Disc device, control method of disc device, and program

Abstract

Provided is a disk device, a control method for a disk device, and a program, which enable a rotational latency to be minimized to access a next logical block address (LBA) regardless of which head is used for access in a disk device having a plurality of heads. The disk device of an embodiment includes a storage unit that stores a table in which a track skew value for each head is stored, and a control unit that reads out a track skew value corresponding to a head that is an object of operation from the table and performs track control.

Description

[0001] This application takes priority from Japanese Patent Application No. 2021-154909 (Filing Date: September 22, 2021). The entire contents of the base application are incorporated herein by reference. TECHNICAL FIELD

[0002] Embodiments of the present application relate to a disk device, a control method for a disk device, and a program. BACKGROUND

[0003] In the past, in a disk device (HDD: Hard Disk Drive) having a plurality of heads, in a case where access is continuously performed in a sequential operation, access is performed in the order of the LBA assigned to each sector, such as the nth sector, the (n+1)th sector, the (n+2)th sector, and the like.

[0004] In addition, in seeking, the disk also rotates, and therefore, in a case where recording is performed across a track, the number of sectors that pass in correspondence with the seek time needs to be considered.

[0005] Therefore, it is desirable to set a track skew with a margin, and to minimize the rotational latency when seeking occurs, and to perform access to the next logical block address (LBA). SUMMARY

[0006] However, in the past, when setting the track skew, a temporary value of the track skew was set for the disk device, a margin that takes into account vibration interference received from a server rack or the like was added, and the track skew was set to be appropriate for the disk.

[0007] In a non-vibration interference environment, in each disk device, after investigating the track skew value at which the performance is the best, a time margin TMgn of the stable time extension amount caused by vibration interference that was investigated in advance was used to set the track skew value.

[0008] That is, for the track skew value TSkewX corresponding to the disk device X, it was set as follows.

[0009] TSkewX = TSkew_tempX + TMgn

[0010] Here, TSkew_tempX is the track skew value at which the performance is the best in the disk device X.

[0011] For the track skew thus set, although it is considered to be the most appropriate value as the disk device, it is not the most appropriate value for the head as the action object, and the track skew value will be excessive or insufficient depending on the head as the action object, and the actual effective access performance will be reduced.

[0012] The present application has been achieved in view of the above-described circumstances, and aims to provide a disk device, a control method for a disk device, and a program, which enable access to a next logical block address (LBA) with a minimum rotational latency in a disk device having a plurality of heads, regardless of which head is used for the access.

[0013] The disk device of the embodiment has, in a disk device having a plurality of heads, a storage section that stores a table holding a track skew value for each head, and a control section that reads out a track skew value corresponding to a head as an action object from the table and performs track control. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic configuration block diagram of a hard disk drive to which the first embodiment relates.

[0015] Figure 2 is an explanatory diagram of a conventional track skew value setting method.

[0016] Figure 3 (A) of is an explanatory diagram of a track skew set in a non-vibration disturbance environment.

[0017] Figure 3 (B) of is an explanatory diagram of an actual action state in a vibration disturbance environment.

[0018] Figure 4 (A) of is an explanatory diagram of one example of a track skew table in units of servo sectors.

[0019] Figure 4 (B) of is an explanatory diagram of one example of a track skew table in units of data sectors.

[0020] Figure 5 (A) of is an explanatory diagram of a slack time investigation method in a prior investigation of the head HdO.

[0021] Figure 5 (B) of is an explanatory diagram of a slack time investigation method in a prior investigation of the head Hd1.

[0022] Figure 5 (C) of is an explanatory diagram of a slack time investigation method in a prior investigation of the head Hd2.

[0023] Figure 5(D) is a diagram for explaining a method of investigating a margin time in advance in the investigation of the magnetic head Hd3.

[0024] Figure 6 (A) is a diagram for explaining a history of the position of the magnetic head in the case where the hard disk drive adjusted for the track skew value by the magnetic head is made to operate in a non-vibration environment.

[0025] Figure 6 (B) is a diagram for explaining a history of the position of the magnetic head in the case where the hard disk drive adjusted for the track skew value by the magnetic head is made to operate in a vibration environment.

[0026] Figure 7 (A) is a diagram for explaining a total data transfer amount per unit time before the present embodiment is applied.

[0027] Figure 7 (B) is a diagram for explaining a total data transfer amount per unit time after the present embodiment is applied.

[0028] Figure 8 is a block diagram of a schematic configuration of a hard disk drive to which the second embodiment relates.

[0029] Figure 9 is a diagram for explaining a zone.

[0030] Figure 10 is a diagram for explaining one example of a track skew table.

[0031] Figure 11 is a diagram for explaining a head switching operation at the time of sequential operation.

[0032] Figure 12 (A) is a diagram for explaining one example of a head group table.

[0033] Figure 12 (B) is a diagram for explaining one example of a track skew table 55B in which the track skew values are allocated by the head group.

[0034] Label Explanation

[0035] 10 Hard disk drive

[0036] 11 to 11B Disk

[0037] 12 Spindle motor

[0038] 13 Voice coil motor

[0039] 14 Frame

[0040] 20 Power control section

[0041] 21 Spindle motor control section

[0042] 22 voice coil motor control section

[0043] 30 head control section

[0044] 31 reproducing head selection section

[0045] 32 reproducing signal detection section

[0046] 40 hard disk control section

[0047] 41 track skew reference section

[0048] 42 head skew reference section

[0049] 43 servo control section

[0050] 44 tracking control section

[0051] 45 seek control section

[0052] 46 non-head change seek section

[0053] 47 head change seek section

[0054] 51 non-volatile memory

[0055] 52 volatile memory

[0056] 53 read / write channel

[0057] 55 track skew table

[0058] 55A head group table

[0059] 55B track skew table

[0060] 55P initial track skew table

[0061] 56 head skew table

[0062] HC host computer

[0063] GrO first head group

[0064] GrI second head group

[0065] HdO to Hd3 magnetic heads

[0066] Hdl, Hd2 inner magnetic heads

[0067] HdO, Hd3 outer magnetic heads

[0068] TMgn time margin

[0069] TR track

[0070] TSkewX track skew value

[0071] Tmgn margin time

[0072] Ton on-orbit time

[0073] Ton_Hd0 to Ton_Hd3 on-orbit time

[0074] Tset settling time

[0075] TsetR interference vibration settling time

[0076] Tsk track skew value

[0077] Tskew track skew value

[0078] Tskew_TMP tentative track skew value

[0079] TskewDat track skew value

[0080] TskewSv track skew value

[0081] X disk device

[0082] SF2 2nd surface

[0083] Z0 to Z3 zones DETAILED DESCRIPTION

[0084] Next, the embodiments will be described with reference to the drawings.

[0085] (1st Embodiment)

[0086] Figure 1 is a schematic configuration block diagram of a hard disk drive to which the 1st embodiment is directed.

[0087] In Figure 1 , for easy understanding, a hard disk is exemplified in which two disk plates are provided and four heads corresponding to the surfaces of the respective disk plates are provided.

[0088] The hard disk drive 10 has: two disks 11A, 11B; a magnetic head HdO provided on a first surface (upper side) SF1 of the disk 11A, supported by a swing arm SAO; a magnetic head HdI provided on a second surface SF2 (lower side) of the disk 11A, supported by a swing arm SAI; a magnetic head Hd2 provided on a first surface (upper side) SF1 of the disk 11B, supported by a swing arm SA2; a magnetic head Hd3 provided on a second surface SF2 (lower side) of the disk 11A, supported by a swing arm SA3; a spindle motor 12 that drives the disks 11A, 11B; a voice coil motor 13 that drives the magnetic heads HdO to Hd3 via the swing arms SAO to SA3; and a frame 14.

[0089] In addition, the hard disk drive 10 has a power control section 20, a head control section 30, a hard disk control section 40, a nonvolatile memory 51, a volatile memory 52, and a read / write channel 53.

[0090] The power control section 20 has: a spindle motor control section 21 that controls the spindle motor 12; and a voice coil motor control section 22 that controls the voice coil motor 13.

[0091] The head control section 30 has: a reproduction head selection section 31 that selects a reproduction target head among the magnetic heads HdO to Hd3 under the control of the hard disk control section 40 via the read / write channel 53; and a reproduction signal detection section 32 that detects a reproduction signal of the selected reproduction target head, and outputs the reproduction signal to the hard disk control section 40 via the read / write channel 53.

[0092] The hard disk control section 40 has a track skew reference section 41 that controls the entire hard disk drive 10 under the control of a host computer HC, and refers to a track skew table described later.

[0093] Here, the servo control section 43 has a tracking control section 44 that performs tracking control, and a seek control section 45 that performs seek control.

[0094] Further, the seek control section 45 has: a non-head change seek section 46 that performs seek control without changing the magnetic head; and a head change seek section 47 that performs seek control with changing the magnetic head. The nonvolatile memory 51 is configured as, for example, a ROM or an EEPROM, and has a track skew table 55 in which track skew is stored in advance.

[0095] The volatile memory 52 is configured as, for example, a RAM, and temporarily stores various data and programs.

[0096] The read / write channel 53 is configured as a communication bus having a control bus and a data bus.

[0097] Before the action explanation of the embodiment, the conventional track skew value setting method and the problem points accompanying it are explained.

[0098] Figure 2 is an explanatory diagram of the conventional track skew value setting method.

[0099] In Figure 2 the position history of the head in the case where the head is driven to the nth track to the (n+l)th track and is in the on-track state is shown.

[0100] In the conventional in-house check point project, based on the position history of the head shown by the solid line in Figure 2 , the track skew value is made variable with respect to each hard disk drive in a non-vibration disturbance environment, and the tentative track skew value Tskew_temp that becomes the best performance is investigated and obtained.

[0101] Also, in the hard disk drive of the same model for which the investigation was performed in advance, the margin time Tmgn that is an amount equivalent to the extension of the settling time in the vibration disturbance environment is obtained as shown by the broken line in Figure 2 . The margin time Tmgn is a common value in the hard disk drive of the same model.

[0102] Also, by adding the tentative track skew value Tskew_temp to the margin time Tmgn, the track skew value Tskew that is unique to each hard disk drive is made.

[0103] That is, as shown in Figure 2 , the track skew value Tskew is set by the following equation.

[0104] Tskew = Tskew_temp + Tmgn

[0105] The set track skew value Tskew is written to the non-volatile memory 51 in the hard disk drive.

[0106] Here, as shown in Figure 1 , a hard disk drive having four heads HdO to Hd3 is assumed as the head.

[0107] Figure 3 is an explanatory diagram of the set track skew and the actual action.

[0108] Figure 3 (A) of is an explanatory diagram of the set track skew in the non-vibration disturbance environment.

[0109] Figure 3 (B) of is an explanatory diagram of the actual action state in the vibration disturbance environment.

[0110] In this case, such as Figure 3 As shown in (A), the track skew value Tskew is set to a value that gives the track a margin relative to the on-track time Ton-Hd0 to Ton-Hd3 of each of the heads Hd0 to Hd3.

[0111] like Figure 3 As shown in (B), the position error increases due to vibration interference, thus extending the stabilization time during track seeking, and consequently extending the on-orbit time Ton-Hd0 to Ton-Hd3.

[0112] In this case, a margin time Tmgn is set for all heads Hd0 to Hd3. Therefore, in the outer heads that are not located between disks and have large positioning deterioration caused by vibration interference, the on-orbit time, which is a longer settling time than the margin time Tmgn, may be extended.

[0113] More specifically, for example in Figure 3 In example (B), the track skew value Tskew in head Hd0 is insufficient, therefore, the on-orbit time Ton-Hd0 exceeds the track skew value Tskew for a period of time.

[0114] Conversely, in the inner head located between disks, which is less susceptible to vibration disturbances, the settling time extension is sometimes less than Tmgn.

[0115] For example in Figure 3 In example (B), the magnetic heads Hd1 and Hd2 become: relative to the track skew value Tskew, the on-orbit time Ton-Hd1 and Ton-Hd2 are very short, and there is a margin of time for the track skew value Tskew.

[0116] Furthermore, if the track skew time (Tskew) is insufficient, the seek completion time for the target cylinder will exceed the Tskew time, meaning the intended sector has already been accessed. This causes the following problem: due to the spin wait until the intended sector is reached again, access performance is reduced.

[0117] On the other hand, when there is ample time for the track skew value Tskew, the following occurs: after the seeker completes the target cylinder, it must wait for the rotation to reach the sector to be accessed, which leads to a decrease in access performance.

[0118] Therefore, when the track skew value Tskew is set uniformly for multiple heads Hd0 to Hd3, the difference in settling time between the outer and inner heads increases when vibration interference is applied, leading to the problem that any head Hd0 to Hd3 may cause a decrease in access performance.

[0119] From a performance perspective, the ideal inspection process within the company is to prepare a vibration environment and determine the individual Tskew_Hd0, ..., Tskew_HdN for each driver and each head.

[0120] However, it is impractical because it requires preparing a new vibration environment for the inspection process within the company, and the inspection time will be longer than it is now when adjusting each driver and each head.

[0121] Next, the first embodiment will be described.

[0122] To address the aforementioned problems, in this first embodiment, the margin time Tmgn_Hd0, ..., Tmgn_HdN is pre-investigated according to the magnetic heads (head numbers) Hd0, ..., HdN. By simply adding this to the track skew value Tskew used in the prior art, it is possible to set a track skew value close to the optimal value for each magnetic head. Furthermore, according to this embodiment, the time required for the company's internal inspection process is the same as before.

[0123] More specifically, in this embodiment, a track skew table 55 is pre-recorded in non-volatile memory 51, and when the disk is started, the track skew table 55 is expanded into volatile memory 52. ​​The track skew table 55 is designed or adjusted during manufacturing based on settling time.

[0124] Furthermore, when the hard disk control unit 40 accesses a data sector, the track skew reference unit 41 reads the track skew table 55 on the volatile memory and applies the track skew value corresponding to the header number.

[0125] Here, an example of the construction of a track skew table will be explained.

[0126] Figure 4 This is an illustrative diagram of an example of a track skew table.

[0127] When making the magnetic track skew table 55, such as Figure 4 As shown in (A), when generating data, the track skew value T in units of servo sectors is obtained in association with the read / write head. skewSv_Hd0 ~T skewSv_Hd3 This constitutes the initial magnetic track skew table 55P.

[0128] Furthermore, during the manufacturing process, Figure 4 The track skew value T shown in (A) is in servo sector units. skewSv_Hd0 ~T skewSv_Hd3 Transform into Figure 4(B) shows the track skew value T in terms of data sector number. skewDat_Hd0 ~T skewDat_Hd3 It is stored in non-volatile memory 51 as a track skew table 55.

[0129] Next, the method for setting the track skew value Tskew in the implementation method will be explained.

[0130] First, in the preliminary investigation, prepare multiple (N+1) hard drives and make them operate under vibration (extra vibration) conditions. Investigate the most suitable margin time Tmgn_Hd0, ..., Tmgn_HdN according to the read / write head.

[0131] Figure 5 This is an illustration of a survey method that utilizes leeway in the preliminary investigation.

[0132] With N+1 heads, the margin times Tmgn_Hd0, ..., Tmgn_HdN corresponding to each head Hd0, ..., HdN are investigated, but... Figure 5 For ease of understanding, we assume there are four magnetic heads Hd0, ..., Hd3, and we investigate the margin time Tmgn_Hd0, ..., Tmgn_Hd3.

[0133] Figure 5 (A) is an illustration of the survey method for the margin time in the preliminary survey of the magnetic head Hd0. Figure 5 (B) is an illustration of the survey method for the margin time in the preliminary survey of the magnetic head Hd1. Figure 5 (C) is an illustration of the survey method for the margin time in the preliminary survey of the magnetic head Hd2. Figure 5 (D) is an illustration of the survey method for the margin time in the preliminary survey of the magnetic head Hd3.

[0134] First, in a non-vibration environment (non-vibration environment), start the path search from data cylinder n, and take the settling time when it is able to move to data cylinder n+1 and access it as the settling time Tset (=Tset_Hd0、……、Tset_Hd3).

[0135] Similarly, the settling time under the disturbance vibration environment in the server rack is taken as the disturbance vibration settling time TsetR (=TsetR_Hd0、……、TsetR_Hd3).

[0136] Furthermore, the difference between the settling time Tset and the settling time TsetR of the disturbance vibration is taken as the amount of time extension caused by the vibration disturbance, which is equivalent to the settling time extension, and is used as the margin time Tmgn (=Tmgn_Hd0、……、Tmgn_Hd3).

[0137] More specifically, the following are obtained:

[0138] Tmgn_Hd0 = TsetR_Hd0 - Tset_Hd0

[0139] Tmgn_Hd1 = TsetR_Hd1 - Tset_Hd1

[0140] Tmgn_Hd2 = TsetR_Hd2 - Tset_Hd2

[0141] Tmgn_Hd3 = TsetR_Hd3 - Tset_Hd3

[0142] In this case, the settling time Tset and the disturbance vibration settling time TsetR differ in the tendency of the inner head located between the disks and the outer head not located between the disks, and therefore the margin time Tmgn_Hd0,..., Tmgn_Hd3 corresponding to each head (head number) also become different values respectively.

[0143] Further, the margin times Tmgn_Hd0,..., Tmgn_Hd3 differ by head, but are common in all drives manufactured in the same form.

[0144] Next, in the in-house inspection process, the track skew value Tskew optimized on a drive basis is calculated as in the prior art.

[0145] Next, the margin times Tmgn_Hd0,..., Tmgn_HdN are added to the track skew value Tskew respectively, and the track skew values Tsk_Hd0,..., Tsk_N of the heads Hd0,..., HdN respectively are calculated.

[0146] Further, the calculated track skew values Tsk_Hd0,..., Tsk_N are stored in the track skew table 55 in the nonvolatile memory 51.

[0147] Figure 6 is a graph explaining the head position history in the case where the hard disk drive in which the track skew value has been adjusted by head is made to operate in a non-vibration environment and in a vibration environment.

[0148] Figure 6 (A) of is a graph explaining the head position history in the case where the hard disk drive is made to operate in a non-vibration environment.

[0149] Figure 6 (B) of is a graph explaining the head position history in the case where the hard disk drive is made to operate in a vibration environment.

[0150] As Figure 6As shown, by setting the track skew value for each magnetic head, when the heads are operated under vibration, there is no significant time deficiency relative to the on-orbit time Ton_Hd0, ..., Ton_Hd3 when the track skew value Tsk_Hd0, ..., Tsk_Hd3 is set. Therefore, the rotational waiting time can be reduced.

[0151] Furthermore, in the first embodiment, a track skew table 55, which is prepared during the design phase or adjusted during the manufacturing phase based on the stabilization time, is recorded in the non-volatile memory 51 in advance, and the track skew table 55 is expanded into the volatile memory 52 when the disk is started.

[0152] Furthermore, when the hard disk control unit 40 accesses a data sector, the track skew reference unit 41 reads the track skew table 55 on the volatile memory and applies the track skew value corresponding to the header number.

[0153] Figure 7 This is a graph illustrating the total amount of data transmitted per unit of time.

[0154] Figure 7 (A) is a diagram illustrating the total amount of data transmitted per unit time before applying this implementation method.

[0155] Figure 7 (B) is a diagram illustrating the total amount of data transmitted per unit time after applying this implementation method.

[0156] In terms of per unit of time, by reducing the rotation waiting time ( Figure 7 As the transmission amount is given for a certain period of time, the ratio of actual effective access time increases. Therefore, compared with the application of the same track skew value to all heads, the transmission amount per unit time increases.

[0157] As explained above, according to the first embodiment, in a hard disk drive equipped with multiple heads, an optimal track skew value can be set for each head even in a vibration-interference environment. In particular, even in environments such as those where the drive is significantly affected by vibrations accompanying the operation of other hard disk drives, the optimal track skew value corresponding to the setting state of each head can be used for operation control. Therefore, the impact of vibration interference can be minimized, and data transmission efficiency can be improved.

[0158] (Second Implementation)

[0159] Figure 8 This is a schematic block diagram of the hard disk drive according to the second embodiment.

[0160] exist Figure 8 In the middle, to andFigure 1 The same part is assigned the same label.

[0161] The difference between this second embodiment and the first embodiment is that it includes a head deflection reference unit 42 for referring to the head deflection table described later and a head deflection table 56 that stores the head deflection in advance. This not only optimizes the track deflection according to the magnetic head, but also optimizes the head deflection.

[0162] First, consider actions that cross partitions during ordered actions.

[0163] Figure 9 This is an explanatory diagram of the partitions.

[0164] exist Figure 9 To make it easier to understand, the case with four partitions Z0 to Z3 will be explained.

[0165] Here, as Figure 9 As shown, partitions Z0 to Z3 are multiple regions arranged on disk 11 like tree rings, each consisting of multiple tracks TR.

[0166] Here, an example of the structure of the head tilt table will be explained.

[0167] Figure 10 This is an illustrative diagram of an example of a track skew table.

[0168] like Figure 4 As shown in (A), the head skew table 56 obtains the track skew value T in servo sector units in association with the read / write head when generating data. skewSv_Hd0 ~T skewSv_Hd3 This constitutes the initial magnetic track skew table 55P.

[0169] Figure 11 This is a summary diagram illustrating the head switching action during ordered movements.

[0170] like Figure 11 As shown, during ordered actions, within a partition (in Figure 10 When a seek operation requiring head switching (hereinafter referred to as head-changing seek) is performed within partition Z0, a zigzag access occurs. During such head-switching access, the extension of the settling time of each head caused by vibrations such as interference vibrations varies.

[0171] However, since the deviation of this extension amount is approximately constant for each magnetic head, the same idea as the track skew in the first embodiment is to store the head skew during head switching in the head skew table 56, and in the case of head change seeking, replace the track skew value of each magnetic head in the first embodiment with the head skew value of each magnetic head.

[0172] First, the head skew reference section 42 of the hard disk control section 40 records the head group table 55A and the track skew table 55B, which are prepared at the design stage according to the settling time, in the nonvolatile memory 51 in advance, and expands the head group table 55A and the track skew table 55B to the volatile memory 52 at the time of disk startup.

[0173] Also, in the case of head change seek accompanied by head switching, the track skew reference section 41 of the hard disk control section 40 determines the head of the operation object for accessing data at the time of accessing a data sector, refers to the head group table 55A, reads out and applies the head skew value corresponding to the head from the track skew table 55 on the volatile memory.

[0174] In addition, the track skew table 55, which is prepared at the design stage according to the settling time, is recorded in the nonvolatile memory 51 in advance, and the track skew table 55 is expanded to the volatile memory 52 at the time of disk startup.

[0175] Also, in the case of normal seek not accompanied by head switching, the track skew reference section 41 of the hard disk control section 40 determines the head of the operation object for accessing data at the time of accessing a data sector, refers to the head group table 55A, reads out and applies the head skew value corresponding to the head from the track skew table 55 on the volatile memory.

[0176] As a result, according to the second embodiment, even in an environment in which the influence of vibration accompanying the driving of another hard disk drive is greater, when head change seek occurs, the most appropriate head skew value corresponding to the setting state of each head is used for operation control, so that the influence of vibration interference can be further reduced as much as possible, and improvement of data transfer efficiency is achieved.

[0177] (Modified example of the embodiment)

[0178] (Modified example)

[0179] In each of the above embodiments, a configuration in which the track skew value is stored for each head in advance is adopted, but for example, in the case of the example described above, the inner heads located between the disks and the outer heads not located between the disks exhibit different tendencies, but the inner heads exhibit the same tendency as each other or the outer heads exhibit the same tendency as each other.

[0180] Therefore, it is also possible to group heads having the same settling mode together, and set and store the track skew value by group.

[0181] Figure 12 is a diagram for the case in which heads having the same settling mode are grouped together, and the track skew value is set by group.

[0182] Figure 12 (A) of FIG. 44 is an example of a head group table.

[0183] In Figure 12 In (A) of FIG. 44, the head group table 55A is an example in which the outer side heads HdO, Hd3 among the four heads are allocated to the first head group GrO, and the inner side heads HdI, Hd2 are allocated to the second head group GrI.

[0184] Figure 12 (B) of FIG. 45 is an explanatory diagram of an example of a track skew table 55B in which track skew values are allocated to head groups.

[0185] In the example of the track skew table 55B, the track skew value T skew_Gr0 is allocated to the head group GrO, and the track skew value T skew_Gr1 is allocated to the head group GrI.

[0186] In this case, the head group table 55A and the track skew table 55B are stored in the nonvolatile memory 51 instead of the track skew table 55 in the first embodiment.

[0187] As a result, in the present modification example, the head group table 55A and the track skew table 55B, which are made at the design time according to the settling time, are recorded in the nonvolatile memory 51 in advance, and the head group table 55A and the track skew table 55B are expanded to the volatile memory 52 at the time of disk startup.

[0188] Further, when the data sector is accessed, the track skew reference section 41 of the hard disk control section 40 refers to the head group table 55A, determines the head of the action object of the data access, reads and applies the track skew value corresponding to the head group to which the head belongs from the track skew table 55B on the volatile memory.

[0189] According to the present modification example, it is possible to obtain the same effects as the above-described embodiments, simplify the control, and reduce the memory capacity.

[0190] (Other Modification Examples)

[0191] Further, the program executed in the hard disk control device of the present embodiment is provided by being previously incorporated in a ROM or the like.

[0192] The program executed in the hard disk device of the present embodiment can also be provided by being recorded in a file in an installable form or an executable form on a recording medium readable by a computer such as a USB memory, a semiconductor memory device such as an SSD, a DVD (Digital Versatile Disk), or the like.

[0193] ​Further, the program executed in the hard disk control device of the present embodiment can be stored in a computer connected to a network such as the Internet, and provided by downloading via the network. Alternatively, the program executed in the hard disk control device of the present embodiment can be provided or distributed via a network such as the Internet.

[0194] The program executed in the hard disk control device of the present embodiment is a module structure including the above-described each section (control section), and as actual hardware, the program is read out from the above-described ROM by a CPU (processor) and executed, whereby the above-described control section is loaded and generated on a main storage device.

[0195] The above-described several embodiments of the present application have been described, but these embodiments are presented as examples, and are not intended to limit the scope of the application. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the application. These embodiments and modifications are included in the scope and spirit of the application, and are included in the scope of the application and equivalents recited in the claims.

Claims

1. A disk drive having a plurality of read / write heads, the disk drive comprising: The storage unit stores a table of track skew values ​​for each of the read / write heads. These track skew values ​​are obtained by adding a pre-set margin of time for each head to a provisional track skew value. This provisional track skew value represents the optimal track skew value for the disk drive's performance under vibration-free conditions. The control unit reads the track skew value corresponding to the read / write head of the object being moved from the table and performs track seek control. The margin time is a time equivalent to the extension of the settling time under vibration disturbance conditions.

2. The disk drive according to claim 1, The track skew value is stored as a value in units of data tracks.

3. The disk drive according to claim 1 or 2, The multiple read / write heads are configured into multiple groups, each group comprising read / write heads that share the same stabilization mechanism. The storage unit stores the table containing the track skew values ​​for each of the aforementioned groups. The control unit reads the track skew value corresponding to the group to which the magnetic head of the object to be operated belongs from the table, and performs track seek control.

4. The disk drive according to claim 3, The magnetic heads are divided into a group consisting of inner magnetic heads located between the platters and a group consisting of outer magnetic heads not located between the platters.

5. The disk drive according to claim 1 or 2, The storage unit stores a table containing the head skew values ​​for each of the magnetic heads. When the seek control includes changes in the read / write head, the control unit reads the head skew value corresponding to the read / write head of the target device from the head skew table and performs seek control.

6. A control method for a disk drive, executed within the disk drive, the disk drive having a plurality of read / write heads and a storage unit, the storage unit storing a table of track skew values ​​for each of the read / write heads, the track skew values ​​being obtained by adding a pre-set margin time for each read / write head to a provisional track skew value, the provisional track skew value being the track skew value that optimizes the performance of the disk drive under non-vibration interference conditions, the margin time being an amount of time equivalent to the stabilization time extension under vibration interference conditions, the control method comprising: The step of reading the track skew value corresponding to the magnetic head of the object being operated from the table; and Based on the read track skew value, the corresponding track seeker control of the magnetic head is performed.

7. A computer program product comprising a computer program executing in a disk drive, the disk drive having a plurality of heads and a storage unit, the storage unit storing a table of track skew values ​​for each of the heads, the track skew values ​​being obtained by adding a pre-set margin time for each of the heads to a provisional track skew value, the provisional track skew value being the track skew value that optimizes the performance of the disk drive under non-vibration interference conditions, the margin time being an amount of time equivalent to the stabilization time extension under vibration interference conditions, the computer program causing the computer to function as a unit: The unit that reads the track skew value corresponding to the read / write head of the object being acted from the table; and A unit that performs track seek control of the corresponding magnetic head based on the read track skew value.

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