KR100585162B1 - Adaptive Light Parameter Determination Method According to Temperature and Disk Drive Using the Same - Google Patents

Abstract

The present invention relates to a data storage device and a method of controlling the same, and more particularly, to a method and an apparatus for adaptively determining light parameters with respect to a change in temperature in consideration of differences in characteristics of disk drives.

In the method for determining the adaptive light parameter according to the temperature according to the present invention, in the method for determining the disk drive parameter, (a) measuring predetermined performance while varying the light parameter in each zone of the disc for each head, (b) the step calculating a correlation of a predetermined performance with respect to a write parameter in each zone of the disc for each head by using the result measured in (a); and (c) a range in which the predetermined performance satisfies a design goal from the correlation. And calculating the light parameter value according to the temperature in proportion to the temperature characteristic of the light parameter in each zone of the disc for each head.

Description

Method for determining adaptive write parameter according to temperature and disc drive using the same}

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 light parameter determination method according to the temperature according to the present invention is applied.

3 is a flowchart illustrating a method of determining an adaptive write current parameter according to temperature according to an embodiment of the present invention.

4 is a flowchart illustrating a method of determining an adaptive write current overshoot parameter according to temperature according to another exemplary embodiment of the present invention.

5 shows a graph of the bit error rate according to the change of the write current overshoot measured in the present invention.

FIG. 6 shows a graph of temperature characteristics of a write current overshoot calculated using a gap analysis technique according to the present invention.

Figure 7 shows a graph of the bit error rate according to the change of the write current measured in the present invention.

The present invention relates to a data storage device and a method of controlling the same, and more particularly, to a method and an apparatus for adaptively determining light parameters with respect to a change in temperature in consideration of differences in characteristics of disk drives.

In general, a hard disk drive, which is one of data storage devices, contributes to computer system operation by reproducing data recorded on a disk by a magnetic head or recording user data on the disk. Such hard disk drives are increasingly used as storage media for A / V (Audio / Video) devices in multimedia systems due to their increased storage capacity.

The hard disk drive includes a plurality of magnetic heads coupled with rotating disks. The head records and reads information by magnetizing the disk surface and sensing the magnetic field. Magnetic heads have been developed that have a recording element for magnetizing the disc and a separate reading element for sensing the magnetic field of the disc. The readout element is typically composed of a magneto-resistive material. The magnetoresistive material has the property that the resistance changes in accordance with the magnetic field of the disk. A head having a magnetoresistive reading element is generally referred to as a magneto-resistive (MR) head.

In general, the characteristics of the hard disk drive vary with temperature. To compensate for this, during the manufacturing process, the averaged fixed amount of compensation value determined by a statistical method by experiments for each of the temperature bands detected for the optimal light parameters for each data zone of the disk is equal to the initially set light parameters. The method of adding and subtracting was used.

However, such a compensation method causes a problem in that accurate temperature characteristics cannot be compensated in consideration of characteristic differences for each disk drive by adding or subtracting the same compensation value for heads having different characteristics.

That is, due to the inherent difference in characteristics between the heads, problems such as deterioration in recording performance in the high and low temperature bands, adjacent track recording problems, and head characteristics deterioration are caused.

In other words, the conventional technique of applying the average temperature compensation method without considering the characteristic difference of each of the disk drives has a problem in that it is impossible to execute the optimum temperature compensation according to the characteristic distribution of each of the disk drives.

The technical problem to be solved by the present invention is to induce a correlation between the light parameters and the temperature through the gap analysis of the light parameters associated with the temperature change during the manufacturing process for each of the disk drive to solve the above problems The present invention provides an adaptive light parameter determining method according to temperature and a disk drive using the same for determining optimal light parameters according to temperature.

In order to achieve the above technical problem, the adaptive light parameter determining method according to the temperature according to the present invention is a disc drive parameter determining method, comprising: (a) measuring a predetermined performance while varying a light parameter in each zone of a disc for each head; (B) calculating a correlation of a predetermined performance with respect to the write parameter in each zone of the disc for each head by using the result measured in step (a); and (c) the predetermined equation from the correlation. Comprising the step of calculating the light parameter value according to the temperature in each zone of the disk for each head in proportion to the temperature characteristic of the light parameter in the range that the performance meets the design goal.

In accordance with another aspect of the present invention, a disk drive includes a disk for storing data, a memory for storing predetermined design parameter information, and a write condition corresponding to a write parameter value. Write / read circuit that reads data from or reads data from the disc according to the optimal read channel parameter value, and measures the predetermined performance by varying write parameters in each zone of the disc for each head and uses the measured result Calculates a correlation of a predetermined performance with respect to the light parameter in each zone of the disc for each head, and proportionally correlates corresponding to the temperature characteristic of the light parameter in the range in which the predetermined performance satisfies a design goal from the correlation. According to temperature It characterized in that it comprises a light-based parameter values by the head controller which executes a control process for calculating respectively for each zone of the disk.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a configuration of a 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. The disk drive 10 also includes a transducer 16 located adjacent to the 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 transducer 16 is coupled to each disk surface 18. Although illustrated and described as a single transducer 16, it should be understood that 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. Read transducers are constructed from Magneto-Resistive (MR) devices. 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 integrated into 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 for rotating the actuator arm 24 relative to the bearing assembly 32. Rotation of the actuator arm 24 moves the transducer 16 across the disk surface 18.

The information is typically stored in an annular track of the disc 12. Each track 34 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). The transducer 16 is moved across the disk surface 18 to read or write information on other tracks.

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

As shown in FIG. 2, the disc drive according to the present invention includes a disc 12, a converter 16, a preamplifier 210, a write / read channel 220, a buffer 230, a controller 240, a ROM. 250, a RAM 260, a voice coil motor driver 270, a host interface 280, and a temperature detector 290.

The ROM 250 stores various programs and data for controlling the disk drive, and the RAM 260 is loaded with various data necessary for the disk drive operation read in the maintenance area of the disk 12 at every boot. .

The buffer 230 sequentially stores data received from the host device through the host interface 280 in the write mode, and sequentially stores data read from the disk 12 in the read mode. .

The preamplifier 210 includes an amplifier circuit for amplifying a signal sensed by the converter 16 and a read current control circuit for supplying read current according to an optimal read channel (RCO) parameter value to the converter 16. Built-in light current control circuit for supplying light current.

The temperature sensor 290 is configured as a sensor for detecting a temperature inside the disk drive, and outputs the detected temperature information to the controller 240.

The controller 240 controls the read / write parameter values of the disk drive corresponding to the sensed temperature information to be read from the RAM 260 to determine the parameters of the write / read channel.

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

In the data read mode, the disc drive amplifies the electrical signal sensed by the transducer 16 (also called a head) from the disc 12 to facilitate signal processing in the preamplifier 210. 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 temporarily stored in the buffer 230, and then the host. It transmits to the host device through the interface 280.

In the data write mode, the disk drive receives data from the host device through the host interface 280 and temporarily stores the data in the buffer 230, and then outputs data from the buffer 230 to the write / read channel 220. After the conversion into a binary data stream suitable for the recording channel, the write current amplified by the preamplifier 210 is recorded on the disc 12 through the converter 16.

The controller 240 controls the disk drive as a whole, and analyzes a command received through the host interface 280 to execute the command.

The controller 240 is also coupled to the VCM driver 270 for supplying a drive current to the voice coil 26 and to the VCM driver 270 to control the excitation of the VCM and the movement of the transducer 16. Supply the control signal.

In addition, the controller 240 measures specific performance (eg, BER or EC) while varying the write parameters (eg, overwrite of the write current and the write current) in each zone of the disc for each head. Using the measured results, a correlation of the specific performance (BER or EC) for the light parameter in each zone of the disc for each head is calculated, and from the calculated correlation, the specific performance (BER or EC) satisfies the design goal. Comparing the temperature characteristics of the write parameters (overshoot of the write current and the write current) in the range, the values of the write parameters (overshoot of the write current and the write current) according to temperature are calculated in each zone of the disc for each head. Perform an adaptive light parameter determination process based on temperature.

Next, an adaptive recording current parameter determining method according to temperature according to an embodiment of the present invention will be described with reference to the flowchart of FIG. 3.

First, one head HD # 0 is selected from among a plurality of heads installed in the disk drive (S301), and the data zone ZN # 0 is located at the outermost periphery of the plurality of zones of the disk 12. The head 16 is moved (S302). Of course, when the test is to be executed from the innermost circumferential side of the disk 12, the head 16 may be designed to move to the data zone on the innermost circumferential side.

Then, the performance of the disk drive is measured while sequentially decreasing / increasing the minimum / maximum threshold write current value by a predetermined unit amount around the write current value determined under the optimized read channel condition (S303). For example, the performance of a disk drive includes bit error rate (BER) performance or error count (EC) performance, and the present invention adopts bit error rate (BER) performance for convenience of description. 7 shows a graph of bit error rate values according to the measured change of the write current.

Next, a correlation equation of the bit error rate with respect to the write current value is calculated (S304). That is, it is possible to derive a correlation equation (equation) as shown in Equation 1 from the measured graph as shown in FIG.

BER = A * (iw) ² + B * (iw) + C

Where BER is the bit error rate, iw is the write current, and A, B, and C are constants.

The constant A, B, and C values can be determined from the graph of FIG.

Next, the temperature characteristic of the recording current is determined using the correlation equation (1) as follows (S305).

It is determined whether the BER value measured at the minimum threshold write current value satisfies the threshold performance. If not, the write current value having the BER value satisfying the threshold performance is obtained using Equation 1. Then, the temperature value is proportionally correlated between the minimum write current value and the maximum threshold current value having a BER value that satisfies the threshold performance. That is, considering the general characteristic that the write current should be decreased as the temperature increases and the write current should be increased as the temperature decreases, the temperature range guaranteed by the disk drive is 0 to 60 ° C, which satisfies the critical performance. 60 ° C corresponds to the minimum recording current value with BER value, 0 ° C to the maximum recording current value, and then, for a certain temperature change through a so-called gap analysis in the range of 0 to 60 ° C. The write current value is calculated proportionally.

In step 305 (S305), the temperature characteristic information of the write current, which is a table of the calculated write current values according to the change in temperature, is stored in the maintenance cylinder of the disk 12 or in the ROM 250 (S306). ).

After changing the data zone in order to calculate the temperature characteristic of the recording current in all the data zones of the disc (S307), it is determined whether the temperature characteristic of the recording current is calculated in all the data zones (S308).

If it is determined in step 308 (S308) that the temperature characteristic of the write current is not calculated in all data zones, the flow returns to step 303 (S303).

 If the temperature characteristic of the recording current is calculated in all the data zones as a result of the determination in step 308 (S308), after the heads are changed in order to calculate the temperature characteristic of the recording current for each data zone for all the heads (S309). In step S310, it is determined whether the temperature characteristic of the recording current is calculated for all the heads.

As a result of the determination in step 310 (S310), when the temperature characteristic of the recording current is calculated in each data zone for all the heads, the step is terminated. Otherwise, the feedback is sent back to step 302 (S302).

In this manner, it is possible to calculate accurate temperature characteristics of the write current for each data zone in consideration of the head characteristics of each disk drive.

Next, a method of determining an overshoot parameter of the adaptive write current according to temperature according to another example of the present invention will be described with reference to the flowchart of FIG. 4.

First, one head HD # 0 is selected from among a plurality of heads installed in the disk drive (S401), and the data zone ZN # 0 located on the outermost side of the plurality of zones of the disk 12 is selected. The head 16 is moved (S402). Of course, when the test is to be executed from the innermost circumferential side of the disk 12, the head 16 may be designed to move to the data zone on the innermost circumferential side.

Then, the performance of the disk drive is measured while sequentially decreasing / increasing the minimum / maximum threshold overshoot value by a predetermined unit centered on the overshoot value of the write current determined under the optimized read channel condition (S403). For example, the performance of a disk drive includes bit error rate (BER) performance or error count (EC) performance, and the present invention adopts bit error rate (BER) performance for convenience of description. 5 shows a graph of bit error rate values according to the measured change of the write current overshoot.

Next, a correlation equation of the bit error rate with respect to the overshoot value of the write current is calculated (S404). That is, it is possible to derive a correlation equation (equation) as shown in Equation 2 from the measured graph as shown in FIG.

BER = X1 * (osa) ² -X2 * (osa)-X3

Here, BER is the bit error rate, osa means overshoot of the write current, and X1, X2, X3 are constant.

The above constants X1, X2, X3 values can be determined from the graph of FIG.

Next, the temperature characteristic of the recording current overshoot value is determined as follows using the correlation formula (2) (S405).

It is determined whether the BER value measured at the minimum threshold overshoot value satisfies the threshold performance, and when it is not satisfied, the write current overshoot value having the BER value satisfying the threshold performance is obtained using Equation 2. Then, the temperature value is proportionally correlated between the minimum overshoot value and the maximum threshold overshoot value having a BER value that satisfies the threshold performance. In other words, considering the general characteristic of reducing the overshoot of the recording current as the temperature increases and increasing the overshoot of the recording current as the temperature decreases, the temperature range guaranteed by the disk drive is 0 to 60 ° C. After matching 60 ℃ to the minimum overshoot value with BER value that satisfies the critical performance, and 0 ℃ to the maximum overshoot value, it is constant through the so-called gap analysis in the range of 0 ~ 60 ℃. The overshoot value of the recording current is calculated in proportion to the temperature change of the unit.

In step 405 (S405), the temperature characteristic information of the recording current overshoot, which is a table of the calculated values of the overshoot of the recording current according to the change in temperature, is stored in the maintenance cylinder of the disk 12 or the ROM 250. Store in (S406).

After changing the data zone in order to calculate the temperature characteristic of the write current overshoot in all data zones of the disc (S407), it is determined whether the temperature characteristic of the write current overshoot is calculated in all the data zones (S408).

If it is determined in step 408 (S408) that the temperature characteristic of the write current overshoot is not calculated in all data zones, the flow returns to step 403 (S403).

 If the temperature characteristic of the recording current overshoot is calculated in all data zones as a result of the determination in step 408 (S408), the head is changed to calculate the temperature characteristic of the above recording current overshoot for each data zone for all heads. After that (S409), it is determined whether the temperature characteristic of the write current overshoot is calculated for all the heads (S410).

As a result of the determination in step 410 (S410), when the temperature characteristic of the write current overshoot is calculated in each data zone for all the heads, the step is terminated. Otherwise, the feedback is returned to step 402 (S402).

In this way, it is possible to calculate the temperature characteristics of the accurate write current overshoot for each data zone in consideration of the head characteristics of each disk drive.

In an exemplary embodiment of the present invention, the temperature characteristics of the recording parameters of the disk drive have been described as an example for convenience of description, but the same method may be applied to other parameters that have a constant regularity according to the temperature change. You could do it.

Specific embodiments shown and described in the accompanying drawings are only to be understood as an example of the present invention, not to limit the scope of the invention, but also within 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, by using the gap analysis (Gap Analysis) to calculate the temperature characteristics of the parameters applied to each of the disk drive individually, it is possible to operate in the optimum conditions by accurately reflecting the differences of characteristics for each disk drive That effect is produced.

Claims (10)

In the disk drive parameter determination method, (a) measuring a predetermined performance while varying a write parameter in each zone of the disc for each head; (b) calculating a correlation of a predetermined performance for the write parameter in each zone of the disc for each head by using the result measured in step (a); And (c) calculating, from the correlation equation, the light parameter value according to the temperature in each zone of the disc for each head in proportion to the temperature characteristic of the light parameter in a range where the predetermined performance satisfies a design goal. Adaptive light parameter determination method according to the temperature, characterized in that it comprises a. The method of claim 1, wherein the write parameter includes a parameter for determining a write current. The method of claim 1, wherein the write parameter comprises a parameter for determining an overshoot of a write current. 2. The method of claim 1, wherein the predetermined performance includes bit error rate (BER) performance. 2. The method of claim 1 wherein the predetermined performance includes error count (EC) performance. In the data storage device, A disk for storing data; A memory for storing predetermined design parameter information; A recording / reading circuit configured to write data on the disc by setting a recording condition corresponding to a write parameter value or to read data from the disc according to an optimal read channel parameter value; And The predetermined performance is measured while varying the write parameters in each zone of the disc for each head, and a correlation of the predetermined performance for the write parameters in each zone of the disc for each head is calculated using the measured result, and the correlation is calculated from the correlation equation. And a controller that executes a control process for calculating the light parameter value according to temperature in each zone of the disc for each head in proportion to the temperature characteristic of the light parameter in a range in which the predetermined performance satisfies a design goal. Disk drive. 7. The disk drive of claim 6, wherein the write parameter includes a parameter for determining a write current. 7. The disk drive of claim 6, wherein the write parameter includes a parameter for determining an overshoot of a write current. 7. The disk drive of claim 6, wherein the predetermined performance includes bit error rate (BER) performance. 7. The disk drive of claim 6, wherein the predetermined performance includes error count (EC) performance.

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