JP2004127351A - Memory device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly operate a memory device when the control board is replaced in a memory device of a constitution to store the control information such as the operation parameters and defective block information. <P>SOLUTION: This memory device has at least a head to write and read information on a recording medium, a control board mounted with a nonvolatile memory, a control section to control information writing and reading on the recording medium depending on the control information read from the nonvolatile memory. The controller writes the control information to back up on the recording medium at optional timing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a storage device, and more particularly to a storage device that writes and reads information to and from a recording medium such as a disk based on operation parameters.
[0002]
[Prior art]
In a conventional hard disk drive (HDD), which is a type of storage device, operating parameters such as read parameters, write parameters, and correction values for optimally writing and reading information to and from a magnetic disk, which is a type of recording medium, are not provided. Are stored in a nonvolatile memory mounted on a control board, which is obtained in advance at a stage before shipment of each HDD. When writing or reading information to or from a magnetic disk, these operation parameters are read from the non-volatile memory, and information is written or read based on the read operation parameters.
[0003]
A general HDD has a plurality of heads and a plurality of magnetic disks, and the individual heads and magnetic disks have some characteristic variations. For this reason, depending on the combination of the head and the magnetic disk, the error rate of the write operation or the read operation increases, or in the worst case, the normal write operation or the read operation cannot be performed.
[0004]
Further, it is necessary to correct mechanical variations such as a slight dimensional error of various components constituting the HDD and a mechanical assembly error at the time of manufacturing. In particular, in recent HDDs in which the recording density has been remarkably improved, the track pitch on a magnetic disk for writing and reading information is very narrow, and mechanical variations greatly affect the performance of the HDD. Correction for variation is essential.
[0005]
On the other hand, in some HDDs, in addition to the above operation parameters, defective block information indicating a defective block on a magnetic disk is obtained in advance before shipment and stored in a nonvolatile memory on a control board.
[0006]
If the control information such as the operation parameter and the defective block information is stored on the magnetic disk, it may not be able to be normally read from the magnetic disk. Therefore, the control information is stored in the nonvolatile memory on the control board.
[0007]
Note that backup of information on a memory is proposed in, for example, Patent Documents 1 and 2, but no backup of control information in an HDD or the like is proposed.
[0008]
[Patent Document 1]
JP-A-11-85628 (page 3, FIG. 1)
[Patent Document 2]
JP-A-2000-322333 (page 4, FIG. 1)
[0009]
[Problems to be solved by the invention]
The control board may be replaced due to a failure of the control board of the HDD or the like. However, if the control board is replaced with a new control board, the non-volatile memory on the new control board does not store control information such as the above operation parameters and defective block information. There was a problem that it might not work.
[0010]
That is, since there is no means for obtaining an optimum operation parameter for the combination of the head and the magnetic disk of each HDD, the operation of the HDD using the new control board becomes unstable. In the worst case, a write error or a read error is generated. Could have occurred.
[0011]
In addition, since there is no means for obtaining defective block information of the magnetic disk of each HDD, in an HDD using a new control board, writing to and reading from an erroneous block are performed. Failure due to garbage could occur.
[0012]
Accordingly, the present invention provides a storage device having a structure in which control information such as operation parameters and defective block information is stored in a non-volatile memory mounted on a control substrate. It is an object to provide a storage device which operates.
[0013]
[Means for Solving the Problems]
The object is to provide at least one recording medium, at least one head for writing and reading information to and from the recording medium, a control substrate provided with a nonvolatile memory, and the recording medium based on control information. And control means for controlling writing and reading of information to and from the storage medium, and the recording medium can be achieved by a storage device characterized by recording the control information.
[0014]
The above object is to provide at least one recording medium, at least one head for writing and reading information to and from the recording medium, a control board provided with a nonvolatile memory, and a control read from the nonvolatile memory. Control means for controlling writing and reading of information to and from the recording medium based on the information, wherein the control means includes a backup means for recording the control information on the recording medium at an arbitrary timing and performing a backup. This can also be achieved by a storage device characterized by the following.
[0015]
Therefore, according to the present invention, in a storage device having a structure in which control information such as operation parameters and defective block information is stored in a non-volatile memory mounted on a control substrate, even if the control substrate is replaced, A storage device that operates normally can be realized.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a storage device according to the present invention will be described below with reference to the drawings.
[0017]
【Example】
FIG. 1 is a block diagram showing a configuration of an embodiment of a storage device according to the present invention. In this embodiment, the present invention is applied to an HDD for convenience of explanation.
[0018]
As shown in FIG. 1, the HDD 1 includes a control board 2 and a storage unit 3. The control board 2 is connected to a host device 4 such as a personal computer, and includes a hard disk controller (HDC) 21, a cache memory (RAM) 22, a nonvolatile memory 23 such as a flash ROM, a read / write channel 24, an MPU 25, and a motor controller. 26. The HDC 21 controls an interface for transferring data between the HDD 1 and the host device 4. The MPU 25 controls the entire HDD 1. A program (firmware) executed by the MPU 25 and control information to be described later are stored in the nonvolatile memory 23. The control board 2 has a configuration that can be replaced with the HDD 1.
[0019]
In the non-volatile memory 23, operation parameters such as read parameters, write parameters, and correction values for optimally performing writing and reading with respect to the magnetic disk 35 are obtained in advance and stored by the MPU 25 before shipment of the HDD 1. Have been. The operation parameters are stored in the nonvolatile memory 23 for each head 31 and each recording area on each magnetic disk 35. Further, in this embodiment, in addition to the operation parameters, defective block information indicating a defective block on the magnetic disk 35 is obtained and stored by the MPU 25 before shipment in the nonvolatile memory 23. The defective block information is stored in the nonvolatile memory 23 for each magnetic disk 35. The control information unique to the HDD 1 stored in the nonvolatile memory 23 is stored in, for example, a specific area in the nonvolatile memory 23, and may include at least one of the operation parameter and the defective block information.
[0020]
As shown in FIG. 1, the storage unit 3 includes one or a plurality of carriages 30, one or a plurality of heads 31, a head amplifier 32, a voice coil motor (VCM) 33, a spindle motor (SPM) 34, and one or a plurality of magnets. It consists of a disk 35.
[0021]
When writing to the magnetic disk 35, write data from the host device 4 is temporarily stored in the cache memory 22 via the HDC 21 and supplied to the head amplifier 32 via the read / write channel 24. The write data from the head amplifier 32 is written on the magnetic disk 35 rotated by the head 32. The magnetic disk 35 is rotated by the SPM 34 under the control of the motor controller 26. The carriage 30 on which the head 31 is mounted is driven in the radial direction of the magnetic disk 35 by the VCM 33 under the control of the motor controller 26. Of the data read from the magnetic disk 35 by the head 31, control data is supplied to the MPU 25 via the read / write channel 24, and the MPU 25 controls the control information read from the nonvolatile memory 23 on the control board 2. , The motor controller 26 is instructed to control the rotation of the magnetic disk 35 and the drive of the carriage 30 to the SPM 34 and the VCM 33.
[0022]
At the time of reading from the magnetic disk 35, of the data read from the magnetic disk 35 by the head 32, read data excluding control data is supplied to the HDC 21 via the read / write channel 24 and temporarily stored in the cache memory 22. Is stored. The read data in the cache memory 22 is supplied to the host device 4 via the HDC 21.
[0023]
It should be noted that the basic configuration of the control board 2 itself and the basic configuration of the storage unit 3 constituting the HDD 1 can use well-known ones, and are not limited to the basic configuration shown in FIG.
[0024]
Next, a backup process according to the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart illustrating an embodiment of the backup process. The processing shown in the figure is performed by the MPU 25 of the control board 2.
[0025]
In FIG. 2, a step S1 determines whether or not it is an arbitrary timing to back up the control information in the nonvolatile memory 23 on the control board 2 to the magnetic disk 35. If this arbitrary timing is, for example, at regular intervals, the backup processing is performed periodically. In the present embodiment, since the control information stored in the nonvolatile memory 23 includes the control information updated by a known method at an arbitrary timing, the backup processing of the control information is periodically performed. However, if the control information stored in the non-volatile memory 23 is not updated, it goes without saying that the backup process only needs to be performed once. In addition, the backup process may be performed at an arbitrary timing only for the control information to be updated among the control information stored in the nonvolatile memory 23.
[0026]
If the decision result in the step S1 is YES, a step S2 reads the control information in the nonvolatile memory 23 on the control board 2. In addition, a step S3 records the read control information in a predetermined area on the magnetic disk 35. The predetermined area on the magnetic disk 35 is not particularly limited, but is, for example, the innermost peripheral area and / or the outermost peripheral area on the magnetic disk 35. A step S4 decides whether or not the control information has been backed up for all the heads 31. If the decision result in the step S4 is NO, the process returns to the step S2. On the other hand, if the decision result in the step S4 is YES, the process returns to the normal operation of the HDD 1 such as the write operation and the read operation.
[0027]
As a result, control information for each head 31 and each magnetic disk 35 is recorded in a predetermined area on the magnetic disk 35. The predetermined area on the magnetic disk 35 where the control information is backed up may be provided at a plurality of locations on the magnetic disk 35 or may be provided at a plurality of locations on the plurality of magnetic disks 35. . That is, in the backup process, control information may be multiplexed and recorded at a plurality of locations on each magnetic disk 35 for each head 31 and each area on each magnetic disk 35.
[0028]
FIG. 3 is a diagram illustrating another embodiment of the backup process. The figure shows a case in which M magnetic disks 35-1 to 35-M are provided, and a pair of heads 31ia and 31ib are provided for each magnetic disk 35-i (i = 1 to M). Show. In this case, the predetermined area in which the control information is backed up includes the areas 31ia-1 to 31ia-3 and 31ib-1 to 31ib-3 on the magnetic disk 35-i. For example, predetermined area numbers 1 to n are assigned to these areas 31ia-1 to 31ia-3 and 31ib-1 to 31ib-3. As described above, by performing the backup process of multiplexing and recording control information at a plurality of locations on each magnetic disk 35 for each head 31 and each area on each magnetic disk 35, the nonvolatile If the control information cannot be read from the memory 23 or the control board 2 is replaced with a new control board and the control information cannot be read from the control board, even if a medium defect exists on the magnetic disk 35 or the magnetic disk 35 Thus, even if a read error occurs during the read operation, the control information unique to the HDD 1 can be reliably read from any of the multiplexed areas.
[0029]
Next, for example, a process after the control board 2 has failed and is replaced with a new control board will be described with reference to FIGS.
[0030]
FIG. 4 is a flowchart illustrating an example of processing after control board replacement. The processing shown in the figure is performed by the MPU 25 of the control board 2.
[0031]
4, step S11 is started, for example, when the power of the HDD 1 is turned on, and determines whether control information is stored in a specific area of the nonvolatile memory 23. For example, when the control board 2 is replaced, the control information unique to the HDD 1 is not stored in the specific area of the nonvolatile memory on the new control board, and the determination result in step S11 is NO. It becomes. In this case, step S12 automatically determines that the control board 2 has been replaced, and the process proceeds to step S13.
[0032]
A step S13 reads the control information from the predetermined area number n on the magnetic disk 35, and determines whether or not the reading is successful. If the decision result in the step S13 is YES, a step S14 reloads the read control information to a specific area of the nonvolatile memory 23 on the new control board, and the process returns to the step S11. On the other hand, if the decision result in the step S13 is NO, a step S15 decides whether or not the retry count N is 0. The initial value of the retry count N is previously defined on the firmware. If the decision result in the step S15 is NO, a step S16 sets the retry count to N = N-1, and the process returns to the step S13.
[0033]
If the decision result in the step S15 is YES, a step S17 decides whether or not the predetermined area number n is 0. If the decision result in the step S17 is NO, a step S18 sets n to n = n-1, and the process returns to the step S13. If the decision result in the step S17 is YES, a step S19 recognizes that the reading of the control information from the magnetic disk 35 has failed, and determines that the reading of the control information from the magnetic disk 35 has failed, for example, in the host device 4. , The process ends.
[0034]
Therefore, a retry process is performed in steps S13 and S15 to S18 until the determination result is YES in step S13.
[0035]
On the other hand, if the decision result in the step S11 is YES, a step S20 reads the control information from the specific area of the nonvolatile memory. In step S31, normal operations of the HDD 1, such as a write operation and a read operation, are performed based on the control information read from the specific area of the nonvolatile memory. In step S32, a backup process as shown in FIG. 3 is performed, and the process returns to step S31.
[0036]
FIG. 5 is a flowchart for explaining another embodiment of the processing after control board replacement. The processing shown in the figure is performed by the MPU 25 of the control board 2 except for step S21.
[0037]
5, in step S21, the operator of the host device 4 inputs information indicating that the control board 2 has been replaced to the host device 4. In response to the input of the information indicating that the control board 2 has been replaced, the host device 4 issues a control information read command instructing the HDD 1 to read control information from a predetermined area of the magnetic disk 35. A step S22 receives a control information read command from the host device 4.
[0038]
A step S23 reads the control information from the predetermined area number n on the magnetic disk 35, and determines whether or not the reading is successful. If the decision result in the step S23 is YES, a step S24 reloads the read control information to a specific area of the nonvolatile memory on the new control board, and the process proceeds to the step S31. Steps S31 and S32 are the same as steps S31 and S32 in FIG. On the other hand, if the decision result in the step S23 is NO, a step S25 decides whether or not the retry count N is 0. The initial value of the retry count N is previously defined on the firmware. If the decision result in the step S25 is NO, a step S26 sets the retry count to N = N-1, and the process returns to the step S23.
[0039]
If the decision result in the step S25 is YES, a step S27 decides whether or not the predetermined area number n is 0. If the decision result in the step S27 is NO, a step S28 sets n to n = n-1, and the process returns to the step S23. If the decision result in the step S27 is YES, a step S29 recognizes that the reading of the control information from the magnetic disk 35 has failed, and informs the host device 4 that the reading of the control information from the magnetic disk 35 has failed. , The process ends.
[0040]
Therefore, the retry process is performed in steps S23 and S25 to S28 until the determination result becomes YES in step S23.
[0041]
When the control board 2 is replaced with a new control board, since the optimal control information for the HDD 1 is not stored in the nonvolatile memory on the new control board, it is possible to read the control information from the magnetic disk 35 normally. Error rate may increase. However, by performing the retry processing, the probability of successfully reading the control information can be improved. Further, even if the reading of the control information by one of the plurality of heads 31 fails, the control information is multiplexed and recorded in a plurality of areas on the magnetic disk 35. 31 makes it possible to improve the probability that control information is successfully read. Further, since the control information is multiplexed and recorded in a plurality of areas on the magnetic disk 35, even if the reading of the control information from one area fails, the reading of the control information from another area succeeds. Can be improved. Therefore, it is possible to successfully read the control information from the magnetic disk 35 with a high probability.
[0042]
In the above embodiment, the present invention is applied to the HDD. However, information is written to and read from the recording medium using control information stored in a nonvolatile memory provided on a replaceable control board. Any storage device having the configuration can be similarly applied. Further, the recording medium used by the storage device is not limited to a magnetic disk, but may be a disk such as an optical disk or a magneto-optical disk, or a recording medium such as a magnetic, optical or magneto-optical card or tape. Needless to say.
[0043]
The present invention also includes the inventions described below.
[0044]
(Supplementary Note 1) At least one recording medium,
At least one head for writing and reading information to and from the recording medium;
A control board provided with a nonvolatile memory;
Control means for controlling writing and reading of information on the recording medium based on the control information,
The storage device, wherein the control information is recorded on the recording medium.
[0045]
(Supplementary Note 2) At least one recording medium,
At least one head for writing and reading information to and from the recording medium;
A control board provided with a nonvolatile memory;
Control means for controlling writing and reading of information to and from the recording medium based on the control information read from the nonvolatile memory,
The storage device, wherein the control unit includes a backup unit that records the control information on the recording medium at an arbitrary timing to perform a backup.
[0046]
(Supplementary Note 3) The control unit includes a unit that controls writing and reading of information to and from the recording medium based on control information read from the recording medium in response to replacement of the control board. 3. The storage device according to claim 1 or 2, wherein
[0047]
(Supplementary Note 4) The storage device according to Supplementary Note 3, wherein the control unit detects replacement of the control board when the control information is not stored in a predetermined area of the control board.
[0048]
(Supplementary note 5) The storage device according to supplementary note 3, wherein the control unit detects the exchange of the control board based on a notification from a host device.
[0049]
(Supplementary note 6) The control unit according to any one of Supplementary notes 1 to 5, wherein when the reading of the multiplexed control information on the recording medium fails, the control unit reads the multiplexed control information by a retry process. The storage device according to claim 1.
[0050]
(Supplementary Note 7) The control means reloads the control information into the non-volatile memory on the control board after the replacement when the control information is successfully read from the recording medium. The storage device according to claim 1.
[0051]
(Supplementary Note 8) The control information is at least one of an operation parameter for guaranteeing a normal write operation and a read operation by a combination of the head and the recording medium, and defective block information indicating a defective block on the recording medium. The storage device according to any one of supplementary notes 1 to 7, further comprising:
[0052]
(Supplementary Note 9) The backup unit performs the backup at the arbitrary timing only on the control information to be updated among the control information stored in the nonvolatile memory, wherein the backup unit performs the backup at the arbitrary timing. 9. The storage device according to claim 8,
[0053]
As described above, the present invention has been described with reference to the embodiments. However, it is needless to say that the present invention is not limited to the above embodiments, and various modifications and improvements are possible.
[0054]
【The invention's effect】
According to the present invention, in a storage device having a structure in which control information such as operation parameters and defective block information is stored in a non-volatile memory mounted on a control substrate, the storage device can be normally operated even when the control substrate is replaced. A storage device that operates can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of a storage device according to the present invention.
FIG. 2 is a flowchart illustrating an embodiment of a backup process.
FIG. 3 is a diagram illustrating another embodiment of the backup process.
FIG. 4 is a flowchart illustrating an example of a process after control board replacement.
FIG. 5 is a flowchart illustrating another embodiment of a process after control board replacement.
[Explanation of symbols]
1 HDD
2 Control board 3 Storage unit 23 Non-volatile memory 25 MPU
31 Head 35 Magnetic disk

Claims (5)

At least one recording medium;
At least one head for writing and reading information to and from the recording medium;
A control board provided with a nonvolatile memory;
Control means for controlling writing and reading of information on the recording medium based on the control information,
The storage device, wherein the control information is recorded on the recording medium. At least one recording medium;
At least one head for writing and reading information to and from the recording medium;
A control board provided with a nonvolatile memory;
Control means for controlling writing and reading of information to and from the recording medium based on the control information read from the nonvolatile memory,
The storage device, wherein the control unit includes a backup unit that records the control information on the recording medium at an arbitrary timing to perform a backup. 2. The apparatus according to claim 1, wherein the control unit includes a unit that controls writing and reading of information to and from the recording medium based on control information read from the recording medium in response to replacement of the control board. Or the storage device according to 2. 4. The control unit according to claim 1, wherein when the control information is successfully read from the recording medium, the control unit reloads the control information into a nonvolatile memory on the control board after the replacement. The storage device according to claim 1. The control information includes at least one of an operation parameter for guaranteeing a normal write operation and a read operation by a combination of the head and the recording medium, and defective block information indicating a defective block on the recording medium. The storage device according to claim 1, wherein the storage device is a storage device.

Images