KR100594328B1 - Method for read channel parameter optimization according to magnetic loss and apparatus thereof - Google Patents

Abstract

Disclosed are a method and apparatus for optimizing a read channel parameter according to a change in magnetization intensity in a hard disk drive.

According to an aspect of the present invention, there is provided a parameter optimization method for a hard disk drive, the method comprising: changing a write parameter value such that the intensity of magnetization at the time of writing to the disc is less than a predetermined magnetization reference value, and using a predetermined test pattern using the changed write parameter value Recording a predetermined test pattern recorded in the predetermined area by changing a read channel parameter value to determine a read channel parameter value having a smallest bit error rate (BER) as a retry parameter. Storing in the maintenance area of the disk.

According to the present invention, in the case where data is lost due to a decrease in write characteristics or an external influence due to a temperature change, the error can be recovered as much as possible to implement a successful read operation and improve the reliability of the disk drive.

Description

Method for reading channel parameter optimization according to the change of magnetization intensity and its device {Method for read channel parameter optimization according to magnetic loss and Apparatus

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

2 is a block diagram of the present invention.

3 is a flowchart of the present invention.

FIG. 4 is a detailed flowchart of a process of obtaining a retry parameter of FIG. 3.

FIG. 5 is a detailed flowchart of a process applied to a read operation or a retry operation in FIG. 3.

The present invention relates to a hard disk drive, and more particularly, to a method and apparatus for optimizing a read channel parameter according to a change in magnetization intensity in a hard disk drive.

In the hard disk drive process, the lead channel optimization process generally optimizes two parameters. The first is the light channel parameter and the second is the read channel parameter.

One way to optimize the read channel parameters is to write the data to disk using the optimized light channel parameters in a common user environment, and then change the parameter values to obtain the optimal values. At this time, the lead channel parameter having the best BER or SNR is selected and used as the lead channel parameter of the corresponding region. Such lead channel parameters are generally optimized for use environments, such as the temperature of a typical user.

However, the environment in which the reliability of the hard disk drive is required is a special environment such as a low temperature or a high temperature environment, a humid environment, a severe vibration environment, and the like, which are not normal use conditions.

In such a special environment, the magnetized data on the disc is weakened due to external influences or coercive forces, or the weakness of the magnetic material is changed due to temperature changes, causing a weak write from the recording stage. do. When this happens, the recorded data will no longer be readable and will eventually be treated as an error or final failure.

The conventional method for optimizing read channel parameters is a method of determining the write ability of the drive to suppress weak writes and adding and subtracting the value of the write channel parameters accordingly.

However, according to the conventional method for optimizing read channel parameters, the error can be suppressed at the time of recording, but the problem is that the error cannot be recovered once the recorded data has changed in intensity of magnetization and can no longer be read. have.

The technical problem to be achieved by the present invention is to simulate the weakening of the weak write (Wak Write) or recorded data to obtain a retry parameter for optimizing the read channel and apply it to the next read operation or retry operation It also provides a method to optimize the read channel parameters according to the change of magnetization intensity, which can recover the error as much as possible in order to recover the error as much as possible when data is lost due to deterioration of the write characteristics or external influences due to temperature changes. There is.

Another object of the present invention is to provide an apparatus for optimizing a read channel parameter according to a change in magnetization intensity to which the method for optimizing the read channel parameter according to the change in magnetization intensity is applied.

In order to solve the above technical problem, the present invention, in the parameter optimization method of the hard disk drive, the step of changing the write parameter value so that the intensity of magnetization is less than a predetermined magnetization reference value when writing to the disc, the changed Writing a predetermined test pattern in a predetermined area of the disc using a write parameter value, and reading a predetermined test pattern recorded in the predetermined area while changing read channel parameter values to read the smallest bit error rate (BER). Determining a channel parameter value as a retry parameter and storing the channel parameter value in a maintenance area of the disc.

In order to solve the above other technical problem, the present invention is connected to the host interface of the hard disk drive in the device for optimizing the parameter, the write parameter such that the intensity of magnetization at the time of writing on the disk is less than a predetermined magnetization reference value A test parameter storage unit for storing a value, a test pattern storage unit for storing a predetermined test pattern recorded in a predetermined area of the disk, and a host interface, and reading test parameters from the test parameter storage unit to write the drive. Set a parameter as the test parameter, read a predetermined test pattern from the test pattern storage unit, and cause the drive to write the test pattern in a predetermined area of the disc, and write in a predetermined area while changing a read channel parameter value. Read out a predetermined test pattern to a bit error rate (BER) is determined by the retry parameters for the small lead-channel parameter value, and a test control section that records in the maintenance area of the disk and transmitted to the drive.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention.

1 shows a configuration of a hard disk drive 100 to which the present invention is applied.

The drive 100 includes at least one magnetic disk 120 that is rotated by the spindle motor 110. The drive 100 also includes a head 130 positioned adjacent to the disk 120 surface.

The head 130 may read or write information in the rotating disk 120 by sensing and magnetizing the magnetic field of each disk 120. Typically head 130 is coupled to the surface of each disk 120. Although illustrated and described as a single head 130, it should be understood that this consists of a recording head for magnetizing the disk 120 and a separate reading head for sensing the magnetic field of the disk 120. The read head is constructed from Magneto-Resistive (MR) elements.

The head 130 may be integrated into the slider 131. The slider 131 is configured to create an air bearing between the head 130 and the surface of the disk 120. The slider 131 is coupled to the head gimbal assembly 132. The head gimbal assembly 132 is attached to an actuator arm 140 having a voice coil 141. The voice coil 141 is located adjacent to the magnetic assembly 150 that specifies a voice coil motor (VCM) 142. The current supplied to the voice coil 141 generates a torque to rotate the actuator arm 140 relative to the bearing assembly 160. Rotation of the actuator arm 140 will move the head 130 across the disk 120 surface.

The information is typically stored in an annular track of the disc 120. Each track 170 generally includes a plurality of sectors. Each sector includes a data field and an identification field. The identification field is composed of a gray code identifying a sector and a track (cylinder). Head 130 is moved across the surface of disc 120 to read or write information on other tracks.

2 is a block diagram of the present invention.

The read channel parameter optimization apparatus according to the magnetization intensity according to the present invention includes a disk 201, a head 202, a preamplifier 203, a read channel 204, a write channel 205, a controller 206, and a memory 207. A test parameter storage unit 221, a test pattern storage unit 222, and a test control unit 220 are further included in components of the hard disk drive.

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

When reading data from the hard disk drive, the signal is read from the disk 201 to the head 202 (magnetic head or magnetoresistive head) to be amplified for easy signal processing by the preamplifier 203, and then amplified. The analog signal is modulated into a digital signal that can be read by a host computer (not shown) and transmitted to the host computer through the host interface. On the contrary, in the case of writing data, after receiving user data from the host computer through the host interface and converting it into an electrical analog signal in the recording channel 205, the write current amplified by the preamplifier 203 is used. On the disc 201 via a magnetic head).

The memory 207 stores various parameter values and measured operating environment information related to the operation of the hard disk drive, and also stores parameter correction information according to the operating environment. The parameter values stored as initial values in the memory 207 are optimized parameter values determined in the burn-in process, which is one of the hard disk drive manufacturing processes. The memory 207 stores the bit error ratio measured by the controller, the basic write channel parameter value and the basic read channel parameter value determined in the burn-in process, and the change in the magnetization intensity. Stores retry parameter values that optimize the read channel.

The controller 206 sets parameter values for optimization of the read channel at regular time intervals in the idle mode of the power-on state of the drive. The controller may include a register for storing a basic write channel parameter value, a basic read channel parameter value, and a retry parameter value stored in a memory. The controller 206 stores various parameter values of the memory 207 and the bit error rate BER measured during the read operation, controls the write channel 205 and the read channel 204, respectively, and through the host interface 210. The received information is recorded by the head 202 on the disk 201 or the information is read from the disk 201 and the read information is transmitted to the host interface 210.

The test control unit 220 reads the test parameter from the test parameter storage unit 221. The test control unit 220 transmits the test parameter to the controller 206 through the host interface 210 to change the write parameter of the recording channel to record the data on the disk, so that the intensity of the magnetization is less than a predetermined magnetization reference value. Be sure to

In this case, the changed light parameter may include at least an overshoot control factor, a write current determination factor, and a write pre-compensation factor.

For example, a change in the light parameter changes the Write Pre-compensation factor to increase the flying height, and write current to reduce the write current. It may be to change the determinant.

In this case, the predetermined magnetization reference value may be the reference value as the intensity of magnetization at the time of the weak write phenomenon or the degree of magnetization of which the data is determined to be deleted due to the decrease in the intensity of magnetization.

The test control unit 220 reads a predetermined test pattern from the test pattern storage unit 222. In this case, the predetermined test pattern may be a predetermined recording pattern, similar to the case of a weak write phenomenon or data corruption due to a decrease in the intensity of magnetization.

The test controller 220 transmits a predetermined test pattern to the controller 206 through the host interface 210 and controls the test controller 220 to record the test pattern in a predetermined area of the disk. The controller 206 thus transmits a predetermined test pattern over the recording channel 205. At this time, the electrical analog signal for the predetermined test pattern is amplified by the preamp 203 and recorded by the head 202 in the predetermined area of the disc 201.

At this time, the predetermined area in which the predetermined test pattern is recorded may be an empty area (Zone) in which no data is generally recorded.

The test control unit 220 instructs the controller 206 to read a predetermined test pattern recorded in a predetermined area of the disk through the host interface 210. Accordingly, when the head 202 reads a predetermined test pattern from a predetermined area of the disc 201, the preamplifier 203 amplifies the signal for the predetermined test pattern, and the read channel 204 converts it into a digital signal. It converts and transmits it to the controller 206.

The test controller 220 repeats the read operation of the predetermined test pattern as described above while changing the value of the read channel parameter to the controller 206 through the host interface 210, and the bit error rate (BER) for each read channel parameter value. ) To measure. The test controller 220 requests the controller 206 to transmit the value of each of the read channel parameters changed above and the corresponding bit error rate BER. Accordingly, the controller 206 transmits the value of each read channel parameter changed above and the corresponding bit error rate BER to the host interface 210, and the test controller 220 receives the value.

Thereafter, the test controller 220 determines the read channel parameter value of which the bit error rate BER is minimum as the retry parameter value, and controls the controller 206 through the host interface 210 to control the controller 206 through the host interface 210. Record it in the Maintenance Cylinder.

The test controller 220 may compare the retry parameter value determined as described above with the basic read channel parameter once more. That is, the test control unit 220 controls the controller 206 through the host interface 210 when the retry parameter value determined as described above is different from the basic lead channel parameter, so that the retry parameter outside the predetermined area. The bit error rate (BER) is measured while reading data from the disc 201 by using. Then, if the measured bit error rate (BER) is less than or equal to a predetermined error reference value, the test control unit 220 controls the controller 206 through the host interface 210, so that the retry parameter determined above is determined. Record it in the Maintanance Cylinder.

In this case, when the retry parameter value is the same as the basic read channel parameter value or the bit error rate BER due to the late try parameter is larger than the predetermined error reference value, the test control unit 220 determines the retry parameter determined above. It is preferable not to write in.

By recording the retry parameters in the maintenance cylinder as described above, when the hard disk drive is powered on, the retry parameters are loaded into the drive's memory, and the retry parameters are executed when the retry operation is performed. Since it is applied to the retry table to be used, the retry parameter can be used at the next read operation or retry.

At this time, the predetermined error reference value can be set to an error level such that the bit error rate during the read operation is high and the retry step must be performed.

3 is a flowchart of the present invention.

First, the write parameter is changed so that the intensity of magnetization at the time of recording on the disc is less than the predetermined magnetization reference value (step 300). This process is a process of artificially changing the light parameters to simulate a case where the intensity of magnetization is weakly recorded due to the weak write phenomenon or the intensity of magnetization of the recorded data is reduced due to other environmental changes.

The predetermined test pattern is recorded in the predetermined area of the disc (step 310). This process artificially generates a pattern of data that is difficult to read as a read channel parameter in a general environment, so that the intensity of magnetization is weakly recorded by a weak write phenomenon, or the data is recorded by other environmental changes. This is a process of recording a data pattern similar to the data pattern when the intensity of the is reduced.

Finally, a parameter for optimizing the read channel in a predetermined region is obtained and applied to the normal read operation or retry (step 320). This process is to read the test pattern recorded above, change the read channel parameter value, determine the retry parameter value with low error rate, and apply it to the read channel. In this case, the obtained retry parameter may be applied when an error occurs more than a predetermined reference value in the read operation rather than the normal read operation.

FIG. 4 is a detailed flowchart of a process of obtaining a retry parameter of FIG. 3.

First, count N is set to 0 (400). At this time, in order to repeat the process of changing the value of the read channel parameter by a predetermined target number of times, a variable for counting each number is initialized.

The value of the count N initialized above is increased by one (step 410). This process counts the number of repetitions of the process of changing the value of the read channel parameter.

The read channel parameter value is changed (step 420). This process gradually increases the value of the read current determinant, finite impulse response, cut-off frequency, filter boost determinant, etc. at every iteration. It is a process of decreasing gradually.

In operation 430, a bit error rate BER is measured while performing a read operation in a predetermined region in which a predetermined test pattern is recorded. This process measures the data error value for each parameter value.

In operation 440, it is determined whether the N-1 th bit error rate BER is greater than the N th bit error rate BER. This process is to determine whether performing a read operation using the parameter value of the current repetition number is more suitable for error recovery than performing a read operation using the parameter value of the previous repetition number. At this time, if the N-th bit error rate (BER) is smaller than the N-1 th bit error rate (BER), which is a previous repetition number, the process proceeds to the next step, otherwise proceeds to step 460.

The read channel parameter value for the Nth measured bit error rate (BER) is determined as a retry parameter and stored in the memory (step 450). This process defines the lead channel parameter value determined to have the least error as a retry parameter and stores it.

Finally, it is determined whether the current repetition number (count) N reaches a predetermined target number (step 460). This process is to compare the current repetition number with the target value in order to repeat the process of changing the read channel parameter value by the repetition number determined as necessary to obtain the retry parameter in the process step. At this time, if the count N is greater than the predetermined target number, all processes are finished, otherwise, the process returns to step 410.

FIG. 5 is a detailed flowchart of a process applied to a read operation or a retry operation in FIG. 3.

First, it is determined whether the retry parameter value obtained above is different from the value of the basic read channel parameter (step 500). This process does not need to go through the following process if the retry parameter is the same as the parameter value before optimization, and thus is a process for skipping unnecessary procedures. In this case, if the retry parameter value is different from the default read channel parameter value, the process proceeds to the next step, otherwise, the process proceeds to step 540.

In operation 510, a bit error rate BER is measured while a read operation is performed by applying a retry parameter value in a region other than a predetermined region where a test pattern is recorded. This process is a process of performing a normal read operation in an area in which normal data is recorded, not in a disk area allocated for optimization of a read channel parameter, and measuring an error occurring at this time.

In operation 520, it is determined whether the bit error rate BER measured above is greater than a predetermined error reference value. At this time, if the measured bit error rate (BER) is greater than the predetermined error reference value, the process proceeds to the next step. Otherwise, it is set to apply the retry parameter value obtained above in the next read operation or retry (step 530). The setting at this time is to store the retry parameter value in the maintenance area of the hard disk so that the retry parameter value stored above is loaded into the drive memory when the hard disk drive is powered on.

Finally, if the read operation using the retry parameter generates an error exceeding the reference value, the retry parameter is not applied, and the default read channel parameter value is set to be applied at the next read operation or retry (step 540). ). The setting at this time is to store the retry parameter value in the maintenance area of the hard disk so that the retry parameter value stored above is loaded into the drive memory when the hard disk drive is powered on.

Preferably, the write parameter for changing the intensity of magnetization at the time of recording to be below a predetermined reference value includes at least an Overshoot Control factor, a Write Current decision factor, and a Write Pre-compensation. ) May be included.

Preferably, the read channel parameter may include at least a read current determination factor, a finite impulse response, a cut-off frequency, and a filter boost determination factor.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. However, such modifications should be considered to be within the technical protection scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, according to the present invention, by simulating a process of weakening the magnetization intensity of weak write or recorded data, a retry parameter for optimizing a read channel is obtained and applied to the next read operation or retry operation. As a result, when data is lost due to a decrease in write characteristics or an external influence due to a temperature change, error recovery can be performed as much as possible to implement a successful read operation and improve the reliability of the disk drive.

Claims (5)

In the parameter optimization method of the hard disk drive, Changing a write parameter value such that the intensity of magnetization at the time of recording on the disc is less than a predetermined magnetization reference value; Recording a predetermined test pattern in a predetermined area of the disc using the changed write parameter value; And Reading a predetermined test pattern recorded in the predetermined area while changing a read channel parameter value, determining a read channel parameter value having a smallest bit error rate (BER) as a retry parameter, and storing the test pattern in the maintenance area of the disc; And optimizing a read channel parameter value according to a change in magnetization intensity. The method of claim 1, The step of storing in the maintenance area of the disk While the read channel parameter value having the smallest bit error rate BER is different from the default read channel parameter value, a read operation is performed using the read channel parameter value having the smallest bit error rate BER outside the predetermined region. Only when the error rate BER is less than or equal to a predetermined error reference value, the step of determining the read channel parameter value having the smallest bit error rate as the retry parameter and storing it in the maintenance area of the disc is changed. How to optimize lead channel parameters accordingly. The method of claim 1, The light parameter is At least an Overshoot Control factor, Write Current decision factor, Write Pre-compensation factor, The retry parameter and the read channel parameter are At least one read current, a finite impulse response, a cut-off frequency, and a filter boost determinant. How to optimize your parameters. In the device connected to the host interface of the hard disk drive to optimize the parameters, A test parameter storage unit for storing a write parameter value such that the intensity of magnetization is less than a predetermined magnetization reference value when writing to the disc; A test pattern storage unit which stores a predetermined test pattern recorded in a predetermined area of the disc; And Connected to the host interface, read test parameters from the test parameter storage unit, set write parameters of the drive as the test parameters, read a predetermined test pattern from the test pattern storage unit, and the drive reads a predetermined area of the disc; The test pattern is recorded in the program, and the read channel parameter value having the smallest bit error rate (BER) is determined as the retry parameter by reading the predetermined test pattern recorded in the predetermined area while changing the read channel parameter value. And a test control unit configured to transmit and write the data in the maintenance area of the disc. The method of claim 4, wherein The test control unit While the read channel parameter value having the smallest bit error rate BER is different from the default read channel parameter value, a read operation is performed using the read channel parameter value having the smallest bit error rate BER outside the predetermined region. Only when the error rate BER is less than or equal to a predetermined error reference value, the read channel parameter value having the smallest bit error rate BER is determined as a retry parameter and transmitted to the drive so that the drive is recorded in the maintenance area of the disc. Read channel parameter optimization device according to the change in magnetization intensity.

Images