KR20060136255A - Recording controll method of harddisk drive and harddisk drive and recording medium for the same - Google Patents

Abstract

The present invention relates to a hard disk drive, and more particularly, to a recording control method of a hard disk drive, a hard disk drive and a recording medium suitable thereto.

In the recording control method of a hard disk drive according to the present invention, a plurality of sectors are provided in one track, and each of the four sectors of the A-D servo burst signals for servo control is radially recorded. CLAIMS 1. A write control method of a method comprising: generating a primary position error signal for a target track by a difference of adjacent servo bursts; Generating a secondary position error signal for the target track by the sum or difference of the primary position error signals; Determining whether the primary position error signal and the secondary position error signal are within a predetermined limit range; And as a result of the determination, allowing the recording operation if the primary position error signal and the secondary position error signal are within a predetermined limit range, and otherwise not allowing the recording operation.

According to the recording control method according to the present invention, even if the primary position error signal is distorted by a poor servo burst, the secondary position error signal effectively checks whether the head is within the limit for recording, thereby effectively preventing the erasing of adjacent tracks. Has an effect.

Description

Recording controll method of harddisk drive and harddisk drive and recording medium for the same}

Figure 1 shows the recording state of the servo bursts by the four servo burst method.

2 shows the profile of the servo burst signal read by the head.

3 schematically shows the relationship between the target offtrack and the PES.

4 is a flowchart showing a conventional recording control method.

5 shows another profile of the servo burst signal read by the head.

FIG. 6 shows the distortion of the PES due to a poor servo burst as shown in FIG.

7 is a flowchart showing a recording control method according to the present invention.

8 is a waveform diagram showing an application example of the present invention.

9 shows the mechanical configuration of a hard disk drive according to the present invention.

FIG. 10 shows an electrical system capable of controlling the hard disk drive 10 shown in FIG. 9.

The present invention relates to a hard disk drive, and more particularly, to a recording control method of a hard disk drive, a hard disk drive and a recording medium suitable thereto.

A hard disk drive is a magnetic recording device used for storing information. The information is recorded in concentric tracks formed on the surface of the disc. The disks are mounted rotatably by the spindle motor, and the information is accessed by read / write heads mounted on the actuator arm that is rotated by the voice coil motor. The voice coil motor is activated by the current to rotate the actuator and consequently move the heads mounted on the actuator arm. When the hard disk drive is operating, the read / write heads must be precisely aligned with the tracks on the disk to ensure reading and writing of the information.

Traditionally, head position control is performed by servo control circuitry, which detects and controls the position of the head using servo bursts recorded on the disk.

In order for the head to follow the track accurately, the servo information including the servo burst in the track is a process in which the STW magnetically records the servo data on the disk.

In order to accurately control the position of the head, the quality of the servo burst recorded in the STW process, that is, the strength and phase of the servo burst is important.

As the storage density of hard disk drives increases, so does the track density. As the track density increases, the track width becomes narrower, and the accuracy of recording servo information including a servo burst on a disk has also reached its limit.

As a result, the servo pattern recorded on the disc is not only uniform for each track, but also uniform for each servo sector even in one track.

The hard disk drive uses the servo burst to determine the position of a head. Thus, if the quality of the servo bursts is not perfect, it is difficult to pinpoint the exact position of the head and, in particular, the possibility of damaging the data of adjacent tracks in the recording operation.

Figure 1 shows the recording state of the servo bursts by the four servo burst method. The four-servo burst method uses A to D four servo bursts, and each servo burst is spaced apart by a predetermined distance in the track direction and the radial direction of the disc.

2 shows the profile of the servo burst signal read by the head. In the graph shown in Fig. 2, the horizontal axis represents the radial head position of the disk, and the vertical axis represents the magnitude of the servo burst read by the head. The position of the head is represented by the degree of deviation (off track) from the track center of the Nth track shown in FIG.

If the servo pattern is written uniformly sector by sector and track by track, the maximum of each servo burst profile should be the same, and the peaks of the A to D servo bursts are offtracked by 50%, 0%, 50%, or 100%. It must be located exactly at.

The hard disk drive locates the head by comparing the magnitudes of the four servo bursts read by the head. Therefore, to accurately locate the head, the servo bursts must be written uniformly in all sectors and all tracks as shown in FIG.

4 The hard disk drive using the servo pattern of the servo burst method generates a position error signal (PES) using the following equation.

Equation 1)

If (-7% <= target offtrack <= 7%)

PES = PES_ (A-B) = A-B

Else if (-43% <target offtrack <-7%) or (7% <target offtrack <43%)

PES = PES_N = (A-B)-(C-D)

PES = PES_P = (A-B) + (C-D)

Else if (-50% <= target offtrack <= 43%) or (43% <= target offtrack <= 50%)

PES = PES_ (C-D) = C-D

Here,% is used to classify the area and may vary depending on the hard disk drive. Also, A to D are used to indicate the magnitude of the servo burst or the name of the servo burst. In the following description, the PES obtained by the difference between two adjacent servo bursts (AB) or (CD) is called a primary PES, and is obtained by the sum of the primary position error signals (PES_P) and the difference (PES_N). Losing PES will be referred to as secondary PES.

3 schematically shows the relationship between the target offtrack and the PES. Referring to Fig. 3, at 7% to 7% from the center of the track (AB area), the PES calculated as AB (PES_ (AB) is used, and at -43% to -50% and 43% to 50% (CD). Area) uses the PES calculated by CD (PES_ (CD), and at -43% -7% and 7% -43% (NP area) is N (= (A-B)-(C-D) It can be seen that PES (PES_NP) calculated as P (= (A-B) + (C-D)) is used.

In the control of the head position of a hard disk drive, when only PES_ (AB) or PES_ (CD) is used, the linearity of PES_ (AB) and PES_ (CD) may be changed by saturation of (AB) or (CD). . On the other hand, when only PES_NP is used, even if there is saturation of (A-B) or (C-D), saturation of PES_NP does not occur, but discontinuity of PES_NP occurs due to the offset at the portion where PES_N and PES_P are switched. Therefore, as shown in FIG. 3, the PES is calculated separately by dividing the interval according to the target offtrack size.

In Fig. 3, the parts indicated by circles are parts in which saturation of (A-B) and (C-D) occurs.

Obtaining PES by Equation 1) assumes that the four servo burst signals are recorded with normal servo bursts as shown in Figs.

4 is a flowchart showing a conventional recording control method. Referring to FIG. 4, it can be seen that the recording operation is started by determining whether the value of PES calculated by A-B in the A-B area of FIG. 3 is within a predetermined limit range.

In step S402 it is determined whether the target off-track is in the A-B area or the C-D area.

As a result of the determination in step S402, if the target offtrack is in the AB area or the CD area, the PES is calculated by AB or CD. (S404) Referring to FIG. 3, by AB in the AB area and CD in the CD area. Calculate the PES.

If the target off-track is not in the A-B region or the C-D region, the PES is calculated by N or P. (S406) Referring to FIG. 3, the PES is calculated by N or P in the NP region.

In step S408, it is determined whether the PES calculated in step S404 or S406 is within a predetermined limit.

If the PES calculated as a result of the step S408 is within a predetermined limit range, the write operation is performed, otherwise the write operation is prohibited (S410).

5 shows another profile of the servo burst signal read by the head. In the profile shown in FIG. 5, the peak of the servo burst signal is distorted in the circled portion, and the peak of the servo burst is not accurately positioned at an off track of 50%, 0%, 50%, or 100%. Able to know. Here, the distortion means that the PES has no linearity.

FIG. 6 shows the distortion of the PES due to a poor servo burst as shown in FIG. Referring to FIG. 6, it can be seen that PES (PES_ (A-B) calculated as A-B is distorted without maintaining linearity by B servo burst smaller than A servo burst.

As shown in FIG. 5, if some servo bursts are poor or the width of the lead head is narrow, distortion occurs in PES (PES_ (AB), PES_ (CD)) calculated by AB or CD, and thus the correct position of the head. It will not reflect. In other words, the PES is determined to be within a recordable range, but in reality, the head may be in a range not recordable.

If the servo pattern is not recorded uniformly across all sectors and all tracks, the profile of the servo burst will be distorted as shown in FIG. 5, resulting in an inaccurate head positioning.

If the position of the head cannot be accurately determined in the recording operation, data may be written out of the center of the data track, making recorded data difficult to reproduce correctly and even damaging the data of adjacent tracks.

For this reason, the defect processing process which detects the servo sector or track which has a bad servo pattern in a manufacturing process of a hard disk drive, and processes it so that data may not be written or read is needed.

In the defect processing process, for example, when a position error signal exceeds a certain threshold value at a position where data is read or written, it is determined that the servo pattern is bad and the corresponding servo pattern is mapped.

By the way, if there is a bad servo pattern at a position slightly separated from this position even if the position error signal is good at the position where the write operation is started, the bad servo pattern will write data to the wrong position during the write operation, Problems with erasing data can occur.

An object of the present invention is to provide a recording control method for controlling a recording operation by determining whether the head is within a limit range in the recording operation.

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

It is another object of the present invention to provide a recording medium that can be read by a computer that stores a program for performing the above recording control method.

The recording control method of the hard disk drive according to the present invention for achieving the above object

In a track control method of a hard disk drive in which a plurality of sectors are provided in one track, and four servo burst signals A to D for servo control are radially recorded for each sector.

Generating a primary position error signal for the target track by the difference between two adjacent servo bursts;

Generating a secondary position error signal for the target track by a sum or difference of primary position error signals;

Determining whether the primary position error signal and the secondary position error signal are within a predetermined limit range; And

As a result of the determination, if the primary position error signal and the secondary position error signal are within a predetermined limit range, the process includes allowing a recording operation and otherwise not writing operation.

Hard disk drive according to the present invention to achieve the above another object

A disk for storing predetermined information;

A spindle motor for rotating the disk;

A head for recording information on the disk and reading information from the disk;

A VCM driver for driving a voice coil motor to move the head across the surface of the disk; And

A controller for controlling the VCM driver to write data to a target servo sector through the head;

Here, the controller determines whether the primary position error signal due to the difference between two adjacent servo bursts and the secondary position error signal due to the sum or difference of the primary position error signals are within a predetermined limit range, and 1 If the secondary position error signal and the secondary position error signal are within a predetermined limit range, the write operation is allowed; otherwise, the write operation is not allowed.

A recording medium according to the present invention for achieving the above another object is

A computer that stores a program for controlling a recording operation of a hard disk drive, in which a plurality of sectors are provided in one track, and four servo burst signals A to D for servo control are radially recorded for each sector. Readable recording medium,

Generating a primary position error signal for the target track by the difference between two adjacent servo bursts;

Generating a secondary position error signal for the target track by the sum or difference of the primary position error signals;

Determining whether the primary position error signal and the secondary position error signal are within a predetermined limit range; And

As a result of the determination, if the primary position error signal and the secondary position error signal are within a predetermined limit range, a program is recorded which includes a process which permits a recording operation and otherwise does not permit the recording operation.

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

7 is a flowchart showing a recording control method according to the present invention.

Referring to FIG. 7, PES (PES_ (AB), PES_ (CD) calculated as AB even when in the AB region of FIG. 3, as well as PES (PES_NP) calculated by N and P, are all within a predetermined limit range. It can be seen that the recording operation is started by determining whether the

In step S702, it is determined whether the target offtrack is in the A-B area or the C-D area.

As a result of the determination in S702, if the target offtrack is in the AB region or the CD region, both PES (PES_ (AB), PES_ (CD) by AB or CD and PES (PES_NP) by N and P are calculated. Referring to FIG. 3, PES (PES_ (AB) is calculated by the AB in the AB area, PES (PES_ (CD) is calculated by the CD in the CD area, and N and P in both the AB area and the CD area. Calculate PES (PES_NP) by.

If the target off-track is not in the AB region or the CD region, the PES (PES_NP) by N or P is calculated. (S606) Referring to FIG. 4, in the NP region, PES (by N and P) is calculated. PES_NP) is calculated.

In step S708, it is determined whether the PES calculated in step S704 or S706 is within a predetermined bump limit.

If the PES calculated as a result of the step S708 is within a predetermined limit limit, the write operation is performed, otherwise the write operation is prohibited (S710).

Using the method shown in FIG. 7, since the position information can be additionally obtained using the PES_NP signal having good linearity in the A-B area and the C-D area of FIG. 3, data loss of adjacent tracks can be effectively prevented.

8 is a waveform diagram showing an application example of the present invention. The circled portion in FIG. 8 is where distortion of PES_ (A-B) occurs by the distorted servo burst signal as shown in FIG. However, it can be seen that PES_NP maintains linearity. In other words, PES_ (A-B) does not represent the actual position of the head due to saturation, whereas PES_NP is represented properly.

Accordingly, it can be seen that data loss of adjacent tracks can be effectively prevented by judging whether the PES_NP signal is within a predetermined range even in the A-B area or the C-D area.

9 shows the mechanical configuration of a hard disk drive according to the present invention. Referring to FIG. 9, the hard disk drive 10 includes a disk 12 that is rotated by the spindle motor 14 and a head 16 that accesses the disk 12 adjacent the disk surface 18.

The disk 12 is rotated by the spindle motor 14, the head 16 magnetizes and senses the magnetic field of the disk 12 to record information on the disk 12 or the information recorded on the disk 12 You can read Although only one head 16 is shown in FIG. 6, a write head for magnetizing the disc 12 and a read head for sensing the magnetic field of the disc 12 are integrated with each other.

The head 16 may be integrated with the slider 20. The slider 20 is configured to create an air bearing between the head 16 and the disk surface 18. Meanwhile, the slider 20 may be integrated into a head gimbal assembly (HGA) 22. The HGA 22 is attached to an actuator arm 24 having a voice coil 26.

The voice coil 26 together with the magnet assembly 28 constitutes a voice coil motor (VCM) 30. Supplying a current 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 causes the head 16 to move across the disk surface 18.

The information is recorded in annular tracks 34 of the disc 12. Each track 34 includes a plurality of sectors, and each sector has a user data area and a servo data area. In the servo data area, gray codes for identifying sectors and tracks (or cylinders), servo burst signals for head position control, and the like are recorded.

FIG. 10 shows an electrical system capable of controlling the hard disk drive 10 shown in FIG. 9. The electrical system 40 shown in FIG. 10 is a controller 42 electrically coupled to the head 16 by read / write (R / W) channel circuits 44 and pre-amp circuits 46. ). The controller 42 may be a digital signal processor (DSP), a microprocessor, a micro controller, or the like. Controller 42 may send control signals to read / write channel circuitry 44 to read information from or write information to disk 12.

Information is transferred between the read / write channel circuit 44 and the host interface circuit 46. The host interface circuit 46 includes a control circuit that controls the hard disk drive 10 to interface with a host system such as a personal computer, and a buffer memory that buffers information exchanged between the hard disk drive 10 and the host system.

The controller 42 is also connected to a VCM driver 48 that provides a drive current to the voice coil 26. The controller 42 sends a control signal to the VCM driver 48 to control the movement of the head 16.

The controller 42 is connected to a nonvolatile memory or RAM device 52, such as a ROM or flash memory device 50. Memory devices 50 and 52 include instructions and data that controller 42 uses to perform software routines. In particular, the software routine includes a write control method according to the present invention as shown in FIG.

In the data read mode, the disc drive amplifies the electrical signal sensed by the converter 16 (also called head) from the disc 12 to facilitate signal processing in the preamplifier 46. Then, in the recording / reading channel 44, 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 54.

Next, in the write mode, the disk drive receives data from the host device through the host interface 54 and temporarily stores the data in a buffer (not shown), and then sequentially outputs the data stored in the buffer to write / read channels. After conversion by means of 44 to a binary data stream suitable for the recording channel, the write current amplified by the preamplifier 46 is recorded on the disc 12 via the converter 16.

The controller 42 analyzes the command received from the host device via the host interface 54 and executes control corresponding to the analyzed result. When a write command is input from the host device, the controller 42 records data in data sectors between the servo sectors while following the track with reference to the servo information recorded in the servo sector.

The recording operation according to the recording control method according to the present invention will be described in detail.

When a write command is input, the controller 42 determines whether the target offtrack is in the A-B area or the C-D area of FIG. If the target offtrack is in the A-B area or the C-D area, both PES calculated by A-B or C-D and PES calculated by N and P are calculated. If the target offtrack is not in the A-B area or the C-D area, PES is calculated by N or P.

The controller 42 determines whether the calculated PES is within a predetermined bump limit. Specifically, data recording is performed on the target off-track only when PES_ (A-B), PES_ (C-D) and PES_NP are all within the limit range, otherwise the recording is prohibited.

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 recording control method according to the present invention, even if the primary position error signal is distorted by a poor servo burst, the adjacent track is erased by additionally checking whether the head is within the limit range for recording by the secondary position error signal. Has the effect of effectively preventing.

Claims (5)

In a track control method of a hard disk drive in which a plurality of sectors are provided in one track, and four servo burst signals A to D for servo control are radially recorded for each sector. Generating a primary position error signal for the target track by the difference between two adjacent servo bursts; Generating a secondary position error signal for the target track by the sum or difference of the primary position error signals; Determining whether the primary position error signal and the secondary position error signal are within a predetermined limit range; And And determining that the primary position error signal and the secondary position error signal are within a predetermined limit range, and permitting the recording operation; otherwise, the recording operation is not permitted. The method of claim 1, AB area using the primary position error signal PES_ (AB) calculated by AB according to the off-track amount of the target track, CD area using the primary position error signal PES_ (CD) calculated by CD, and primary position error It is divided into the NP region using the secondary error signal (PES_NP) by the sum or difference of the signals PES_ (AB) and PES_ (CD), A recording control method for a hard disk drive, characterized in that in the A-B area and the C-D area, writing operation to the target track is allowed only when the primary position error signal as well as the secondary position error signal are within the limit ranges. A disk for storing predetermined information; A spindle motor for rotating the disk; A head for recording information on the disk and reading information from the disk; A VCM driver for driving a voice coil motor to move the head across the surface of the disk; And A controller for controlling the VCM driver to write data to a target servo sector through the head; The controller determines whether the primary position error signal due to the difference between adjacent servo bursts and the secondary position error signal due to the sum or difference of the primary position error signals are within a predetermined limit range, and the primary position error. And the write operation is allowed if the signal and the secondary position error signal are within a predetermined limit range, and the write operation is not allowed otherwise. A computer that stores a program for controlling a recording operation of a hard disk drive, in which a plurality of sectors are provided in one track, and four servo burst signals A to D for servo control are radially recorded for each sector. Readable recording medium, Generating a primary position error signal for the target track by the difference between two adjacent servo bursts; Generating a secondary position error signal for the target track by the sum or difference of the primary position error signals; Determining whether the primary position error signal and the secondary position error signal are within a predetermined limit range; And And as a result of the determination, a program is recorded which includes a process of allowing a recording operation if the primary position error signal and the secondary position error signal are within a predetermined limit range, and otherwise not permitting the recording operation. The method of claim 4, wherein AB area using the primary position error signal PES_ (AB) calculated by AB according to the off-track amount of the target track, CD area using the primary position error signal PES_ (CD) calculated by CD, and primary position error It is divided into the NP region using the secondary error signal (PES_NP) by the sum or difference of the signals PES_ (AB) and PES_ (CD), And a process for allowing a recording operation on the target track only when the primary position error signal as well as the secondary position error signal are within the limit ranges in the A-B area and the C-D area.

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