JP3754199B2 - Disc recording / reproducing apparatus and error processing method applied to the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disk recording / reproducing apparatus which is applied to, for example, a hard disk drive and has an error processing function.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a disk recording / reproducing apparatus such as a hard disk drive (HDD) has a mechanical mechanism for reading / writing data from / to a disk storage medium (hereinafter simply referred to as a disk) by a head. For this reason, when an impact (shock) is received from the outside during the operation, there is a high possibility that a situation will occur in which the head moves out of the allowable range after being positioned at a specified position on the disk. In particular, when a shock occurs during data write operations, the head moves from a specified track to a nearby track, such as an adjacent track, and data is written (overwrite), destroying the data recorded on that track. It becomes a situation to do.
[0003]
In order to prevent such a situation, there is a device provided with a shock sensor for detecting an impact in the main body of the HDD, and having a function of stopping the write operation when the impact is detected by the shock sensor. .
[0004]
[Problems to be solved by the invention]
As described above, in an HDD using a shock sensor, the write operation can be stopped when an impact is detected. However, the detection performance of the shock sensor is, for example, 0. Since there is a delay time of several μs, there is a high possibility that most of the data of adjacent tracks such as adjacent tracks will be destroyed by this delay time.
[0005]
Therefore, a method has been proposed in which data destroyed by impact is recovered by error correction processing using an error correction code (referred to as ECC data). In a normal HDD, ECC data that can be subjected to error correction processing in units of sectors is recorded at the end of each sector. However, since such ECC data can only correct recording data in units of sectors, error correction is impossible when the entire track or the ECC data itself is destroyed. For this reason, as a method of using ECC data, ECC data in units of tracks (usually, ECC recorded after the last sector of each track) is used to perform error correction processing in units of tracks and the sectors described above. A method that combines unit error correction processing has been proposed.
[0006]
In this method, when a read error occurs when a read operation is performed from a track in which data is destroyed, error correction processing using ECC data in units of sectors is first executed. Shift to correction processing. In other words, the retry process associated with the occurrence of a read error requires a read operation according to a two-step procedure, and requires a processing time corresponding to at least one disk rotation time. Such retry processing is executed every time a read request is made to a track in which a read error occurs (that is, a track whose data is destroyed due to an impact).
[0007]
Therefore, an object of the present invention is to reduce the processing time required for retry processing accompanied by error correction processing from a data area such as a track in which a read error caused by data destruction due to external impact is generated, and as a result. The object is to improve the data recovery performance against shock and the like.
[0008]
[Means for Solving the Problems]
The present invention performs error correction processing and data recovery processing when a read error occurs due to a read operation on a sector to be accessed, particularly when the recording data of the sector to be accessed is destroyed due to an external impact during a write operation. And a disk recording / reproducing apparatus having error correction means. Furthermore, when this apparatus detects a read error again from the recovered data recovered by the data recovery process, it sets a data destruction flag indicating that the recording data of the sector has been destroyed, and a read error is detected from the recovered data. When it is not detected, it has a control means for executing a write operation so as to re-record the recovery data in the sector.
[0009]
Specifically, the error correction means corrects the read data from the sector using ECC data recorded in the sector where the read error has occurred, and recovers the normal recorded data. The control means executes an error determination process for the recovery data, and if an error does not occur from the recovery data, the control means executes a write operation so as to re-record in the sector. As a result, normally recovered recording data is re-recorded in a sector whose data has been destroyed due to an external impact, so that error correction processing is executed each time the sector is accessed. No special processing is required.
[0010]
On the other hand, when an error occurs again due to the error determination process for the recovery data, the control means sets a data destruction flag indicating that the recording data of the sector is destroyed. An error correction function can be improved by providing track error processing means for executing error correction processing and data recovery processing of a track including the sector by using the data destruction flag. Specifically, the track error processing means executes error correction processing and data recovery processing for all data of the track including the sector, using ECC data for each track recorded in each track. Then, the write operation is executed so that the recovery data for each track recovered by the data recovery processing is re-recorded on the track.
[0011]
As another aspect of the present invention, there is provided an impact detection means (shock sensor) for detecting an impact from the outside, and when an impact is detected during a data write operation, an impact flag indicating the detection of the impact is set, and the write A disk recording / reproducing apparatus having means for storing a track number to be accessed for operation. Furthermore, when the impact flag is set, the apparatus activates an estimation unit and an error processing unit that estimate a track in which data destruction has occurred.
[0012]
That is, the estimation means estimates that, for example, a range of ± 3 tracks is a data area in which data destruction has occurred with reference to the track number stored together with the impact flag. This is based on the assumption that there is a high possibility that the head will move within a range of ± 2 tracks from the track during the write operation due to an external impact. The error processing means executes error detection processing and error correction processing for each track in the estimated range. Here, it is desirable that the error processing means execute the error correction processing and error recovery processing in units of sectors as described above, and execute error correction processing and error recovery processing in units of tracks.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the main part of the HDD related to this embodiment, FIG. 2 and FIG. 3 are conceptual diagrams showing the configuration of the disk related to the first embodiment, and FIG. 4 and FIG. It is a flowchart for demonstrating operation | movement of 1st Embodiment.
(System configuration)
In the present embodiment, as shown in FIG. 1, a hard disk drive (HDD) is assumed as a disk recording / reproducing apparatus, and a disk 1 is used as a disk storage medium. The HDD includes a head 2 that reads / writes data from / to the disk 1 and a head actuator 3 that holds and moves the head 2. The disk 1 is rotated at high speed by a spindle motor (SPM) 5. The head actuator 3 is a head moving mechanism that is driven by a voice coil motor (VCM) 4 to move (seek) the head 2 in the radial direction of the disk 1 to position the head 2 at a target position (access target track). .
[0014]
The head 2 is composed of an inductive head that is also used for recording / reproducing or a recording / reproducing separated head. The recording / reproducing separated type head is usually composed of a read head made up of MR (magnetoresistive) elements and a write head made up of an induction type head. The HDD has a head amplifier circuit 6 and a read / write circuit 7 for processing a read signal read from the head 2 and a write signal supplied to the head 2, respectively. The head amplifier circuit 6 has a reproduction amplifier for amplifying the read signal and a recording amplifier for amplifying the write signal. The read / write circuit 7 comprises a dedicated IC (also referred to as a read channel), and executes read / write signal processing related to the recording / reproducing operation.
[0015]
Furthermore, the HDD includes a servo circuit 8, a microprocessor (CPU) 9, a memory 10, a disk controller (HDC) 11, and a motor driver 12. The HDC 11 constitutes an interface between the HDD and a host system (a host computer such as a personal computer) 13 and executes transfer control of read / write data mainly according to a read / write command from the host system 13. Further, the HDC 11 has a function of executing error correction processing and data recovery processing using ECC data related to the present embodiment.
[0016]
The servo circuit 8 is a circuit for extracting servo data recorded in the servo area from the read signal reproduced by the read / write circuit 7. The read signal is read by the read head of the head 2 and input to the read / write circuit 7 via the reproduction amplifier. Servo data is used for positioning control of the head 2 by the CPU 9.
[0017]
The CPU 9 constitutes a main control device of the HDD, and executes read / write operation control and head 2 positioning control. The CPU 9 executes control of error correction processing and data recovery processing related to the present embodiment. In addition to the program of the CPU 9, the memory 10 stores flag information (DD flag 10a and SS flag 10b, which will be described later) related to the present embodiment and a track number (see the second embodiment) at the time of impact detection. The motor driver 12 has a D / A converter for inputting a control amount (digital value) for head positioning control calculated by the CPU 9 and converting it into a drive current for driving the VCM 4. The motor driver 12 generates a drive current for driving the spindle motor 5. Furthermore, the HDD according to the present embodiment has a shock sensor 14 for detecting an impact from the outside, for example, in the vicinity of the head actuator 3 in the drive. In response to a detection signal from the shock sensor 14, the CPU 9 performs error processing (error determination processing or retry processing) described later when an impact outside the allowable range (particularly, occurrence of data destruction during a write operation) is received. Execute.
(First embodiment)
In the HDD, a first embodiment relating to error processing in units of sectors and tracks will be described with reference to FIGS.
[0018]
First, as shown in FIG. 2, one surface of the disk 1 of the same embodiment includes a central portion 22 including a rotation shaft hole of the spindle motor 5 and a CSS area, and a data area 20. In the data area 20, a large number of concentric tracks 21 are arranged. As shown in FIG. 3, each track 21 is divided into a plurality of sectors (data sectors) 30, for example, about 50. Each sector 30 has a data area for recording data and an area of ECC data for use in error correction processing.
[0019]
In the data area 20, for example, 50 servo areas 23 are arranged at a predetermined interval at the same position in the radial direction. Servo area 23 is recorded with servo data to be used for head 2 positioning control (seek control and track following control). Note that the HDD normally uses a plurality of discs 1, but in the present embodiment, it is assumed that only one surface is used for convenience.
(Operation of the first embodiment)
In the present embodiment, it is assumed that the CPU 9 seeks and positions the head 2 to the designated track to be accessed and executes a read operation in response to a read request from the host system 13 (steps S1 and S2). . The CPU 9 executes a read operation in units of sectors for reading and reproducing the recording data from the sectors 30 included in the designated track. In the read operation, a read signal read by the read head of the head 2 is signal-processed by the read / write circuit 7 and sent to the HDC 11. If there is no read error in the error determination process, the HDC 11 transfers the read sector unit read data (reproduced data) to the host system 13 (NO in steps S3 and S4).
[0020]
Here, it is assumed that, during a write operation before the read operation, the HDD receives an impact from the outside and the recording data of the sector to be accessed is destroyed. That is, the HDC 11 detects that a read error has occurred from the read data that has been read by error determination processing (YES in steps S3 and S4). Here, in the present embodiment, the CPU 9 causes the HDC 11 to execute error correction processing and data recovery processing using the ECC data of the sector (step S5).
[0021]
Further, the CPU 9 executes an error determination process on the data recovered by the data recovery process (recovered data obtained by recovering the recording data of the sector). If the recovery data is normal by this error determination process, the CPU 9 causes the write operation to re-record the recovery data in the sector (NO in step S6, S8). That is, the recording data (sector data) recovered by the error correction process and the data recovery process is re-recorded in the sector where the read error has occurred.
[0022]
On the other hand, when an error occurs again from the recovered data by the error determination process, the CPU 9 sets a data destruction flag (DD flag) 10a indicating data destruction in the memory 10 (step S7). That is, there is a high possibility that not only the recording data but also the ECC data is destroyed in the sector due to an external impact. Therefore, sector-by-sector error correction processing and data recovery processing using the sector ECC data are impossible.
[0023]
The CPU 9 executes the error processing (error determination processing, error correction processing, data recovery processing, and error determination processing again) for all sectors of the designated track (step S9). Next, when the DD flag 10a is set with reference to the memory 10, the CPU 9 proceeds to a track error determination process (YES in step S10, S11). In the track error determination process, the CPU 9 reads all data (record data of all sectors) from the track including the sector where the error has occurred, and executes the error determination process (steps S20 and S21).
[0024]
In this embodiment, as shown in FIG. 3, ECC data 31 that can be subjected to error correction processing in units of tracks is recorded after the last sector 30 in each track. The HDC 11 executes error determination processing for all data read from the track based on the ECC data 31 under the control of the CPU 9.
[0025]
When an error occurs due to this error determination process, the CPU 9 causes the HDC 11 to perform error correction processing and data recovery processing for each track using the ECC data 31 (step S23). Further, the CPU 9 executes an error determination process on the data recovered by the data recovery process (recovered data obtained by recovering all recorded data of the track). If the recovery data is normal by this error determination process, the CPU 9 causes the write operation to re-record the recovery data on the track (NO in step S24, S25). That is, the recording data (track data) recovered by the error correction process and the data recovery process is re-recorded on a track including a sector that cannot be recovered due to a read error.
[0026]
On the other hand, if an error occurs again from the recovered data by the error determination process, the CPU 9 determines that the error correction process and the data recovery process in units of tracks are impossible, and shifts to the conventional alternative process (step S24). YES, S26). In the replacement process, the sector in which an error has occurred is disabled as a defective sector, and a replacement sector included in the track is set. In addition, a track including the defective sector cannot be used as a defective track, and an alternative track prepared in advance is set.
[0027]
As described above, according to the present embodiment, when the recording data of the sector to be accessed is destroyed due to the impact during the write operation, error correction processing and data recovery processing are performed using the ECC data of the sector. Execute. If the recovery data obtained by this data recovery process is normal by the error determination process, it is re-recorded in the sector. Therefore, when the sector is re-accessed, normal re-recorded data is reproduced without causing a read error. In other words, conventionally, error correction processing is executed every time a sector in which a read error has occurred is accessed, but in this embodiment, error correction processing is performed only once, and thereafter normal read operation is performed. That is, after recovering the recording data by the data recovery processing (which constitutes the original recording data including not only error correction but also normal data), in order to re-record the recovery data as recording data, The number of times can be greatly reduced.
[0028]
If error correction and data recovery are impossible in the error correction processing and data recovery processing in units of sectors due to the destruction of the ECC data itself, the data destruction flag (DD flag 10a) is set. Based on the set of the DD flag, the process proceeds to error correction processing and data recovery processing in units of tracks. The destruction of the ECC data itself is determined by a determination process using, for example, a CRC (cyclic redundancy code) added to the ECC data. If the recovery data for each track is normal, the recovery data is re-recorded on the track. Therefore, as described above, it is not necessary to execute an error correction process every access, and a normal read operation is performed by one error correction process and data recovery process. As a result, it is possible to shorten the processing time of the retry process associated with the occurrence of an error.
(Second Embodiment)
In the second embodiment, when a write operation is performed when an external impact is received, there is a possibility that data is erroneously written to a track other than the track to be accessed and the recorded data is destroyed. It is related to the function of estimating the track where the data destruction has occurred, assuming that the data is high. Hereinafter, a specific description will be given with reference to FIGS.
[0029]
In this embodiment, as shown in FIG. 6, the CPU 9 assumes a state in which the head 2 is positioned on the track of the track number (N) as the designated track to be accessed and the write operation is executed (step S30). , S31). In this state, when the CPU 9 senses that it has received an external shock from the detection signal from the shock sensor 14, it sets a shock detection flag (SS flag 10b) in the memory 10 (YES in step S32, S33). Along with the setting of the SS flag 10b, the CPU 9 stores the track number (N) during the write operation in the memory 10 (step S34).
[0030]
After executing such processing, the CPU 9 estimates the retry processing due to the impact, that is, the track where the data destruction has occurred, and executes predetermined error processing (the above-described error determination processing, error correction processing, data recovery processing). (Refer to the flowchart of FIG. 8).
[0031]
First, the CPU 9 refers to the memory 10 to confirm the setting of the SS flag 10b and identifies the track number (N) at the time of setting (when an impact occurs) (YES in step S40, S41). Here, the CPU 9 sets a predetermined value (here, 2) as the offset value OF for setting the range of the track where the data destruction has occurred (step S42). As shown in FIG. 6, the offset value is set (OF = 2) with a range of ± 2 tracks (track numbers (N + 2) to (N− 2)).
[0032]
Based on the offset value OF, the CPU 9 causes an error determination process to be executed for tracks in the set range (steps S43 to S45). That is, here, the head 2 is sought to the track of the track number (N + 2), and the read operation is executed. The HDC 11 performs an error determination process on the recording data of the track obtained by the read operation under the control of the CPU 9. The CPU 9 executes such a series of processes for all tracks in the set range (steps S46 to S53).
[0033]
Here, as described in the first embodiment, the error determination process of the embodiment is performed by performing error correction and data recovery process from the error determination process for each sector at first, and then further for each track. Shift from error determination processing to error correction and data recovery processing. Therefore, also in the embodiment, when the recording data of a sector with a track number (N + 2) is destroyed due to the impact, for example, error correction and data recovery processing for each sector is first executed. Is done. If data recovery is impossible by this sector unit error processing, track unit error correction and data recovery processing are executed. If data recovery is impossible even in the error processing for each track, the processing shifts to alternative processing. The above error processing is executed for all the set tracks (track numbers ± N + 2, ± N−1).
[0034]
As described above, according to the present embodiment, when it is detected that the shock is received from the shock sensor 14 during the write operation, the SS flag 10b is set and the track number during the write operation is stored. When an impact is received during the write operation, there is a high possibility that the head during the write operation moves to a nearby track and erroneous data writing is performed, resulting in the destruction of the recorded data. For this reason, in this embodiment, it is estimated that the recording data is destroyed in the range of several nearby tracks on the basis of the track during the write operation. Then, by executing the error processing (error determination processing, error correction processing, data recovery processing) described in the first embodiment for each track in the estimated range, according to the impact. This increases the possibility of recovering recorded data that has been destroyed. In other words, for the retry process associated with the impact, the error correction process is not performed every time a read error occurs in order to execute the error process for the error occurrence track estimated in advance. It is possible to improve the efficiency of retry processing.
(Third embodiment)
The third embodiment corresponds to a modification of the first embodiment. As shown in FIG. 9, the data area 20 on the disk 1 is divided into a plurality of zones 24a to 24c, and each zone 24a is divided. It is assumed that the HDD is provided with tracks 25a to 25c in which ECC data in units of zones is recorded every 24c. A large number of tracks are arranged in each of the zones 24a to 24c. These tracks 25a to 25c are the innermost tracks of each zone, and ECC data for each zone is recorded on the whole track or a part thereof.
[0035]
In the first embodiment described above, it is assumed that when error correction processing and data recovery processing are performed in units of tracks and an error occurs in the recovery data, the processing shifts to alternative processing. On the other hand, in the embodiment, as shown in the flowchart of FIG. 10, when an error occurs, the CPU 9 records the ECC data recorded on the track 25b in the zone (24b) included in the track. An error correction process and data recovery process in units of zones using the “S” are executed (YES in step S61, S63). If no error occurs in the recovery data for each track, as described above, the process of re-recording on the track is executed (NO in step S61, S62).
[0036]
On the other hand, if an error does not occur as a result of the error determination process for the recovery data in units of zones, the recovery data in units of zones is recorded in the corresponding zone (24b) (NO in step S64, S65). If an error occurs, predetermined error processing is executed (YES in step S64, S66). As the predetermined error processing, for example, error correction processing and data recovery processing in units of drives are assumed.
[0037]
【The invention's effect】
As described above in detail, according to the present invention, in a disk recording / reproducing apparatus such as an HDD, when a shock is applied particularly during a write operation, there is a high possibility that recorded data in a track near the track during the write operation is destroyed. Therefore, it is possible to recover the destroyed recording data by executing retry processing by error correction processing and data recovery processing in units of sectors and tracks. Therefore, since it is not necessary to execute retry processing every time a read error occurs as in the prior art, the processing time required for retry processing accompanied by error correction processing is shortened, and as a result, data recovery performance against impact etc. is improved. Can be improved. Further, by estimating the range of the track where the recording data is likely to be destroyed based on the detection of the impact, it is possible to execute a retry process with an error correction process in advance. As a result, the efficiency of the retry process associated with the impact can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a main part of an HDD related to an embodiment of the present invention.
FIG. 2 is a conceptual diagram showing the configuration of a disk related to the first embodiment.
FIG. 3 is a conceptual diagram showing the configuration of a disk related to the first embodiment.
FIG. 4 is a flowchart for explaining the operation of the first embodiment;
FIG. 5 is a flowchart for explaining the operation of the first embodiment;
FIG. 6 is a conceptual diagram showing a disk configuration related to the second embodiment.
FIG. 7 is a flowchart for explaining the operation of the second embodiment;
FIG. 8 is a flowchart for explaining the operation of the second embodiment;
FIG. 9 is a conceptual diagram showing the configuration of a disk related to the third embodiment.
FIG. 10 is a flowchart for explaining the operation of the third embodiment;
[Explanation of symbols]
1 ... Disk (disk storage medium)
2 ... Head
3. Head actuator
4. Voice coil motor (VCM)
5 ... Spindle motor (SPM)
6 ... Head amplifier circuit
7. Read / write circuit
8. Servo circuit
9 ... Microprocessor (CPU)
10: Memory (DD flag, SS flag)
11 ... Disk controller (HDC)
12 ... Motor driver
13 ... Host system
14 ... Shock sensor

Claims (6)

A disk recording / reproducing apparatus in which sectors as data access units are arranged on a disk storage medium, tracks configured by a predetermined number of sectors are arranged , and read / write of data in sector units is performed.
Error detection means for detecting the occurrence of a read error during a read operation of reading recorded data from a sector to be accessed ;
When a read error is detected by the error detection means, an error correction process for read data in units of sectors , and a data recovery process that constitutes original recording data including data after error correction by the error correction process and normal data Error correction means for executing
When an error is detected from the recovery data recovered by the data recovery process, a data destruction flag indicating that the recording data of the sector is destroyed is set, and when no error is detected from the recovery data, the sector is set. Sector error processing means for executing a write operation so as to re-record the recovery data ;
According to the set of the data destruction flag, the track including the sector is accessed, the error correction processing for the track unit and the data recovery processing are executed, and the recovery data for the track unit recovered by the data recovery processing is re-recorded on the track. A disc recording / reproducing apparatus comprising: track error processing means for executing a write operation as described above . Sector ECC data for performing error detection and error correction for each sector is recorded in each sector, and track ECC data for performing error detection and error correction for each track is recorded for each track. And
The error detection unit and the error correction unit respectively execute a read error detection process and an error correction process in units of sectors using the sector ECC data ;
2. The disc recording / reproducing apparatus according to claim 1 , wherein the track error processing means is configured to execute an error correction process and a data recovery process in units of tracks using the track ECC data. . When an error has occurred from the recovery data in units of tracks obtained by the data recovery processing of the track error processing means, the replacement processing in units of sectors or in units of tracks is executed to set the alternative sector of the sector in which the read error has occurred or 3. The disk recording / reproducing apparatus according to claim 1, further comprising an alternative processing unit for setting an alternative track for a track including a sector . A zone area composed of a plurality of tracks is set on the disk storage medium, and zone ECC data for performing error detection and error correction in units of zones is recorded on a predetermined track included in the zone area,
When an error has occurred from the recovery data in units of tracks obtained by the data recovery processing of the track error processing means, the zone including the track is accessed using the zone ECC data, and error correction processing and data in units of zones are performed. 3. A zone error processing means for executing a recovery operation and executing a write operation so as to re-record the recovery data for each zone recovered by the data recovery processing in the zone. The disc recording / reproducing apparatus according to any one of the above. An impact detection means for detecting an impact from outside during a data write operation;
Means for setting an impact flag indicating detection of impact by the impact detection means, and storing identification information for identifying a data area to be accessed for write operation;
Estimating means for estimating a data area where data corruption has occurred based on the data area identified by the identification information according to the set of the impact flag;
Error processing means for reading recorded data from the data area estimated by the estimating means and executing predetermined error processing;
The disc recording / reproducing apparatus according to claim 1, further comprising: An access unit of data on a disk storage medium sector is arranged, is arranged the track consists of a predetermined number of sectors, it is applied to a disk recording and reproducing apparatus which executes read / write of data in sectors An error handling method,
When the occurrence of a read error is detected during a read operation for reading recorded data from the sector to be accessed, an error correction process for the read data of the sector, and a source including normal data and data after error correction by the error correction process Executing a data recovery process that constitutes the recorded data;
When an error is detected from the recovery data recovered by the data recovery process, a data destruction flag indicating that the recording data of the sector is destroyed is set, and when no error is detected from the recovery data, the sector is set. Performing a write operation to re-record the recovery data;
Accessing a track including the sector according to the set of the data destruction flag, and performing an error correction process and a data recovery process in units of tracks;
Performing a write operation so as to re-record the recovery data in units of tracks recovered by the data recovery processing on the track; and
An error processing method characterized by executing a procedure consisting of:

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