the refresh area to a predetermined recording area
(B1902), executes the refresh processing in the refresh area
(B1903), clears the flag (B1904), and ends the processing.
[0192] According to the second embodiment, the magnetic disk device
1 writes a boundary band track in a band boundary area of the
boundary shingled recording band area SBA in a predetermined zone.
The magnetic disk device 1 writes a start track at a predetermined
distance in the forward direction from the boundary band track in
the non-band boundary area of the boundary shingled recording band
area SBA. The magnetic disk device 1 executes recording of a
plurality of tracks from the start track to the last track in the
forward direction at the shingled recording track pitch in the
non-band boundary area of the boundary shingled recording band area
SBA. The magnetic disk device 1 writes a boundary band track at a
predetermined distance from the last track in the band boundary
area of the boundary shingled recording band area SBA. In addition,
the magnetic disk device 1 counts the number of retries in two
adjacent band boundary areas with the zone boundary of two zones
that are adjacent in the radial direction interposed therebetween.
When the number of retries in the band boundary areas exceeds a
refresh threshold corresponding to the band boundary areas, the
magnetic disk device 1 executes refresh processing in the band
boundary areas. Therefore, the magnetic disk device 1 can improve
reliability.
Third Embodiment
[0193] The magnetic disk device 1 of a third embodiment differs
from the magnetic disk device 1 of the first embodiment, the second
embodiment, and the modification example in the write
processing.
[0194] The recording area management unit 620 sets, for example,
the entire area of the user data area 10a of the disk 10 as the
shingled recording band area SBA.
[0195] For example, when the recording area management unit 620
sets the entire area of the user data area 10a of the disk 10 as
the shingled recording band area SBA, the read/write control unit
610 writes a boundary band track in a band boundary area of each
shingled recording band area SBA of the user data area 10a. The
read/write control unit 610 writes the first boundary area band
track at a boundary track pitch in the forward direction from the
boundary band track in the band boundary area of each shingled
recording band area SBA. The read/write control unit 610 writes at
least one boundary area band track from the first boundary area
band track to the last boundary area band track at the boundary
track pitch in the forward direction in the band boundary area of
each shingled recording band area SBA. The read/write control unit
610 writes the start track at a boundary track pitch in the forward
direction from the last boundary area band track in the non-band
boundary area of each shingled recording band area SBA.
[0196] The read/write control unit 610 executes shingled recording
of a plurality of tracks from the start track to the last track at
the shingled recording track pitch in the forward direction in the
non-band boundary area of each shingled recording band area SBA.
The read/write control unit 610 writes the first boundary area band
track at a boundary track pitch in the forward direction from the
last track in the band boundary area of each shingled recording
band area SBA. The read/write control unit 610 writes at least one
boundary area band track from the first boundary area band track to
the last boundary area band track at the boundary track pitch in
the forward direction in the band boundary area of each shingled
recording band area SBA. The read/write control unit 610 writes a
boundary band track at a boundary track pitch in the forward
direction from the last boundary area band track in the band
boundary area of each shingled recording band area SBA.
[0197] For example, when the recording area management unit 620
sets the entire area of the user data area 10a of the disk 10 as
the shingled recording band area SBA, the read/write control unit
610 writes a boundary band track in a band boundary area of the
shingled recording band area SBA. The read/write control unit 610
writes the start track at a boundary track pitch in the forward
direction from the boundary band track in the non-band boundary
area of each shingled recording band area SBA. The read/write
control unit 610 executes shingled recording of a plurality of
tracks from the start track to the last track at the shingled
recording track pitch in the forward direction in the non-band
boundary area of each shingled recording band area SBA. The
read/write control unit 610 writes a boundary band track at a
boundary track pitch from the last track in the band boundary area
of each shingled recording band area SBA.
[0198] When the recording area management unit 620 sets the entire
area of the user data area 10a of the disk 10 as the shingled
recording band area SBA, the write retry counter 630 counts the
number of retries in the outermost band boundary area of a
predetermined shingled recording band area SBA and the number of
retries in the innermost band boundary area of the shingled
recording band area SBA. In other words, when the recording area
management unit 620 sets the entire area of the user data area 10a
of the disk 10 to the shingled recording band area SBA, the write
retry counter 630 counts the number of retries in the band boundary
areas (that is, the innermost band boundary area and the outermost
band boundary area) of these shingled recording band areas SBA that
are adjacent in the radial direction with the band boundary BB
between two shingled recording band areas SBA that are adjacent in
the radial direction interposed therebetween.
[0199] For example, when the recording area management unit 620
sets the entire area of the user data area 10a of the disk 10 as
the shingled recording band area SBA, the write retry counter 630
counts the number of retries of the outermost band track and the
number of retries of the innermost band track in each shingled
recording band area. In other words, the write retry counter 630
counts the number of retries of boundary band tracks of two
shingled recording band areas SBA that are adjacent in the radial
direction with the band boundary BB in the radial direction
interposed therebetween.
[0200] FIG. 20 is a schematic diagram illustrating an arrangement
of zones. FIG. 20 illustrates zones Z0 and Z1 that are adjacent in
the radial direction. FIG. 20 illustrates a zone boundary ZB0
between the zones Z0 and Z1. The zone Z0 includes band areas BA00,
BA01, . . . , BA0(n-1), and BA0n. The band areas BA00, BA01, . . .
, BA0(n-1), and BA0n are arranged in the stated order from the
outside to the inside. For example, in the zone Z0, the band areas
BA00 to BA0n each correspond to the shingled recording band area
SBA. In FIG. 20, the band area BA0n corresponds to the zone
boundary band area BA0n. The zone Z1 includes band areas BA10,
BA11, . . . , BA1(n-1), and BA1n. The band areas BA10, BA11, . . .
, BA1(n-1), and BA1n are arranged in the stated order from the
outside to the inside. For example, in the zone Z1, the band areas
BA10 to BA1n correspond to the shingled recording band area SBA,
respectively. In FIG. 20, the band area BA10 corresponds to the
zone boundary band area BA10.
[0201] In the example illustrated in FIG. 20, when the recording
area management unit 620 sets the entire area of the user data area
10a of the disk 10 as the shingled recording band area SBA, the
read/write control unit 610 writes each of the band areas BA00,
BA01, . . . , BA0(n-1), and BA0n in the zone Z0, as illustrated in
FIG. 4.
[0202] In the example illustrated in FIG. 20, when the recording
area management unit 620 sets the entire area of the user data area
10a of the disk 10 as the shingled recording band area SBA, the
read/write control unit 610 writes each of the band areas BA10,
BA11, . . . , BA1(n-1), and BA1n in the zone Z1, as illustrated in
FIG. 4.
[0203] FIG. 21 is a diagram illustrating a table TB2 for storing
the number of retries according to the third embodiment. The table
TB2 illustrated in FIG. 21 corresponds to, for example, FIG. 20. In
FIG. 21, the table TB2 includes a zone, a band area, the number of
retries of the innermost band track, and the number of retries of
the outermost band track.
[0204] In the example illustrated in FIG. 21, when the write retry
processing is executed a predetermined number of times, for
example, five times, in the innermost band track of the shingled
recording band area BA01, the write retry counter 630 increases the
number of retries of the innermost band track of the shingled
recording band area BA01 and the number of retries of the outermost
band track of the shingled recording band area BA00 of the table
TB1 by five.
[0205] In the example illustrated in FIG. 21, when the number of
retries of the innermost track of the shingled recording band area
BA01 exceeds a refresh threshold of the shingled recording band
area BA01, the refresh control unit 640 executes refresh processing
in the shingled recording band area BA01, and resets the number of
retries of the innermost band track and the number of retries of
the outermost band track of the shingled recording band area BA01,
for example, to 0.
[0206] In the example illustrated in FIG. 21, when the write retry
processing is executed a predetermined number of times in the
innermost band track of the shingled recording band area BA0n, the
write retry counter 630 increases the number of retries of the
innermost band track of the shingled recording band area BA0n and
the number of retries of the outermost band track of the shingled
recording band area BA0(n-1) in the table TB1 by the predetermined
number.
[0207] In the example illustrated in FIG. 21, when the number of
retries of the innermost band track of the shingled recording band
area BA0n exceeds a refresh threshold of the shingled recording
band area BA0n, the refresh control unit 640 executes refresh
processing in the shingled recording band area BA0n, and resets the
number of retries of the innermost band track and the number of
retries of the outermost band track in the shingled recording band
area BA0n, for example, to 0.
[0208] FIG. 22 is a schematic diagram illustrating the table TB2
when a reset write pointer is received or a media conversion is
executed. The table TB2 illustrated in FIG. 22 corresponds to the
table TB2 illustrated in FIG. 21.
[0209] In the example illustrated in FIG. 22, when a reset write
pointer is received for the inner boundary shingled recording band
area BA00 or when a media conversion is performed, the write retry
counter 630 resets the number of retries of the innermost band
track and the number of retries of the outermost band track in the
shingled recording band area BA00, for example, to 0.
[0210] FIG. 23 is a flowchart of processing of counting the number
of retries according to the third embodiment.
[0211] The MPU 60 determines whether the area where a write retry
has occurred is a band boundary area (B2301). For example, the MPU
60 determines whether the area where a write retry has occurred is
a boundary band track. When it is determined that the area where a
write retry has occurred is not a band boundary area (NO in B2301),
the MPU 60 ends the processing. For example, when it is determined
that the area where the write retry has occurred is not a boundary
band track, the MPU 60 ends the processing. When it is determined
that the area where a write retry has occurred is a band boundary
area (YES in B2301), the MPU 60 counts up the number of retries in
the area where the write retry has occurred, for example,
increments the number of retries in the area where the retry has
occurred (B1802), and ends the processing. For example, when it is
determined that the area where a write retry has occurred is a
boundary band track, the MPU 60 counts up the number of retries in
the area where the retry has occurred and ends the processing.
[0212] According to the third embodiment, the magnetic disk device
1 writes a boundary band track in the band boundary area of the
shingled recording band area SBA. The magnetic disk device 1 writes
a start track at a predetermined distance in the forward direction
from the boundary band track in the non-band boundary area of the
shingled recording band area SBA. The magnetic disk device 1
executes recording of a plurality of tracks from the start track to
the last track in the non-band boundary area of the shingled
recording band area SBA in the forward direction at the shingled
recording track pitch. The magnetic disk device 1 writes a boundary
band track at a predetermined distance from the last track in the
band boundary area of the shingled recording band area SBA. In
addition, the magnetic disk device 1 counts the number of retries
in two adjacent band boundary areas with the band boundary of two
band areas that are adjacent in the radial direction interposed
therebetween. When the number of retries in the band boundary areas
exceeds a refresh threshold corresponding to the band boundary
areas, the magnetic disk device 1 executes refresh processing in
the band boundary areas. Therefore, the magnetic disk device 1 can
improve reliability.
[0213] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the disclosure. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the disclosure. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
disclosure.
* * * * *