JP3977611B2 - Disk storage device and sector replacement processing method in the same device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disk storage device to which an arbitrary sector in a replacement area secured on the disk is assigned as a replacement destination of a defective sector on the disk, and particularly has a function of determining a defective sector to be replaced. The present invention relates to a disk storage device and a sector replacement processing method in the device.
[0002]
[Prior art]
In a disk storage device using a disk as a recording medium (recording medium), a data recording unit for each track on the disk is called a sector (data sector). If there are defective sectors due to defects (scratches) among the sectors on the disk, an alternative process of assigning an arbitrary sector in the alternative area secured on the disk as an alternative sector of the defective sector is performed. It is common to execute. In the conventional disk storage device, this defective sector is detected as follows.
[0003]
First, for example, when a sector read operation fails, that is, when a sector read error occurs, a read retry (retry of the read operation) is performed. If the read can be correctly performed by performing this read retry for a predetermined number of times or more, it is determined that the corresponding sector is a defective sector to be subjected to a replacement process.
[0004]
When a defective sector is detected, an arbitrary sector in the replacement area is assigned as a replacement sector of the defective sector, and a replacement process (reassignment process) for writing the read data to the replacement sector is performed. Thereafter, access to the defective sector is replaced with access to the alternative sector. As a result, even if the defect of the defective sector progresses and the contents of the sector cannot be read, correct data can be read by accessing the alternative sector. Become.
[0005]
[Problems to be solved by the invention]
The above-described alternative processing performed in the conventional disk storage device is processing for dealing with media abnormality such as scratches occurring after the manufacturing stage of the disk storage device, that is, subsequent media abnormality.
[0006]
By the way, for example, when the disk storage device is used in an environment in which vibration is continuously applied, there is a high possibility that retry will occur more than a predetermined number of times due to the vibration. If retries occur more than a predetermined number of times, in the conventional disk storage device, a sector with a large number of retries is replaced as a subsequent defective sector having a media abnormality such as a scratch.
[0007]
Accordingly, in a disk storage device that is continuously vibrated and frequently used in an environment, many sectors are replaced. However, many of the sectors subjected to the replacement process are determined to be defective sectors because of retrying more than a predetermined number of times due to vibration, and are originally “normal sectors”.
[0008]
As described above, in a conventional disk storage device, since a sector with a large number of retries is a target for substitution processing because it is a subsequent defective sector, when used in an environment with a lot of external vibration, The substitution process is also performed on the “sector” due to vibration, and there is a possibility that the substitution area may be used up. In addition, not only in environments where there is a lot of external vibration, but also in disk storage devices used in environments where the temperature is abnormally high or low, or where the atmospheric pressure is abnormally high or low, the number of retries tends to increase. There is a possibility that the replacement process is performed on the “normal sector” and the replacement area is used up.
[0009]
The present invention has been made in view of the above circumstances, and its purpose is to prevent substitution processing for normal sectors from occurring as a result of frequent retry processing due to the use environment, and to perform substitution processing appropriately. To provide a disk storage device and a sector replacement processing method in the same device.
[0010]
[Means for Solving the Problems]
The present invention provides an environment detection means for detecting an environment in which a disk storage device is used in a disk storage device to which an arbitrary sector in an alternative area secured on the disk is assigned as a replacement destination of a defective sector on the disk. And a first determination means for determining whether or not the sector is a defective sector according to the number of retries during a read or write operation on the sector on the disk, and the first determination means If it is determined that there is a second sector, the second sector is determined to determine whether the cause of the defective sector is in the usage environment of the disk storage device detected by the environment detector; An alternative processing means for executing an alternative process assigned to an arbitrary sector in an area, wherein the cause determined as a defective sector is a disk storage device If it is determined by the in use environment said second determination means, the sector is characterized in that a substitute processing means for suppressing the alternative process as a normal sector.
[0011]
As described above, according to the present invention, when a defective sector is determined according to the number of retries during a read or write operation on a sector on the disk, an alternative process of assigning the sector as it is to an arbitrary sector in the alternative area is performed. Instead of executing, it is determined whether or not the cause determined as the defective sector is in the use environment of the device, and the replacement process of the sector is performed only when it is determined as the defective sector due to a cause other than the use environment of the device. If the sector is determined to be a defective sector due to the use environment of the apparatus, the replacement process is suppressed because the sector is originally a normal sector.
[0012]
As a result, it is possible to prevent the originally normal sector from being subjected to the replacement process due to temporary deterioration of the use environment of the apparatus, and to prevent the replacement area from being consumed unnecessarily.
[0013]
Here, an environment counter is provided for counting the number of retries caused by the use environment of the disk storage device detected by the environment detection unit during the retry in the read or write operation, and the second determination unit This determination, that is, whether or not the cause of the defective sector being determined by the first determining means is in the usage environment of the disk storage device, may be determined based on the value of the environment counter.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments in which the present invention is applied to a magnetic disk apparatus will be described below with reference to the drawings.
[0015]
FIG. 1 is a block diagram showing a configuration of a magnetic disk apparatus according to an embodiment of the present invention.
[0016]
In the magnetic disk device (hereinafter referred to as HDD) 1 in FIG. 1, 11 is a disk (magnetic disk medium) as a recording medium on which data is magnetically recorded, 12 is data writing (data recording) to the disk 11 and disk 11 This is a head (magnetic head) used for reading data from (reproducing data) from. The head 12 is provided corresponding to each recording surface of the disk 11. In the configuration of FIG. 1, an HDD including a single disk 11 is assumed, but an HDD in which a plurality of disks 11 are stacked may be used.
[0017]
On each recording surface of the disk 11, a user area 11a that can be used by a user, a replacement area 11b in which a replacement track as a replacement destination of a defective sector is secured, and information (system management information) necessary for system management are stored. Management area 11c to be assigned. The system management information includes defective sector management information indicating a correspondence relationship between the defective sector and a replacement destination sector of the sector. The alternative area 11b and the management area 11c are non-user areas that are used only by the system, that is, not visible to the user. An area obtained by combining the alternative area 11b and the management area 11c is called a system area. Only the management area 11c may be referred to as a system area.
[0018]
The disk 11 is rotated at high speed by a spindle motor (hereinafter referred to as SPM) 13. The head 12 is attached to an actuator (rotary head actuator) 14 as a head moving mechanism, and moves in the radial direction of the disk 11 according to the rotation (angular rotation) of the actuator 14. As a result, the head 12 is sought and positioned at the target position of the target track. The actuator 14 has a voice coil motor (hereinafter referred to as VCM) 15 that is a driving source of the actuator 14, and is driven by the VCM 15. The SPM 13 and the VCM 15 are driven by drive currents (SPM current and VCM current) respectively supplied from the VCM / SPM driver 16.
[0019]
The CPU 17 serves as a main control unit of the HDD 1 and controls the entire HDD 1 and the VCM / SPM driver 16 in a time-sharing manner.
[0020]
The CPU 17 is connected to the CPU bus 18. The CPU bus 18 includes a ROM 19 that stores a program (control program) to be executed by the CPU, a RAM 20 that is used as a work area and a variable area that the CPU 17 uses, and a disk controller (hereinafter referred to as HDC). ) 21 and a gate array 22 for generating various signals necessary for controlling the HDD 1 are connected.
[0021]
In the RAM 20, areas for a retry counter 20a and a vibration counter 20b are secured. The retry counter 20a is a down counter that is decremented by one every time a data read failure from the disk 11 occurs. The retry counter 20a is always subtracted regardless of the cause of the data read failure. The vibration counter 20b is an up-counter that is incremented by 1 only when data read failure occurs and the cause of the failure is vibration.
[0022]
The HDC 21 and the gate array 22 have a control register group (not shown). This control register group is assigned to a part of the memory area of the CPU 17, and the CPU 17 controls the HDC 21 and the gate array 22 by reading and writing to this area.
[0023]
The head 12 is connected to a head IC (head amplifier circuit) 23. The head IC 23 has a read amplifier that amplifies a read signal read by the head 12 and a write amplifier that converts write data into a write current. The head IC 23 is connected to a read / write IC (read / write channel) 24. The read / write IC 24 executes various signal processing such as A / D (analog / digital) conversion processing, write data encoding processing, and read data decoding processing for the read signal.
[0024]
In addition to the CPU bus 18, the HDC 21 is connected to a gate array 22, a read / write IC 24, a gate array 22, and a buffer RAM 25. The HDC 21 is also connected via a host interface 3 to a host system 2 such as a personal computer that uses the HDD 1.
[0025]
When a read command is executed from the host system 2, the data signal recorded in the area on the disk 11 designated by the command is read by the head 12. A signal (analog signal) read by the head 12 is amplified by the head IC 23 and encoded by the read / write IC 24. The HDC 21 processes the data encoded by the read / write IC 24 according to each control signal from the gate array 22 to generate data (read data) to be transferred to the host system 2. This data is once stored in the buffer RAM 25 and then transferred to the host system 2.
[0026]
When executing a write command from the host system 2, the data (write data) transferred from the host system 2 to the HDC 21 is temporarily stored in the buffer RAM 25 and then encoded by the HDC 21 in accordance with each control signal from the gate array 22. And transferred to the read / write IC 24. The write data encoded by the HDC 21 is converted into a signal for writing by the read / write IC 24, guided to the head 12 via the head IC 23, and the area designated by the command of the disk 11 by the head 12. Is written to.
[0027]
A vibration detection mechanism 26 that detects vibration (vibration) applied to the HDD 1 is connected to the gate array 22. The vibration detection result by the vibration detection mechanism 26 is periodically read into the gate array 22 and converted into a digital value, and held in a predetermined vibration register in the gate array 22.
[0028]
Next, an overall flow of command processing in the HDD 1 having the configuration shown in FIG. 1 will be described with reference to the flowchart of FIG.
When the CPU 17 in the HDD 1 performs processing for starting the HDD 1 when the apparatus is turned on, etc., the CPU 17 enters a command wait loop waiting for a command to be transferred from the host system 2 (step 101).
[0029]
When the command is transferred from the host system 2 and received by the HDC 21 in a command waiting loop, the CPU 17 receives the command from the HDC 21 and interprets it (step 102).
[0030]
As a result of command interpretation, if the received command is other than a read command, the CPU 17 performs processing according to the command. Then, the CPU 17 sets an end status corresponding to the result for notifying the host system 2 of the result of command processing (step 120), ends the command (step 107), and then waits for a command waiting loop (step 101). Return to).
[0031]
On the other hand, if the received command is a read command, the CPU 17 controls the VCM / SPM driver 16 to move the head 12 to a track (target track) on the HDD 1 in which data designated by the command is recorded. Seek control is performed (step 103). Then, the CPU 17 starts read control (step 104) for sequentially reading data from the head sector on the target track designated by the command. With this read control, the CPU 17 permits the start of data transfer from the HDC 21 to the host system 2, and data normally read from the target track on the disk 11 is transferred from the HDC 21 to the host system 2 via the buffer RAM 25. To be controlled.
[0032]
When the read operation (disk read operation) designated by the read command from the host system 2 is completed, the CPU 17 checks whether or not an error has occurred in the read operation (step 105).
[0033]
If an error has occurred, the CPU 17 sets the error content in the end status notified from the HDC 21 to the host system 2 (step 110), ends the command (step 107), and then waits for a command waiting loop ( Return to step 101).
[0034]
On the other hand, if no error has occurred, that is, if the read operation has been performed normally, the CPU 17 sets the content indicating normal termination in the termination status (step 106) and terminates the command (step 107). Thereafter, the process returns to the command wait loop (step 101).
[0035]
Next, details of the read operation in the HDD 1 of FIG. 1 will be described with reference to the flowchart of FIG.
At the start of the read operation, the CPU 17 sets the head address (access start sector address) designated by the read command from the host system 2 in the access start address register in the HDC 21 (step 201). Further, the CPU 17 initializes the retry counter 20a and the vibration counter 20b (regions thereof) arranged in a predetermined region on the RAM 20 (step 202). Here, the initial value of the retry counter 20a is an upper limit value (the upper limit retry number) N of the number of retries, and the initial value of the vibration counter 20b is 0.
[0036]
In the present embodiment, if data read from the disk 11 fails, a retry is performed with the number N as the upper limit. The retry counter 20a and the vibration counter 20b secured in the RAM 20 are used for managing the number of retries and for performing the reassignment determination. Reassignment means assigning an arbitrary sector (empty sector) in the replacement area 11b secured on the disk 11 as a replacement destination of the defective sector.
[0037]
When the CPU 17 initializes the retry counter 20a and the vibration counter 20b, the CPU 17 performs control for reading data from the disk 11 (step 203). If an error occurs during a data read operation from a certain sector (sector block) and a read error is detected (determined) (step 204), the CPU 17 performs processing for retrying the read operation as follows. Do.
[0038]
First, the CPU 17 checks whether or not the cause of the read error is external vibration by referring to the vibration register in the gate array 22 (step 210). The CPU 17 increments the value of the vibration counter 20b by 1 only when the cause of the read error is external vibration (step 211). Then, the CPU 17 decrements the value of the retry counter 20a by 1 regardless of the cause of the read error (step 212).
[0039]
When executing the step 212, the CPU 17 checks whether or not the value of the retry counter 20a after the decrement in the step 212 is 0 (step 213). If the value of the retry counter 20a is not 0, the CPU 17 returns to step 203 to execute the read operation again in order to continue retrying the sector block in which the read error has occurred.
[0040]
On the other hand, when the value of the retry counter 20a is 0, the CPU 17 determines that the error cannot be read correctly even if the retry is executed N times, that is, the upper limit retry count, and notifies the host system 2 from the HDC 21. The contents indicating the error are set in the end status to be executed (step 214), and the read operation is ended (step 209).
[0041]
If it is determined in step 204 that no read error has occurred in the state determination (read error determination), the CPU 17 determines whether or not the corresponding sector block needs to be reassigned as follows. Judgment.
[0042]
First, the CPU 17 reads the value of the retry counter 20a, and determines whether or not the read retry operation has been performed for the first specified number of times n (n is an integer satisfying n <N) (step 205). If the first specified number of times n or more has not been retried, that is, if the data can be read correctly from the sector block without performing n or more retries, the CPU 17 determines that the sector is not defective. . In this case, the CPU 17 sets the content indicating normal end in the end status (step 208), and ends the read operation (step 209).
[0043]
On the other hand, when retrying has been performed for the first specified number of times n or more, that is, when reading has been correctly performed from the sector block by performing retrying n times or more, the CPU 17 temporarily determines that the sector block is a defective sector. Then, the CPU 17 reads the value of the vibration counter 20b in order to determine whether the sector block tentatively determined as a defective sector is a defective sector block or a normal sector block, and the value is the second specified value. It is determined whether or not the number of times is greater than or equal to m, that is, whether or not m times or more of n or more retries are caused by vibration (external vibration) (step 206). Here, the first specified number of times n is set to N or less, that is, a value equal to or less than the initial value of the retry counter 20a, and the second specified number of times m is set to a value equal to or less than the first specified number of times n.
[0044]
Even if retries of the first specified number of times n or more have been performed, from the value of the vibration counter 20b, out of the retries of n times or more, the second specified number of times m or more is a retry caused by vibration. For example, the CPU 17 determines that the corresponding sector block on the disk 11 is not defective and that the sector block is suitable for recording and reproduction. In this case, the CPU 17 sets the content indicating normal end in the end status (step 208), and ends the read operation (step 209).
[0045]
On the other hand, if the retry is performed n times or more and the retry due to vibration is less than the second specified number m of the n or more retries (step 206), the CPU 17 It is determined that the cause is not due to vibration but due to a defect such as a scratch on the corresponding sector block. In this case, the CPU 17 assumes that the corresponding sector block is a real defective sector (subsequent defective sector), assigns an arbitrary empty sector in the alternative area 11b of the disk 11 to the defective sector, and steps to the alternative sector. A reassign process (alternative process) for writing data that has been successfully read in 203 is executed (step 207). Then, the CPU 17 sets the content indicating normal end in the end status (step 208), and ends the read operation (step 209).
[0046]
As described above, in the present embodiment, even when a read operation can be correctly performed with n or more retries, if the number of retries caused by vibration among the n or more retries is m or more, this is true. Since the sector block is normal and suitable for recording and reproduction, reassignment processing is suppressed. Thereby, it is possible to prevent a substitute process for a normal sector from occurring due to a retry caused by vibration, and to prevent the substitute area 11b from being consumed unnecessarily.
[0047]
In the above embodiment, the case of a read error in which data cannot be correctly read from the target sector block in the read operation has been described. However, the present invention is not limited to this. For example, the present invention can be similarly applied to a write error in which a target sector block cannot be detected by a write operation. That is, even if the write operation can be performed correctly with n or more retries, if the retry due to vibration is m times or more among the n or more retries, the corresponding sector block is normal and is recorded / reproduced. The reassignment process is suppressed as it is suitable.
[0048]
In the above-described embodiment, a case has been described in which a substitute process for a normal sector is prevented from occurring due to a retry caused by vibration. However, the present invention is not limited to this. In other words, there are various reasons other than vibrations that cause a retry even though it is normally a normal sector. For example, there are a temperature that affects the characteristics of the head 12 and the rotational accuracy of the SPM 13 (temperature at which the HDD 1 is placed), an atmospheric pressure that affects the flying height of the head 12 (atmospheric pressure at which the HDD 1 is placed), and the like. That is, when the temperature is too high or too low, the atmospheric pressure is too high, or too low. As described above, even in an environment where the HDD 1 is used other than the vibration, if the environment is out of the specified environmental conditions, a retry may occur, and an alternative process may occur although it is normally a normal sector. . Therefore, even if a read / write operation can be performed correctly with n or more retries, if the number of retries due to the use environment is m or more during the n or more retries, the corresponding sector is normal. It is preferable to suppress the reassignment process as being suitable for recording and reproduction. Here, the values of n, m, and N may be set separately for reading and writing.
[0049]
In the embodiment described above, the case where the present invention is applied to an HDD (magnetic disk device) has been described. However, the present invention is not limited to this, and the present invention is also applicable to a disk storage device other than an HDD such as a magneto-optical disk device. Applicable.
[0050]
In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not deviate from the summary. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.
[0051]
【The invention's effect】
As described above in detail, according to the present invention, when a sector is determined as a defective sector according to the number of retries during a read or write operation on a sector on the disk, the cause of the determination as a defective sector is the use environment of the apparatus. If the sector is determined to be a defective sector due to the use environment of the apparatus, the replacement process is suppressed because the sector is originally a normal sector. However, it is possible to prevent substitution processing due to temporary deterioration of the use environment of the apparatus, and to prevent the substitution area from being consumed unnecessarily.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a magnetic disk device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the overall flow of command processing in the embodiment;
FIG. 3 is a flowchart for explaining details of a read operation in the embodiment;
[Explanation of symbols]
1 HDD (magnetic disk device, disk storage device)
2 ... Host system 11 ... Disk 11a ... User area 11b ... Alternative area 11c ... Management area 12 ... Head 17 ... CPU
20 ... RAM
20a ... retry counter 20b ... vibration counter (environment counter)
21 ... HDC (disk controller)
26. Vibration detection mechanism (environment detection means)

Claims (2)

In a disk storage device to which an arbitrary sector in an alternative area secured on the disk is assigned as a replacement destination of a defective sector on the disk,
Vibration detecting means for detecting vibration applied to the disk storage device;
Retry control means for controlling the retry of the read operation within the range of the upper limit retry count when an error occurs in the read operation for the sector on the disk;
Whenever an error occurs in the retry of the read operation, it is checked whether or not vibration is detected by the vibration detecting unit, and when the vibration is detected, the first determining unit determines that the cause of the error is vibration. When,
A vibration counter that counts the number of times determined by the first determination means that the cause of the error is vibration during the retry period of the read operation;
In the retry period of the read operation, when data can be normally read from the sector with a retry less than the first specified number of times, it is determined that the sector is a normal sector, and the data exceeds the first specified number of times. When data can be normally read from the sector by retrying, by determining whether the value of the vibration counter at that time is equal to or more than a second specified number of times less than the first specified number of times, Second determination means for determining whether the sector is a normal sector or a defective sector to be subjected to a replacement process in which an arbitrary sector in the replacement area is assigned to the sector ;
An arbitrary sector in the replacement area is assigned as a replacement destination of the sector determined to be a defective sector by the second determination means, and the sector determined to be the defective sector is assigned to the arbitrary sector. An alternative processing means for executing an alternative process of writing data read normally by retry ;
An end status setting means for setting an end status for notifying the host system of an error when data cannot be read normally even after retrying the upper limit retry count . In a sector replacement processing method in a disk storage device that allocates an arbitrary sector in a replacement area secured on the disk as a replacement destination of a defective sector on the disk,
When an error occurs in a read operation on a sector on the disk, executing a retry of the read operation within a range of the upper limit number of retries;
Each time an error occurs due to the retry of the read operation, it is checked whether vibration applied to the disk storage device is detected by the vibration detection means provided in the disk storage device, and if vibration is detected, an error is detected. Determining that the cause of the vibration is vibration,
Incrementing a vibration counter provided in the disk storage device each time it is determined that the cause of the error is vibration during the retry period of the read operation;
Determining that the sector is a normal sector when data can be normally read from the sector with a retry less than the first specified number of times during the retry period of the read operation;
When data can be normally read from the sector by retrying the first specified number of times or more, the value of the vibration counter at that time is equal to or more than the second specified number of times less than the first specified number of times. Determining whether the sector is a normal sector or a defective sector to be subjected to a replacement process in which an arbitrary sector in the replacement area is assigned to the sector;
The assign any sector in the alternate area as an alternative destination of the determined sector to be the defective sector, to the arbitrary sector successfully be read by the retry from the determined sector to be the defective sector Executing an alternative process of writing the data ,
A step of setting an end status for notifying the host system of an error when data cannot be read normally even after retrying the upper limit retry count; and
A sector replacement processing method in a disk storage device comprising :

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