Abstract:
An apparatus can include a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/017,657 filed on Jan. 22, 2008 which claims the priority of Korean Patent Application No. 10-2007-0007605, filed on 24 Jan. 2007, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present general inventive concept relates to a hard disk drive apparatus, a method to compensate repeatable run out of a hard disk drive apparatus, and a computer-readable recording media recording the method, and more particularly, to a hard disk drive apparatus which can adaptively operate an RRO compensator according to a seeking path of a magnetic head and accordingly improve the servo control and track mis-registration (TMR) performances, a method to compensate RRO of a hard disk drive apparatus, and a computer-readable recording media recording the method. 
         [0004]    2. Description of the Related Art 
         [0005]    Hard disk drive apparatuses (HDDs) are one of memory devices formed of electronic parts and mechanical parts and recording and reproducing data by converting digital electric pulses to a magnetic field that is more permanent. The HDDs are widely used as auxiliary memory devices of computer systems because of fast access time for a large amount of data. 
         [0006]    With the recent development in the technology related to the head, the storage density of an HDD has been sharply increased. Accordingly, it becomes more important to maintain a track mis-registration (TMR) performance over an appropriate level without losing stability in recording and reproducing performance of the head. 
         [0007]    Repeatable run out (RRO) and non-repeatable run out (NRRO) are factors that affect the TMR performance. Among them, RRO is mainly generated due to the eccentricity of tracks with respect to the center of a disk or the deformation of a disk. RRO works as a disturbance in servo control to deteriorate the servo control performance of a head. RRO can be divided into RRO components having various frequencies such as  1 x,  2 x,  3 x, . . . , Nx. Here, the unit “x” signifies a frequency corresponding to the rotational speed of a disk. 
         [0008]    Of the RRO components, the  1 x,  2 x, and  3 x RRO components are generated mainly due to the eccentricity of tracks with respect to the disk center and exist throughout the overall area of the disk. The RRO components over  4 x are generated mainly due to the disk deformation and tend to greatly decrease from the inner diameter (ID) area of a disk to the outer diameter (OD) area. 
         [0009]    To compensate RRO, an RRO compensator and a RRO correction code (RCC) are used. In general, the RRO components under a predetermined frequency are compensated using the RRO compensator while the RRO components over the predetermined frequency are compensated using the RRO correction code. For example,  1 x through  6 x RRO components are compensated using the RRO compensator and  7 x or higher RRO components are compensated using the RRO correction code. The RRO compensators are provided in parallel in a number corresponding to the number of RRO components to be compensated. 
         [0010]    However, when the conventional RRO compensator is used, a plurality of RRO compensators provided corresponding to the RRO components under a predetermined frequency are all turned on regardless of a seeking path of a magnetic head. Accordingly, the  4 x or higher RRO components that are greatly decreased in the OD area of the disk are compensated by the RRO compensator without discrimination. As a result, when the magnetic head located in the ID area is set to seek data in a middle diameter (MD) area or the OD area and data recording or reproducing is performed, over-compensation is made to the  4 x or higher RRO components by the RRO compensator. Thus, seek time increases and a position error signal (PES) increases. 
       SUMMARY OF THE INVENTION 
       [0011]    The present general inventive concept provides a hard disk drive apparatus which can adaptively operate an RRO compensator according to a seeking path of a magnetic head so as to improve servo control and TMR performances of a hard disk drive apparatus, a method to compensate repeatable run out (RRO) of a hard disk drive apparatus, and a computer-readable recording media recording the method. 
         [0012]    Additional aspects and utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept. 
         [0013]    The foregoing and/or other aspects and utilities of the present general inventive concept may be achieved by providing a method to compensate RRO of a hard disk drive apparatus includes receiving a write or read command to respectively write or read data with respect to a disk having an inner diameter (ID) area, a middle diameter (MD) area, and an outer diameter (OD) area which are preset, determining a present position of a magnetic head and a position where the magnetic head writes or reads data, stopping an operation of at least one of the RRO compensators for RRO components of particular frequencies when the present position of the magnetic head is the ID area and the position where the magnetic head writes or reads the data is the MD area or OD area of the disk, and performing data writing or reading by performing seeking and settling of the magnetic head. 
         [0014]    In the stopping of the operation of at least one of the RRO compensators for RRO components of particular frequencies, the RRO components of the particular frequencies may be RRO components of  4 x or higher frequencies, where “x” represents a frequency corresponding to a rotational speed of the disk. 
         [0015]    The  4 x or higher frequencies may be  4 x,  5 x, and  6 x frequencies. 
         [0016]    The method further comprises operating the RRO compensators for the RRO components of the particular frequencies again after the data writing or reading is complete. 
         [0017]    The ID area may be located at an innermost area of the disk when cylinders where user data is written are divided into three areas according to a distance from a center of the disk, the OD area may be located at an outermost area of the disk, and the MD area may be located between the ID area and the OD area, and each of the ID area, the MD area, and the OD area may have substantially a same number of the cylinders. 
         [0018]    The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a computer-readable recording medium having embodied thereon a computer program to execute a method, wherein the method includes receiving a write or read command to respectively write or read data with respect to a disk having an inner diameter (ID) area, a middle diameter (MD) area, and an outer diameter (OD) area which are preset, determining a present position of a magnetic head and a position where the magnetic head writes or reads data, stopping an operation of at least one of the RRO compensators for RRO components of particular frequencies when the present position of the magnetic head is the ID area and the position where the magnetic head writes or reads the data is the MD area or OD area of the disk, and performing data writing or reading by performing seeking and settling of the magnetic head. 
         [0019]    The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing a hard disk drive apparatus including a disk having an inner diameter (ID) area, a middle diameter (MO) area, and an outer diameter (OD) area which are preset, a magnetic head to write or read data on the disk, and a controller to receive a data write or read command, to determine a present position of the magnetic head and a position where the magnetic head writes or reads the data, to stop an operation of RRO compensators for RRO components of particular frequencies when the present position of the magnetic head is the ID area of the disk and the position where the magnetic head writes or reads the data is the MD area or the OD area of the disk, and to perform the data writing or reading by allowing the magnetic head to seek and settle. 
         [0020]    The RRO components of the particular frequencies may be RRO components of  4 x or higher frequencies. 
         [0021]    The  4 x or higher frequencies may be  4 x,  5 x, and  6 x frequencies. 
         [0022]    The controller may operate the RRO compensators for the RRO components of the particular frequencies again after the data writing or reading is complete. 
         [0023]    The ID area may be located at an innermost area of the disk when cylinders where user data is written are divided into three areas according to a distance from a center of the disk, the OD area may be located at an outermost area of the disk, and the MD area may be located between the ID area and the OD area, and each of the ID area, the MD area, and the OD area may have substantially a same number of the cylinders. 
         [0024]    The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing a repeatable run out (RRO) compensator unit usable with a disk drive apparatus including a disk having an inner diameter area and an outer diameter area including a plurality of RRO compensators to compensate a plurality of RRO components, respectively and a controller to control the plurality of RRO compensators by placing or maintaining at least one of the plurality of RRO compensators in a non-compensating mode when a position of the head is proximate to the inner diameter area of the disk and is set to seek data in the outer diameter area of the disk. 
         [0025]    The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing disk drive apparatus including at least one disk having an inner diameter area and an outer diameter area, a head to at least one of read or write data on the at least one disk and a repeatable run out (RRO) compensator unit including a plurality of RRO compensators to compensate a plurality of RRO components, respectively and a controller to control the plurality of RRO compensators by placing or maintaining at least one of the plurality of RRO compensators in a non-compensating mode when a position of the head is proximate to the inner diameter area of the disk and is set to seek data in the outer diameter area of the disk. 
         [0026]    The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing method of compensating for one or more repeatable run out (RRO) components in a disk drive apparatus, the method including determining a position of a head relative to an inner diameter and an outer diameter of a disk, compensating for one or more RRO components by one or more RRO compensators, placing or maintaining at least one of the one or more RRO compensators in a non-compensating mode when the determination that the position of the head is proximate to the inner diameter area of the disk and is set to seek data in the outer diameter area of the disk. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The above and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings of which: 
           [0028]    These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0029]      FIG. 1  is a partially exploded perspective view illustrating a hard disk drive apparatus according to an embodiment of the present general inventive concept; 
           [0030]      FIG. 2  is a block diagram of a drive circuit illustrating the hard disk drive apparatus of  FIG. 1 ; 
           [0031]      FIG. 3  is a flowchart illustrating a method to compensate RRO of the hard disk drive apparatus  FIG. 1 ; and 
           [0032]      FIG. 4  is a graph illustrating a result of a comparison between adopting a method to compensate RRO of a hard disk drive apparatus according to an embodiment of the present general inventive concept and not adopting the method. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    Reference will now be made in detail to embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. 
         [0034]      FIG. 1  is a partially exploded perspective view illustrating a hard disk drive apparatus according to an embodiment of the present general inventive concept.  FIG. 2  is a block diagram illustrating a drive circuit of the hard disk drive apparatus of  FIG. 1 .  FIG. 3  is a flowchart illustrating a method to compensate repeatable run out (RRO) of the hard disk drive apparatus of  FIG. 1 .  FIG. 4  is a graph illustrating a result of a comparison between adopting the method to compensate RRO of a hard disk drive apparatus according to the present general inventive concept and not adopting the method. 
         [0035]    Referring to  FIG. 1 , a hard disk drive apparatus (HDD)  1  according to an embodiment of the present general inventive concept includes a disk  10  to record and store data, a spindle motor  20  to support and rotate the disk  10 , a head stack assembly (HSA)  30  to read data on the disk  10 , a base  40  on which constituent units are assembled, a printed circuit board assembly (PCBA)  50  coupled to the lower portion of the base  40  and having circuit units on a printed circuit board (PCB) to control various units, and a cover  60  to cover the upper portion of the base  40 . 
         [0036]    The disk  10  is a media to record and store data and provided in a plural number. The disk  10  is divided into an inner diameter (ID) area, a middle diameter (MD) area, and an outer diameter (OD) area in the order of being close to a center of the disk  10 . These areas include a plurality of circular tracks that are concentric with the center of the disk  10 . The spindle motor  20  receives a control signal of a controller  70  and rotates the disk  10 . The rotational angular speed of the spindle motor  20  may be 3,600 rpm, 5,400 rpm, 7,200 rpm, or 10,000 rpm. 
         [0037]    The centers of tracks of the disk  10  may accurately match the center of the spindle motor  20 . However, it is common that the centers of tracks of the disk  10  are eccentric to the center of the spindle motor  20  due to disturbance during a servo track write process or an error during the assembly process of the disk  10  and the spindle motor  20 . The eccentricity causes the generation of a  1 x repeatable run out (RRO) component of RRO components. Also,  2 x and  3 x RRO components are generated. 
         [0038]    Although the disk  10  is designed as a circular disc, the disk  10  can be deformed. The deformation can generate  4 x or higher RRO components of the RRO components. The RRO components disturb the positioning of a magnetic head  31  at the center of a track to record or reproduce data. That is, the RRO components deteriorate or increase a position error signal (PES) that indicates a degree of the magnetic head  31  locating out of the center of a target track. Thus, there is a need to control the position of the magnetic head  31  by compensating the RRO components. Accordingly, the present embodiment provides an RRO compensator that will be described later. 
         [0039]    The HSA  30 , which is a carriage to record or reproduce data with respect to the disk  10 , includes the magnetic head  31  recording data on the disk  10  or reproducing recorded data, an actuator arm  33  to pivot across the disk  10  around a pivot shaft  32  so that the magnetic head  31  can access data on the disk  10 , a pivot shaft holder  34  to support the pivot shaft  32  capable of rotating, to which the actuator arm  33  is coupled and supported, and a voice coil motor (VCM)  35  provided at the opposite side of the actuator arm  33  with respect to the pivot shaft holder  34  to rotate the actuator arm  33 . 
         [0040]    The magnetic head  31  reads data from the disk  10  by detecting a magnetic field formed on the surface of the disk  10  or records data on the disk  10  by magnetizing the surface of the disk  10 . The actuator arm  33  has an end connected to the magnetic head  31  and the other end rotatably coupled to the pivot shaft  32 . The actuator arm  33  is extended long so that the magnetic head  31  can move over the surface of the disk  10 . 
         [0041]    The pivot shaft holder  34  supports the pivot shaft  32  capable of rotating and simultaneously supports the actuator arm  33  coupled to the pivot shaft holder  34 . The VCM  35  makes the actuator arm  33  rotate around the pivot shaft holder  34 . The VCM  35  includes a voice coil (not illustrated) and a magnet (not illustrated). The VCM  35  makes the actuator arm  33  pivot by an electromagnetic force generated by the interaction between lines of a magnetic force generated by the magnet and current flowing in the voice coil. 
         [0042]    Although in the present embodiment the VCM  35  is provided to rotate the actuator arm  33 , a stepper motor capable of rotating the actuator arm  33  by a predetermined angle according to an input signal can be used instead. However, the VCM  35  has advantages in that it is resistant to heat, a periodic format is not needed, and reliability is superior. 
         [0043]    Also, the hard disk drive apparatus  1  needs a drive circuit to control parts of the hard disk drive apparatus  1 . The hard disk drive apparatus  1 , as illustrated in  FIG. 2 , includes a pre-amplifier (pre-AMP)  71 , a read/write channel (R/W channel)  72 , a host interface  73 , a VCM driver  36 , a spindle motor driver (SPM)  22 , a controller  70 , and a memory  74 . 
         [0044]    Referring to  FIG. 2 , the pre-AMP  71  amplifies a data signal that the magnetic head  31  reads from the disk  10  or write current converted by the R/W channel  72  and provides the amplified signal to the magnetic head  31 . When receiving the write current from the pre-AMP  71 , the magnetic head  31  can generate a magnetic field. The magnetic head  31  magnetizes the disk  10  using the magnetic field to record data on the disk  10 . 
         [0045]    In a data read mode in which data recorded on the disk  10  is read, the R/W channel  72  converts a signal read from the disk  10  by the magnetic head  31  and amplified by the pre-AMP  71  to a digital signal and inputs the converted signal to the controller  70 . In a data write mode in which data is recorded on the disk  10 , the R/W channel  72  receives user input data received through the host interface  73 , converts the received data to a binary data stream that is easy to record, and outputs the converted data to the pre-AMP  71 . 
         [0046]    A host device  2  may include components that generally control and operate a computer system including the hard disk drive apparatus like a CPU or an I/O controller of a computer. The host interface  73  transmits the data converted to a digital signal to the host device  2  in the date read mode and receives the user input data from the host device  2  and outputs the received data to the controller  70  in the data write mode. 
         [0047]    The VCM driver  36  receives the control signal of the controller  70  and controls the amount of current applied to the VCM  35 . The SPM driver  22  receives the control signal of the controller  70  and controls the amount of current applied to the spindle motor  20 . 
         [0048]    The controller  70  may be a digital signal processor (DSP), a micro-processor, or a micro-controller. The controller  70  in the data write mode receives the user input data from the host device  2  through the host interface  73  and outputs the received data to the R/W channel  72  and in the data read mode receives a data signal read by the magnetic head  31 , amplified by the pre-AMP  71 , and converted by the R/W channel  72  to a digital signal and outputs the received signal to the host interface  73 . Also, the controller  70  controls the VCM  35  to move the magnetic head  31  to a desired position on the disk  10  and the spindle motor  20  to adjust the rotational speed of the disk  10 . 
         [0049]    The controller  70  includes an RRO compensator (not illustrated) that compensates RRO generated due to the eccentricity of tracks of the disk  10  or the deformation of the disk  10 . As described above, RRO includes various RRO components according to frequencies. Accordingly, the RRO compensator is provided in a plural number corresponding to the RRO components to be compensated. In the present embodiment, a total of six RRO compensators are provided corresponding to  1 x to  6 x RRO components of the RRO components. The RRO components are arranged in parallel and operated individually. An RRO compensation method of the hard disk drive apparatus  1  which is described later can be stored in a memory  74  in a form of software or firmware and then embodied by the controller  70 . 
         [0050]    An RRO compensation method of the hard disk drive apparatus  1  according to an embodiment of the present general inventive concept is described below. Referring to  FIG. 3 , when the controller  70  receives a data write or read command from the host interface  73  (operation S 210 ), the controller  70  determines whether the present position of the magnetic head  31  is the ID area of the disk  10  (operation S 220 ). The present position of the magnetic head  31  can be determined from servo information read by the magnetic head  31 . 
         [0051]    If the present position of the magnetic head  31  is not the ID area of the disk  10 , the magnetic head  31  is moved to seek a target track to write or read data and settled at the target track to perform writing or reading data (operation S 250 ). If the present position of the magnetic head  31  is the ID area of the disk  10 , it is determined that the position of the target track to write or read data is the MD or OD area of the disk  10  (operation S 230 ). The information about the position of the target track to write or read data is given with the write or read command received from the host interface  73 . 
         [0052]    If the position of the target track to write or read data is not the MD or OD area of the disk  10 , the magnetic head  31  is moved to seek the target track to write or read data and settled at the target track to perform writing or reading data (operation S 250 ). If the position of the target track to write or read data is the MD or OD area of the disk  10 , the operations of the RRO compensators for the  4 x,  5 x, and  6 x RRO components, of the plural RRO compensators provided in the controller  70 , are stopped (operation S 240 ). Since the plural RRO compensators of the controller  70  are connected in parallel, each RRO compensator can be independently turned on or off. The operations of the RRO compensators for the  4 x,  5 x, and  6 x RRO components are stopped when the magnetic head  31  positioned in the ID area is moved to seek the MD or OD area to write or read data. The operations of the RRO compensators for the  4 x,  5 x, and  6 x RRO components are stopped because the  4 x,  5 x, and  6 x RRO components of the RRO components are greatly decreased in the MD or OD area of the disk  10 . 
         [0053]    Next, the magnetic head  31  is moved to seek the target track and settled at the target track to write or read data (operation S 250 ). Since the operations of the RRO compensators for the  4 x,  5 x, and  6 x RRO components are already stopped in the above-described operation, the compensation for the  4 x,  5 x, and  6 x RRO components is not performed during which the magnetic head  31  seeks the target track. Thus, since no time is spent for the compensation for the  4 x,  5 x, and  6 x RRO components, the seek time to the target track by the magnetic head  31  is reduced. Also, since over-compensation for the  4 x,  5 x, and  6 x RRO components is not generated, the deterioration of the PES due to the over-compensation for the  4 x,  5 x, and  6 x RRO components after the magnetic head  31  performs seeking and settling can be prevented. 
         [0054]    Finally, when the writing or reading data at the target track is complete, the RRO compensators for the  4 x,  5 x, and  6 x RRO components are turned on (operation S 260 ). In the present embodiment, the stopping of the operations of the RRO compensators for the  4 x,  5 x, and  6 x RRO components is made only when the magnetic head  31  performs a seek operation from the  10  area to the MO or OD area. Thus, the RRO compensators for the  4 x,  5 x, and  6 x RRO components are turned on until the seek operation is performed again. 
         [0055]      FIG. 4  is a graph illustrating a result of a comparison between adopting a method to compensate RRO of the hard disk drive apparatus  1  according to the present general inventive concept and not adopting the method. The test is carried out for a first hard disk drive apparatus (hard disk drive- 1 ) and a second hard disk drive apparatus (hard disk drive- 2 ) that have a same structure as that of the hard disk drive apparatus  1 . In hard disk drive- 1 , two magnetic heads head 1  and head 2  are tested and, in hard disk drive- 2 , one magnetic head head 3  is tested. Of the three magnetic heads used for the test, head 1  of the magnetic heads of hard disk drive- 1  has a large  4 x or higher RRO in the MO and OD areas while two other magnetic heads head 2  and head 3  have a small  4 x or higher RRO in the MO and OD areas. 
         [0056]    Also, the test is performed by repeating an operation of the magnetic heads&#39; seeking data from the ID area to the OD area and simultaneously writing arbitrary data to tracks existing on the seeking path, and counting the number of write faults generated in doing so. The test is performed by applying the RRO compensation method according to the present general inventive concept once and then not applying the method. 
         [0057]    Referring to  FIG. 4 , the magnetic heads head 1  and head 2  of hard disk drive- 1 , the magnetic head head 1  having a large  4 x or higher RRO in the MO and OD areas is not substantially affected in the number of the generated write faults by the application of the above-described RRO compensation method. However, in the magnetic heads head 2  and head 3  having a small  4 x or higher RRO in the MO and OD areas, the write fault can be reduced by applying the RRO compensation method. The reduction in the write faults by applying the RRO compensation method as described above results in PES or TMR performance being improved. Since the  4 x or higher RRO greatly decreases toward the OD area of the disk  10 , the PES or TMR performance of the hard disk drive apparatus can be improved by applying the above-mentioned RRO compensation method. 
         [0058]    According to the RRO compensation method of a hard disk drive apparatus according to various embodiments of the present general inventive concept, the RRO compensators are adaptively operated according to the seeking path of the magnetic head to write or read data. That is, the operations of the RRO compensators for  4 x or higher RRO components are stopped only when the magnetic head  31  performs seeking operation from the ID area of the disk  10  to other areas such as the MO or OD areas. Accordingly, since unnecessary compensation for the  4 x or higher RRO components is not performed during the seeking operation, the seek time of the magnetic head  31  is reduced (improvement of the servo control performance) and the deterioration of PES due to the unnecessary RRO compensation after seeking and settling can be prevented (improvement of the TMR performance). 
         [0059]    The present general inventive concept can also be embodied as computer-readable codes on a computer-readable medium. The computer-readable medium can include a computer-readable recording medium and a computer-readable transmission medium. The computer-readable recording medium is any data storage device that can store data that can be thereafter read by a computer system. Examples of the computer-readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer-readable code is stored and executed in a distributed fashion. The computer-readable transmission medium can transmit carrier waves or signals (e.g., wired or wireless data transmission through the Internet). Also, functional programs, codes, and code segments to accomplish the present general inventive concept can be easily construed by programmers skilled in the art to which the present general inventive concept pertains. 
         [0060]    Although various embodiments of the present general inventive concept have been illustrated and described, the present general inventive concept is not limited to the described embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined by the claims and their equivalents. 
         [0061]    According to the above-described embodiments of the present general inventive concept, a hard disk drive apparatus which can adaptively operate the RRO compensators according to the seeking path of the magnetic head and accordingly improve the servo control and TMR performances of the hard disk drive apparatus, a method to compensate RRO of a hard disk drive apparatus, and a computer-readable recording media recording the method are provided.