KR20060023896A - Method and apparatus for detecting a growing defect in disk drive - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for inspecting a disk drive, and more particularly, to a method and apparatus for detecting progressive defects of a disk drive for detecting scratch defects in which a defect is increased with use time of a disk drive. will be.

In the disk drive control method according to the first embodiment of the present invention, in the disk drive control method, (a) determining a screen window of a predetermined size based on the sector in which the defect is generated, (b) Detecting the total number of defect sectors generated in the screen window region and (c) determining that the scratch is defective when the total number of defect sectors detected in the screen window region exceeds a predetermined threshold value. It is characterized by including.

Description

Method and apparatus for detecting a growing defect in disk drive

1A and 1B show examples of scratch defects generated in a disc.

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

3 is an electrical circuit diagram of a hard disk drive according to the present invention.

4 is a flowchart illustrating a progressive defect detection method of a disk drive according to a first embodiment of the present invention.

5 is a flowchart illustrating a progressive defect detection method of a disk drive according to a second embodiment of the present invention.

6 is a view for explaining a method for determining a screen window according to the present invention.

7 is a view for explaining a method for setting a scratch fill according to the present invention.

The present invention relates to a method and apparatus for inspecting a disk drive, and more particularly, to a method and apparatus for detecting progressive defects in a disk drive for detecting scratch defects in which the occurrence of defects increases with the use time of the disk drive. It is about.

Technical documents published in connection with the present invention include Korean Patent Publication No. 2001-0060247 and Korean Patent Publication No. 2002-0053762.

Korean Patent Publication No. 2001-0060247 describes a technique for analyzing defect characteristics using a ferromagnetic liquid to precisely identify the defects by using precise coordinates and DC erasure on the disk as a method of marking defects in a thin film hard disk. In the Korean Patent Laid-Open Publication No. 2002-0053762, a technique for inspecting defects in the shape pattern of a ferromagnetic thin film layer for recording initial information of a master disk for a magnetic recording medium used in an A / V HDD is presented.

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. As such hard disk drives are gradually increasing in capacity, density, and miniaturization, bit per inch (BPI) in the direction of disk rotation and track per inch (TPI) in the thickness direction are increasing. do.

The disc drive may cause scratches as shown in FIGS. 1A and 1B due to foreign matter in the head or the inside, and in this case, damage to the head may occur, Therefore, a phenomenon in which the disc defect is progressively increased may occur.

According to the prior art, even if scratchable defects are generated in the disc drive, the defects are treated as if the defects are caused by other factors and ignored if the disc drive falls within an acceptable range.

However, as mentioned above, the scratchable defect may be developed as a progressive defect in which the defect is increased as the use time elapses, and thus there is a problem that may be a potential cause of a disk drive malfunction in the future.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for detecting a scratch defect in a disk drive and adaptively determining a scratch fill which is an area for restricting access to a scratch defect. The present invention provides a method and apparatus for detecting a progressive defect of a disk drive.

In order to achieve the above technical problem, in the progressive drive detection method of a disk drive according to the first embodiment of the present invention, (a) a screen window having a predetermined size is determined based on a sector where a defect is generated. (B) detecting the total number of defect sectors generated in the screen window area, and (c) when the total number of defect sectors detected in the screen window area exceeds a predetermined threshold. Determining that the scratch is bad.

In order to achieve the above technical problem, in the progressive drive detection method of a disk drive according to the second embodiment of the present invention, in the disk drive control method, (a) a screen window having a predetermined size is determined based on a sector where a defect is generated. (B) detecting the total number of defect sectors generated in the screen window region; and (c) the total number of defect sectors detected in the screen window region exceeds a first threshold value. Counting the number of times; and (d) if the total number of defects detected in the screen window area exceeds a predetermined first threshold value and the counting value is smaller than a predetermined second threshold value, A scratch fill, which is an area for restricting access, is created, and if the counting value is greater than or equal to a second predetermined threshold, And determining the scratch drive as a scratch failure.

In accordance with another aspect of the present invention, a disk drive includes a disk for storing data, a host interface for performing data transmission / reception with a host device, and a disk for storing data. Inspection to detect a defect, determine a screen window having a predetermined size based on the sector where the defect is generated, calculate the total number of defect sectors generated in the screen window area, and the total number is a predetermined threshold Data processing for writing data received via the host interface or reading data from the disk in accordance with a controller executing a control process for determining that a scratch is defective when the value is exceeded and a control command of the controller Lead / light channel times running A characterized in that it comprises.

In accordance with another aspect of the present invention, a disk drive includes a disk for storing data, a host interface for performing a data transmission / reception process with a host device, and the disk. Inspection to detect a defect, determine a screen window having a predetermined size based on the sector where the defect is generated, and the number of times that the total number of defect sectors generated in the screen window area exceeds a first threshold value; And limiting access to a predetermined size when the total number of defect sectors detected in the screen window area exceeds a predetermined first threshold value and the counting number is smaller than a predetermined second threshold value. Create an scratch scratch, the counting number being greater than or equal to a predetermined second threshold In this case, a controller for executing a control process for determining a disk drive as a scratch failure and data processing for reading data from the disk or writing data received through the host interface according to a control command of the controller is executed. And a read / write channel circuit to execute.

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

First, a hard disk drive to which the present invention is applied will be described.

2 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. The drive 10 also includes a transducer 16 located adjacent the surface of the disk 12.

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 the surface of each disk 12. 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 can be integrated into the slider 20. The slider 20 is structured to create an air bearing between the transducer 16 and the surface of the disk 12. 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 to rotate the actuator arm 24 relative to the bearing assembly 32. Rotation of the actuator arm 24 will move the transducer 16 across the disk 12 surface.

The information is typically stored in an annular track of the disc 12. A disc is generally divided into a plurality of zones, each zone is composed of a plurality of tracks, and each track 34 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 surface of the disc 12 to read or write information on other tracks.

Next, the operation of the electrical system of the hard disk drive will be described.

3 shows an electrical system 40 capable of controlling the hard disk drive 10. The electrical system 40 includes a controller 42 coupled to the converter 16 by a lead / right (R / W) channel circuit 44 and a pre-amp circuit 46. The controller 42 may be a digital signal processor (DSP), a microprocessor, a microcontroller, or the like. The controller 42 supplies a control signal to the read / write channel 44 for reading from or writing information to the disc 12. Information is typically sent from the R / W channel to the host interface circuit 54. The host interface circuit 54 includes a buffer memory and control circuitry that allows a disk drive to interface to a system such as a personal computer.

The controller 42 is also coupled to a VCM drive circuit 48 that supplies a drive current to the voice coil 26. The controller 42 supplies a control signal to the VCM drive circuit 48 to control the excitation of the voice coil motor VCM and the movement of the transducer 16.

The controller 42 is connected to a nonvolatile memory device 50 such as a read only memory (ROM) or a flash memory device, and collectively controls the disk drive according to a program stored in the memory.

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

In the data read mode, the disk drive amplifies the electrical signal sensed by the transducer 16 (magnetic head or magnetoresistive head) from the disk 12 to facilitate signal processing in the preamplifier 45. The read / write channel 44 then encodes the amplified analog signal into a digital signal that can be read by a host device (not shown), converts it into stream data, and sends it to the host device via the host interface 54. send.

In contrast, in the write mode of the data, the disc drive receives user data from the host device through the host interface 54 and converts the read / write channel 44 into a binary data stream suitable for the write channel. The recording current amplified by 45 is recorded on the disc 12 via the transducer 16 (magnetic head).

Next, a method of detecting scratchable defects by the control process of the controller 50 will be described.

First, a method of detecting the scratchable defect according to the first embodiment of the present invention according to the control process of the controller 42 will be described with reference to the flowchart of FIG. 4.

The controller 50 checks whether a defect is detected in the disk 12 (S401).

If the defect is detected, a screen window is generated based on the sector in which the defect is generated (S402). The size of the screen window is, for example, as shown in FIG. 6, and has a predetermined number of sector widths symmetrically in the disk rotation direction (ie, sector direction) around the sector where the defect is generated, and the disk radial direction. In other words, the cylinder direction is determined to have a length from the cylinder where the defect is generated to the last cylinder of the zone.

Then, the total number Defect_count of defects existing in the screen window is detected (S403).

Next, the total number Defect_count detected in the screen window is compared with the initially set threshold value Scratch_defet_cnt (S404). Here, the threshold value Scratch_defet_cnt is a reference value for determining whether or not scratchability defects.

If the total number of defect sectors (Defect_count) detected in the screen window is smaller than the initial threshold value (Scratch_defet_cnt) as a result of the comparison of step 404 (S404), there is no general possibility that there is no possibility of development other than the defect generated by the scratch phenomenon. Since it is determined to be a defect, after moving to a defect sector position other than the inspected screen window (S405), it executes again from step 402 (S402).

However, if the total number of defect sectors (Defect_count) detected in the screen window is greater than or equal to the initially set threshold value (Scratch_defet_cnt) as a result of the comparison of step 404 (S404), it corresponds to the potential defect generated by the scratch phenomenon. In step S406, the disk drive is judged to be scratch bad.

If it is determined that the defect is caused by the scratch phenomenon, it is highly likely that the scratch defects will continue to occur as the use time elapses in the future, so the disk drive is determined to be a scratch defect.

Next, a method of detecting the scratchable defect according to the second embodiment of the present invention according to the control process of the controller 42 will be described with reference to the flowchart of FIG. 5.

First, the controller 42 checks whether a defect is detected on the disc (S501).

When the defect is detected, a screen window is generated based on the sector in which the defect is generated (S502). The size of the screen window is determined in the same manner as described in the first embodiment.

Then, the total number Defect_count of defects existing in the screen window is detected (S503).

Next, the total number Defect_count detected in the screen window is compared with the initially set threshold Scratch_defet_cnt (S504). Here, the threshold value Scratch_defet_cnt is a reference value for determining whether or not scratchability defects.

If the total number of defect sectors (Defect_count) detected in the screen window as a result of the comparison of step 504 (S504) is smaller than the initially set threshold value (Scratch_defet_cnt), it corresponds to a normal defect, not a defect generated by a scratch phenomenon. After moving to a defect sector position other than the screen window examined above (S505), execution is resumed from step 502 (S502).

However, if the total number of defect sectors (Defect_count) detected in the screen window is greater than or equal to the initially set threshold value (Scratch_defet_cnt) as a result of the comparison of step 504 (S504), the controller to count the number of defects caused by the scratch phenomenon. (42) The value Cs of the counter inside is increased by one (S506).

Then, the value Cs of the counter is compared with the threshold value N (S507). Here, the threshold value N may be arbitrarily determined according to the design specification as a threshold value of the number of scratch occurrences that the disk drive can tolerate. That is, the threshold value N is a reference value that finally determines whether or not the scratchability defect can be developed in the future.

If the value Cs of the counter as a result of the comparison in step 507 (S507) is smaller than the threshold value N, the size of the scratch fill is determined by reflecting the position of the defect detected in the screen window (S508). .

The scratch fill is an area in the disk drive that restricts access and means a disk area that cannot be used for data storage. The size of the scratch fill is determined to be at least a size that can include all defects that occur within the screen window area. The scratch fill size is, for example, a constant margin (eg, ± 1) from the left and right outermost sectors in which the defect in the screen window occurs in the disk rotation direction (ie, the sector direction), as shown in FIG. 7. Sector), and in the disc radial direction (i.e., the cylinder direction), determine from the top or bottom cylinder from which the defect was generated to have a constant margin (e.g., ± 1 cylinder).

However, if the value Cs of the counter in the comparison result of step 507 (S507) is greater than or equal to the threshold value N, the number of occurrences of scratch defects generated in the disk drive is set to a standard that the disk drive can accept. It is judged that the scratchability defect has a very high possibility of power generation as exceeded, and finally the disk drive is judged to be a scratch failure (S509).

The difference between the first embodiment of the present invention illustrated in FIG. 4 and the second embodiment of the present invention illustrated in FIG. 5 described above is as follows.

According to the first embodiment of the present invention, if the scratchable defect is detected only once, it is determined that the scratchable defect is likely to continue to occur in the future, and the disk drive is determined to be scratchable.

On the contrary, according to the second embodiment of the present invention, when the scratchable defect is detected within an allowable number of times, the scratch fill is set to restrict access to only the scratch generating region, and the scratchable defect can be allowed. It is judged that the scratchable defects that can be generated only when it occurs in excess of the value of the disk drive are judged to be scratchable.

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, Etc. 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 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.

As described above, according to the present invention, by accurately determining whether the defect detected by the disc drive corresponds to the scratchable defect, the effect of early detection of a growth defect that is likely to occur in the future is generated. In addition, scratch scratches, which are expected to be less likely to occur in the future, generate scratch fills to restrict access, thereby effectively utilizing disk capacity.

Claims (8)

In the disk drive control method, (a) determining a screen window of a predetermined size based on the sector in which the defect is generated; (b) detecting a total number of defect sectors generated in the screen window area; And (c) determining that the scratch is bad when the total number of defect sectors detected in the screen window area exceeds a predetermined threshold value. The size of the screen window has a predetermined number of sector widths symmetrically in a disk rotation direction about a sector where a defect is generated, and a zone from the cylinder where the defect is generated in a disk radial direction. To have a length up to the last cylinder of In the disk drive control method, (a) determining a screen window of a predetermined size based on the sector in which the defect is generated; (b) detecting a total number of defect sectors generated in the screen window area; (c) counting a number of times that the total number of defect sectors detected in the screen window area exceeds a first predetermined threshold; And (d) If the total number of defect sectors detected in the screen window area exceeds a predetermined first threshold value and the counting value is smaller than a predetermined second threshold value, the area is restricted to a predetermined size. Generating a scratch fill, and determining the disk drive as a scratch failure if the counting value is greater than or equal to a predetermined second threshold value. The size of the screen window is a predetermined number of sector widths symmetrically in the disk rotation direction with respect to the sector in which the defect is generated, and the size of the zone from the cylinder in which the defect is generated in the disk radial direction. Characterized by determining the length to the last cylinder 4. The method of claim 3, wherein the size of the scratch fill is determined to include a size including at least all defects generated in the screen window area. 4. The method of claim 3, wherein the size of the scratch fill is determined to be equal to the screen window size. In the data storage device, A disk for storing data; A host interface for performing data transmission / reception processing with the host device; The disk is inspected to detect a defect, a screen window having a predetermined size is determined based on the sector where the defect is generated, the total number of defect sectors generated in the screen window area is calculated, and the total number is calculated. A controller that executes a control process for determining a scratch failure when exceeding a predetermined threshold value; And And a read / write channel circuit configured to write data received through the host interface to a disk or to perform data processing for reading data from the disk according to a control command of the controller. In the data storage device, A disk for storing data; A host interface for performing data transmission / reception processing with the host device; Defects are detected by inspecting the disk, and a screen window having a predetermined size is determined based on the sector in which the defect is generated, and the total number of defect sectors generated in the screen window area is determined as a predetermined first threshold value. Counting the exceeding number of times, and access is made to a predetermined size when the total number of defect sectors detected in the screen window area exceeds a predetermined first threshold value and the counting number is smaller than a predetermined second threshold value. A controller for generating a scratch fill, which is a limiting area, and executing a control process for determining a disk drive as a scratch failure if the counting count is greater than or equal to a predetermined second threshold value; And And a read / write channel circuit for writing data received through the host interface to the disk or performing data processing for reading data from the disk according to a control command of the controller.

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