KR100459718B1 - Recording medium in which a program that measures magnetic write width of a head in a hard disk drive is recorded - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disc drive, in particular a machine having a program recorded thereon which enables the hard disc drive to automatically measure the magnetic write width (MWW) of the head itself. It relates to a recording medium which can be read in.

The recording medium according to the present invention comprises the steps of selecting a target track and positioning a head on the selected target track; Controlling the head to record a burst signal of a predetermined frequency on a target track and adjacent tracks, and offtracking the adjacent tracks by a predetermined width toward the target track; Reading the recorded burst signal while moving the head to radially transverse the tracks in which the burst signal is recorded, and obtaining a profile of the recorded burst signal from the output of the head; Calculating a peak value in each track from the profile of the burst signal; And calculating a magnetic recording width of the hard disk drive with reference to the peak values.

Description

Recording medium in which a program that measures magnetic write width of a head in a hard disk drive is recorded}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disc drive, in particular a machine having a program recorded thereon which enables the hard disc drive to automatically measure the magnetic write width (MWW) of the head itself. It relates to a recording medium which can be read in.

The magnetic recording width of a hard disk drive is a recording width that can effectively record magnetic signals without being influenced by writing to adjacent tracks. It is mainly influenced by the width of the head, but even if the same head is used, ATE (Adjacent Track Erase) characteristics and the mechanical environment around the head.

Conventionally, the magnetic recording width was measured in a single unit step before assembling into a hard disk drive, but not in the assembled hard disk drive.

Magnetic recording width measurement at the part level leads to an increase in test time and thus an increase in part price. On the other hand, the magnetic recording width should be considered not only the head width but also the ATE (Adjacent Track Erase) characteristics and the mechanical environment. In other words, when the magnetic recording width is obtained by only one track profile without interference of adjacent tracks, such as the magnetic recording width test in the unit stage, an error with the actual magnetic recording width in the hard disk drive in the assembly stage occurs. Therefore, the reliability of the magnetic recording width measured in the single product step is inevitably deteriorated.

In order to improve this, the present applicant has applied for a patent application (application number; 02-41989, title of the invention; a method for measuring the magnetic recording width of a magnetic head using a burst pattern and the apparatus, the inventor; Yeo Chang-dong, Kim Jong-yun, Park Chul-hoon) In this paper, a method of measuring the magnetic recording width in the assembling stage of the hard disk drive has been proposed.

According to the invention of Application No. 02-41989, a burst signal having a predetermined frequency is recorded in three adjacent tracks, and the burst signal in which the outer tracks are recorded is recorded by overlapping the center track by a predetermined width, and the three tracks are recorded. A method and an apparatus suitable for obtaining a profile (envelope) of a burst signal recorded in < RTI ID = 0.0 > and < / RTI >

Apparatus No. 02-41989 has a burst pattern recording unit for controlling a hard disk drive to record a burst signal of a predetermined frequency in three adjacent tracks, and a profile generation unit for detecting a profile of the burst signal recorded in the adjacent tracks. And a magnetic recording width measuring unit for calculating a magnetic recording width of the hard disk drive with reference to the profile.

However, the apparatus of Application No. 02-41989 is composed of members operating outside of the hard disk drive, so there is a problem that each hard disk drive must be used separately.

In addition, since the operation of the magnetic recording width measuring apparatus must be manually operated by the operator, productivity is reduced by the overtime process, which also increases the price of the hard disk drive.

Accordingly, an object of the present invention is to solve the above problems, and an object thereof is to provide a recording medium which can be read by a machine on which a program is recorded, which enables the hard disk drive to measure its own recording width. .

1 is a characteristic diagram showing a track profile used in a conventional magnetic recording width measuring method.

2 is a block diagram showing the configuration of a magnetic recording width measuring apparatus 200 according to Patent Application No. 02-41989.

3 is a flowchart showing a method of measuring a magnetic recording width in the apparatus shown in FIG.

FIG. 4 schematically shows a burst signal recorded in three adjacent tracks by the pattern recording unit 220 shown in FIG.

FIG. 5 is a waveform diagram showing a profile obtained by the profile constitution unit 230 shown in FIG. 2.

6 is a characteristic diagram showing the correlation between the amplitude reduction ratio of the target track and the magnetic recording width.

FIG. 7 schematically shows a process of measuring the magnetic recording width of the hard disk drive 300 using the apparatus shown in FIG.

8 is a flowchart showing the operation of a program recorded on a recording medium according to the present invention.

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

In a recording medium on which a program for measuring the magnetic recording width of a hard disk drive is recorded,

Selecting a target track and positioning the head on the selected target track;

Controlling the head to record a burst signal of a predetermined frequency on a target track and adjacent tracks, and offtracking the adjacent tracks by a predetermined width toward the target track;

Reading the recorded burst signal while moving the head to radially transverse the tracks in which the burst signal is recorded, and obtaining a profile of the recorded burst signal from the output of the head;

Calculating a peak value in each track from the profile of the burst signal; And

A program including a process of calculating a magnetic recording width of the hard disk drive with reference to the peak values is recorded.

The recording medium may further include recording the measured magnetic recording width in a predetermined area of the hard disk drive, and reading and outputting the recorded measurement result in response to an external command applied from the outside of the hard disk drive. It is desirable to be recorded.

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

1 is a characteristic diagram showing a track profile used in the conventional magnetic recording width measuring method, in which the vertical axis represents the output signal of the head and the horizontal side represents the position of the disc in the radial direction.

The measurement of the magnetic recording width in the single product stage was calculated using the Guzik Spinstand equipment, as shown in FIG. 1, after the track profile was obtained and calculated based on the values at the upper and lower specific threshold levels. That is, the magnetic recording width is obtained by tangentially drawing a 50% value of the track average amplitude in the track profile. In FIG. 1, reference numeral 110 denotes a magnetic recording width and the sum of reference numerals 120 and 130 (110+). 120 + 130) represents a magnetic read width.

2 is a block diagram showing the configuration of the magnetic recording width measuring apparatus 200 according to Patent Application No. 02-41989, wherein the measurement target hard disk drive 300 drives the magnetic disk 251 and the magnetic disk 251. The spindle 253, the driving device 255, and the magnetic head 257, and the magnetic recording width measuring device 200 includes a recording current setting unit 210, a pattern recording unit 220, a profile construction unit 230, And a database 240 and a magnetic recording width measurement unit 250.

The pattern recording unit 220 applies a control command to the hard disk drive 300 to record burst signals having predetermined frequencies in three adjacent tracks. The profile constructing unit 230 applies a control command to the hard disk drive 300 to detect a profile of the burst signal recorded on three tracks that are folded. The magnetic recording width measuring unit 250 measures the magnetic recording width by referring to the profile detected by the profile configuring unit 230.

3 is a flowchart showing a method of measuring a magnetic recording width in the apparatus shown in FIG.

FIG. 4 schematically shows a burst signal recorded in three adjacent tracks by the pattern recording unit 220 shown in FIG. 2, which is located on the target track N and is reduced by overlapping recording in adjacent tracks. The recording width 410, the magnetic recording widths 420 and 430 located in the adjacent tracks N-1 and N + 1 and overwritten toward the target track N, the target track N and the adjacent track N-1. Or magnetic recording widths 440 and 450 superimposed by writing at N + 1).

FIG. 5 is a waveform diagram showing a profile obtained by the profile constitution unit 230 shown in FIG. 2.

The magnetic recording width measuring method according to the invention of Application No. 02-41989 is described in detail with reference to FIGS.

The write current setting unit 210 sets a maximum overshoot of the write current and the write current (step 310). The characteristics of ATE (Adjacent Track Erase) are different for each magnetic head, and these ATE characteristics are sensitive to the recording current and the maximum overshoot value of the recording current, and the ATE characteristics affect the adjacent track regardless of the magnetic recording width. Therefore, the same write current and maximum overshoot value of the write current are set in order to minimize such an influence factor.

The pattern recording unit 220 finds the target track N of the magnetic disk 251 through the magnetic head 257, records the burst pattern (step 320), and the track N-1 adjacent to the target track N. Find and offtrack 20 [%] in the direction of the target track to record the burst pattern (step 330). In addition, the track N + 1 adjacent to the target track N is found, and the track pattern is recorded by off-tracking 20 [%] in the direction of the target track N (step 340).

The pattern recording unit 220 records the burst pattern once on the target track N and off-tracks 20 [%] on the adjacent tracks N-1 and N + 1, respectively, for any target track. The measurement will be performed.

The profile construction unit 230 records the output signal read by moving the magnetic head 257 in the radial direction of the magnetic disk 251 to generate an off-track profile as shown in FIG. 5 (350). The amplitude of the output signal of the target track N in the off-track profile represents a reduced maximum amplitude compared to the amplitudes of the adjacent tracks N-1 and N + 1. The database 240 stores data of the magnetic recording width with respect to the amplitude reduction ratio of the target track.

The magnetic recording width measuring unit 250 obtains the maximum amplitude of the target track N and the adjacent tracks N-1 and N + 1 (step 360), and applies the target track N to the target track N according to Equation 1 below. The amplitude reduction ratio is calculated (step 370).

here, Is the maximum amplitude for the target track (N) And Denotes a maximum amplitude value for tracks N-1 and N + 1 adjacent to the target track.

When the amplitude reduction ratio is calculated, the magnetic recording width of the head in the hard disk drive stage is calculated (step 380) by the correlation with the data on the magnetic recording width stored in the database 240.

Fig. 6 is a characteristic diagram showing the correlation between the amplitude reduction ratio of the target track and the magnetic recording width, wherein the vertical axis and the horizontal axis represent the amplitude reduction ratio [%] and the magnetic recording width [µm], respectively. Since the correlation between the amplitude reduction ratio and the magnetic recording width is represented by the first-order equation by the trend line, the correlation value between the amplitude reduction ratio and the magnetic recording width is stored in the database 230, and the information on the magnetic recording width is calculated when the amplitude reduction ratio is calculated. Can be calculated.

The magnetic write width measuring apparatus 200 shown in FIG. 2 operates outside the hard disk drive. As a result, every time the magnetic recording width of the hard disk drive is measured, a connector for connecting the hard disk drive and the magnetic recording width measuring device 200 must be manually connected, thereby preventing productivity improvement.

In addition, there is a problem that the magnetic write width calculated for each hard disk drive is not recorded on the hard disk drive itself, so that it cannot be referred to later.

FIG. 7 schematically shows a process of measuring the magnetic recording width of the hard disk drive 300 using the apparatus shown in FIG. In the burst writing process, burst signals are written to a target track and a track adjacent thereto. In the burst reading process, a burst signal recorded on adjacent tracks is read to obtain a profile of the burst signal, and the magnetic recording width is calculated by referring to the burst signal. The reading and writing of the burst signal is performed by a command to control the hard disk drive, and the calculation of the magnetic recording width using the profile of the burst signal is accomplished by a numerical calculation program.

A process of calculating the magnetic recording width will be described in detail with reference to FIG. 7.

1. First, an external command is used to cause the hard disk drive 300 to position the head on the target track to which the burst signal will be written.

2. Use an external command to cause the hard disk drive 300 to write the burst signal E1 to the target track.

3. Using the external command, causes the hard disk drive 300 to write the burst signal E2 to the adjacent track N-1.

4. The external command causes the hard disk drive 300 to write the burst signal E3 to the adjacent track N + 1.

5. Using an external command, the hard disk drive 300 obtains the profile of the burst signal recorded on the three tracks, and enters it.

6. Using the numerical program, the peak values of the burst signal in each track are calculated, and the magnetic recording width of the hard disk drive 300 is calculated by referring to the peak values.

7. Change the head and repeat steps 1-6.

8. Repeat steps 1-7 for another hard disk drive.

As described above, the apparatus illustrated in FIG. 2 requires manual manipulation of all processes for each hard disk drive, causing serious overtime process problems, resulting in reduced productivity and increased hard disk drive prices.

In order to improve this, the present invention is characterized in that the hard disk drive itself has a program for calculating a magnetic recording width. In this way, as the device of FIG. 2 allows the magnetic recording width to be measured manually for each hard disk drive automatically, the cost can be achieved by the hard disk drive itself.

8 is a flowchart showing the operation of a program recorded on a recording medium according to the present invention.

The program recorded on the recording medium according to the present invention measures the magnetic recording width of the hard disk by itself in response to a command recorded in at least a part of the disk, that is, inside the hard disk drive, The results are recorded again on the disc (result recording area). The program selects the recording capacity of the hard disk drive by referring to the contents recorded in the result recording area. Normally, the recording capacity is expressed as TPI (Track Per Inch).

In addition, the program further includes a process of outputting the contents recorded in the result recording area, that is, the measured magnetic recording width, externally in response to a command applied from the outside of the hard disk drive.

First, the head is determined. (S802) A hard disk drive is usually composed of several disks, each of which is accessed by a corresponding head of each.

The track is determined (s804). The disk is composed of a number of tracks, among which a target track to record the burst signal is selected.

The burst signals are recorded in three tracks in total, the target track and two tracks adjacent thereto (s806). Here, when the burst signals are recorded in the two tracks adjacent to the target track, the target tracks are provided with a predetermined width (the embodiment of the present invention). In the case of 20% of the head width, the data is recorded off-track.

The peak value in each track is detected. (S808) In step s808, the profile of the burst signal is obtained while moving the head in the radial direction of the disk, and three peak values are detected from the obtained profile.

The obtained peak values are stored (s810). In step s810, the obtained peak values are stored in a predetermined area of the disk.

The magnetic recording width is calculated. (S812) Using the three peak values obtained from the profile, the magnetic recording width is calculated in accordance with the method represented by Equation (1).

The obtained magnetic recording width is stored in a table of the internal code memory and the process returns to step s804. (S814) Steps s804 to s814 are performed by a predetermined number of tracks, and then the process returns to step s802 to measure the magnetic recording width of another disk. do.

Returning to step s802 is performed by the number of heads, and then proceeds to step s816.

The measurement results for the disks are stored (s816).

Read the stored measurement result (s818).

The recording capacity is determined by referring to the measurement result (s820). The TPI is determined according to the measured magnetic recording width, and this TPI represents the recording capacity. Even when the heads of the same width are used, different recording capacities are shown when the magnetic recording widths are different.

The program shown in Fig. 8 is stored in the hard disk itself, and automatically calculates the magnetic recording width and recording capacity of the hard disk drive in response to a control command applied from the outside of the hard disk drive. Therefore, the overtime process is fundamentally eliminated because the operator does not need to manually operate the magnetic recording width measuring apparatus as shown in FIG. 2 as in the conventional method, thus increasing the productivity of the hard disk drive, thereby You can expect a price reduction.

As described above, the recording medium according to the present invention can simplify the manufacturing process by allowing the hard disk drive to calculate the magnetic recording width and the recording capacity of the head by itself, thereby reducing the cost of the hard disk drive. Exert.

Claims (3)

In a recording medium on which a program for measuring the magnetic recording width of a hard disk drive is recorded, Selecting a target track and positioning the head on the selected target track; Controlling the head to record a burst signal of a predetermined frequency on a target track and adjacent tracks, and offtracking the adjacent tracks by a predetermined width toward the target track; Reading the recorded burst signal while moving the head to radially transverse the tracks in which the burst signal is recorded, and obtaining a profile of the recorded burst signal from the output of the head; Calculating a peak value in each track from the profile of the burst signal; And And a program including a step of calculating a magnetic recording width of the hard disk drive with reference to the peak values. 2. The recording medium of claim 1, wherein the recording of the measured magnetic recording width in a predetermined area of the hard disk is further recorded. The method of claim 2, further comprising reading the contents recorded in the predetermined area, that is, the measured magnetic recording width, and outputting them to the outside of the hard disk drive in response to a command applied from the outside of the hard disk drive. The recording medium which can be read by the machine characterized.