KR100604862B1 - Method for controlling a retry process in hard disk drive and apparatus therefor - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a retry control method for a hard disk drive, and more particularly, to an improved retry control method and a suitable apparatus for speeding up the retry processing speed.

The retry control method according to the present invention includes a first retry process of performing a retry using a parameter used to correct an error in a previous retry process when an error occurs; Determining whether the error is cured by the first retry process; If the error is healed by the first retry process, the retry operation is terminated. Otherwise, the second retry is performed by sequentially applying parameters for a plurality of error occurrence factors with reference to the retry table. process; And storing the parameter used to heal the error so that the error can be referred to in the subsequent retry process, if the error has been cured by the second retry process.

According to the present invention, it is possible to improve the retry processing speed and increase the performance of the hard disk drive by preferentially using the parameters used to heal the error in the previous retry process.

Description

Method for controlling a retry process in hard disk drive and apparatus therefor}

1 is a plan view of a configuration of a hard disk drive to which the present invention is applied.

2 is an electrical circuit diagram of a hard disk drive to which the adaptive retry control method according to the present invention is applied.

3 is a flowchart illustrating an embodiment of a retry control method according to the present invention.

Figure 4 shows the parameter information and retry table used in the previous retry processor used in the method shown in FIG.

5 is a flowchart illustrating another embodiment of a retry control method according to the present invention.

FIG. 6 shows a retry table used in the method illustrated in FIG. 5.

TECHNICAL FIELD The present invention relates to a retry control method for a hard disk drive, and more particularly, to an improved retry control method and a suitable apparatus for speeding up the retry processing speed.

A hard disk drive, which is one of the data storage devices, plays back data recorded on the disk by the magnetic head or records user data on the disk.

On a hard disk drive, an error may occur during the data read operation. To remedy this, if an error occurs during read execution of data, a retry process is executed.

That is, when an error occurs during the read operation, the data read is repeatedly executed a maximum number of times while changing off-track read or data read related parameter values.

Known technical documents related to the present invention include Korea Patent Publication No. 2000-182292 and Japanese Patent Application Laid-open No. Hei 11-195211.

Korean Patent Laid-Open Publication No. 2000-182292 discloses a technique for increasing the retry success rate by preserving the parameter set value of a successful retry as read information and updating the default parameter values using the statistics information. 11-195211 discloses a technique for sensing an ambient temperature using a change in resistance of an MR lead sensor and compensating hard disk drive performance using the sensed temperature.

However, according to the related art, the retry process performs various retrys in a predetermined order each time it is executed. As a result, unnecessary time is consumed until the error occurrence factor corresponding to the sector in which the error occurs is checked. The lower the order of error occurrence factors corresponding to an error sector on the retry table is, the longer the time for retry becomes, and thus the performance of the hard disk drive is also degraded.

Therefore, there is a need for a retry control method capable of improving the performance of a hard disk drive.

It is an object of the present invention to provide an improved retry control method for improving the retry speed as designed to solve the above problems.

Another object of the present invention is to provide a hard disk drive suitable for the retry control method described above.

According to one aspect of the present invention, there is provided a retry control method for improving retry speed by using correlation of errors occurring in a hard disk drive.

An embodiment of the retry control method according to the present invention

If an error occurs, performing a retry using a parameter used to heal the error in a previous retry process;

Determining whether an error is cured by the first retry process;

If the error is healed by the first retry process, the retry operation is terminated. Otherwise, the second retry is performed by sequentially applying parameters for a plurality of error occurrence factors with reference to the retry table. process; And

If the error is healed by the second retry process, the method may include storing a parameter used to heal the error for reference in a subsequent retry process.

Another embodiment of the retry control method according to the present invention

Retrying a retry by selecting one of the parameters for a plurality of error occurrence factors according to an entry order when an error occurs, by referring to a retry table;

Determining whether an error has been cured by the retry process; And

If the error is healed by the retry process, the first entry of the retry table is updated with the parameters used to heal the error for future reference. Process.

According to another aspect of the present invention, there is provided a hard disk drive that improves the retry speed by using the correlation of errors that occur.

Hard disk drive according to the present invention

A host interface for performing data transmission / reception processing with the host device;

A memory that contains firmware and control information for controlling the hard disk drive;

A buffer for storing data received from the host device through the host interface in a write mode and storing data reproduced from the disc in a read mode;

A plurality of parameters that are used to heal the error when the error is healed by the retry process, and selectively used according to the parameter information in the stored previous retry processor and the entry order when the retry process is performed. A controller which controls to perform the retry process by using the retry table having the first and second retry tables; And

And a write / read circuit that writes data stored in the buffer to a disk or executes data processing for reading data from the disk and storing the data in the buffer.

The features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the invention shown in the accompanying drawings.

Reference will be made in detail to exemplary embodiments of the invention, wherein like reference numerals denote like elements. In addition, in order to simplify the description, anything that is not novel or well known to those skilled in the art will be omitted.

1 shows a configuration of a hard disk drive 10 to which the present invention is applied. The drive 10 includes at least one magnetic disk 12 that is rotated by a spindle motor 14. Hard disk drive 10 also includes a transducer 16 located adjacent disk surface 18.

The transducer 16 can read or write information on the rotating disk 12 by sensing and magnetizing the magnetic field of each disk 12. Typically each transducer 16 is associated with a respective disk surface 18. On the other hand, although shown and described as a single transducer 16 in FIG. 1, in practice this consists of a write transducer for magnetizing the disc 12 and a separate read transducer for sensing the magnetic field of the disc 12. It should be understood that there is. Typically, write converters consist of magnetic circuits with voids, and read converters consist of Magneto-Resistive (MR) elements. The transducer 16 is also commonly referred to as a head.

The transducer 16 can be integrated into the slider 20. The slider 20 is structured to create an air bearing between the transducer 16 and the disk surface 18. The slider 20 is coupled to the head gimbal assembly 22. The head gimbal assembly 22 is attached to an actuator arm 24 having a voice coil 26. The voice coil 26 is located adjacent to the magnetic assembly 28 that specifies the voice coil motor 30 (VCM). The current supplied to the voice coil 26 generates a torque that rotates the actuator arm 24 relative to the bearing assembly 32. Rotation of actuator arm 24 will move transducer 16 across disk surface 18.

The information is typically stored in concentric circular tracks on the disc 12. Each track 34 generally includes a plurality of sectors. Each sector includes a data field and an identification field (also called a servo field). The identification field consists of a gray code identifying the sector and the track (cylinder), and burst signals for detecting the extent to which the transducer 16 deviates from the track center. The transducer 16 is moved across the disk surface 18 by the movement of the actuator arm.

2 shows an electrical circuit of a hard disk drive to which the present invention is applied.

As shown in FIG. 2, the hard disk drive according to the present invention includes a disk 12, a converter 16, a preamplifier 210, a write / read channel 220, a host interface 230, and a controller 240. , A memory 250, a temperature sensor 260, and a voice coil motor (VCM) driver 270.

The circuit configuration including the preamplifier 210 and the write / read channel 220 above will be referred to as a write / read circuit.

The memory 250 stores various programs and data for controlling the hard disk drive. In particular, the retry table and previous retry information are stored to execute the retry control method according to an exemplary embodiment of the present invention. In this case, the memory 250 is designed as a nonvolatile memory.

The retry table stores parameter values to ensure optimal performance of the hard disk drive.

First, the operation of a general hard disk drive will be described.

In the data read mode, the hard disk drive amplifies the electrical signal sensed by the converter 16 (also called a head) from the disk 12 in the preamplifier 210 to facilitate signal processing. Then, in the recording / reading channel 220, the amplified analog signal is encoded into a digital signal that can be read by a host device (not shown), converted into stream data, and transmitted to the host device through the host interface 230. send.

In contrast, in the data write mode, the hard disk drive receives data from a host device and temporarily stores the data in a buffer (not shown) embedded in the host interface 230, and sequentially outputs the data stored in the buffer. The write / amplify channel 220 converts the write current amplified by the preamplifier 210 to the disk 12 via the converter 16 after conversion to a binary data stream suitable for the write channel.

The controller 240 may be a digital signal processor (DSP), a microprocessor, a microcontroller, or the like. The controller 240 supplies a control signal to the write / read channel 220 to read from or write information to the disk 12. Information is typically sent from the R / W channel to the host interface circuit 2320. The host interface circuit 230 includes a buffer memory and control circuitry that allows a hard disk drive to interface to a system such as a personal computer.

The controller 240 is also coupled to the VCM drive circuit 270 which supplies a drive current to the voice coil 26. The controller 240 supplies a control signal to the VCM driving circuit 270 to control the excitation of the VCM and the movement of the transducer 16.

The controller 240 is coupled to a nonvolatile memory device 250 such as a flash memory device. The memory device 250 stores instructions and data used by the controller 240 to execute a software routine. One software routine is a seek routine that moves the transducer 16 from one track to another. The seek routine includes a servo control routine to ensure that the transducer 16 is moved to the correct track.

In addition, when the retry mode is performed, the controller 240 uses the retry table information stored in the memory 250 to reset the retry parameters related to the data read or the data write performance according to the retry number according to the retry number. Or control to repeat the write.

3 is a flowchart illustrating an exemplary embodiment of a retry control method of a hard disk drive according to the present invention.

The controller 240 of the hard disk drive determines whether a data read command is input from the host device via the host interface 260 (S302).

If the inputted command is a read command as a result of the determination in step 302 (S302), the counter i in the controller 240 for checking the number of retries is initialized to 0 (S304), and the target cylinder and sector positions are reset. The data is read by SEEK (S306).

The controller 240 determines whether an error occurs in the data reading process in step 306 (S306). As is known, in a hard disk drive, data recorded on the disk is read in sector units and error correction is performed. User data and an error correction code are recorded in the data sector. An error correction code is used to determine if an error has occurred in user data when reading data. In step 308 (S308), it is determined whether there is an error that is not corrected by the error correction code in the data read in the target cylinder and sector position.

If an error has occurred as a result of the determination in step 308 (S308), the state transitions to the read retry mode.

In the retry mode, first, it is determined whether the value of the counter i in the controller 240 for checking the retry count is 0. If the value of the counter i is 0, the first retry is performed on the generated error, and the retry is performed with reference to the result of the previous retry process.

If the value of the counter i is 0 as a result of the determination in step 310 (S312), the value of the counter i is increased by 1 (s312), and the result of the previous retry process, that is, adjustment in the previous data read process, is performed. The parameters are adjusted by referring to the parameter values (S314).

Returning to step 306 (S306), the data of the target cylinder and sector are read once again, and it is determined whether the error has been cured in step 308 (S308).

The source of error in a hard disk drive can be considered to be largely constant except in the event of an accident such as an external shock. For example, if a hard disk drive is used in a low temperature user environment, it is easy to see that it is reasonable to apply a low temperature read parameter across the disk. Therefore, if an error occurred in the operation of reading a sector on the disk and the error was healed by a parameter suitable for the low temperature condition, the parameter suitable for the low temperature condition even if an error occurred in the operation of reading another sector. It is reasonable to try the retry operation first.

On the other hand, in a densified hard disk drive, an error due to the same error occurrence factor is likely to occur over several sectors. Therefore, if an error is healed through a retry operation in a sector, there is a high probability that the error is healed in the adjacent sector through the same healing method as in the previous sector. Therefore, the retry processing speed can be improved by referring to the result of the previous retry operation.

If no error has occurred as a result of the determination in step 308 (S308), it is determined whether the value of the counter i is 0. (S322) As a result of the determination in step 322 (S322), if the value of the counter i is 0, the retry is performed. The read operation is terminated as it has not been done. If the value of the counter i is not 0, the error is cured through the retry operation, and thus the read operation is terminated after storing the retry parameter Pi information (S324). Here, the retry parameter Pi is stored in the maintenance cylinder or the memory 250 of the disk 12. The stored retry parameter Pi is referred to in a retry operation performed at the next error occurrence.

Meanwhile, if the value of the counter i is not 0 in step 310 (S310), the retry operation is performed by referring to the retry table because it is not the first retry.

The value of the counter i and the maximum retry possible number Max_retry) are compared (S316).

If the result of the comparison in step 316 (S316) does not exceed the value of the maximum retryable number Max_retry), the value of the counter i is increased by 1 (S318), and the retry table is referred to. After setting the parameters in the entry order (S320), the process feeds back to step 306 (S306) to execute data reading again.

If the error is not healed as a result of the determination of step 308 (S308), step 310 (S310) to step 320 (S320) are performed again. At this time, in step 320 (S320) it is set to the parameter of the next entry in the order of entries in the retry table.

If the error is healed as a result of the determination in step 308 (S308), steps 322 (S322) to S324 (S324) are performed and the read operation is terminated.

By the above operation, the retry process is generated during the data read mode execution, and when the data read is successful by performing the retry process, the retry parameter information is stored in the disk 12 or the memory 250.

FIG. 4 shows the previous retry results and the retry table used in the method shown in FIG. 3.

The retry table stores parameters for various errors. The retry process uses the parameters stored in the retry table in order of entry number. As shown in Figure 4, the OFFTRACK parameter represents the degree of offtracking the head, RC is the magnitude of the read current, Adaptive FIR is the adaptive adjustment of the coefficients of the digital filter, and WC is the magnitude of the write current. Indicates.

The method shown in FIG. 3 uses the previous retry result, that is, the parameters and parameter tables used to heal the error in the previous retry processor. The parameters used in the previous retry process are stored in the first memory 402 and the parameter table is stored in the second memory 404. The first and second memories 402 and 404 are storage regions in the maintenance cylinder or nonvolatile memory.

The controller 240 may use the parameter used in the previous retry processor stored in the first memory 402 or the retry stored in the second memory 404 according to the value of the counter i when the retry process is performed. Determines whether to use the parameters stored in the table.

Fig. 5 is a flowchart showing another exemplary embodiment of the retry control method according to the present invention. The method shown in FIG. 5 is characterized in that the parameters used in the previous retry process in the retry table can be used first, without using two memories as in the method shown in FIG.

If the result of the comparison in step 316 (S316) is not greater than the maximum retryable number Max_retry, the parameter is set in the order of entry with reference to the retry table (S502), and the counter (i ) Is increased by 1 (S504), and fed back to step 306 (S306) to execute data reading again.

Here, the entry number 0 of the retry table stores a parameter for resolving an error in the retry processor performed previously. When the hard disk drive is shipped, the entry number 0 of the retry table stores a parameter of an appropriate value, for example, the same value as entry number 1. Once the retry process is performed, the parameters used to heal the error are stored in entry number 0.

If the error is not healed as a result of the determination of step 308 (S308), steps 316 (S316) to 504 (S504) are performed again. At this time, in step 502 (S502), the parameters of the next entry are set according to the entry order in the retry table.

If no error has occurred as a result of the determination in step 308 (S308), it is determined whether the value of the counter i is 0. (S322) As a result of the determination in step 322 (S322), if the value of the counter i is 0, the retry is performed. The read operation is terminated as it has not been done. If the value of the counter i is not 0, the error is cured through the retry operation. Therefore, the read operation is terminated after storing the retry parameter Pi information (S506). Here, the retry parameter Pi is stored in entry number 0 of the retry table. The retry parameter (Pi) information stored in entry number 0 of the retry table is used preferentially in the retry process performed at the next error occurrence.

FIG. 6 shows an example of a retry table used in the method shown in FIG. 5. The retry table 602 shown in FIG. 6 is stored in a maintenance cylinder or nonvolatile memory.

In the retry table 602 shown in FIG. 6, entry number 0 stores parameters that were used to heal the error in the retry process performed previously. Accordingly, in the method illustrated in FIG. 5, the parameter having the highest priority entry number 0, that is, the parameter used to cure the error in the previously performed retry processor is used first. This achieves the same effect as in the method shown in FIG.

The invention can be practiced as a method, apparatus, system, or the like. When implemented in software, the constituent means of the present invention are code segments that necessarily perform the necessary work. The program or code segments may be stored in a processor readable medium or transmitted by a computer data signal coupled with a carrier on a transmission medium or network. Processor readable media includes any medium that can store or transmit information. Examples of processor-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memory, erasable ROM (EROM), floppy disks, optical disks, hard disks, optical fiber media, radio frequency (RF) networks, and the like. There is this. Computer data signals include any signal that can propagate over transmission media such as electronic network channels, optical fibers, air, electromagnetic fields, RF networks, and the like.

Specific embodiments shown and described in the accompanying drawings are only to be understood as examples of the present invention, and not to limit the scope of the present invention, even in the scope of the technical spirit described in the present invention in the technical field to which the present invention belongs As various other changes may occur, it is obvious that the invention is not limited to the specific constructions and arrangements shown or described. That is, it is a matter of course that the present invention can be applied not only to various disk drives including hard disk drives, but also to various kinds of data storage devices.

 As described above, according to the present invention, it is possible to improve the retry processing speed and increase the performance of the hard disk drive by preferentially using the parameters used to heal the error in the previous retry process.

Claims (5)

delete Claims [1] A method of controlling a retry process to heal an error occurring during an operation of a hard disk drive. When an error occurs, the retry process is performed by selecting one of the parameters for a plurality of error occurrence factors according to the entry order by referring to the retry table having a plurality of parameters that are selectively used according to the entry order when performing the retry process. Retry process to perform; Determining whether an error has been cured by the retry process; If the error is healed by the retry process, the first entry of the retry table is updated with the parameters used to heal the error for future reference. Retry control method of a hard disk drive including the process. A host interface for performing data transmission / reception processing with the host device; A memory that contains firmware and control information for controlling the hard disk drive; A buffer for storing data received from the host device through the host interface in a write mode and storing data reproduced from the disc in a read mode; A plurality of parameters that are used to heal the error when the error is healed by the retry process, and selectively used according to the parameter information in the stored previous retry processor and the entry order when the retry process is performed. A controller which controls to perform the retry process by using the retry table having the first and second retry tables; And A write / read circuit for writing data stored in the buffer to a disc or performing data processing for reading data from the disc and storing the data in the buffer, And the controller updates the first entry of the retry table with parameter information used to heal the error in the previous retry processor. delete delete

Images