JP2007226857A - Disk drive device and its initial setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurately a head selection test, to shorten its test time, and to short a start time of an HDD. <P>SOLUTION: The HDD performs a head selection test and a magnetic recording test in POR (Power On Reset) processing. In the past POR processing , accurate test data is written previously in respective recording planes of a magnetic disk with the skewness. In the head selection test, the test data with the skewness is read out, it is confirmed whether read data is accurate or not. Thereby, the head test time can be shortened by performing the head selection test. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disk drive device and a head test method thereof, and more particularly to a head selection test in a disk drive device.

  As a disk drive device, a device using a recording disk of various modes such as an optical disk and a magneto-optical disk is known. Among them, a hard disk drive (HDD) is a computer storage device. As one of the devices indispensable in the current computer system. Furthermore, applications of HDDs such as a removable memory used in a moving image recording / reproducing apparatus, a car navigation system, a digital camera, etc. are expanding more and more due to its excellent characteristics.

  The HDD has one or a plurality of magnetic disks and a plurality of data tracks formed concentrically on each recording surface of each magnetic disk. Each data track is recorded with a plurality of data sectors including a plurality of servo data having address information and user data. 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.

  As described above, the number of cases in which HDDs are currently installed as mass storage devices in consumer electronics (CE) is increasing. One of the problems compared to other storage devices in the introduction is COME READY TIME delay. In general, the COME READY TIME in the HDD is taken as the time from when the power is set to ON until the interface of the device becomes READY. However, a problem particularly in consumer electronics is the time until HDD read / write preparation is completed. This is because the information of the storage device incorporated therein is indispensable for the activation of the CE device itself. In this specification, this time is referred to as COME READY TIME.

  When the HDD is turned on, the HDD executes a POR process (Power On Reset process) that is an initial setting process. When this POR process ends normally, a command can be received from the host. That is, this POR processing time corresponds to COME READY TIME. If an unresolvable error occurs in the POR process, the HDD itself fails and cannot be used.

  In a typical POR process, the HDD performs a write test. The write test tests the correct data writing and data reading to the magnetic disk. Many HDDs include a plurality of recording surfaces and a plurality of head sliders corresponding to the recording surfaces in order to increase the storage capacity. For this reason, the light test checks for two points. For one thing, it is checked that the target head element is correctly selected (head selection check). As another one, it is checked whether or not the selected head element unit can actually write and read data (magnetic recording check).

In order to shorten the COME READY TIME, it is desirable to shorten the execution time of the write test. One such technique is disclosed in Patent Document 1, for example. The technique disclosed in Patent Literature 1 detects the occurrence of a failure by diagnosing the head element unit regularly or irregularly. In order to shorten the diagnostic processing time of the head element unit, the diagnostic area for each head element unit is arranged on the magnetic disk while being shifted by the head switching processing time. As a result, the diagnostic area can be written or read by the plurality of head element portions during one rotation of the magnetic disk, and the diagnostic processing time can be shortened.
JP 2003-263703 A

  However, when writing and reading test data by the magnetic head while shifting the head switching processing time, there is a case where the head selection check cannot be performed accurately. Specifically, a case where the HDD includes two head element units of head 0 and head 1 will be described. Each head element unit sequentially writes data on the recording surface, and then each head element unit sequentially reads data. The circumferential position of the data written on each recording surface is shifted by the switching time of the head element unit.

  If the HDD mistakenly selects the head 1 instead of the head 0, the HDD writes the data with the head 1 and then selects the head 1 again and writes the data. Further, the HDD selects the head 1 with the intention of selecting the head 0, and reads the data written first. Further, the HDD selects the head 1 and reads the data written for the second time.

  Since each data written by the head 1 is shifted by the head switching processing time, the second data does not overwrite the first data. Therefore, the HDD erroneously recognizes that the first and second data are correctly read and the head selection is performed correctly. Incorrect selection of the head element unit results in erasing user data or transferring erroneous data to the host. Specifically, erroneous selection of the head element unit in read processing reads data different from the data requested by the host and transfers the erroneous data to the host. In addition, erroneous selection of the head element unit in the write processing overwrites user data to be saved and transfers erroneous data to the host in response to a data read request from the host. For this reason, it is necessary to reliably prevent erroneous selection of the head element portion.

  As a method for surely performing the head selection test, it is conceivable that the head 0 and the head 1 write unique data in the same data sector of the same cylinder. If there is a selection error, the second data overwrites the first data. When there is a miss selection similar to that described above, when the HDD attempts to read data from the head 0, data from the head 1 is read out, so that a selection error can be detected.

  However, when each head element unit writes data in the same data sector, the magnetic disk rotation twice as many as the number of head element units is required for data writing and data reading. This leads to an increase in COME READY TIME. In particular, a small HDD has a short stabilization time for magnetic disk rotation, and a large head test time in COME READY TIME. Therefore, shortening the head test time is an important problem.

  A disk drive device according to one aspect of the present invention includes one or more disks having one or more recording surfaces, a plurality of heads accessing the one or more recording surfaces, and an external trigger. In response, each test data written before the trigger and skewed corresponding to each of the plurality of heads is read by selecting the plurality of heads sequentially, and performing a head selection test. A controller is provided for execution. By using test data written in advance before external triggering, it is possible to perform accurate head selection test by reading each test data with skew. It can be shortened.

  The one or more disks have a plurality of recording surfaces, each of the plurality of heads corresponds to each of the plurality of recording surfaces, and the controller responds to the external trigger, The head selection test is executed by sequentially selecting the multiple heads and reading the skewed test data written to the data tracks of the same cylinder on multiple recording surfaces before the trigger. can do. In a disk drive apparatus having a plurality of recording surfaces and corresponding heads, an accurate head selection test can be performed, and the test time can be shortened.

  It is preferable that the test data is written in a plurality of data sectors of each data track. As a result, the test can be started quickly in response to an external trigger. Further, for each test data in each data track, the test data is written ahead of the predetermined number of data sectors in another data track, and the controller It is preferable to switch and read test data ahead of a predetermined number of sectors from the test data read immediately before. As a result, a test can be performed quickly regardless of which test data is started.

  It is preferable that the test data is written in all data sectors of each data track. Thus, the test can be started immediately in response to an external trigger, and test data having a desired skew can be read out.

  The test data preferably includes data for specifying a corresponding head and data representing the head selection test. As a result, a head selection error can be detected, and it can be confirmed that the target cylinder is read in the test.

  After the head selection test, the controller writes data to each of the plurality of recording surfaces while switching the head, and further reads the written data while switching the head to confirm the written data. Preferably it is done. As a result, the head test can be performed more fully.

  The controller writes the skewed data while switching the head to each data track of the same cylinder of the plurality of recording surfaces after the head selection test, and further writes the data while switching the head. It is preferable to check the written data by reading the read data. As a result, the head test can be performed more thoroughly and the write data can be confirmed quickly.

  The controller executes the head selection test in an initial setting process in response to an external trigger, and in the initial setting process prior to the initial setting process for executing the head selection test, the test data Is preferably written to each data track. By writing test data in the initial setting process, reliable test data can be written easily.

  Furthermore, it is preferable that the controller writes the test data to each data track after executing a confirmation test for confirming that a head accurately selected from the plurality of heads correctly writes data. This ensures that the test data is written correctly.

  Further, it is preferable that a test method of the confirmation test is different from the head selection test. Since a test for writing test data is different from a test using the test data, a more reliable head test can be performed. Alternatively, it is preferable to end the initial setting process without performing the head selection test after writing the test data. Another head test is performed, which can reduce processing time.

  Another aspect of the present invention is an initial setting method in a disk drive device, wherein test data is written in advance using a plurality of heads on one or a plurality of recording surfaces, and the test data is written. In response to an external trigger received, an initial setting process is started. In the initial setting process, each test data having a skew corresponding to each of the plurality of heads is sequentially selected from the plurality of heads. Read out and execute the head selection test.

  The disk drive device includes a plurality of recording surfaces, and in each of the plurality of recording surfaces, using a head corresponding to each recording surface, test data is written in advance on a data track of the same cylinder, and the test drive In response to an external trigger received after writing the data, the initial setting process is started, and in the initial setting process, each test test at a position having a skew in each data track on the plurality of recording surfaces is started. Data can be read out by selecting the plurality of heads sequentially, and a head selection test can be executed.

  Further, after the head selection test, data with skew was written while switching the head to each data track of the same cylinder of the plurality of recording surfaces, and the data was written while switching the head. It is preferable to check the write data by reading the data.

  It is preferable that the test data is written to each of the data tracks after performing a confirmation test for confirming that the head selected from the plurality of heads accurately writes data. The test method of the confirmation test is preferably different from the head selection test.

  According to the present invention, the head selection test can be performed accurately and the test time can be shortened.

  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 for clarification of description.

  In the following, embodiments of the present invention will be described by taking a hard disk drive (HDD) as an example of a disk drive device as an example. The HDD according to this embodiment executes a POR (Power On Reset) process as an initial setting process in response to a power-on which is an example of an external trigger or a command from the host. In the POR process, the HDD executes a head test. The head test includes a head selection test and a magnetic recording test. The head selection test checks that the target head element unit is accurately selected from a plurality of head element units. In the magnetic recording test, it is checked whether the selected head element unit can accurately write data to a desired position on the magnetic disk and then read the data.

  In the HDD of this embodiment, accurate test data is written in advance on each recording surface of the magnetic disk before POR processing. By executing the head selection test using this test data, the head test time can be shortened. In order to facilitate understanding of the present invention, the entire configuration of the HDD will be described first before describing the POR processing of the present embodiment.

  FIG. 1 is a block diagram schematically showing the configuration of the HDD 1 according to the present embodiment. As shown in FIG. 1, an HDD 1 includes a magnetic disk 11 as an example of a recording disk, a head element unit 12 as an example of a head, an arm electronic circuit (AE: Arm Electronics) 13, a spindle motor (inside an enclosure 10). SPM) 14, voice coil motor (VCM) 15, and actuator 16. The HDD 1 according to this embodiment includes a plurality of head element units 12, and two head element units 12 are illustrated in FIG.

  The HDD 1 further includes a circuit board 20 fixed to the outside of the enclosure 10. On the circuit board 20, there are a read / write channel (R / W channel) 21, a motor driver unit 22, a hard disk controller (HDC) and an MPU integrated circuit (hereinafter referred to as HDC / MPU) 23, a RAM 24, etc. Each IC is provided. Each circuit configuration can be integrated into one IC, or can be divided into a plurality of ICs.

  User data from the external host 51 is received by the HDC / MPU 23 and written to the magnetic disk 11 by the head element unit 12 via the R / W channel 21 and the AE 13. The user data stored in the magnetic disk 11 is read by the head element unit 12, and the user data is output from the HDC / MPU 23 to the external host 51 via the AE 13 and the R / W channel 21. The

  The magnetic disk 11 is fixed to the SPM 14. The SPM 14 rotates the magnetic disk 11 at a predetermined angular velocity. The motor driver unit 22 drives the SPM 14 according to control data from the HDC / MPU 23. Each head element unit 12 is fixed to a slider (not shown). Hereinafter, this assembly is referred to as a head slider. The head slider is fixed to the tip of the actuator 16. The actuator 16 is connected to the VCM 15, and moves in the radial direction on the magnetic disk 11 rotating the head element unit 12 (head slider) by swinging about the swing axis. The motor driver unit 22 drives the VCM 15 in accordance with control data (hereinafter referred to as DACOUT) from the HDC / MPU 23.

  The head element unit 12 includes a write element that converts an electric signal into a magnetic field according to data recorded on the magnetic disk 11 and a read element that converts a magnetic field from the magnetic disk 11 into an electric signal. The write current value of the write element changes according to the control value set by the HDC / MPU 23. One or more magnetic disks 11 may be provided, and the recording surface can be formed on one side or both sides of the magnetic disk 11.

  The AE 13 selects one head element unit 12 for accessing the magnetic disk 11 from the plurality of head element units 12 in accordance with an instruction from the HDC / MPU 23, and a reproduction signal reproduced by the selected head element unit 12 Is amplified (preamplifier) with a constant gain and sent to the R / W channel 21. Further, the recording signal from the R / W channel 21 is sent to the selected head element unit 12. In the read process, the R / W channel 21 amplifies the read signal supplied from the AE 13 to have a constant amplitude, extracts data from the acquired read signal, and performs a decoding process. Data to be read out includes user data and servo data. The decoded user data is supplied to the HDC / MPU 23. In the write process, the R / W channel 21 code-modulates the write data supplied from the HDC / MPU 23, converts the code-modulated write data into a write signal, and supplies the write signal to the AE 13.

  In the HDC / MPU 23, the MPU operates according to the code loaded in the RAM 24. Along with the activation of the HDD 1, the RAM 24 is loaded with data necessary for control and data processing from the magnetic disk 11 or ROM (not shown) in addition to the code operating on the MPU. The HDC / MPU 23 performs necessary processing related to data processing such as read / write processing control, command execution order management, positioning control (servo control) of the head element unit 12 using a servo signal, interface control, defect management, etc. The entire control of the HDD 1 is executed. In particular, the HDC / MPU 23 of the present embodiment performs execution control of POR processing. The POR process of this embodiment will be described in detail later.

  FIG. 2 schematically shows the configuration of the SPM 14, the magnetic disk 11, and the head stack assembly (HSA) in the HDD 1. The example of FIG. 2 includes two magnetic disks 11 stacked in the rotation axis direction, and each magnetic disk 11 includes recording surfaces on both sides for recording data. Accordingly, the HDD 1 includes four recording surfaces 11a-11d. Further, four head sliders 12a-12d are provided corresponding to the recording surfaces 11a-11d. The head sliders 12a-12d are fixed to the suspensions 16a-16d of the actuator 16, respectively. In this specification, the assembly of the actuator 16 and the head sliders 12a-12d is referred to as HSA.

  Pressure due to the viscosity of air between the ABS (Air Bearing Surface) surface of each head slider 12a-12d facing each recording surface 11a-11d and the rotating recording surface 11a-11d is caused by the suspensions 16a-16d. By balancing with the pressure applied in the recording surface 11a-11d direction, each head slider 12a-12d floats on each recording surface 11a-11d with a certain gap. Although the HDD 1 of this embodiment includes a plurality of recording surfaces, it is sufficient if it includes one or more magnetic disks 11, and the recording surfaces can be formed on one or both surfaces of the magnetic disk 11.

  As described above, the HDC / MPU 23 controls the execution of the POR process. The HDC / MPU 23 executes the POR process in response to turning on the power of the HDD 1 or in accordance with a command from the host 51. The POR process is an initial setting process of the HDD 1 and includes several processing steps. For example, the POR process executes micro code loading from ROM, various hardware diagnosis, SPM 14 activation, micro code loading from the magnetic disk 11, servo parameter adjustment, defect table loading, and the like. In addition, the POR process executes a head test (write test). The head test checks that the correctly selected head element unit 12 correctly writes and reads data. This embodiment is characterized by this head test.

  FIG. 3 is a flowchart showing the overall processing configuration of the head test of this embodiment. When a head test is started in the POR process (S11), the HDC / MPU 23 starts a head selection test (S12). In the head selection test (S12), it is checked that the head element unit 12 selected correctly accesses the magnetic disk 11. This embodiment has a feature point in the head selection test (S12). Details of the head selection test (S12) will be described later.

  When the head selection test (S12) confirms that each head element unit 12 is correctly selected using the test data written in the preprocessing step (S19) described later (YES in S13), the HDC / The MPU 23 executes a magnetic recording test (S14). In the magnetic recording test (S14), each head element unit 12 writes data to a desired position on each recording surface 11a-11d, reads the written data, and confirms whether the data has been correctly written. .

  When the magnetic recording test (S14) confirms that each head element unit 12 accurately accesses each recording surface 11a-11d correctly (YES in S15), the head test ends as “pass” ( S16). When other processing ends normally, the POR ends normally, and the HDD 1 is ready to accept a command from the host 51.

  When an error is detected in the magnetic recording test (S14) (NO in S15), the HDC / MPU 23 transmits a failure result to the host 51 (S20). When an error occurs in the head selection test (S12) (NO in S13), the HDC / MPU 23 is different from the head selection test (S12) and the magnetic recording test (S14). The head test is executed (S17).

  In this test step (S17), head selection and magnetic recording tests are simultaneously performed. When this test ends normally (YES in S18), the HDC / MPU 23 performs a pre-process for the head selection test in the next POR process (S19). Specifically, the HDD 1 writes test data for the head selection test on the recording surfaces 11 a to 11 d of the magnetic disk 11. If an error is detected in the head test of S17 (NO in S18), the HDC / MPU 23 transmits a failure result to the host 51.

  In the first POR process of HDD1, since the test data of the head selection test (S12) is not written, the head selection magnetic recording test of (S17) and the next POR process are performed. Preprocessing (S19) is executed and the process ends. In the subsequent POR process, if no error occurs, a head selection test (S12) and a magnetic recording test (S14) are executed. When an error occurs in the head selection test (S12), the HDD 1 executes a head test (S17) and pre-processing (S19), and when an error occurs in the magnetic recording test (S14). The HDD 1 notifies the host 51 of a failure.

  Hereinafter, each test process shown in the flowchart of FIG. 3 will be described in detail. First, the head selection test (S12) of this embodiment will be described. As shown in FIG. 4, the head selection test of this embodiment is performed by using the head element portion of each head slider 12a-12d to write test data previously written in a specific cylinder of each recording surface 11a-11d. read out. Test data is written in the same cylinder of the recording surfaces 11a-11d. That is, test data is written in data tracks 111a to 111d of the same cylinder. Hereinafter, the head element portions of the head sliders 12a-12d are denoted by the same reference numerals 12a-12d.

  Here, the magnetic disk format will be described. On each recording surface 11a-11d of the magnetic disk, a plurality of servo areas extending radially from the center of the magnetic disk 11 and spaced apart by a predetermined angle, and between two adjacent servo areas are provided. A data area is formed. In each servo area, servo data for performing positioning control of the head element units 12a to 12d is recorded. User data is recorded in each data area. A plurality of data tracks having a predetermined width in the radial direction and concentric circles are formed on each recording surface 11a-11d.

  User data is recorded along the data track. One data track includes a plurality of data sectors (user data recording units), and typically includes a plurality of data sectors between servo areas. Each data sector in the HDD 1 can be specified by using a so-called CHS address, that is, a cylinder number, a head number, and a data sector number. The cylinder number corresponds to the data track number, and the head number corresponds to the recording surface number. When the data sector length is large, one data sector may exceed one servo area.

  Preferably, test data is written in all data sectors of each data track 111a-111d. That is, as shown in FIG. 4, all the data sectors of the data tracks 111a to 111d are data sectors 112 in which test data is written. The test data includes a head ID (HEAD ID) 113 that identifies each head element unit (head slider) 12a-12d, and a selection test ID (SELECTION TEST) that indicates data for a head selection test. ID) 114. The test data written to each data track 111a-111d may be the same test data. Further, the selection test ID 114 may be the same in each data track 111a-111d.

  The HDC / MPU 23 compares the data read from each of the data tracks 111a to 111d with a head ID and a selection test ID provided in advance, and confirms that they are the same. If the read data is test data corresponding to the selected head element unit, the HDC / MPU 23 determines that the head selection has been performed correctly. What is important here is that each data track 111a-111d is guaranteed to be written with test data having an accurate head ID.

  As shown in FIG. 3, this test data is written in each data track 111a-111d in the pre-processing (S19) of the head selection test (S12). Prior to this preprocessing, the HDD 1 performs a head test of another aspect (S17), and confirms that head selection and magnetic recording have been performed accurately. Therefore, it is guaranteed that accurate test data is written to each data track 111a-111d.

  FIG. 5 schematically shows a head selection method in the head selection test (S12). FIG. 5 shows an example in which each head sector 12a-12d accurately reads each data sector 115a-115d. The HDC / MPU 23 first selects the head element unit 12a and reads the data sector 115a of the data track 111a. Next, the HDC / MPU 23 reads the data sector 115b of the data track 111b using the head element unit 12b.

  The data sector 115b is at a position having a skew with respect to the data sector 115a. This skew is preferably equal to or longer than the head switching time. The head switching time is the time from when the data sector of one data track is read to when the reading of the data sector of another data track can be started. In the example of FIG. 5, the head switching time corresponds to 2 data sectors.

  Subsequently, the HDC / MPU 23 reads the data sector 115c of the data track 111c using the head element unit 12c. The positional relationship between the data sector 115c and the data sector 115b is the same as the positional relationship between the data sector 115c and the data sector 115b. Further, the HDC / MPU 23 reads the data sector 115d of the data track 111d using the head element unit 12d. The skew between the heads is the same as described above.

  As described above, the test time of the head selection test can be shortened by sequentially reading out the data sectors of the respective data tracks at positions having skews. In the above example, the head section test can be completed within one rotation of the magnetic disk. In this example, since the test data is written in all the data sectors of each data track, the test can be started at the earliest timing regardless of the head position.

  As described above, the reason why data can be read with a skew for each head element portion in the head selection test is based on the fact that accurate test data is written in advance in each data track. In this embodiment, a more accurate test can be performed by using a test (S17) in a mode different from the head selection test (S12) to guarantee it.

  FIG. 5 shows an example in which each head element unit 12a-12d reads each data sector 115a-115d accurately. In contrast, FIGS. 6A and 6B show an example in which any of the head element units cannot accurately read the test data. The data read error includes a case where the head element unit cannot actually read the target data sector, or a case where the read test data is not the test data of the data track. FIG. 6A shows an example in which the head element unit 12b cannot accurately read the test data of the data sector 116 in the data track 111b.

  After the head element unit 12a reads the test data of the data sector 115a, the HDC / MPU 23 tries to read the test data of the data sector 116 by the head element unit 12b. However, due to an error, the HDC / MPU 23 reads the data sector 117b that is four data sectors ahead. In order to avoid repeated errors due to disturbances or scratches on the magnetic disk 11, it is preferable to re-read data in a plurality of data and sectors ahead. Note that 4 data sectors are an example. The head element unit 12b accurately reads the test data of the data sector 117b, and the HDC / MPU 23 reads the data sector 117c of the data track 111c using the head element unit 12c. The above-described skew is provided between the data sector 117c and the data sector 117b. Further, the HDC / MPU 23 reads the data sector 117d of the data track 111d using the head element unit 12c, and the head selection test is completed.

  In the example of FIG. 6A, read retry is started from the data track 111b in which an error has occurred. However, as shown in FIG. 6B, the retry can be started from the first data track 111a. If the reading of the data sector 116 of the data track 111b fails, the HDC / MPU 23 selects the head element unit 12a and reads the data sector 117a. Thereafter, the HDC / MPU 23 reads the data sectors 117b, 117c, and 117d arranged with skew. In this example, since the test data is written in all sectors of the data track, the test data read process can be started regardless of the head position, which contributes to shortening of the test time.

  If the test data cannot be read accurately even after repeating the specified number of retries, the head selection test results in an error (NO in S13 in FIG. 3). The HDC / MPU 23 performs head selection and magnetic recording. Move to the simultaneous test process.

  A specific process of the head selection test (S12) will be described with reference to the flowchart of FIG. When the head selection test is started (S121), the HDC / MPU 23 sets initial values for each variable (S122). The variables to be set are the retry count RETRY_CNT, the test cylinder TEST_CYL, the test head TEST_HD, and the test sector TEST_SCT.

  The retry count RETRY_CNT is set to the maximum number MAX.RETRY # at which read retry is performed, and the test cylinder number TEST_CYLINDER # is set to the test cylinder TEST_CYL. The test cylinder TEST_CYL is typically set in a management area where user data is not written on each recording surface. The maximum head number MAX.HEAD # is assigned to the test head TEST_HD as the head element section to be tested first (3 in the example of FIG. 2), and the data read out in the cylinder TEST_CYLINDER # to be tested in the test sector TEST_SCT Sector number S # is set.

  The HDC / MPU 23 reads the data in the data sector indicated by the variables TEST_CYL, TEST_HD, and TEST_SCT, and confirms the read test data (S123). The confirmation is performed by comparing the read data with the head ID stored in advance corresponding to the data sector and the selection test ID. The reference data to be compared can be loaded from the magnetic disk 11 or the ROM and stored in the register of the HDC / MPU 23 or the RAM 24. This point is the same in the following verify process.

  When accurate data can be read from the target sector (YES in S124), the HDC / MPU 23 sets a head element unit (recording surface) to be tested next and a data sector to be read from the recording surface (S125). ). In this example, an adjacent head element unit is selected, and specifically, a head element unit having a head number immediately before (one smaller by 1) the head element unit for which the test has been completed is selected. In order to shorten the access time, a data sector having a skew corresponding to the head switching time is selected. The skew value is registered in advance in the management area of the magnetic disk 11, and the HDC / MPU 23 uses the skew value.

  When the set head number is 0 (YES in S126), the head selection test (S12) is normally completed (S127) because all the head element units and the recording surface have been tested. If the head number has not reached 0 (NO in S126), data read and read data confirmation processing are executed for the selected head element unit and data sector. This loop is repeated until the head number reaches 0, that is, until all head element units have been tested. The cylinders corresponding to the head element portions are all the same.

  If the data cannot be read correctly (NO in S124), the HDC / MPU 23 reads different data sectors in the same data track of the head element unit. In this example, the HDC / MPU 23 sets a data sector ahead of 4 data sectors as a target sector to be read (S128). Further, the HDC / MPU 23 subtracts 1 from the variable RETRY_CNT indicating the number of retries (S128).

  When the variable RETRY_CNT reaches 0 and the specified number of retries is repeated (YES in S129), the HDC / MPU 23 determines that the head selection test is a failure (S130). If the number of retries has not reached the specified number (NO in S129), the HDC / MPU 23 executes read verify for the set target data sector. Thereafter, the above process is repeated.

  As described above, the test data is preferably written in all data sectors of the data track. However, test data can be written in a plurality of spaced data sectors in each data track. FIG. 8A shows a case where the head selection test ends without a read verify error, and FIG. 8B shows an example where an error occurs in the data track 111b.

  FIGS. 8A and 8B show an example in which test data is written every 6 data sectors, and there are 5 between the data sectors 112 where the test data is written. There is a data sector 118 in which no test data is written. Between data tracks, the data sector 112 in which test data is written is selected with a skew. That is, in two adjacent data tracks, the interval between adjacent data sectors 112 is 3 data sectors. Two data sectors correspond to the head switching time.

  Referring to FIG. 8A, the HDC / MPU 23 reads the data sector 115a of the data track 111a by the head element unit 12a and confirms the read data. When the correct data reading is confirmed, the HDC / MPU 23 reads the data sector 115b of the data track 111b by the head element unit 12b and confirms the read data. Thereafter, the same processing is executed for the data tracks 111c and 111d.

  As shown in FIG. 8B, when a read verify error occurs in the data sector 116 of the data track 111b, the HDC / MPU 23 causes the next test data of the data sector 117b of the same data track 111b. Is read. Thereafter, the data sectors 117b, 117c, and 117d of the data tracks 111b, 111c, and 111d are read and a confirmation process is performed. Note that the HDC / MPU 23 may perform reread processing from the data track in which an error has occurred, as in the example of FIG.

  Next, specific processing of the magnetic recording test (S14) will be described. In the magnetic recording test of this embodiment, data is sequentially written to the data tracks 111a to 111d, and then the write data of the data tracks 111a to 111d is sequentially read. The HDC / MPU 23 compares the read data with the previously stored write data, and performs confirmation processing that the data has been correctly written / read. In this example, the cylinder used by the magnetic recording test is the same as the head selection test. The data to be written includes a random number generated for each test, in addition to the head ID and selection test ID used in the head selection test. Since the data size required for the head selection test is smaller than the size of one sector, a random number generated for each test is embedded in the remaining area, and confirmation is performed at the time of reading. Thus, the verify process can be surely performed.

  In the magnetic recording test (S14), the data tracks 111a to 111d are accessed with a skew. That is, as shown in FIG. 9, the HDC / MPU 23 writes data in the data sectors 119a-119d selected with a skew corresponding to the head switching time in each of the data tracks 111a-111d. Data writing can be completed within one rotation of the magnetic disk 11.

  Further, after the data is written, the HDC / MPU 23 sequentially reads the data sectors 119a to 119d and executes a confirmation process for the read data. The time required for reading data is the same as that for writing data, and all data sectors 119a to 119d can be read within one rotation of the magnetic disk. Each time the HDC / MPU 23 reads each data sector 119a-119d, the HDC / MPU 23 checks whether correct data has been read. Thus, by accessing the data sector of each data track selected with a skew, the test time of the magnetic recording test can be shortened.

  A specific process of the magnetic recording test (S14) will be described with reference to the flowchart of FIG. When the magnetic recording test is started (S141), the HDC / MPU 23 sets initial values for each variable (S142). The variables to be set are the retry count RETRY_CNT, the test cylinder TEST_CYL, the test head TEST_HD, and the test sector TEST_SCT.

  The maximum number MAX.RETRY # to be retried is assigned to the retry count RETRY_CNT, and the test cylinder number TEST_CYLINDER # is assigned to the test cylinder TEST_CYL. The maximum head number MAX.HEAD # is assigned to the test head TEST_HD, and the data sector number S # read in the cylinder TEST_CYLINDER # to be tested is assigned to the test sector TEST_SCT.

  The HDC / MPU 23 performs a write process to the data sector indicated by the variables TEST_CYL, TEST_HD, and TEST_SCT (S143). As described above, the write data is a head ID, a selection test ID, and a random number generated for each test. If the write abort is not performed and data can be written to the target sector (YES in S144), the HDC / MPU 23 sets the head element unit (TEST_HD) to be tested next (S145) and the recording surface thereof. The data sector (TEST_SCT) to be read is set (S146).

  In this example, the head element unit having the head number immediately before (one smaller than) the head element unit that has finished writing is selected (S145). That is, the adjacent head element part is selected. In order to shorten the access time, a data sector having a skew corresponding to the head switching time is selected (S146). The skew value is registered in advance in the management area of the magnetic disk 11, and the HDC / MPU 23 uses the skew value.

  If the set head number is 0 (YES in S147), since data writing by all the head element units is completed, data writing to each data track is normally completed. If the head number has not reached 0 (NO in S147), data is written into the selected data sector by the selected head element unit. This loop is repeated until the head number reaches 0, that is, until the data writing of all the head element units is completed.

  When a write abort occurs during data writing by the head element unit (NO in S144), the HDC / MPU 23 executes a write retry. Specifically, the HDC / MPU 23 returns to the first selected head element unit and repeats the write process from the beginning. The HDC / MPU 23 tries to write data to different data sectors of the same data track by the first head element unit (MAX.HEAD #). In this example, the HDC / MPU 23 executes a write process to a data sector ahead of a predetermined number of sectors. In this example, a write process to a data sector four data sectors ahead is executed (S155). Therefore, before the write retry, the HDC / MPU 23 subtracts 1 from the variable retry count RETRY_CNT, adds 4 to the variable test sector TEST_SCT, and substitutes MAX.HEAD # into the test head TEST_HD (S155). .

  If the variable retry count RETRY_CNT indicates 0 (YES in S156), it means that the specified number of retries has been executed. Therefore, the HDC / MPU 23 determines that there is an unrecoverable error in the magnetic recording test, and the test Fail determination is performed (S156). If the number of retries has not reached the specified number (NO in S156), the write process is executed from the first head element unit (MAX.HEAD #) as shown in S144 to S147.

  When the data writing process is completed, the HDD 1 next executes a data reading process. The HDC / MPU 23 substitutes MAX.HEAD # for the test head TEST_HD (S148), and starts the read verify process from the head element unit of the head number MAX.HEAD # (S149), similarly to the write process. If the read verify process is successful (YES in S150), the next head element unit is selected (S151), and the data sector to be read by the head element unit is set (S152). The head number of the selected head element unit is obtained by subtracting 1 from the number of the previous head element unit, and is an adjacent head element unit (S151). In addition, the data sector to be read is the skew read out in the data writing process with respect to the previous read data sector (S152).

  If the head number is 0 (YES in S153), since the read verify processing by all the head element units has already been completed normally, the HDC / MPU 23 normally ends the magnetic recording test (S154). If the head number is not 0 (NO in S153), there is a head element unit that has not finished read verification, so the HDC / MPU 23 continues the processing.

  If an error occurs in the read verify process by any head element unit (NO in S150), the HDC / MPU 23 resumes from the first step of the magnetic recording test, that is, the data write process. At this time, the data sector number to which data is written differs from the data sector number at the time of error occurrence by a predetermined number. Specifically, as in the case where an error has occurred in the write process, a data sector separated by 4 data sectors is selected (S155). The following processing is the same as described above.

  Next, the simultaneous test (S17) of head selection and magnetic recording will be described. In this test, as shown in FIG. 11, data is written to the same sector 120a-120d of each data track 111a-111d, each written data is read, and a confirmation process is executed. The data to be written includes a head ID (HEAD ID) that identifies each head element unit and a random number (RANDOM DATA) generated for each simultaneous test.

  Specifically, as shown in FIG. 11, the HDC / MPU 23 selects the head element unit 12a and writes data to the data sector 120a of the data track 111a. Next, after waiting for one rotation of the magnetic disk 11, data is written to the same data sector 120b of the data track 111b. Thereafter, data is written to the same data sectors 120c and 120d of the data track 111c and the data track 111d after the magnetic disk 11 is rotated.

  Subsequently, the HDC / MPU 23 executes a confirmation process for the written data. First, the HDC / MPU 23 selects the head element unit 12a, reads the data sector 120a of the data track 111a, and checks whether the data is correct data. Next, after the magnetic disk 11 makes one rotation, the read verify process of the data sector 120b of the data track 111b is performed. Thereafter, the read verify processing is performed for the same data sectors 120c and 120d of the data track 111c and the data track 111d after the magnetic disk 11 is rotated.

  By writing data in the same sector of each data track 111a-111d, a head selection test and a magnetic recording test can be performed simultaneously. For example, when the head element unit 12b is selected by mistake instead of the head element unit 12a, data corresponding to the head element unit 12b is written in the data track 111a. Therefore, since the data track 111a confirmation process reads data corresponding to the head element unit 12b, the HDC / MPU 23 can detect a head selection error.

  As will be understood from the above description, this simultaneous test requires a time of 8 rotations of the magnetic disk if it is completed without error. On the other hand, the head selection test (S12) and the magnetic recording test (S14) using pre-written test data each require time for one rotation of the magnetic disk and two rotations of the magnetic disk. Therefore, using test data written in advance shortens the time by 5 revolutions.

  The specific process of the simultaneous test (S17) is shown in the flowchart of FIG. The difference between this test flowchart (FIG. 12) and the magnetic recording test (S14) flowchart (FIG. 10) is that the flowchart of FIG. 10 includes steps S146 and S152. That is, whether or not the data sectors to be written to the data tracks 111a to 111d are arranged with a skew, and whether or not the HDC / MPU 23 waits for the rotation of the magnetic disk 11 for data writing. Therefore, detailed description of the flowchart of FIG. 12 is omitted. The correspondence of each process is as follows. S171-S175 corresponds to S141-S145, S176-S180 corresponds to S147-S151, and S181-S185 corresponds to S153-S157.

  Finally, pre-processing (S19) for the head selection test (S12) will be described. In this process, the base data for the head selection test (S12) is written to the data tracks 111a to 111d of the selected cylinder. The pre-process (S19) is executed when an error occurs in the first POR process or the head selection test (S12) in the POR process. The data to be written is as described above. Further, errors in the head selection test (S12) include test data and servo data errors, head positioning errors due to disturbance, and selection errors due to poor contact of the circuit board 20.

  Specific steps will be described with reference to the flowchart of FIG. When pre-processing for the head selection test is started (S191), the HDC / MPU 23 sets initial values for each variable (S192). The variables to be set are a cylinder CYL for writing test data, a head HEAD for writing data first, and a data sector SCT for writing data first. A predetermined cylinder number CYLINDER # is assigned to the variable CYL, the maximum head number MAX.HEAD # is assigned to the variable HEAD, and 0 is assigned to the variable SCT.

  Next, the HDC / MPU 23 sets test data to be written as background data (S193). Specifically, each data sector includes data HEAD # that specifies a head number from the 0th bit. Further, each data sector includes data representing head selection test data from the 16th bit, and ABCD1234H (hexadecimal number) is exemplified in FIG. The HDC / MPU 23 uses the set MAX.HEAD # head element section to perform test data write processing on all sectors of all data tracks in the cylinder CYLINDER # (S194).

  In this write process, if an error such as a write abort occurs in data write of any data sector (NO in S195), the data write to the error data sector is skipped and the next data • Start the sector write process. Specifically, the HDC / MPU 23 determines whether the data sector in which the error has occurred is the last data sector of the track (S199). If it is not the last data sector (NO in S199), the data sector next to the error sector is set as the write target sector (S200), and the test data write process is continued (S194).

  When an error occurs, data is not written to all data sectors of the data track, but the error is rare and even if test data is not written to a small number of data sectors. There is no substantial effect on the test time of the head selection test. on the other hand. Since rewriting to a data sector in which an error has occurred increases the processing time, it is preferable to skip as described above from the viewpoint of shortening the processing time. If the processing time of this process is not considered, rewrite processing to the error sector may be performed.

  When the error sector is the last data sector of the track (YES in S199), the HDC / MPU 23 selects the next head element unit (S196). The head number of the head element unit to be selected is obtained by subtracting 1 from the head number of the previous head element unit, and is the adjacent head. The same applies when the test data is normally written in all data sectors of the data track (YES in S195).

  The HDC / MPU 23 executes the above processing for all the head element units (a loop due to NO in S197). When the test data write process by the last head element unit is completed (YES in S197), the pre-process for the head selection test is completed (S198).

  Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, the present invention is suitable for an HDD, but can be applied to other disk drive devices. In each of the above-described processes, adjacent head element portions are sequentially selected, but the selection order of the head element portions can be changed depending on the design. For example, the head selection order of write processing and read processing can be different. In the above description, each test is performed in one test cylinder. For example, a head selection test and a magnetic recording test can be performed in different cylinders.

  Although the above example describes the head test in POR, the present invention can be applied to the head test in other modes. In order to perform a reliable head test, it is preferable to perform a head selection test and a magnetic recording test as a set as in the above example, but in other embodiments, only the head selection test is performed. Is possible.

As described above, it is preferable to write the test data of the head selection test in one or more previous POR processes. For example, in the manufacturing process such as servo write, the data is written on the magnetic disk. It is also possible. In the HDD described above, one head corresponds to one recording surface, but the HDD includes a plurality of head element units on one recording surface, and each head element unit can be tested differently from the above-described method. Alternatively, when an error occurs in the head selection test (S12) in the second and subsequent POR processes, the simultaneous test in (S17) and the result check (S18) may be skipped.

In this embodiment, it is a block diagram which shows typically the whole structure of HDD. In this embodiment, it is a figure which shows typically the structure of SPM, HDD, and HSA in HDD. It is a flowchart which shows the whole process structure of the head test of this embodiment. It is a figure which shows typically the test data read in the head selection test of this embodiment. In this embodiment, it is a figure which shows typically the head selection method in a head selection test. In the head selection test of this embodiment, it is a figure which shows typically the example in case one of head element parts cannot read test data correctly. It is a flowchart which shows the specific process of the head selection test of this embodiment. It is a figure which shows typically the other example of the test data read in the head selection test of this embodiment, and its reading method. It is a figure which shows typically the data sector to access and the access method in the magnetic recording test of this embodiment. It is a flowchart which shows the specific process of the magnetic recording test of this embodiment. It is a figure which shows typically the data sector to access and the access method in the simultaneous test of the head selection and magnetic recording of this embodiment. It is a flowchart which shows the specific process of the simultaneous test of the head selection and magnetic recording of this embodiment. In this embodiment, it is a flowchart which shows typically the process which writes the test data for a head selection test beforehand before the next POR.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Enclosure, 11 Magnetic disk, 11a-11d Recording surface 12 Head element part, 13 Arm electronics, 14 Spindle motor 15 Voice coil motor, 16 Actuator 16a-16d Suspension, 20 Circuit board, 21 R / W channel 22 Motor driver unit, 23 HDC / MPU, 24 RAM
51 Host, 111a-111d Data track

Claims (17)

One or more discs having one or more recording surfaces;
A plurality of heads accessing the one or more recording surfaces;
In response to an external trigger, each test data written before the trigger and skewed corresponding to each of the plurality of heads is read by selecting the plurality of heads in sequence. A controller that performs a selection test, and
A disk drive device comprising: The one or more discs have a plurality of recording surfaces;
Each of the plurality of heads corresponds to each of the plurality of recording surfaces,
In response to the trigger from the outside, the controller writes each of the test data written with skew to each data track of the same cylinder of the plurality of recording surfaces before the trigger. The disk drive device according to claim 1, wherein the heads are sequentially selected and read, and a head selection test is executed.   3. The disk drive device according to claim 2, wherein the test data is written in a plurality of data sectors of each data track. For each test data in each data track, the test data is written ahead of the predetermined number of data sectors in another data track,
The controller switches the head and reads the test data ahead of a predetermined number of sectors from the test data read one before.
The disk drive device according to claim 3.   3. The disk drive device according to claim 2, wherein the test data is written in all data sectors of each data track.   The disk drive device according to claim 2, wherein the test data includes data specifying a corresponding head and data representing the head selection test.   After the head selection test, the controller writes data to each of the plurality of recording surfaces while switching the head, and further reads the written data while switching the head to confirm the written data. The disk drive device according to claim 2, which is performed.   The controller writes the skewed data while switching the head to each data track of the same cylinder of the plurality of recording surfaces after the head selection test, and further writes the data while switching the head. The disk drive device according to claim 2, wherein the read data is read to check the write data.   The controller executes the head selection test in an initial setting process in response to an external trigger, and in the initial setting process prior to the initial setting process for executing the head selection test, the test data The disk drive device according to claim 2, wherein the data is written to each data track.   10. The controller according to claim 9, wherein the controller writes the test data to each of the data tracks after executing a confirmation test for confirming that a head accurately selected from the plurality of heads correctly writes data. Disk drive device.   The disk drive apparatus according to claim 10, wherein a test method of the confirmation test is different from the head selection test.   11. The disk drive device according to claim 10, wherein after the test data is written, the initial setting process is terminated without performing the head selection test. An initial setting method in a disk drive device,
In one or more recording surfaces, test data is written in advance using a plurality of heads,
In response to an external trigger received after writing the test data, start the initial setting process,
In the initial setting process, a method of performing a head selection test by sequentially selecting and reading each test data with skew corresponding to each of the plurality of heads. The disk drive device comprises a plurality of recording surfaces,
In each of a plurality of recording surfaces, using a head corresponding to each recording surface, test data is written in advance on the data track of the same cylinder,
In response to an external trigger received after writing the test data, start the initial setting process,
In the initial setting process, each test data at a position having a skew in each data track of the plurality of recording surfaces is read by sequentially selecting the plurality of heads, and a head selection test is executed. The method of claim 13.   Further, after the head selection test, data with skew was written while switching the head to each data track of the same cylinder of the plurality of recording surfaces, and the data was written while switching the head. The method according to claim 14, wherein the data is read to check the written data.   The method according to claim 14, wherein the test data is written to each of the data tracks after performing a verification test that confirms that a head selected from the plurality of heads accurately writes data.   The method according to claim 16, wherein a test method of the confirmation test is different from the head selection test.

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