Magnetic disk device, control method of magnetic disk device, and computer program product

Abstract

The invention provides a magnetic disk device, a control method of the magnetic disk device, and a computer program product, which can suppress magnetic head vibration generated at the time of switching a microactuator, improve positioning accuracy, and suppress reduction of access performance. A magnetic disk device according to an embodiment includes: a first MA amplifier that drives a first microactuator that positions a corresponding magnetic head; a second microactuator that positions the corresponding magnetic head; a second MA amplifier that drives the second microactuator; and a control unit that, when switching from the switching-source MA amplifier in the ON state to the switching-target MA amplifier in the OFF state, maintains the switching-source MA amplifier in the ON state, activates the switching-target MA amplifier, and activates the switching-source MA amplifier in the OFF state. And switching from the MA amplifier of the switching source to the MA amplifier of the switching target after a predetermined time has elapsed.

Description

[0001] This application claims the priority of Japanese Patent Application No. 2023-093996 (filing date: June 7, 2023) as a basic application. The present application incorporates the entire contents of the basic application by reference. Technical Field

[0002] The present embodiment relates to a magnetic disk device, a control method of the magnetic disk device, and a computer program product. Background Art

[0003] In the past, in order to improve the characteristics of the microactuator that performs head positioning in the HDD which is a magnetic disk device, and to shorten the processing time in SSW (Self Servo Write) that writes the product servo pattern through an external circuit using only the offset control function and / or the mechanical structure of the HDD body, a function of driving multiple microactuators simultaneously has been proposed.

[0004] When such a structure is adopted, one HDD has a plurality of micro-actuator amplifier (MA amplifier) ​​systems, and standby power increases in an environment where a product actually uses the HDD.

[0005] As a countermeasure to this, the MA amplifiers of the magnetic heads not in use are turned off.

[0006] In the prior art, the on / off switching of the MA amplifier that supplies driving power for driving the microactuator is performed at the beginning of the track seek. However, during this switching, the suspension that holds the magnetic head vibrates, causing the positioning accuracy of the magnetic head to deteriorate, thereby deteriorating the random access performance of the HDD.

[0007] To solve this problem, for example, a technique has been proposed to set a slope for the voltage of the MA amplifier in the piezoelectric drive circuit. However, if the slope of the voltage of the MA amplifier is simply slowed down, switching will take time, and as a result, the random access performance of the HDD will still deteriorate. Summary of the invention

[0008] Embodiments of the present invention provide a magnetic disk device, a control method of the magnetic disk device, and a computer program product that can suppress vibration of a magnetic head generated when a microactuator is switched, thereby improving positioning accuracy and suppressing degradation of access performance.

[0009] According to an embodiment of the present invention, the magnetic disk device comprises: a first MA amplifier, which drives a first microactuator, and the first microactuator positions a corresponding magnetic head; a second microactuator, which positions a corresponding magnetic head; a second MA amplifier, which drives the second microactuator; and a control unit, which, when switching from an MA amplifier of a switching source in an on state to an MA amplifier of a switching target in an off state, maintains the MA amplifier of the switching source in an on state, starts the MA amplifier of the switching target, and switches from the MA amplifier of the switching source to the MA amplifier of the switching target after a predetermined time. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an explanatory diagram of an example of the schematic configuration of a magnetic disk device according to an embodiment.

[0011] Figure 2 It is a plan view showing a schematic configuration example of a magnetic disk device according to an embodiment.

[0012] Figure 3 This is an explanatory diagram of an example of operation when a conventional magnetic head is changed.

[0013] Figure 4 This is an explanatory diagram showing an example of the operating principle of the first embodiment.

[0014] Figure 5 It is an explanatory diagram of an operation example when the magnetic head is changed according to the first embodiment.

[0015] Figure 6 This is an explanatory diagram showing an example of a control data table used in the first embodiment.

[0016] Figure 7 1 is a flowchart showing an example of a procedure of a switching process of a microactuator according to the embodiment.

[0017] Figure 8 (A) and (B) are explanatory diagrams of an example of switching of the MA amplifier according to the first embodiment.

[0018] Fig. 9 (A) and (B) are explanatory diagrams of an example of switching of the MA amplifier according to the second embodiment.

[0019] Fig.10 This is an explanatory diagram showing an example of a control data table used in the third embodiment.

[0020] Fig.11 (A) and (B) are explanatory diagrams of an example of switching of the MA amplifier according to the third embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments will be described with reference to the drawings.

[0022] [1] First Embodiment

[0023] Figure 1 It is an explanatory diagram of an example of the schematic configuration of a magnetic disk device according to an embodiment.

[0024] The magnetic disk device 10 is, for example, a hard disk drive (HDD). Alternatively, the magnetic disk device 10 may be another magnetic disk device such as a hybrid HDD.

[0025] The disk device 10 can be connected to the host 2 via a communication line. Here, the disk device 10 and the host 2 can communicate via the communication line using a communication protocol that complies with the SAS (Serial Attached SCSI) standard, for example. In addition, the standard of the communication line between the disk device 10 and the host 2 is not limited to this example.

[0026] The host 2 is configured as, for example, a processor, a personal computer, or a server. The magnetic disk device 10 can receive access commands (for example, read commands and write commands) from the host 2.

[0027] Figure 2 It is a plan view showing a schematic configuration example of a magnetic disk device according to an embodiment.

[0028] The magnetic disk device 10 includes a spindle motor (SPM) 11 , a plurality of magnetic disks 12 , a plurality of magnetic heads 13 , an actuator unit 14 , a ramp load mechanism 15 , a head amplifier 16 , a SoC 17 , and a servo controller (SVC) 18 .

[0029] The spindle motor 11 has a rotation shaft 19. The plurality of magnetic disks 12 are held on the rotation shaft 19 by, for example, a clamp. The spindle motor 11 rotates the plurality of magnetic disks 12 around the rotation shaft 19 in unison.

[0030] Recording surfaces on which data can be recorded are formed on both sides of the plurality of magnetic disks 12. The number of the plurality of magnetic heads 13 is set so that the plurality of magnetic heads 13 can access the recording surfaces of the plurality of magnetic disks 12.

[0031] Each of the plurality of magnetic heads 13 is provided so as to be able to face the recording surface of the corresponding magnetic disk 12. Each of the plurality of magnetic heads 13 can record data on and reproduce data from the recording surface of the magnetic disk 12 to which the magnetic head 13 faces.

[0032] exist Figure 1 In order to simplify the diagram and facilitate understanding, six magnetic heads 13 having head IDs = H0 to H5 are shown in the figure, but in reality, more magnetic heads 13 (for example, 20) are provided.

[0033] In addition, if Figure 1 As shown, the actuator unit 14 includes a plurality of suspensions 21 , a plurality of actuator arms 22 , a rotating shaft 23 , a voice coil motor (VCM) 24 , and a plurality of microactuators (MA) 25 .

[0034] Each of the plurality of suspensions 21 is formed in an elastically deformable plate shape and supports a corresponding one of the plurality of magnetic heads 13 near the front end of each of the plurality of suspensions 21 .

[0035] One end portion of the plurality of actuator arms 22 is supported by the rotation shaft 23 so as to be rotatable around the rotation shaft 23. A corresponding one of the plurality of suspensions 21 is attached to the other end portion of each of the plurality of actuator arms 22.

[0036] The voice coil motor 24 rotates the actuator arm 22 and the suspension 21 attached to the actuator arm 22 within a predetermined range around the rotation axis 23. The rotation axis 19 of the SPM 11 and the rotation axis 23 of the actuator unit 14 are provided substantially parallel to and spaced apart from each other.

[0037] Therefore, the voice coil motor 24 can move the magnetic head 13 supported by the suspension 21 relative to the magnetic disk 12 .

[0038] The voice coil motor 24 moves the actuator arm 22 substantially parallel to the recording surface of the magnetic disk 12. The voice coil motor 24 of the present embodiment moves the magnetic head 13 in a radial direction substantially orthogonal to the rotation axis 19 relative to the magnetic disk 12.

[0039] The microactuator 25 is provided at a connection portion between the suspension 21 and the actuator arm 22. The microactuator 25 is an actuator element such as a piezoelectric element.

[0040] The microactuator 25 can move the suspension 21 substantially parallel to the recording surface of the magnetic disk 12. That is, the actuator unit 14 is configured as a two-stage actuator that moves the magnetic head 13 using the voice coil motor 24 and the microactuator 25.

[0041] In the above-described configuration, the number of suspensions 21, actuator arms 22, and microactuators 25 is set according to the number of magnetic heads 13. In addition, the actuator unit 14 may include a plurality of voice coil motors 24.

[0042] The actuator unit 14 is capable of moving the magnetic head 13 along the track T relative to the recording surface of the magnetic disk 12 through the voice coil motor 24 and the microactuator 25. The ramp loading mechanism 15 is provided on the track T near the outer end of the magnetic disk 12. Therefore, the voice coil motor 24 is capable of moving the magnetic head 13 between the ramp loading mechanism 15 and the rotation axis 19.

[0043] The ramp loading mechanism 15 is used to park the plurality of magnetic heads 13 during unloading and retracting. For example, the ramp loading mechanism 15 can support a lift tab disposed at the front end of the suspension 21 to maintain the magnetic heads 13 supported by the suspension 21 at the retracted position.

[0044] Figure 1 The head amplifier 16 shown amplifies the signal read from the magnetic disk 12 by the magnetic head 13, outputs the amplified signal, and supplies the amplified signal to the SoC 17. The SoC 17 demodulates the signal supplied from the head amplifier 16 into digital data through a read channel circuit.

[0045] The head amplifier 16 is supplied with a signal corresponding to the digital data from the SoC 17. The head amplifier 16 amplifies the signal supplied from the SoC 17 and supplies the amplified signal to the magnetic head 13. The magnetic head 13 records the signal supplied from the head amplifier 16 on the recording surface of the magnetic disk 12.

[0046] The SVC 18 controls the voice coil motor 24 and the microactuator 25 of the actuator unit 14 . Specifically, the SVC 18 drives the actuator unit 14 based on an instruction from the SoC 17 , thereby positioning the magnetic head 13 at a position instructed by the SoC 17 .

[0047] Furthermore, the SVC 18 drives the spindle motor 11 based on an instruction from the SoC 17. The SVC 18 drives the spindle motor 11 so that the rotation speed of the spindle motor 11 becomes constant at a predetermined target speed.

[0048] The SVC 18 retracts the magnetic head 13 when the power supply to the magnetic disk device 10 is cut off. Furthermore, the SVC 18 may retract the magnetic head 13 when a seek error occurs in the positioning control of the magnetic head 13.

[0049] The SoC 17 is electrically connected to the host 2. The SoC 17 interprets an access command from the host 2, and executes various controls such as access to the magnetic disk 12 based on the interpretation result.

[0050] SoC17 has an MPU (Micro-Processing Unit) 17a. MPU17a operates according to the firmware program. The firmware program is stored in a predetermined non-volatile storage area. The predetermined non-volatile storage area can be either the disk 12 or the ROM (Read Only Memory) of SoC17.

[0051] The MPU 17a controls the overall operation of the magnetic disk device 10. For example, the MPU 17a controls access to the magnetic disk 12 using the magnetic head 13 via the head amplifier 16. The MPU 17a also instructs the SVC 18 to control the rotation of the spindle motor 11 or to control loading / unloading of the actuator unit 14 via the SVC 18.

[0052] In addition, MPU17a calculates the indicated value of the driving voltage of VCM24 and the indicated value of the driving voltage of MA25 in the positioning control so that the position of the magnetic head 13 follows the target position pos_target. MPU17a uses the position signal pos read out by the magnetic head 13 from the servo information formed on the recording surface of the magnetic disk 12 as a feedback input to calculate each indicated value, and sends each obtained indicated value to SVC18.

[0053] The SVC 18 applies a voltage corresponding to the instruction value of the drive voltage of the voice coil motor 24 to the voice coil motor 24, and applies a voltage corresponding to the instruction value of the drive voltage of the microactuator 25 to the microactuator 25. Thus, the magnetic head 13 is positioned at the target position.

[0054] Next, before explaining the operation of the embodiment, conventional problems will be explained.

[0055] Figure 3 This is a diagram illustrating the operation of a conventional magnetic head change.

[0056] exist Figure 3 In the example, when the microactuator (MA) is turned on, the voltage applied from the MA amplifier to the microactuator is set to 10 V, and when the microactuator (MA) is turned off, the voltage applied from the MA amplifier to the microactuator is set to 0 V.

[0057] exist Figure 3 In the example, when microactuator MA1 in the off state is turned on and microactuator MA2 in the on state is turned off, the microactuator is switched by changing the output voltage of the MA amplifier at the first slew rate at time t10 before time t11 corresponding to the head change timing.

[0058] In more detail, when the voltage output from the first MA amplifier for driving the microactuator MA1 is set to VMA11 and the voltage output from the second MA amplifier for driving the microactuator MA2 is set to VMA12, at time t10, the voltage VMA11 output from the first MA amplifier is increased at the first conversion rate and the voltage VMA12 output from the second MA amplifier is decreased at the first conversion rate.

[0059] In this case, the suspension holding the magnetic head vibrates, such as Figure 3 As shown, after the head change, the deviation of the head position from the target position PTG becomes larger, and the positioning accuracy decreases.

[0060] Next, the operating principle of the first embodiment will be described.

[0061] Figure 4 This is a diagram for explaining the operating principle of the first embodiment.

[0062] exist Figure 4 In the example, as a plurality of magnetic heads 13, the number of magnetic heads 13 having a magnetic head ID is an even number (in Figure 4 In the example, the head ID is H0, H2, H4, ..., H2n. Where n is an integer greater than 0) and the number of head IDs is an odd number (in Figure 4 In the example of FIG. 1 , there are n magnetic heads 13B with head ID=H1, H3, H5, ..., H2n+1 (where n is an integer greater than or equal to 0).

[0063] In the above-described configuration, the magnetic head 13A is driven by the corresponding microactuator MA1, and the magnetic head 13B is driven by the corresponding microactuator MA2.

[0064] Furthermore, all the microactuators MA1 are driven by power supplied from the first MA amplifier 30A.

[0065] Likewise, all microactuators MA2 are driven by power supplied from the second MA amplifier 30B.

[0066] Figure 5 It is an explanatory diagram of the operation when the magnetic head is changed in the first embodiment.

[0067] exist Figure 5 In the embodiment, when the microactuator 25 (MA1 or MA2) is turned on, the voltage applied from the first MA amplifier 30A or the second MA amplifier 30B to the microactuator 25 is set to 10 V, and when the microactuator 25 (MA1 or MA2) is turned off, the voltage applied from the first MA amplifier 30A or the second MA amplifier 30B to the microactuator 25 is set to 0 V.

[0068] exist Figure 5In the example, when the microactuator MA1 in the off state is turned on and the microactuator MA2 in the on state is turned off, the output voltage of the MA amplifier is changed at the absolute value of the second slew rate (< the absolute value of the first slew rate) at the time t0 (t1-t0>t11-t10) before the time t1 corresponding to the head change timing. Here, the first slew rate is the slope of the signal when the signal rises, and the second slew rate is the slope of the signal when the signal falls.

[0069] More specifically, when the corresponding microactuator MA1 in the off state is turned on by the first MA amplifier 30A and the corresponding microactuator MA2 in the on state is turned off by the second MA amplifier 30B, the output voltage of the first MA amplifier 30A is increased from 0V to 10V at the first conversion rate, and the output voltage of the second MA amplifier 30B is decreased from 10V to 0V at the second conversion rate.

[0070] Then, the voltage VMA11 applied by the first MA amplifier 30A to the microactuator MA1 in the on state is increased at the first slew rate from time t0 , so that at time t1 , the voltage VMA11 reaches 10 V corresponding to the on state.

[0071] This state is further maintained until time t2 when the vibration of the suspension holding the magnetic head becomes small and stable, and then the microactuator to be controlled is switched from microactuator MA2 to microactuator MA1.

[0072] In this case, at the time point from time t1 to time t2 , both microactuator MA1 and microactuator MA2 are in the on state.

[0073] Then, at time t2, the voltage VMA12 applied by the second MA amplifier 30B to the microactuator MA2 in the OFF state is gradually decreased at the second slew rate, so that at time t3, the voltage VMA12 becomes 0 V corresponding to the OFF state.

[0074] By performing the above operation, the microactuator to be controlled is switched. However, in this case, Figure 5 As shown, the suspension holding the magnetic head 13B driven by the second MA amplifier 30B also vibrates.

[0075] However, it can be seen that according to the embodiment, Figure 3 Compared with the case shown in FIG. 1 , the vibration is reduced, and the deviation of the head position after the head change relative to the target position PTG is smaller than before, which can improve the positioning accuracy.

[0076] Next, the detailed operation of the first embodiment will be described.

[0077] Figure 6 This is an explanatory diagram of the control data table used in the first embodiment.

[0078] The control data table TB1 of the first embodiment includes head ID data 31 for identifying each magnetic head 12 and corresponding MA data 32 for identifying a microactuator corresponding to the magnetic head identified by the head ID data 31 .

[0079] For example, the microactuator corresponding to the head identified by head ID="H1" is driven by microactuator MA2, and the microactuator corresponding to the head identified by head ID="H4" is driven by microactuator MA1.

[0080] In other words, Figure 6 , it is shown that the first MA amplifier 30A drives a plurality of magnetic heads 13A identified by head ID="H0", "H2", "H4", "H6", . . . via the corresponding microactuator MA1.

[0081] Similarly, the second MA amplifier 30B is shown to drive a plurality of magnetic heads 13B identified by head ID="H1", "H3", "H5", "H7", . . . via the corresponding microactuator MA2.

[0082] Figure 7 1 is a process flow chart of a switching process of a microactuator according to an embodiment.

[0083] The switching process of the microactuator is performed by the MPU 17 a of the SoC 17 controlling the SVC 18 .

[0084] SoC17 refers to Figure 6 The control data table TB1 shown (step S11) is displayed, and based on the content of the control data table, it is determined whether the MA amplifier needs to be switched (step S12).

[0085] When it is determined in step S12 that the MA amplifier does not need to be switched (step S11 : No), the process ends.

[0086] In the determination of step S12, if it is necessary to switch the MA amplifier (step S12: Yes), based on the referenced in step S11, Figure 6 The control data table TB1 shown is used to select the MA amplifier to be switched (step S13).

[0087] Figure 8 This is an explanatory diagram of an example of switching of the MA amplifier according to the first embodiment.

[0088] Figure 8(A) shows the switching order of the MA amplifier when the seek order is rearranged by NCQ (Native Command Queuing) in the past. Figure 8 (B) shows the switching sequence of the MA amplifiers according to the first embodiment.

[0089] In the past, for example, Figure 8 As shown in (A), assuming that the data access order is head ID = "H0" → head ID = "H3" → head ID = "H4" → head ID = "H1" → head ID = "H6" → head ID = "H5", the microactuator that should be in the on state must be changed each time the head is switched.

[0090] The results, such as Figure 3 As shown in the figure, vibration occurs and positioning accuracy deteriorates.

[0091] Therefore, in the first embodiment, the SoC 17 performs control so that, in the switching order of the MA amplifiers when the seek order is rearranged by NCQ, the magnetic head driven by the same microactuator as the microactuator currently in the on state is preferentially used.

[0092] exist Figure 8 In FIG. 1 , it is shown that a plurality of magnetic heads 13A identified by head IDs "H0", "H4", and "H6" are driven by corresponding microactuators MA1 supplied with electric power from first MA amplifiers 30A.

[0093] Similarly, it is shown that the plurality of magnetic heads 13B identified by the head IDs "H1", "H3", and "H5" are driven by the corresponding microactuators MA2 supplied with electric power from the second MA amplifier 30B.

[0094] That is, in Figure 8 In the case corresponding to the situation shown in (A), SoC17 is based on the control data table TB1 referred to in step S13, as shown in FIG. Figure 8 As shown in (B), first, when the microactuator currently in the on state is MA1, the data access order is set to head ID="H0" corresponding to microactuator MA1→head ID="H4"→head ID="H6".

[0095] Therefore, during this series of data accesses, the microactuator MA1 does not transition to the off state.

[0096] Next, the SoC 17 selects the microactuator MA2 as the switching target MA amplifier (step S13 ).

[0097] Then, in Figure 8 In the case shown in (B), Figure 5 Similarly to the case of , the switching target MA amplifier activation process is performed to turn the microactuator MA2 in the OFF state into the ON state (step S14). That is, the activation process of the second MA amplifier 30B is performed.

[0098] More specifically, the output voltage of the second MA amplifier 30B is increased at the first slew rate.

[0099] Then, for the plurality of microactuators MA2 that are turned on, it is determined whether a first predetermined time (in seconds) has elapsed since the voltage applied by the second MA amplifier 30B started to rise at the first slew rate. Figure 5 In the example, whether time t2 has arrived (step S15).

[0100] In the determination of step S15 , when the first predetermined time has not elapsed (step S15 : No), the system is put into a standby (waiting) state.

[0101] In the judgment of step S15, when the first predetermined time has passed, the voltage applied to the microactuator MA2 becomes the predetermined on-state voltage (10V in the above example), and the vibration should also become smaller, so the microactuator of the control object is switched from microactuator MA1 to microactuator MA2 (step S16).

[0102] Furthermore, the microactuator currently in the on state is the microactuator MA2 driven by the second MA amplifier 30B, and therefore the data access sequence is set to head ID="H1" → head ID="H3" → head ID="H5" corresponding to the microactuator MA2.

[0103] In parallel with these operations, the first MA amplifier 30A, which is the switching source MA amplifier, starts to be turned off (step S17 ). More specifically, the output voltage of the first MA amplifier 30A starts to decrease at the second slew rate.

[0104] Then, it is determined whether or not the second predetermined time has elapsed since the voltage applied from the first MA amplifier 30A to the microactuator MA1 set in the OFF state was dropped at the second slew rate (step S18 ).

[0105] In the determination of step S18 , when the second predetermined time has not elapsed (step S18 : No), the system enters the standby state.

[0106] When it is determined in step S18 that the second predetermined time has elapsed (step S18 : Yes), the first MA amplifier 30A corresponding to the microactuator MA1 is turned off to be in an OFF state, and the process ends.

[0107] According to the above structure, Figure 8 In the conventional case shown in (A), the switching of the microactuator and the switching of the MA amplifier need to be performed five times. Figure 8 In the first embodiment shown in (B), the microactuator only needs to be switched once, and the influence of the switching of the microactuator, that is, the switching of the MA amplifier, can be reduced, thereby achieving an improvement in the positioning accuracy of the magnetic head.

[0108] In the above description, Figure 5 The controls shown and Figure 8 Although both are controlled as shown in (B), even if only one of them is controlled, the influence of switching of the microactuator can be reduced, thereby improving the positioning accuracy of the magnetic head.

[0109] [2] Second Embodiment

[0110] Next, a second embodiment will be described.

[0111] Fig. 9 This is an explanatory diagram of an example of switching of the MA amplifier according to the second embodiment.

[0112] Fig. 9 (A) shows the switching order of the MA amplifier during the conventional sequential access. Fig. 9 (B) shows the switching order of the MA amplifiers during the sequential access according to the second embodiment.

[0113] Here, sequential access generally refers to a process of accessing areas in order from small to large LBA (Logical Block Address).

[0114] exist Fig. 9 , it is also shown that the plurality of magnetic heads 13A identified by the head IDs "H0", "H2", . . . , "H18" corresponding to the plurality of microactuators MA1 supplied with power by the first MA amplifier 30A are driven by the microactuators MA1.

[0115] Similarly, it is shown that the plurality of magnetic heads 13B identified by the head IDs "H1", "H3", . . . , "H19" corresponding to the plurality of microactuators MA2 supplied with power by the second MA amplifier 30B are driven by the microactuators MA2.

[0116] Therefore, in the second embodiment, when switching from the MA amplifier of the switching source in the on state to the MA amplifier of the switching target in the off state, logical addresses are allocated in advance so that during sequential access, the head using the MA amplifier of the switching source becomes the first in sequence and the head using the MA amplifier of the switching target becomes the last in sequence.

[0117] That is, in the case of the above example, the LBA is configured from the small side to the large side so that the order of the multiple heads 13B determined by the head ID = "H1", "H3", ..., "H19" corresponding to the multiple microactuators MA2 supplied with power by the second MA amplifier 30B is after the order of the multiple heads 13A determined by the head ID = "H0", "H2", ..., "H18" corresponding to the multiple microactuators MA1 supplied with power by the first MA amplifier 30A.

[0118] Below, refer again Figure 7 Processing flow chart of .

[0119] In the past, for example, Fig. 9 As shown in (A), the data access order is assumed to be head ID = "H0" → head ID = "H2" → head ID = "H4" → ... → head ID = "H16" → head ID = "H17" → head ID = "H18".

[0120] In this case, as in the first embodiment, the switching of the corresponding microactuators occurs frequently, such as Figure 3 As shown in the figure, vibration occurs and positioning accuracy deteriorates.

[0121] That is, in Fig. 9 The situation shown in (A) corresponds to the case where Fig. 9 As shown in (B), first, when the microactuator currently in the on state is MA1, that is, when the MA amplifier currently supplying power is the first MA amplifier 30A, logical addresses are allocated in advance so that the data access order becomes the head ID = "H0" corresponding to the microactuator MA1 → head ID = "H2" → head ID = "H4" → ... → head ID = "H18".

[0122] Next, SoC 17 refers to control data table TB1 (step S12), and when access to the magnetic head corresponding to microactuator MA1 is completed, selects second MA amplifier 30B corresponding to multiple microactuators MA2 as the switching target MA amplifier based on the order of sequential access (step S13).

[0123] Then, in Fig. 9 In the case shown in (B), Figure 4 Similarly to the case of , the switching target MA amplifier activation process is performed to turn the microactuator MA2 in the OFF state into the ON state (step S14). That is, the activation process of the second MA amplifier 30B is performed.

[0124] More specifically, the output voltage of the second MA amplifier 30B is increased at the first slew rate.

[0125] Then, it is determined whether or not the first predetermined time has elapsed since the output voltage of the second MA amplifier 30B started to rise at the first slew rate (step S15).

[0126] In the determination of step S15 , when the first predetermined time has not elapsed (step S15 : No), the system enters the standby state.

[0127] In the judgment of step S15, when the first predetermined time has passed (step S15: yes), the voltage applied to the microactuator MA2 becomes the predetermined on-state voltage (10V in the above example), and the vibration should also become smaller, so the microactuator of the control object is switched from microactuator MA1 to microactuator MA2 (step S16).

[0128] Moreover, the microactuator currently in the on state is microactuator MA2, so according to the predetermined logical address, the data access order becomes head ID="H19" corresponding to microactuator MA2→head ID="H17"→...→head ID="H1".

[0129] In parallel with these operations, the first MA amplifier 30A, which is the switching source MA amplifier, starts to be turned off (step S17 ). More specifically, the output voltage of the first MA amplifier 30A starts to decrease at the second slew rate.

[0130] Then, it is determined whether or not the second predetermined time has elapsed since the voltage applied to the microactuator MA1 set to the OFF state was dropped at the second slew rate (step S18 ).

[0131] In the determination of step S18 , if the second predetermined time has not elapsed (step S18 : No), the system enters the standby state.

[0132] When it is determined in step S18 that the second predetermined time has elapsed, the first MA amplifier 30A corresponding to the microactuator MA1 is turned off and the process ends.

[0133] According to the above structure, Fig. 9 In the conventional case shown in (A), the microactuator needs to be switched multiple times. Fig. 9 In the second embodiment shown in (B), the microactuator only needs to be switched once, and the influence of switching of the microactuator can be reduced even in sequential access, thereby improving the positioning accuracy of the magnetic head.

[0134] [3] Third Embodiment

[0135] Next, a third embodiment will be described.

[0136] Fig.10 It is an explanatory diagram of a control data table used in the third embodiment.

[0137] The control data table TB2 of the third embodiment includes: head ID data 41 for identifying each head, corresponding MA data 42 for identifying the microactuator corresponding to the head identified by the head ID data 41, and vibration level (rank) data 43 for storing the vibration level (level) when the microactuator starts to be driven.

[0138] In this case, the vibration level refers to a level obtained by dividing the magnitude of the vibration amount of the magnetic head 13 into multiple levels.

[0139] In the above configuration, the vibration level data is determined in advance by measurement. Fig. 9 In the case of the example, there are three levels: vibration level = "S", which is the level with the least vibration amount, and the vibration amount is less than the first predetermined vibration amount; vibration level = "L", which is the level with the largest vibration amount, and the vibration amount is more than the second predetermined vibration amount, and the second predetermined vibration amount is more than the first predetermined vibration amount; and vibration level = "M", which is the level with a vibration amount greater than the first predetermined vibration amount and less than the second vibration amount.

[0140] For example, let the microactuator corresponding to the magnetic head determined by the magnetic head ID = "H0" be the microactuator MA1, and the corresponding vibration level = "S". In addition, let the microactuator corresponding to the magnetic head determined by the magnetic head ID = "H3" be the microactuator MA2, and the corresponding vibration level = "M". Furthermore, let the microactuator corresponding to the magnetic head determined by the magnetic head ID = "H18" be the microactuator MA1, and the corresponding vibration level = "L".

[0141] Fig.11 This is an explanatory diagram of an example of switching of the MA amplifier according to the third embodiment.

[0142] Fig.11 (A) shows the switching order of the MA amplifier during the conventional sequential access. Fig.11 (B) shows the switching order of the MA amplifiers during the sequential access according to the third embodiment.

[0143] Below, refer again Figure 7 Processing flow chart of .

[0144] In the past, for example, if Fig.11As shown in (A), the data access order is head ID = "H0", MA1, vibration level = "S" → head ID = "H1", MA2, vibration level = "S" → head ID = "H2", MA1, vibration level = "M" → head ID = "H3", MA2, vibration level = "M" → ... → head ID = "H16", MA1, vibration level = "S" → head ID = "H17", MA2, vibration level = "S" → head ID = "H18", MA1, vibration level = "L" → head ID = "H19", MA2, vibration level = "L".

[0145] In this case, as in the first embodiment, the switching of the corresponding microactuators occurs frequently, and after the switching, the MA amplifier with a high vibration level is driven. Thus, further, as shown in FIG. Figure 3 As shown, vibration occurs, and there is a possibility that the time when positioning accuracy deteriorates will increase.

[0146] Therefore, in the third embodiment, the LBA allocation is changed so that when the next microactuator to be turned on is switched in the switching order of the MA amplifier when the seek order is rearranged during sequential access, the head driven by the microactuator with the lowest vibration level among the selectable microactuators is used.

[0147] First, SoC17 refers to Figure 6 The control data table TB1 shown (step S11) is displayed, and it is determined whether the MA amplifier needs to be switched based on the content of the control data table (step S12).

[0148] In the determination of step S12 , when it is not necessary to switch the MA amplifier (step S12 : No), the process ends.

[0149] In the determination of step S12, if it is necessary to switch the MA amplifier (step S12: Yes), the Figure 6 The control data table TB1 shown is displayed (step S13).

[0150] That is, in Fig.11 In the case corresponding to the situation shown in (A), SoC17 refers to the control data table TB2, such as Fig.11 As shown in (B), first, when the microactuator currently in the on state is MA1, the data access order is set to the head ID = "H0", MA1, vibration level = "S" corresponding to the microactuator MA1 → head ID = "H2", MA1, vibration level = "S" → ... → head ID = "H18", MA1, vibration level = "L" → head ID = "H16", MA1, vibration level = "S".

[0151] Next, when access to the magnetic head corresponding to the microactuator MA1 is completed, the SoC 17 selects the microactuator MA2 as the switching target MA amplifier (step S13 ).

[0152] Then, in Fig.11 In the case shown in (B), Figure 5 Similarly to the case of , the switching destination MA amplifier activation process is performed to turn the microactuator MA2 in the OFF state into the ON state (step S14).

[0153] Then, it is determined whether or not a first predetermined time has elapsed since the voltage applied to the microactuator MA2 turned on was increased at the first slew rate (step S15 ).

[0154] In the judgment of step S15, when the first predetermined time has passed, the voltage applied to the microactuator MA2 becomes the predetermined on-state voltage (10V in the above example), and the vibration should also become smaller, so the microactuator of the control object is switched from microactuator MA1 to microactuator MA2 (step S16).

[0155] Moreover, the microactuator currently in the on state is microactuator MA2, and therefore the data access order is set to the head ID = "H17", MA2, vibration level = "S" corresponding to the microactuator MA2 → head ID = "H19", MA2, vibration level = "L" → ... → head ID = "H1", MA2, vibration level = "S".

[0156] Therefore, in the case of the above example, when the microactuator is switched, the magnetic head corresponding to the vibration level "S" becomes the switching target, so the switching time of the microactuator can be shortened, and the positioning accuracy can be improved.

[0157] In parallel with these operations, the switching source MA amplifier is turned off (step S17), and it is determined whether the second predetermined time has passed since the voltage applied to the microactuator MA1 set to the OFF state was dropped at the second slew rate (step S18).

[0158] In the determination of step S18 , when the second predetermined time has not elapsed (step S18 : No), the system enters the standby state.

[0159] When it is determined in step S18 that the second predetermined time has elapsed, the MA amplifier corresponding to the microactuator MA1 is turned off to be in an OFF state, and the process ends.

[0160] According to the above structure, Fig.11In the conventional case shown in (A), the microactuator needs to be switched multiple times. Fig.11 In the third embodiment shown in (B), the microactuator only needs to be switched once, and the influence of switching of the microactuator can be reduced even in sequential access, thereby improving the positioning accuracy of the magnetic head.

[0161] [4] Fourth Embodiment

[0162] In the above, each microactuator and the MA amplifier corresponding to the microactuator are described. Figure 1 As shown, except Figure 1 The actuator arms 22 other than the uppermost actuator arm 22 and the lowermost actuator arm 22 face the magnetic disks 12 in the up-down direction, and therefore, the magnetic head 13 is provided for each magnetic disk 12 .

[0163] Furthermore, in the fourth embodiment, the microactuators 25 corresponding to the pair of upper and lower magnetic heads 13 can be independently controlled and are exclusively turned on.

[0164] Here, the upper and lower pair refers to the first surface (for example, Figure 1 The upper surface of the actuator arm 22 in the embodiment of the present invention is a second surface (in the case of the above example, a second surface) opposite to the first surface in a direction intersecting the recording surface of the magnetic disk 12. Figure 1 The magnetic heads 13 are respectively arranged on the lower surface of the actuator arms 22 in the figure.

[0165] More specifically, the magnetic head 13B is provided on the first surface, and the magnetic head 13A is provided on the second surface.

[0166] In this case, the MA amplifier in the on state of the second MA amplifier 30B that drives the microactuator 25 (= microactuator MA2) corresponding to the magnetic head 13B disposed on the upper surface side of the actuator arm 22 and the first MA amplifier 30A that drives the microactuator 25 (= microactuator MA1) corresponding to the magnetic head 13A disposed on the lower surface side of the actuator arm 22 is set as the MA amplifier of the switching source, and the other MA amplifier is set as the MA amplifier of the switching target.

[0167] Moreover, when switching from the MA amplifier of the switching source to the MA amplifier of the switching target in the off state, it is desirable to set the voltage conversion rate when switching the MA amplifier in the off state to the on state (the conversion rate when rising) and the voltage conversion rate when switching the MA amplifier in the on state to the off state (the conversion rate when falling) to values ​​that avoid the resonant frequency of the corresponding microactuator.

[0168] This makes it possible to suppress the vibration of the microactuator associated with the switching of the MA amplifier, thereby preventing the access performance from being degraded.

[0169] As a result, in the fourth embodiment as well, the influence of vibrations associated with switching of the microactuator can be reduced, thereby improving the positioning accuracy of the magnetic head.

[0170] Furthermore, it is possible to provide a magnetic disk device that can perform high-speed access while suppressing an increase in access time associated with switching of microactuators.

[0171] As described above, according to each embodiment, the influence of vibration accompanying the switching of the microactuator can be reduced, and the positioning accuracy of the magnetic head can be improved.

[0172] Furthermore, it is possible to provide a magnetic disk device that can perform high-speed access while suppressing an increase in access time associated with switching of microactuators.

[0173] In addition, the program executed by the SoC of this embodiment is preliminarily incorporated into a ROM or the like and provided as a computer program product.

[0174] The program executed in the magnetic disk device of the present embodiment may also be configured to be provided as a computer program product by recording a file in an installable or executable form on a computer-readable recording medium such as a USB memory, a semiconductor memory device such as an SSD (Solid State drive), or a DVD (Digital Versatile Disk).

[0175] Furthermore, it is also possible to configure that the program executed in the disk device of the present embodiment is stored on a computer connected to a network such as the Internet, and is provided by downloading via the network. In addition, it is also possible to configure that the program executed in the disk device of the present embodiment is provided or issued via a network such as the Internet.

[0176] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. 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 invention. These embodiments and their variations are included in the scope and spirit of the invention, and are included in the invention described in the claims and the scope of their equivalents.

[0177] For example, by limiting the switching of the microactuator to only when a long-distance seek occurs, the switching frequency of the microactuator can be reduced.

[0178] In the above description, the case of switching two microactuators (MA1, MA2) driven by two different MA amplifiers is described, but three or more (three or more systems) of microactuators driven by three or more different MA amplifiers may be switched.

[0179] In addition, the MA amplifier can be started and closed not only with a certain slope, but also with Figure 5 As shown by the thin dotted line Lstp in FIG. 1 , the output voltage is turned on or off in a step-like manner. In this case, the number of steps (number of stages) and the height of each stage can be appropriately set from the perspective of suppressing vibration.

Claims

1. A magnetic disk device comprising: a first MA amplifier driving a first microactuator, wherein the first microactuator performs positioning of a corresponding magnetic head; a second microactuator for positioning the corresponding magnetic head; a second MA amplifier driving the second microactuator; and A control unit that, when switching from an MA amplifier of a switching source in an on state to an MA amplifier of a switching target in an off state, maintains the MA amplifier of the switching source in an on state, starts the MA amplifier of the switching target, and switches from the MA amplifier of the switching source to the MA amplifier of the switching target after a predetermined time has passed.

2. The magnetic disk device according to claim 1, The predetermined time is set to a time during which the vibration accompanying the switching of the microactuator corresponding to the switching target MA amplifier becomes smaller than a predetermined size.

3. The magnetic disk device according to claim 1, The control unit performs control so that the driving force of the switching destination MA amplifier increases stepwise at a predetermined slew rate or a predetermined ratio.

4. A magnetic disk device comprising: a first MA amplifier driving a first microactuator, wherein the first microactuator performs positioning of a corresponding magnetic head; a second microactuator for positioning the corresponding magnetic head; and a second MA amplifier, which drives the second microactuator, The magnetic head is provided on a first surface of an actuator arm and a second surface opposite to the first surface in a direction intersecting with a recording surface of the magnetic disk. The microactuators corresponding to the pair of magnetic heads corresponding to the actuator arms can be independently controlled and exclusively turned on. The magnetic disk device includes a control unit that sets one of the MA amplifiers corresponding to the pair of magnetic heads and is in an on state as a switching source MA amplifier and sets the other MA amplifier as a switching target MA amplifier, and performs switching from the switching source MA amplifier to the switching target MA amplifier in an off state. The control unit sets a voltage slew rate when the MA amplifier in the OFF state is switched to the ON state and a voltage slew rate when the MA amplifier in the ON state is switched to the OFF state to values ​​avoiding a resonance frequency of a corresponding microactuator.

5. A magnetic disk device comprising: a first MA amplifier driving a first microactuator, wherein the first microactuator performs positioning of a corresponding magnetic head; a second microactuator for positioning the corresponding magnetic head; a second MA amplifier driving the second microactuator; and A control unit, which, when rearranging the seek order of the magnetic heads and switching from the MA amplifier of the switching source in an on state to the MA amplifier of the switching target in an off state according to the rearranged seek order, arranges the magnetic heads using the MA amplifier of the switching source in a sequence-first manner and arranges the magnetic heads using the MA amplifier of the switching target in a sequence-last manner in the rearrangement.

6. The magnetic disk device according to claim 1, Logical addresses are allocated in advance so that the heads driven by the same MA amplifier can access them continuously during sequential access.

7. The magnetic disk device according to claim 4, Logical addresses are allocated in advance so that the heads driven by the same MA amplifier can access them continuously during sequential access.

8. The magnetic disk device according to claim 1, The vibration level when switching to the micro-actuator is divided into a plurality of levels in advance, The control unit selects a MA amplifier belonging to a class with the least vibration as a MA amplifier selectable as a switching target MA amplifier when switching the MA amplifier.

9. The magnetic disk device according to claim 4, The vibration level when switching to the micro-actuator is divided into a plurality of levels in advance, The control unit selects a MA amplifier belonging to a class with the least vibration as a MA amplifier selectable as a switching target MA amplifier when switching the MA amplifier.

10. The magnetic disk device according to claim 1, The control unit switches the MA amplifier when a long seek of a predetermined distance or more occurs.

11. The magnetic disk device according to claim 4, The control unit switches the MA amplifier when a long seek of a predetermined distance or more occurs.

12. A control method for a magnetic disk device, the magnetic disk device comprising a plurality of sets of micro-actuators for positioning a magnetic head and corresponding MA amplifiers, the control method comprising: When switching from the MA amplifier of the switching source in the on state to the MA amplifier of the switching target in the off state, the step of maintaining the MA amplifier of the switching source in the on state; The step of maintaining the MA amplifier of the switching source in an on state and starting the MA amplifier of the switching target at a predetermined conversion rate; and The step of switching from the switching source MA amplifier to the switching target MA amplifier after a predetermined time has passed, wherein the predetermined time is a time when vibration accompanying the switching of the microactuator corresponding to the switching target MA amplifier becomes smaller than a predetermined size.

13. The control method of the magnetic disk device according to claim 12, Logical addresses are allocated in advance so that the heads driven by the same MA amplifier can access them continuously during sequential access.

14. The control method of the magnetic disk device according to claim 12, The vibration level when switching to the micro-actuator is divided into a plurality of levels in advance, At the time of switching of the MA amplifier, the MA amplifier belonging to the class with the least vibration is selected as the MA amplifier that can be selected as the switching target MA amplifier.

15. The control method of the magnetic disk device according to claim 12, The MA amplifier is switched when a long seek distance exceeding a predetermined distance occurs.

16. A method for controlling a magnetic disk device, The magnetic disk device comprises: a first MA amplifier for driving a first microactuator for positioning a corresponding magnetic head, a second microactuator for positioning a corresponding magnetic head, and a second MA amplifier for driving the second microactuator. The control method comprises: When the seek sequence of the magnetic head is rearranged, In the rearrangement, the magnetic heads using the switching source MA amplifier are arranged in a sequentially preceding manner, and the magnetic heads using the switching destination MA amplifier are arranged in a sequentially following manner, According to the rearranged seek order, the switching source MA amplifier in the on state is switched to the switching target MA amplifier in the off state.

17. A computer program product capable of being executed in a computer, having a computer-readable recording medium including a plurality of commands for controlling a magnetic disk device, The magnetic disk device comprises: a first MA amplifier for driving a first microactuator for positioning a corresponding magnetic head, a second microactuator for positioning a corresponding magnetic head, and a second MA amplifier for driving the second microactuator. The plurality of commands cause the computer to execute: When switching from the switching source MA amplifier in the on state to the switching target MA amplifier in the off state, the switching source MA amplifier is maintained in the on state, The MA amplifier of the switching source is maintained in an on state, and the MA amplifier of the switching target is started at a predetermined conversion rate, The switching source MA amplifier is switched to the target MA amplifier after a predetermined time has passed, wherein the predetermined time is a time when vibration accompanying the switching of the microactuator corresponding to the target MA amplifier becomes smaller than a predetermined size.

18. A computer program product capable of being executed in a computer, having a computer-readable recording medium including a plurality of commands for controlling a magnetic disk device, The magnetic disk device comprises: a first MA amplifier for driving a first microactuator for positioning a corresponding magnetic head, a second microactuator for positioning a corresponding magnetic head, and a second MA amplifier for driving the second microactuator. The plurality of commands cause the computer to execute: When the seek sequence of the magnetic head is rearranged, In the rearrangement, the heads using the MA amplifiers of the switching sources are arranged in a sequentially preceding manner, Arrange the heads of the MA amplifiers that use the switching targets in order, According to the rearranged seek order, the switching source MA amplifier in the on state is switched to the switching target MA amplifier in the off state.

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