JP2009093756A - Disk driving device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate handling of a control area more and to efficiently adjust the data format of a user area in a HDD where the data track pitch and the servo track pitch of the user area are different. <P>SOLUTION: According to an embodiment of the present invention, the servo and data track pitches of user areas 115a and 115b are different. The data track pitch is adjusted according to characteristics of a head slider and a recording surface. The recording surface includes, in addition to a user area for storing user data, a control area 116 for storing firmware or parameters. The position of the control area on the recording surface is defined by servo data. Thus, handling of the control area is facilitated more, and the data format of the user area is efficiently adjusted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a disk drive device and a method of manufacturing the disk drive device, and more particularly to a disk drive device having a different data track pitch and servo track pitch on a recording surface and a method of manufacturing the same.

  As a disk drive device, a device that uses media of various modes such as an optical disk, a magneto-optical disk, or a flexible magnetic disk is known. Among them, a hard disk drive (HDD) is a storage device of a computer. As one of the storage devices indispensable in the present computer system, it is widely used. Furthermore, applications of HDDs such as moving image recording / playback apparatuses, car navigation systems, and mobile phones are expanding more and more due to their excellent characteristics.

  A magnetic disk used in an HDD has a plurality of data tracks and servo tracks formed concentrically. Each servo track is composed of a plurality of servo data having address information. Each data track is recorded with a plurality of data sectors including user data. Data sectors are recorded between servo data spaced apart in the circumferential direction. The head element part of the head slider supported by the oscillating actuator accesses the desired data sector according to the servo data address information, thereby writing data to the data sector and reading data from the data sector. It can be performed.

In order to increase the storage capacity of the HDD or to improve the reliability of the HDD, it has been proposed to determine the data track pitch for each head (for each recording surface) (see, for example, Patent Document 1). ). By determining the data track pitch according to the head characteristics such as the read width and write width, the influence on adjacent data tracks in data writing (Adjacent Track Interference: ATI) is suppressed, and the recording area per recording surface Data capacity can be increased. Alternatively, Patent Document 2 discloses writing servo data at a constant servo track pitch and changing the data track pitch in accordance with the zone.
JP 2006-114142 A Japanese Patent Laying-Open No. 2005-71433

  On the recording surface of the magnetic disk, there is a control area for storing control data such as microcode (firmware) and parameters for operating the HDD, in addition to a user area for storing user data. Typically, only control data is recorded in the control area, and no user data is recorded. Therefore, the host can access the user area by designating an address, but does not designate and access the address in the control area, and the HDD accesses the control area in its internal operation.

  As described above, in an HDD in which the servo track pitch and data track pitch in the user area are different, the HDD uses an LBA (Logical Block Address) designated by the command and data designating the target data sector. • Convert to address, and then convert the data address to servo address. The data address specifies a data cylinder, a head slider, and a data sector. A data cylinder is a group of data tracks having the same data track number on each recording surface. The servo address specifies a servo cylinder, a head slider, a servo sector, and a data sector position within the servo sector.

  In such an HDD, the definition method of the control area greatly affects the flexibility of the microcode, the HDD manufacturing process, and the data format. For example, when the position of the control area is defined by the data address, the position of the control area cannot be determined until the data track pitch is determined, and the manufacturing process becomes complicated. Alternatively, since the data track pitch differs for each head slider (recording surface), it is necessary to change the handling of the control area for each head slider. On the other hand, when the control area is defined by a data address, once the physical position on the recording surface of the control area is determined, the data track pitch cannot be changed thereafter. That is, if the position of the control area is determined first, the data format of the user area cannot be freely adjusted.

  Therefore, in the HDD in which the data track pitch of the user area and the servo track pitch are different, the handling of the control area is made easier and the data format of the user area is adjusted efficiently. A technique that can be used is required.

  A disk drive device according to an aspect of the present invention includes a control area in which control data is recorded on a recording surface of a disk, and a servo track pitch and a data track pitch on the recording surface are different from each other. A user area in which data is recorded; a head that accesses the recording surface; a moving mechanism that moves the head on the recording surface; and a controller that controls the moving mechanism and the head. The controller performs necessary address correction of the target at the servo address level so that the control area defined by the servo address is skipped when accessing the target in the user area specified by the command. Do. By defining the control area with the servo address, it is easier to handle the control area in the disk drive device in which the data track pitch and servo track pitch of the user area are different. • The data format of the area can be adjusted efficiently.

  Preferably, the controller converts the designated address of the command designating the target into a temporary servo address, and skips the control area in accordance with the value of the temporary servo address. • Make the necessary corrections to the address and determine the actual servo address of the target. As a result, the actual servo address can be determined efficiently and accurately.

  Preferably, the servo address of the user area monotonously increases from the inner circumference side or the outer circumference side, and the controller has a smaller address order than the temporary servo address in correcting the temporary servo address. The number of servo tracks in the control area is added to the temporary servo address. As a result, the actual servo address can be determined efficiently and accurately.

  In a preferred example, the recording surface has only one control area, and the control area exists in a central area obtained by dividing the recording surface into three equal parts in the radial direction. Furthermore, when the track of the temporary servo address is smaller than the minimum servo track of the control area, the controller determines the temporary servo address as the actual servo address, and sets the temporary servo address. If the address track is equal to or greater than the minimum servo track, the actual servo address is determined by adding the number of servo tracks in the control area to the temporary servo address. As a result, the access to the control area can be made efficient, and the actual servo address can be determined efficiently and accurately.

  In the control area, the data track pitch is preferably equal to or greater than the servo track pitch. Thereby, the safety | security of control data can be improved. Alternatively, the disk drive device preferably has a plurality of recording surfaces, and the servo addresses at the control area ends of the plurality of recording surfaces coincide with each other. Control area handling can be unified between recording surfaces.

  Preferably, the controller determines a data address from an address designated by the command, and determines the temporary servo address from the data address using a preset mathematical expression. As a result, the data track pitch can be finely adjusted, and the actual servo address can be determined efficiently and accurately.

  Another aspect of the present invention is a method for manufacturing a disk drive device. In this manufacturing method, a disk, a head, and a moving mechanism of the head are mounted on a housing. Servo data is written on the recording surface of the disk. On the recording surface on which the servo data is recorded, the control data is recorded by the head in a control area defined by a servo address. On the recording surface on which the control data is recorded, the format of the user area is determined by measurement using the head. Since the control area is defined by the servo address, the format of the user area can be adjusted efficiently.

  Preferably, in the determination of the format of the user area, the control data is updated in the control area whose position is fixed as the process proceeds. Since the control area is fixed in position and only the control data is updated in adjusting the format of the user area, the processing can be performed efficiently.

  Preferably, in the determination of the format of the user area, when a preset criterion is not satisfied, it is determined to change the grade of the disk drive device, and the user ID is changed according to the changed grade. The format of the area is determined, and the control data is updated in the control area whose position is fixed. Thereby, the yield of a product can be improved.

  Preferably, in determining the format of the user area, the recording frequency of the plurality of heads is adjusted so that the error rate is averaged. Thereby, the reliability of the disk drive device can be improved.

  According to the present invention, in a disk drive device in which the data track pitch and servo track pitch of the user area are different, the handling of the control area is made easier and the data format of the user area Can be adjusted efficiently.

  Hereinafter, embodiments to which the present invention can be applied will be described. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, in each drawing, the same code | symbol is attached | subjected to the same element and the duplication description is abbreviate | omitted as needed. In the following, a hard disk drive (HDD) that is an example of a disk drive device will be described.

  In the HDD of this embodiment, the servo track pitch and data track pitch in the user area are different. The data track pitch is adjusted according to the characteristics of the head slider and the recording surface. Adjacent Track Interference (ATI) is suppressed by determining the data track pitch according to the characteristics of the head slider, such as the read width and write width, and the characteristics of the magnetic disk. In addition, the data capacity per recording surface can be increased.

  The recording surface has a control area for storing microcode (firmware), parameters and the like in addition to a user area for storing user data. As a characteristic point of this embodiment, the position of the control area on the recording surface is defined by servo data. As a result, handling of the control area can be made easier and the data format of the user area can be adjusted efficiently.

  Before describing the feature points of the present embodiment, first, the overall configuration of the HDD will be described. FIG. 1 is a block diagram schematically showing the overall configuration of the HDD 1. The HDD 1 includes a circuit board 20 that is fixed to the outside of the enclosure 10. On the circuit board 20, a read / write channel (RW channel) 21, a motor driver unit 22, a hard disk controller (HDC) and an MPU integrated circuit (HDC / MPU) 23, a semiconductor memory RAM 24, etc. It has a circuit. Within the enclosure 10, a spindle motor (SPM) 14 rotates the magnetic disk 11 at a predetermined angular velocity. The magnetic disk 11 is a disk for storing data. The motor driver unit 22 drives the SPM 14 according to control data from the HDC / MPU 23.

  Each head slider 12 includes a slider that floats on the magnetic disk, and a head element unit that is fixed to the slider and converts between a magnetic signal and an electric signal. The head slider 12 is an example of a head. An arm electronic circuit (AE: Arm Electronics) 13 selects a head slider 12 that accesses (reads or writes) the magnetic disk 11 from a plurality of head sliders 12 according to control data from the HDC / MPU 23, and Amplifies the write signal. Each head slider 12 is fixed to the tip of the actuator 16. The actuator 16 is connected to a voice coil motor (VCM) 15, and moves in the radial direction on the magnetic disk 11 that rotates the head slider 12 by rotating about a rotation axis. The assembly of the actuator 16 and the VCM is a head moving mechanism. The motor driver unit 22 drives the VCM 15 according to control data from the HDC / MPU 23.

  In the read process, the RW channel 21 extracts servo data and user data from the read signal acquired from the AE 13 and performs a decoding process. The decoded data is supplied to the HDC / MPU 23. In the write process, the RW channel 21 code-modulates the write data supplied from the HDC / MPU 23, converts the code-modulated data into a write signal, and supplies the write signal to the AE 13. In the HDC / MPU 23, the HDC is a logic circuit, and the MPU operates according to the microcode loaded in the RAM 24. The HDC / MPU 23 is an example of a controller, and performs overall control of the HDD 1 in addition to necessary processing relating to data processing such as head positioning control, interface control, and defect management.

  2A schematically shows the data structure of the entire recording surface of the magnetic disk 11, and FIG. 2B schematically shows a part of the data format on the recording surface. On the recording surface of the magnetic disk 11, a plurality of servo areas 111 extending radially from the center of the magnetic disk 11 and spaced apart from each other by a predetermined angle, and between two adjacent servo areas 111. A data area 112 is formed. Servo data for controlling the positioning of the head slider 12 is recorded in each servo area 111. In each data area 112, user data and data used for controlling the HDD 1 are recorded.

  On the recording surface of the magnetic disk 11, a plurality of data tracks (DTr) 114 having a predetermined width in the radial direction and formed concentrically are formed. User data is recorded along data track 114. One data track 114 has a data sector which is a recording unit of user data, and is typically composed of a plurality of data sectors. Typically, each of the plurality of data tracks is grouped into a plurality of zones 113 a to 113 c according to the radial position of the magnetic disk 11. TPI (Track Per Inch) and BPI (Bit Per Inch) are set in each zone. TPI corresponds to the data track pitch, and BPI corresponds to the recording frequency.

  Similarly, the magnetic disk 11 includes a plurality of servo tracks (STr) 115 having a predetermined width in the radial direction and formed concentrically. Each servo track 115 is composed of a plurality of servo data separated in the data area 112. The servo data includes a servo track number, a servo sector number in the servo track, and a burst pattern for fine position control. The burst pattern is composed of, for example, four burst patterns A, B, C, and D having different radial positions. The position in the servo track can be determined by the amplitude of the reproduction signal of each burst pattern. The position in the servo track can be expressed by what is called a PES (Position Error Signal) value. The PES is calculated from the amplitude values of the burst patterns A, B, C, and D. For example, one servo track is divided into 256 PES values in the radial direction.

  As shown in FIG. 2B, in this embodiment, the servo track pitch of the user area and the data track pitch do not coincide on one recording surface. The data track pitch is individually set according to the characteristics of each head slider 12. By determining the data track pitch for each head slider 12, the optimum data track pitch according to the characteristics of the head slider 12 is determined, and the influence on the adjacent data track in data writing is reduced. In addition, the storage capacity (number of data tracks) can be increased.

  Hereinafter, handling of the control area in the process (read or write) corresponding to the command from the control area and the host 51 of this embodiment will be described. As shown in FIG. 3A, the recording surface of the magnetic disk 11 includes user areas 115 a and 115 b and a control area 116. The user area 115a stores user data from the host 51 in units of data sectors. The control area 116 stores data used by the HDC / MPU 23 for controlling the HDD 1. Specifically, the microcode that the MPU operates according to, a defect table in which defects on the magnetic disk 11 are registered, a zone table having information about each zone 113a to 113c, channel parameters of the RW channel 21, Other data necessary for the operation of the HDD 1 is stored in the control area 116.

  As shown in FIG. 3A, the control area 116 is preferably arranged in the central area of the data area. Specifically, an area where data on the recording surface is stored is divided into three equal parts in the radial direction, and the control area 116 is arranged in the central area. Alternatively, the control area 116 is secured in a zone including the center position in the radial direction within the area where data is stored. As a result, the control area 116 can be accessed most quickly on average regardless of the position of the head slider 12 on the recording surface. Preferably, one recording surface has only one control area 116. That is, the control area is not divided and formed at spaced positions on the recording surface, but only one continuous control area 116 exists on one recording surface. Thereby, on the recording surface where the data track pitch and servo track pitch of the user area are different, access to the control data can be simplified, and a reduction in data capacity can be suppressed.

  In this embodiment, the position of the control area 116 is defined by a servo address. That is, the start position and end position of the control area 116 or the inner peripheral edge and the outer peripheral edge are designated by the servo address. In the example of FIG. 3B, the start servo track of the control area 116 is STr_s, and the end servo track is STr_t. Further, in the present embodiment, data in the control area 116 is designated by a servo address. When the data in the control area 116 is read / written, the HDC / MPU 23 accesses the address position directly designated by the servo address. The servo address includes a servo cylinder number (C), a head slider number (H), and a servo sector number (S, and further indicates the order of data sectors between the servo sectors. This servo address is also called a servo CHS In a typical example, the servo track number monotonously increases from the outer periphery side, and this example is assumed in the following description.

  Preferably, the data track pitch in the control area 116 is an integral multiple of the servo track pitch, more preferably twice or more. The data track center preferably coincides with the servo track center (position of PES 128). By forming a data track with a servo track pitch or more, it is possible to reduce the possibility of important control data being erased or a read-hard error of the control data. From the viewpoint of data safety, it is preferable to record one data track on a plurality of servo tracks such as one servo track.

  As shown in FIG. 3B, preferably, guard bands 117a and 117b exist between the control area 116 and the user areas 115a and 115b. It is preferable that a guard band wider than one servo track, that is, a band in which no data is recorded in the data area, exists between the control area 116 and the user areas 115a and 115b. Thereby, the safety | security of control data can be improved more.

  When the HDD 1 has a plurality of recording surfaces, it is preferable to define the position of the control area 116 with the same servo address on all the recording surfaces. That is, in all the control areas 116, it is preferable that the servo tracks at the inner peripheral end and the outer peripheral end coincide. Thereby, each control area 116 can be handled uniformly, and the control processing of HDC / MPU 23 can be simplified.

  In the access to the user areas 115a and 115b, the HDC / MPU 23 converts the designated address by the command. The command from the host 51 specifies an access destination target by an LBA (Logical Block Address). Specifically, the command specifies the LBA of the start data sector and the number of data sectors. LBA is represented by a continuously increasing number. As shown in FIG. 4, in the read / write, the HDC / MPU 23 converts this LBA into a data address, and further converts the data address into a servo address. The data address indicates a data cylinder number (C), a head slider number (H), and a data sector number (S). Therefore, in this specification, this data address is also referred to as data CHS. In a typical example, the data track number increases monotonically from the outer peripheral side. In the following description, this example is assumed.

  The HDC / MPU 23 performs defect management and zone format definition using data addresses. On the other hand, in reading / writing user data, the HDC / MPU 23 uses the servo address to access the target (data reading or data writing). This is because the HDC / MPU 23 controls the actuator 16 and the head slider 12 by servo control using servo data.

  In order for the HDC / MPU 23 to access the user areas 115a and 115b accurately, the HDC / MPU 23 needs to avoid the control area 116 in reading / writing. Since the position of the control area 116 in this embodiment is defined by a servo address, the HDC / MPU 23 preferably performs the processing at the servo address level. As shown in the block diagram of FIG. 4, the HDC / MPU 23 of this embodiment converts the LBA designated by the command into a servo address, and corrects the servo address according to the address position of the converted servo address. . Thereby, it is possible to accurately access the position specified by the command.

  The access processing to the user areas 115a and 115b will be described more specifically with reference to the block diagram of FIG. 4 and the flowchart of FIG. The host 51 issues a read command or a write command 511. The command 511 designates the command type, the target start address, and the number of data sectors by LBA. The HDC / MPU 23 acquires the command (S11), and converts the designated LBA of the command 511 into the data address 231 (S12).

  Specifically, the HDC / MPU 23 refers to the zone table 241 and generates a data address 231 from the designated LBA. The zone table 241 has control information such as the start data track number of each zone and the number of data tracks of that zone. The zone table 241 is stored in the control area 116 and is stored in the RAM 241 during the operation of the HDD 1.

  The HDC / MPU 23 temporarily converts the data address 231 into a temporary servo address 232 (S13). Specifically, the HDC / MPU 23 calculates the function value of the data address 231 by calculation. During this time, the numerical value is the temporary servo address 232. The function formula f (x) is appropriately selected according to the design, and is preferably a cubic function or a function having a higher order.

  The HDC / MPU 23 performs necessary correction so as to skip the control area 116 according to the calculated value of the temporary servo address 231. Specifically, the HDC / MPU 23 acquires data 242 indicating the start servo track number and the number of servo tracks in the control area 116 (S14). These data are stored in the control area 116 and are stored in the internal memory of the HDC / MPU 23 during the operation of the HDD 1. The HDC / MPU 23 compares the information in the control area 116 with the temporary servo address 231 to identify the positional relationship between the temporary servo address 231 and the control area 116.

  When the servo track number of the temporary servo address 231 is smaller than the start servo track number of the control area 116 (when the target is on the outer peripheral side of the control area 11) (Y in S15), the HDC / MPU 23 The temporary servo address 232 is determined as the actual servo address of the target (S17). That is, the HDC / MPU 23 accesses the servo address designation destination directly converted from the data address without correcting the servo address.

  When the servo track number of the temporary servo address 231 is greater than or equal to the start servo track number of the control area 116 (when the target is in the control area 11 or on the inner periphery side thereof) (N in S15), HDC The / MPU 23 corrects the temporary servo address 231 (S16). The HDC / MPU 23 determines the corrected servo address 233 obtained by the correction as the actual servo address of the target (S17), and accesses the destination specified by the corrected servo address 233. The HDC / MPU 23 corrects the temporary servo address 232 by adding the number of servo tracks in the control area 11 to the temporary servo address.

  With the above processing, the HDC / MPU 23 can accurately and efficiently perform address conversion so as to skip the control area 116 defined by the servo address, and can accurately access the command-specified data sector. . In the above example, the recording surface has only one control area 116, but the address conversion can also be applied to the case where the recording surface has a plurality of control areas. In this case, the HDC / MPU 23 performs correction for adding the number of servo tracks in all control areas having a start servo track before the servo address of the target to the temporary servo address. The actual servo address can be calculated.

  Next, a manufacturing process of the HDD 1 of this embodiment will be described with reference to the flowchart of FIG. The HDD 1 is manufactured by mounting the SPM 14, the magnetic disk 11, the actuator 16 and the head slider 12 assembly and the VCM 15 in the enclosure 10 to manufacture an HDA (Head Dick Assembly) (S20). Thereafter, servo data is written on each recording surface by each head slider 12 (S21).

  As this servo write process, there is a method of using a servo track writer (STW) as an external device, or a method of writing servo data by controlling the VCM 15 of the HDD 1 (self-servo write: SSW). . The STW has a pin, and the actuator 16 is moved from the outside by the pin, thereby positioning the actuator 16 at the target position. In the SSW, an external control device controls the VCM 16 to position the actuator 16 at the target position. The servo track pitch is not constant and changes according to the radial position. By such servo writing, servo tracks are written at the same radial position on each recording surface. The present invention can also be applied to a manufacturing method for writing servo data before mounting the magnetic disk 11 in the enclosure 10 and the HDD 1 manufactured thereby. Further, a circuit in which the servo write is mounted on the HDD 1 may be executed.

  After the servo data is written on the recording surface, the control circuit board 20 is mounted on the HDA, and the HDC / MPU 23 executes an operation test and a defect detection test (S22). It should be noted that an external test apparatus can perform the steps after step S22. In the HDD 1 that has passed the test, the HDC / MPU 23 writes control data in the control area 116 of each recording surface. The control data to be written is a microcode, a defect table, a channel parameter or the like. Servo data is recorded on the recording surface. Further, since the control area 116 is defined by a servo address, the control area 116 can be defined on each recording surface, and control data can be recorded in that area.

  Next, a process for adjusting the data format of the user areas 115a and 115b is performed (S24). The main control data to be adjusted are parameters such as TPI, BPI, and data track number for each zone. The format adjustment of the user area will be described in detail later. When the HDC / MPU 23 adjusts the format of the user area, the HDC / MPU 23 updates the corresponding data in the control area 116 (S25). The data to be updated includes data in the zone table 241 and a coefficient of a function for calculating a servo address from the data address. If the adjusted data format satisfies the preset criteria, the data format adjustment processing ends (S29).

  If the data format of the user area does not satisfy the criteria matching the planned grade, the HDC / MPU 23 determines to lower the grade of the HDD 1 (S27). The grade of the HDD 1 is represented by the capacity of the HDD 1 or reliability (for example, guaranteed error rate). When the grade of the HDD 1 is changed from the planned grade, the HDC / MPU 23 updates the control data in the control area 116 (S28) and readjusts the data format of the user areas 115a and 115b (S24). The criteria are typically defined by storage capacity, error rate, and the like.

  Since the position of the control area 116 is defined by the servo address, even if the data track pitch in the data format changes, it is not necessary to change the position. Thus, since the position of the control area 116 is fixed and only the control data in the control area 116 is updated, the data format of the user areas 115a and 115b can be adjusted efficiently. When starting the data format adjustment of the user areas 115a and 115b (S24), the HDC / MPU 23 repeats the subsequent steps described above.

  The HDC / MPU 23 determines that the HDD 1 is failed when the adjusted data format does not satisfy the lowest criteria. The HDD 1 is subjected to rework processing. Further, the HDC / MPU 23 may change the grade so as to raise the grade of the HDD 1 in accordance with the format adjustment result. As described above, according to the control area defining method of the present embodiment, it is possible to efficiently change the grade in manufacturing the HDD 1, and to greatly improve the manufacturing yield of the HDD 1.

  The data format adjustment of the user areas 115a and 115b will be described. The TPI and BPI of the user area are set to appropriate values depending on the characteristics of the head slider 12 and the corresponding recording surface. Typically, the HDC / MPU 23 selects a plurality of points in the user areas 115a and 115b and performs a predetermined measurement at each point. Based on the measurement result, the HDC / MPU 23 determines an appropriate TPI for each point. The TPI is determined based on the write width, the measured SER, and the like. Note that the TPI determination method is a known technique, and detailed description thereof is omitted. The HDC / MPU 23 calculates a data track pitch curve that varies depending on the radial position from each data track pitch determined by measurement.

  This curve is an approximate curve of the measured value, and the measured value is not necessarily on the curve. The HDC / MPU 23 calculates an approximate curve representing the data track pitch for each recording surface (head slider 12). The HDC / MPU 23 can determine an approximate line by adjusting a coefficient of a preset function. The HDC / MPU 23 can specify the servo address on the recording surface using the integral of the approximate curve of the determined data track pitch from the specified address of the command from the host 51. The HDC / MPU 23 can also determine the data track pitch so as to interpolate between the measured values. Thereby, an appropriate data track pitch can be determined according to the radial position.

  Since the data track pitch is different for each head slider 12, the total number of data tracks on the recording surface is also different for each head slider 12. The servo track pitch is substantially the same on all recording surfaces. The HDD 1 has a data track for each head slider 12 in accordance with the head characteristics such as the write width (the radial width of the write element) and the read width (the radial width of the read element) of each head slider 12. Determine the pitch. The data track pitch is not constant and changes according to the radial position.

  The HDC / MPU 23 determines the BPI according to the determined TPI. Typically, the HDC / MPU 23 determines the BPI for each of the zones 113a to 113c. Within one zone, the BPI is constant. The HDC / MPU 23 determines the TPI level of each of the zones 113a to 113c with reference to a preset standard, and further selects a BPI level corresponding to the TPI level. Each BPI level is associated with a specific BPI value. For example, there are 10 TPI and BPI levels, and one TPI level and one BPI level are associated with each other.

  When a TPI is determined by measurement and a BPI associated with the TPI is selected in advance, it is considered that the error rate varies due to the characteristics of the head slider 12. The HDD 1 as a whole preferably has a small variation in the relay rate between the head slider 12. As a result, the occurrence of errors in the HDD 1 can be reduced, and the number of HDDs 1 that are failed can be reduced to improve the yield. On the other hand, since the data capacity of the HDD 1 is determined, the error rate cannot simply be improved by lowering the BPI of the head slider 12 having a large error rate.

  The HDC / MPU 23 of this embodiment averages the error rate variation among the head sliders 12 by adjusting the BPI of the plurality of head sliders 12. The HDC / MPU 23 compares the error rates of the head sliders 12 to reduce the BPI of the head slider 12 having a large error rate and to increase the BPI of the head slider having a low error rate. As a result, variations in the error rate of each head slider 12 are reduced, and a decrease in the data capacity of the entire HDD 1 can be suppressed.

  Specifically, the HDC / MPU 23 readjusts the BPI for each zone. The minimum error rate of the head slider 12 is set in advance. The HDC / MPU 23 adjusts the BPI so that each head slider 12 satisfies this criterion. If this criterion cannot be satisfied, the HDC / MPU 23 determines the grade change or rework of the HDD 1.

  An example of the two head sliders 12 will be described with reference to FIG. In FIG. 7, the value of BPI is the largest at BPI 0 and monotonously decreases to BPI 9. Each number in the table indicates a multiplier of the error rate. The smaller the number (the larger the absolute value), the smaller the error. In this example, the BPI previously associated with the TPI determined by the HDC / MPU 23 from the measurement result is BPI3 and BPI7 for HEAD0 and HEAD1, respectively.

If the minimum error rate as a criterion is 10 ^−5.5 , HEAD0 does not satisfy the criteria, and HEAD1 satisfies the criteria. In order for HEAD0 to satisfy this criterion, it is necessary to select BPI6. For HEAD1, a BPI level of BPI3 or higher satisfies the criteria. For example, the HDC / MPU 23 selects BPI6 for HEAD0 and BPI4 for HEAD1. As a result, the error rate criteria for both head sliders 12 are satisfied, and the error rates are averaged. Furthermore, the HDC / MPU 23 increases the BPI of HEAD1 while decreasing the BPI of HEAD0. Therefore, a decrease in the data capacity of the entire HDD 1 can be suppressed.

  In actual BPI adjustment, the HDC / MPU 23 does not need to measure the error rate at all BPI levels. The HDC / MPU 23 sequentially increases the BPI level of HEAD 1 and measures the error rate of each BPI level. Further, the HDC / MPU 23 sequentially decreases the BPI level of HEAD0 and measures the error rate of each BPI level. Although the above example has two heads, the BPI can be similarly adjusted when three or more head sliders are provided. Also, BPI adjustment can be performed for some of the head sliders.

  Although the present invention has been described using preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Of course. For example, in the above-described embodiment, the HDD has been described as an example. However, the present invention can be applied to a disk drive device that uses another disk such as an optical disk or a magneto-optical disk. The present invention can be applied not only to HDDs having a common servo track pitch between recording surfaces but also to HDDs having different servo track pitches and their rate of change for each recording surface.

1 is a block diagram schematically showing an overall configuration of a hard disk drive according to an embodiment. In this Embodiment, it is a figure which shows typically the data format on a recording surface. In this Embodiment, it is a figure which shows typically the control area on a recording surface. In this Embodiment, it is a block diagram which shows the functional component which performs the process which converts the address which a command designates. 4 is a flowchart showing processing for converting an address designated by a command in the present embodiment. 4 is a flowchart showing a manufacturing process of an HDD in the present embodiment. In this Embodiment, it is a figure which shows an example of the method of adjusting BPI after TPI determination.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hard disk drive, 10 Enclosure, 11 Magnetic disk 12 Head slider, 13 Arm electronics, 14 Spindle motor 15 Voice coil motor, 16 Actuator, 20 Circuit board 21 RW channel, 22 Motor driver unit 23 Hard disk・ Controller / MPU, 24 RAM
111 Servo area, 112 Data area, 113a to 113c Zone 115a, 115b User area, 116 Control area 117a, 117b Guard band, 231 Data address 232 Temporary servo address, 233 Correction servo address 241 Zone table, 242 Control area information

Claims (11)

On the recording surface of the disc, a control area where control data is recorded,
On the recording surface, the servo track pitch and the data track pitch are different, and a user area in which user data is recorded, and
A head for accessing the recording surface;
A moving mechanism for moving the head on the recording surface;
The target at the servo address level is controlled so as to skip the control area defined by the servo address when accessing the target in the user area that controls the moving mechanism and the head and is specified by a command. A controller that performs the necessary address correction,
A disk drive device. The controller converts the designated address of the command for designating the target into a temporary servo address, and sets the temporary servo address to skip the control area according to the value of the temporary servo address. Make the necessary corrections and determine the actual servo address of the target,
The disk drive device according to claim 1. The servo address of the user area increases monotonously from the inner circumference side or the outer circumference side,
In the correction of the temporary servo address, the controller adds the number of servo tracks in the control area having an address order smaller than the temporary servo address to the temporary servo address.
The disk drive device according to claim 2. The recording surface has only one control area, and the control area exists in a central area obtained by dividing the recording surface into three equal parts in the radial direction,
When the track of the temporary servo address is smaller than the minimum servo track of the control area, the controller determines the temporary servo address as the actual servo address, and sets the temporary servo address. If the track is equal to or greater than the minimum servo track, the actual servo address is determined by adding the number of servo tracks in the control area to the temporary servo address.
The disk drive device according to claim 3. Within the control area, the data track pitch is greater than or equal to the servo track pitch.
The disk drive device according to claim 1. The disk drive device has a plurality of recording surfaces,
Servo addresses at the end of each control area of the plurality of recording surfaces match,
The disk drive device according to claim 1. The controller determines a data address from an address specified by the command, and determines the temporary servo address from the data address using a preset mathematical formula.
The disk drive device according to claim 1. A disk, a head, and a moving mechanism of the head are mounted on a housing,
Write servo data on the recording surface of the disk,
On the recording surface on which the servo data is recorded, the control data is recorded by the head in a control area defined by a servo address,
On the recording surface on which the control data is recorded, the format of the user area is determined by measurement using the head.
A method of manufacturing a disk drive device. In the determination of the format of the user area, the control data is updated in the control area that is fixed in position as the process proceeds.
9. A method of manufacturing a disk drive device according to claim 8. In the determination of the format of the user area, if preset criteria are not satisfied, it is determined to change the grade of the disk drive device,
Determine the format of the user area according to the changed grade, and update the control data in the fixed control area.
9. A method of manufacturing a disk drive device according to claim 8. Adjusting the recording frequency of the plurality of heads so that the error rate is averaged in determining the format of the user area;
9. A method of manufacturing a disk drive device according to claim 8.

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