KR100712536B1 - Method for optimal write reodering of a hard disk drive and Apparatus thereof - Google Patents

Abstract

Disclosed are an optimized recording order rearrangement method of a hard disk drive and an apparatus thereof.

The present invention provides a method of performing a write operation using a predetermined seek time prediction value and a predetermined settling time predicted value, and measuring seek time, settling time, and total write time from starting to seek until the actual write operation is started. Updating the seek time predicted value with a seek time, updating the settling time predicted value with the measured settling time, if the measured total write time is greater than one rotation time of the disc, and the updated seek time predicted value and settling Rearranging the recording order of the data to be recorded according to the time prediction value.

According to the present invention, it is possible to properly predict the seek time which changes according to the change of external environment such as disturbance, and to predict the change of the settling time in addition to the change of the seek time to achieve the optimization of the lead channel and the optimization of the recording order. This prevents frequent write retries or idling, thus improving the drive's write performance.

Description

Method for optimal write reodering of a hard disk drive 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 hard disk drive of FIG. 1 operably connected to a host computer.

3 is a graph illustrating the concept of seek time, settling time, and time from completion of settling until the head starts writing to the disc.

4 is a block diagram of an optimized recording order rearrangement apparatus according to the present invention.

5 is a flowchart of an optimized recording order rearrangement method according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disk drive, and more particularly, to a method and apparatus for optimizing recording order of a hard disk drive.

In general, read / write cache is used to maximize hard disk drive performance. The write cache is configured to store data received from the host in a buffer and later store the data in the buffer. Algorithm to be recorded in When the data stored in the buffer is written to disk, a recording reordering algorithm is used to maximize performance.

In general, the recording order rearrangement algorithm performs magnetic recording from data stored in the buffer based on the seek time required for recording the data and the position on the circumference of the data. Use channel optimization.

However, if the recording sequence rearrangement algorithm is performed using the read channel optimization method as described above, if the actual seek time does not match the predicted seek time, the data that can be recorded within the shortest time cannot be recorded first. do. For this reason, the recording performance of a hard disk drive cannot be exhibited to the maximum.

Conventional recording order rearrangement compensates for these drawbacks by taking into account the AAM mode, temperature, and external voltage in order to compensate for these shortcomings. As a result, the seek time characteristic changes, and the seek time cannot be properly compensated.

Therefore, the conventional recording order rearrangement method does not properly predict the seek time that is changed by the change of the external environment such as disturbance, and does not properly predict the change of the settling time in addition to the change of the seek time, thereby causing frequent write retry or There is a problem in that idling is not prevented, and thus recording performance of the drive is deteriorated.

The technical problem to be achieved by the present invention is to properly predict the seek time that changes according to the external environment change such as disturbance, and to predict the change of the settling time in addition to the change of seek time to optimize the lead channel and the recording order. To provide a lead channel optimization method of the hard disk drive to achieve the.

Another object of the present invention is to provide an apparatus to which the read channel optimization method of the hard disk drive is applied.

In order to achieve the above technical problem, the present invention starts the seek time, the settling time and the seek until the actual write operation is started while performing the write operation with the predetermined seek time prediction value and the predetermined settling time prediction value. Measuring a time, updating the seek time predicted value with the measured seek time, and if the measured total write time is greater than one rotation time of the disc, updating the settling time predicted value with the measured settling time. And rearranging the recording order of data to be recorded according to the updated seek time prediction value and the settling time prediction value.

In order to solve the above other technical problem, the present invention provides a memory for storing a predetermined seek time predicted value and a predetermined settling time predicted value, a seek time while performing a write operation with the predetermined seek time predicted value and a predetermined settling time predicted value, A settling time, a time measuring unit for measuring the total write time from the start of the seek until the actual write operation is started, and controlling the stored seek time to be stored as the seek time predicted value in the memory; If the time is greater than one rotation time of the disk, the update determination unit for controlling to store the measured seating time in the memory as a seating time prediction value, the seek time prediction value in the memory to the measured seek time under the control of the update determination unit And the measured settling time as a predicted settling time in the memory. And a read write channel for rearranging the recording order of data to be recorded according to the seek time predicted value and the settling time predicted value stored in the memory.

Hereinafter, the configuration of the present invention will be described with reference to the drawings.

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 the 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 hard disk drive 100 of FIG. 1 operably connected to a host computer 240.

The circuits used to control the HDA include spindle control circuitry 242 and read / write channel 246, all of which are under the control of system processor 250. The interface circuit 252 also includes a sequencer (not shown) comprised of hardware used to form a variable timing sequence while the read / write channel 246 is operating.

Spindle control circuit 242 controls the rotational speed of the spindle motor.

The servo control circuit 244 ("servo controller" in the present invention) controls the position of the head 220 on the disk surface by applying a current to the actuator coil 213 in response to the servo information read through the head 220. do.

The read / write channel 246 encodes and sequentially encodes the data in response to user data provided to the channel from the interface circuit 252, and then generates a write current to magnetize a particular track on the disc, thereby causing the disc 220 to generate a write current. Have them record their data. In the read operation, the read / write channel 246 retrieves the stored data by decoding the data from the read signal generated by the head 220 when the head 220 passes a specific track on the disc.

Various operations of the drive are controlled by the system processor 250 according to programming stored in the memory MEM 254. Preferably, memory MEM 254 includes both volatile memory devices such as dynamic random access memory (DRAM) and non-volatile memory devices such as flash memory.

3 is a graph illustrating the concept of seek time, settling time, and time from completion of settling until the head starts writing to the disc.

The vertical axis of the graph represents the moving speed of the head, and the horizontal axis represents the elapsed time. The unit is milliseconds (ms).

The first section 310 represents a seek time, and is a time theoretically predicting a time taken to seek a target track based on a track corresponding to a position where data is to be recorded. The moving speed of the head gradually increases toward the target track, and the moving speed decreases as the target track approaches.

The second section 320 represents the settling time. The head may not be directly positioned at the center of the target track due to external factors such as disturbance or internal factors such as overshoot of the head. It's time to find the center. Excessive overshoot, undershoot, and external factors such as external heads can alter this settling time.

The third section 330 is the time from the completion of seating until the head starts recording on the disk. When the head starts to follow the target track correctly, it will search for the target sector. The time taken to search the target sector depends on the rotational speed of the disk.

In order to actually record data, it is necessary to go through all processes such as seek, settling, and target sector search. Therefore, in order to start the seek and actually perform the write, the above-described periods 310, 320, and 330 must be summed to obtain the total write time. have. Of course, even in the actual case, even if the target sector search is completed, delay may occur due to external factors such as disturbance or read / write channel operation, so that the total write time may be slightly increased.

In the present invention, the lead channel is optimized by updating the settling time, which is sensitive to different seek times and disturbances, for each operation depending on the position at which data is to be recorded, so that the data that can be recorded in the shortest time can be recorded first.

4 is a block diagram of an optimized recording order rearrangement apparatus according to the present invention.

4 is a block diagram of a memory 254, a servo controller 244, and a read / write channel 246 centering on the system processor 250 of FIG. 2.

In FIG. 4, the memory 400, 405 is divided into nonvolatile and volatile, the nonvolatile memory 400 is used to store updated seek time and settling time, and the volatile memory 405 is a nonvolatile memory 400. Temporarily storing the seek time and the settling time stored therein, the data is provided for various calculation processes performed by the update determiner 410. In addition, the volatile memory 405 loads initial seek time and settling initial values stored in the nonvolatile memory 400 when the drive is powered on.

The initial seek time and settling time initial values mentioned above are predetermined seek time prediction values and predetermined settling time prediction values measured in advance in the burn-in process step of the drive.

The nonvolatile memory 400 mentioned above may include a table storing a seek time prediction value and a settling time prediction value corresponding to the target track.

As the volatile memory 405, a DRAM or the like may be used, and the nonvolatile memory 400 may be a device that can read and write and permanently store data, such as a flash memory.

The update determining unit 410 controls the recording unit 470 to store the seek time measured by the time measuring unit 455 in the nonvolatile memory 400 as the seek time prediction value. Also, if the total write time measured by the time measurer 455 is greater than one rotation time of the disk, the update determiner 410 seats the settling time measured by the time measurer 455 in the nonvolatile memory 400. The recording unit 470 is controlled to store the time prediction value.

The time measuring unit 455 performs the write operation using the predetermined seek time predicted value and the predetermined settling time predicted value, which are initial parameter values, and calculates the total write time from starting the seek time, settling time, and seek until the actual write operation is started. Measure through the servo control unit 460.

The time measuring unit 455 may be divided into a seek time measuring unit 430, a seating time measuring unit 440, and a recording time measuring unit 450 according to a function thereof. Here, the recording time measuring unit 450 measures the total write time from the start of the seek until the start of the actual write operation, or the head of the disc from the time of completion of the seating plus the measured seek time and the measured settling time. The total write time can be calculated by adding the time required to start recording.

The recorder 470 stores the seek time measured by the time measurer 455 as a seek time predicted value in the nonvolatile memory 400 under the control of the update determiner 410, and measures the measured time by the time measurer 455. The settling time is stored in the nonvolatile memory 400 as a settling time prediction value.

The read write channel 420 rearranges the recording order of the data to be recorded according to the seek time prediction value and the settling time prediction value stored in the nonvolatile memory 400. Also, the read write channel 420 may rearrange the recording order of data to be recorded according to the seek time prediction value and the settling time prediction value loaded from the nonvolatile memory 400 to the volatile memory 405.

At this time, the recording order rearrangement method uses a plurality of recordings on the disk by using recording information including a logical recording position of the data stored in the buffer (not shown), data size, etc., and the seek time prediction value and the settling time prediction value updated above. Rearrange the order for recording the data with positions.

In more detail, the physical recording position is calculated based on the logical recording positions of the data stored in the buffer. Here, the logical recording position is position information that can be recognized by the host side, and generally refers to LBA, and the physical recording position is position information that can be recognized by the disk side, and generally refers to an address of a physical CHS scheme. The sector arrival time for the calculated physical write positions is then calculated. Subsequently, the total write time is obtained by adding the sector arrival time to the sum of the seek time prediction value and the settling time prediction value updated above. Then, the data having the positional information on the position where the minimum write time is taken is determined as the data to be recorded first. Then, the above process is repeated using other logical recording positions.

The read write channel 420 is connected to the interface 252 of FIG. 2 to store data received from the host in a buffer, and rearranges the recording order of the data stored in the buffer in the optimized order as described above. 220 to obtain an optimum recording performance.

5 is a flowchart of an optimized recording order rearrangement method according to the present invention.

First, when the drive is powered on, the predetermined seek time predicted value and the predetermined settling time predicted value measured in the burn-in process step are loaded as initial values (step 500). At this time, the parameters of the read channel are set to a predetermined seek time predicted value and a predetermined settling time predicted value.

When the disc write reputation is input, the seek time is measured while performing the write operation using the set read channel parameter (steps 510 and 520). At this time, the seek time may be a point where the moving speed of the head increases in the direction of the target track and then decreases to zero.

The seek time prediction value is updated with the measured seek time (step 525). The update of the seek time prediction value means that the previously stored seek time prediction value is deleted from the table storing the seek time prediction value corresponding to the target track, and the currently measured seek time is stored as the seek time prediction value in the above table. Therefore, the next write operation uses the updated seek time prediction value for the same target track. In addition, updating of the seek time prediction value may be performed after measuring the settling time.

When updating of the seek time is completed, the settling time and the total write time from the seek start until the actual write operation is started are measured (steps 530 and 540).

The process of measuring the total write time measures the total time from the start of the seek until the start of the actual write operation, or the head writes to the disc from the time of completion of the set-up plus the measured seek time and the measured settling time. This can be done by calculating the total write time with the time to start up.

It is determined whether the measured total write time is greater than one rotation time of the disc (step 550). If the measured total write time is greater than one rotation time of the disc, using the current seek time prediction value and the settling time prediction value, there is a high probability that a write retread or idle occurs. Therefore, in such a case, it is necessary to update the seek time prediction value and the settling time prediction value in order to increase the efficiency of the recording order rearrangement algorithm described above.

At this time, if the measured total write time is greater than one rotation time of the disk, the settling time prediction value is updated with the measured settling time (step 555). The update of the settling time prediction value means that the previously stored settling time prediction value is deleted from the table storing the settling time prediction value corresponding to the target track, and the currently measured settling time is stored as the settling time prediction value in the table.

On the other hand, if the measured total write time is not greater than one rotation time of the disk, the update of the settling time prediction value is unnecessary and the process proceeds to step 560.

Of course, even in the actual case, even if the target sector search is completed, delay may occur due to external factors such as disturbance or read / write channel operation, so that the total write time may be slightly increased. Accordingly, when the time obtained by adding a predetermined delay to the measured total write time is greater than one rotation time of the disc, the settling time prediction value may be updated by the measured settling time.

The seek time and settling time updated above are applied at the next write command input (step 560). This process is performed by performing the recording sequence rearrangement algorithm by using the seek time prediction value and the settling time prediction value for the same target track stored in the nonvolatile memory 400 when the write command is input to the same target track next time. This is a process of obtaining recording performance. This process rearranges the recording order of the data to be recorded according to the seek time prediction value and the settling time prediction value updated above.

Preferably, a program for executing the read channel optimization method of the hard disk drive of the present invention on a computer can be recorded on a computer-readable recording medium.

The invention can be implemented via software. When implemented in software, the constituent means of the present invention are code segments that perform the necessary work. The program or code segments may be stored on a processor readable medium or transmitted by a computer data signal coupled with a carrier on a transmission medium or network.

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, the lead channel is optimized and recorded in accordance with the change in external environment such as disturbance, and the change in the settling time is predicted appropriately in addition to the change in seek time. By achieving the optimization of, it is possible to prevent frequent write retries or idling, thereby improving the write performance of the drive.

Claims (5)

The seek time, the settling time, and the total write time from the start of the seek to the start of the actual write operation are performed while performing the write operation using the seek time estimate value required to seek the target track and the settling time estimate value required to find the exact center of the target track. Measuring; Updating the seek time prediction value with the measured seek time; If the measured total write time is greater than one rotation time of the disc, updating the settling time prediction value with the measured settling time; And And rearranging the recording order of the data to be recorded according to the updated seek time prediction value and the settling time prediction value. The method of claim 1, The step of updating the settling time prediction value Optimization of the hard disk drive, characterized in that for updating the settling time predicted value to the measured settling time, if the value of the total write time plus the delay time caused by disturbance, etc. is greater than one rotation time of the disk. Recorded order rearrangement method. A computer-readable recording medium having recorded thereon a program for executing the method of claim 1 on a computer. A memory for storing a seek time prediction value for seeking a target track and a settling time prediction value for finding a true center of the target track; A time measuring unit configured to perform a write operation using the seek time prediction value and the settling time prediction value and measure the total write time from the seek time, the settling time, and the seek until the actual write operation is started; Controlling to store the measured seek time as a seek time predicted value in the memory, and when the measured total write time is greater than one rotation time of the disk, controlling the measured settling time as a predicted settling time in the memory. An update determination unit; A recording unit for storing the measured seek time as a seek time predicted value in the memory under the control of the update determiner, and storing the measured settling time as a predicted settling time in the memory; And And a read write channel for rearranging the recording order of the data to be recorded according to the seek time prediction value and the settling time prediction value stored in the memory. The method of claim 4, wherein And the memory is a nonvolatile memory device.

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