KR100392615B1 - Method for controlling head position of hard disk drive having three bursts - Google Patents

Abstract

PURPOSE: A method for controlling a head position of a hard disk drive having three bursts is provided to increase the recording density of data in recording data on a disk by controlling a position of a disk driver by using a disk recording medium having three bursts. CONSTITUTION: A control unit of a hard disk drive reads a gray code area recording track identifying information. The control unit reads first, second, and third burst recording intervals recorded on a disk recording medium through heads(4). The control unit calculates a first position error signal from the read data amplitude in the gray code area and the first burst. The control unit calculates a second position error signal from the read second and third bursts. The control unit combines the calculated first and second position error signals with the read gray code for generating seek information, and outputting a current position error signal.

Description

How to control the head position of a three-burst hard disk drive

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disk drive for magnetic recording / reading of digital information, and more particularly to a method for accurately and quickly tracking a head to a track in order to read data from a specific track on a magnetic disk.

In general, hard disk drives are widely used as auxiliary storage devices of computer systems because they are devices that magnetically write / read data on a rotating magnetic disk. Such hard disk drives are stored in tracks arranged concentrically on a rotating magnetic disk. These tracks are accessed by magnetic heads for reading and writing data on magnetic disks. Such hard disk drives are stored in tracks arranged concentrically on a rotating magnetic disk. These tracks are accessed by magnetic heads for reading and writing data on magnetic disks. The magnetic head is moved in the radial direction on the magnetic disk by the control of a head position servo mechanism that can be selectively positioned on any selected track of the tracks. As such, to selectively position the magnetic head on a particular track, it is necessary to know the current head position relative to each track. Servo information informing the position of the head relative to the tracks as described above is provided by using a particular servo pattern that is read on the magnetic disk by the head. This servo pattern is permanently recorded in advance on the magnetic disk when assembling the hard disk delive on the magnetic disk. This servo pattern is detected by the head when accessing data on the magnetic disk and used as track position information. One example of a method for providing servo information is an embedded servo system. In the embedded servo system, the servo information is alternately arranged with the data areas between the data areas on the magnetic disk. Each servo information includes track position information, track address, index information, and the like. Positioning on a specific track using such servo information is performed by two steps consisting of track seek and track following. Track search is the step of moving the head from the current track to the desired track. Track tracking is a step of accurately following a track that has been searched, and keeps the head following the track's centerline for accurate reading and writing operations once the head is located on one track. For example, in the embedded servo type magnetic disk driving apparatus, four burst signals are recorded in advance on a magnetic disk as part of servo information on the magnetic disk for tracking following the track. Referring to FIG. 1, the A burst signal and the B burst signal are recorded alternately around each track center line, so that the head searches for the track at high speed, and the C burst and D burst are one track center line. It is recorded alternately around the track and track tracking to detect the deviation of the head from the center line of the track. In addition, the A burst and the B burst are detected as the presence or absence of a burst signal when the heads of the A and B burst signals are recorded in the corresponding tracks. In this case, the amplitude level of the detected burst signal becomes the maximum value. The undetected level becomes a value of "0" to obtain the position error signal (PES1) which is the track search information. The PES1 is obtained as in Equation 1 below.

PES1 = B Burst Detection Level-A Burst Detection Level

In addition, the amplitude levels of the respective bursts at which the C-burst and the D-burst are detected by the head are equal to one-half of the maximum detection level when the head is exactly positioned at the trek center, and the C-burst and D-burst detection is performed. The difference between the levels is "0". Therefore, it is possible to know the deviation state and the amount of deviation of the head with respect to the trek center by the difference between the C burst and the D burst detection levels. The PES2 is obtained as shown in Equation 2 below.

PES2 = D Burst Detection Level-C Burst Detection Level

Therefore, in the Trek search mode, as shown in FIG. 2, the head position is determined by combining gray codes with PES1 and PES2 values, and when tracking the track, the head position is controlled using only PES2. . As described above, the method of controlling the position of the head by using the four burst signals has the advantage that the head can speed up the track, but the number of bursts to be detected decreases the recording density to record the actual data. This occurred.

It is an object of the present invention to provide a method of controlling the position of a disc driver using a disc recording medium having three bursts.

In order to achieve the above object, the present invention provides a method for detecting a head position of a hard disk drive having three bursts among servo areas recorded on a disc recording medium, wherein the control means of the hard disk drive tracks in the servo area. A first reading step of reading the gray code area in which the identification information is recorded, and a control means of the hard disk drive reading the first, second and third burst recording sections recorded on the disk recording medium through the head, respectively; Taking a reading step, calculating a first position error signal from a read data amplitude and a first burst in the gray code region, calculating a second position error signal from the read second burst and third burst; And generating search information by combining the calculated first and second position error signals and the read gray code, and outputting a current position error signal. Characterized by the step made of an.

1 is a diagram in which four burst signals of servo information recorded on a magnetic disk of a hard disk drive are recorded.

2 is an exemplary diagram of a head position when the head tracks by reading the four burst signals recorded in FIG.

Figure 3 is a block diagram of a hard disk drive applied to the present invention.

4 is a diagram showing three burst signals of servo information recorded on a magnetic disk of a hard disk drive according to an embodiment of the present invention;

5 is an exemplary diagram of a head position when the head tracks by reading the three burst signals recorded in FIG. 4; FIG.

6 is a control flowchart for outputting a final position control signal according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 shows a block diagram of a general hard disk drive according to the present invention, and shows an example of a hard disk drive having two disks 2 and four heads 4 corresponding thereto. The disks 2 are typically stacked and mounted on the drive shaft of the spindle motor 30 and are designed such that one head 4 corresponds to each disk surface. The head 4 is located on the surface of the disk 2 and is mounted on a vertically extending arm 8 of the arm assembly of the VCM 24. The preamplifier 12 preamplifies the signal picked up by one of the heads 4 during data read and applies the analog read signal to the read / write channel circuit 14. During data write, encoded write data applied from the read / write channel circuit 14 is written onto the disc 2 via the switched selected head 4. At this time, the preamplifier 12 switches to select one of the heads 4 under the control of a disk data controller (DDC) 32. The read / write channel circuit 14 decodes the read signal path applied from the preamplifier 12 to generate read data RDATA. The read / write channel circuit 14 encodes the write data WDATA applied from the disk data controller 32 to the preamplifier 12. Is authorized. The read / write channel circuit 14 also demodulates the head position information (burst signal) which is a part of the servo information written on the disc 2 and outputs it to the microcontroller 18. At this time, the A / D converter 16 is positioned between the read / write channel circuit 14 and the microcontroller 18 so that the PES applied from the read / write channel circuit 14 corresponds to its level. The value is converted into a value and provided to the microcontroller 18. The disk data controller 32 writes the data received from the host computer onto the disk 2 through the read / write channel circuit 14 and the preamplifier 12 or the data read from the disk 2 to the host computer. Send. The disk data controller 32 also interfaces the communication between the host computer and the microcontroller 18. On the other hand, the microcontroller 18 controls the disc data controller 32 in response to a data read / write command received from the host computer and controls track search and track following. At this time, the microcontroller 18 controls the track tracking by using the PES value input from the A / D converter 16, and responds to various servo control signals output from a gate array (not shown). Perform control. The D / A converter 20 converts a control value for position control of the heads 4 generated from the microcontroller 18 into an analog signal and outputs the analog signal. The VCM driver 22 generates a current I (t) for driving the actuator by a signal applied from the D / A converter 20 and applies it to the VCM 24. The VCM 24 located at the other side of the actuator having the heads 4 attached to one side may be configured to level the heads 4 on the disk 2 in correspondence with the direction and the level of the current input from the VCM driver 22. Move it. The motor controller 26 controls the spindle motor driver 28 according to a control value for rotation control of the disks 2 generated from the microcontroller 18. The spindle motor driver 28 rotates the disks 2 by driving the spindle motor 30 under the control of the motor controller 26. The buffer memory 34 connected to the disk data controller 32 temporarily stores data transferred between the disk 2 and the host computer under the control of the disk data controller 32.

4 is a diagram showing three burst signal recordings recorded on a magnetic disk for track following in a hard disk driver according to the present invention; Three burst signals are recorded in advance as part of the servo information for one track, and the B-burst signal is recorded up to the boundary line of the next track starting from each track boundary, and the C-burst and D-burst signals are It is recorded alternately around one track center line, so that A burst is omitted in the conventional format of recording four burst signals.

FIG. 5 shows an exemplary diagram when the head tracks the three burst signals recorded as shown in FIG. 4.

FIG. 6 is a control flowchart of calculating position information of a final head using three bursts recorded as shown in FIG. 4.

Hereinafter, the flowchart of FIG. 6 will be described in detail with reference to the block diagram of FIG. 3 and the recording formats of FIGS. 4 and 5 attached to the present invention. First, the three burst signals B, C, D and gray code regions shown in FIGS. 4 and 5 are read by the head 4 and sampled through the read / write channel circuit 14 and applied to the microcontroller 18. . In this case, the control flow for calculating PES1 and PES2 using the applied three burst signals and the gray code read out will be described with reference to FIG. 6. In operation 610, the microcontroller 18 reads / writes the channel 14. Receives three burst signals and gray code code input through). Then, in step 620, the microcontroller 18 calculates the amplitude levels of the three burst signals read out and the gray code read signal by the following equations (3) and (4).

PES1 = amplitude of gray code read signal-2 x B burst signal

PES2 = C Burst Signal-D Burst Signal

Then, in step 630, the microcontroller 18 determines the position of the final head by the combination of the internal search information flag Skflg. In this case, the search information flag (Skflg) is composed of three-bit data consisting of a combination of good and excellent track information (Digodd), PES sum (Digpha) and PES difference (Digphb).

As a result, the present invention deletes the A burst from the four burst signals recorded on the conventional disk, and shows the result of the same PES1 as shown in Table 1 below. For example, first, the numerical values recorded in Table 1 below divide the total PES value for one track into 256 equal parts and set the center of the track to "PES = 0". The PES value at the boundary is -128, and the PES value at the boundary between the N track and the N + 1 track described above is +127, so the PES resolution is 256 resolution as an example. At this time, when the position of the head 4 is at, since the resolution of the conventional A burst is "64" and the resolution of the B burst is "64", PES1 becomes "0". In addition, the PES1 according to the present invention also becomes "0" because the amplitude (AMP, gray code) of the gray code read signal is "128" and the B burst is "4". In Table 1 below, since all other positions of the head show the same result, detailed description thereof will be omitted.

PES1 head center position Conventional PES1 Invention PES1 A-B = PES1 AMP (gray code)-2 × B = PES1 end 64-64 = 0 128-2 × 4 = 0 I 96-32 = 64 128-2 × 32 = 64 All 128-0 = 128 128-2 × 0 = 128 la 96-32 = 64 128-2 × 32 = 64 hemp 64-64 = 0 128-2 × 64 = 0 bar 32-96 = -64 128-2 × 96 = -64 four 0 -128 = -128 128-2 × 128 = -128 Ah 32-96 = -64 128-2 × 96 = -64 character 64-64 = 0 128-2 × 64 = 0

As described above, the present invention provides a method of controlling the position of a disk driver by using a disk recording medium having three bursts, thereby increasing the recording density of data in recording data on the disk.

Claims (3)

In the head position detection method of a hard disk drive having three bursts of servo areas recorded on a disk recording medium, A first reading step of the control means of the hard disk drive reading out the gray code area in which the track identification information is recorded in the servo area; A reading step of controlling means of the hard disk drive to read first, second and third burst recording sections recorded on the disk recording medium through a head; Calculating a first position error signal from a read data amplitude and a first burst in the gray code region; Calculating a second position error signal from the read second burst and third burst; A head of a hard disk drive having three bursts, comprising: generating search information by combining the calculated first and second position error signals and the read gray code, and outputting a current position error signal Position detection method. The method of claim 1, wherein the method of calculating the first position error signal comprises: 3. The method of claim 3, wherein the read data amplitude and the first burst in the gray code area are read and calculated using the following equation. [Equation 1] 1st position error signal = amplitude of gray code read signal-2 x 1st burst signal The method of claim 1, wherein the second position error signal is calculated. And a third burst signal calculated by the difference between the second burst signal and the third burst signal.