JPH01134711A - Tracking adjuster for magnetic disk driver - Google Patents

Abstract

PURPOSE:To improve the position adjusting accuracy of a carriage and to improve a producibility according to an adjusting time shortening by operating a reference adjusting quantity signal based on the address data of a storing means after a reference adjusting signal is converted to a digital signal. CONSTITUTION:The reference adjusting signal reproduced with a magnetic head is converted to the digital signal by a converting means 5, an adjusting quantity arithmetic-prepared by an arithmetic means based on the digital memory address data of the storing means is displayed by an adjusting quantity displaying means 7, simultaneously, it is moved in a radius direction by a control means to output the adjusting quantity control signal of a magnetic disk driver 2 based on the adjusting quantity signal, and an off-track quantity is grasped. Thus, which component of the magnetic disk driver 2 is not within an adjustment permitting value, or whether an assembly is defect or not is proved on the adjusting quantity displaying screen 7, the producibility and reliability at the time of a reassembly can be improved, and the position adjusting accuracy of the carriage can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tracking adjustment device used to adjust a helad carriage drive part of a magnetic disk drive to a specified track radial position, and particularly relates to The present invention relates to a tracking adjustment device for a magnetic disk drive device, which is suitable for adjusting work for a magnetic disk drive device that is standardized.

[Conventional technology]

A conventional tracking adjustment device for a magnetic disk drive uses a magnetic head of a magnetic disk drive to reproduce an alignment disk adjustment signal in which indicator marks and track diameter position adjustment signals are recorded as described in Japanese Patent Publication No. 59-7142. This was done by displaying it on an oscilloscope, and it was possible to adjust the position in the track radial direction. However, the resolution of adjustment using an oscilloscope is low, and the 4aTI
Although it was possible to guarantee data compatibility with I-class magnetic disk drives, the high-density 96TPI.

This has been difficult with magnetic disk drives of 100 TPI or more. Also, other adjustment factors necessary for data compatibility were not considered.

Another conventional example will be described with reference to FIG. 11. In the alignment disk 1, an index timing adjustment signal 22 is provided in the outer track, and a track diameter adjustment signal 36 is provided in the center track.

A large diameter signal 37 that is larger than the reference diameter by δ/2 = 0.075 mm and a small diameter signal 38 that is smaller by the same dimension are provided, which are eccentric from the rotation center axis 39 by approximately ε = 0.1 field, which is a specified dimension, It used a detection method using a signal called the so-called cat's eye. Also, the azimuth adjustment signal 19 is applied to the inner track with the Cw (clockwise) signal 20. The CCw (counterclockwise) signal 21 is provided. Also, the same signal is written on the back side of the alignment disk 1.
The two heads, top and bottom, can be adjusted.

The actual adjustment method, as shown in FIG. 12, is to insert this alignment disk 1 into the magnetic disk drive device 2, move the carriage to a specific position, and reproduce each adjustment signal.
This signal is displayed on the oscilloscope 40.

In the case of index timing adjustment, the time from the fall of the index signal to the index adjustment signal 22 is adjusted by adjusting the position of the index detection sensor.

To adjust the track diameter, finely adjust the stepping motor so that the ratio of the large diameter signal 37 and the small diameter signal 38 is the same.
Azimuth adjustment adjusts the inclination of the head so that the four signal ratios fall within a certain range.

According to this method, it is possible to adjust the index timing and azimuth of the magnetic disk drive device, but the resolution is low when adjusting the track diameter using the cat's eye signal.
Highly densified 96TPI.

It has been difficult to guarantee data compatibility for high-density magnetic disk drives of 100 TPI class or higher. Furthermore, it was not possible to determine the chucking error from the form of the signal.

Here, the data compatibility of the high-density magnetic disk drive will be explained. Since multiple magnetic disk drives mutually record and reproduce data via removable magnetic disks, the difference between the specified track radial position and the position where the magnetic head is positioned in the actual magnetic disk drive (hereinafter referred to as (abbreviated as "off-track"), and its main causes are: (1) Carriage position adjustment error that occurs when adjusting the magnetic head so that it is below the specified amount of off-track after assembling the magnetic disk drive.

(2) Carriage positioning error due to manufacturing accuracy of the transmission system.

(3) Chucking error that occurs when chucking a magnetic disk into a magnetic disk drive device.

(4) Errors in expansion and contraction between the magnetic disk and the magnetic disk drive due to temperature and humidity.

is raised. Also, errors in index timing and azimuth occur between the two magnetic disk drive devices. Here, in the magnetic disk drive device for 96TPr, the above off-track tolerance value is based on the magnetic head R/
W gap width W = 165μm, erase core + 1jE
r = 100 μm, and it is necessary to allocate the error items (1) to (4) above for 50 μm to ensure data compatibility, but the difference in expansion and contraction due to temperature and humidity (4) is difficult to reduce because of the influence of the physical properties of the material.

Therefore, if we analyze (1) to (3), (1) the carriage position adjustment error is closely related to the adjustment time;
In order to suppress the error, the adjustment time will be significantly increased.

(2) Positioning errors of the carriage can be caused by errors in the static angle of the stepping motor (hereinafter abbreviated as STM) itself, which is the drive source, and errors in the transmission system, but in high-density magnetic disk drives, STM is also transmitted. The manufacturing accuracy of the system has also reached its limit, and any attempt to further improve accuracy will result in lower yields, increased costs, and destabilized quality.

(3) The main cause of chucking error is the accuracy of the chucking parts of the magnetic disk and magnetic disk drive.
Similar to (2), the required accuracy improvement in high-density magnetic disk drive devices has reached its limit.

[Problem that the invention seeks to solve]

With the above conventional technology, when increasing the density of magnetic disk drives, the accuracy required for each component has reached its limit, and ensuring data compatibility between multiple magnetic disk drives increases costs. It is necessary to take measures to improve the accuracy required for each component, or to improve the accuracy of carriage position adjustment, which increases assembly and adjustment time, which poses a problem in terms of improving productivity and, ultimately, improving reliability.

The purpose of the present invention is to verify the accuracy that occurs in each component of a magnetic disk drive according to a probability distribution using an alignment disk' when assembling each magnetic disk drive, and to improve and adjust the positioning accuracy of the carriage. An object of the present invention is to provide a tracking adjustment device that can improve productivity by reducing time.

[Means for solving problems]

The above object includes: a magnetic head for recording data on a magnetic recording medium and reproducing the data; a carriage for mounting the magnetic head; and a drive device for moving the carriage in a track radial direction on the magnetic recording medium. A tracking adjustment device for a magnetic disk drive device comprising: a magnetic disk drive device; and a display device that displays an analog reference adjustment signal input to the magnetic head; further comprising a conversion means for outputting a digital signal, and the display device has a storage means for storing a digital signal.

calculation means for calculating and generating an adjustment signal for the drive device based on the digital signal stored in the storage means; adjustment amount display means for displaying the adjustment amount based on the adjustment amount; and adjustment amount display means for displaying the adjustment amount based on the adjustment amount. This is achieved by configuring a control means for outputting an adjustment amount signal of the device.

[Effect]

After the conversion means reproduces the reference adjustment signal of the alignment disk inserted into the magnetic disk drive device with a magnetic head and converts it into a digital signal, the storage means stores the digital output of the conversion means in a digital memory, and the calculation means stores the digital output of the conversion means. The reference adjustment amount signal is calculated and generated based on the address data of the storage means, and the adjustment amount display means determines, based on the calculation result of the calculation means, how much the magnetic disk is in the specified position in the radial direction and the actual position. The control means adjusts the magnetic disk drive device based on the adjustment amount signal. Outputs an I amount control signal.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 10. In FIG. 1, an alignment disk 1 on which track radial direction, azimuth, and index timing adjustment signals are recorded on predetermined tracks is inserted into a magnetic disk drive device 2. As shown in FIG. A personal computer 7 is equipped with a sequence for moving the carriage from the inner circumference to the outer circumference and from the outer circumference to the inner circumference, a calculation means, a storage means, a display means, and a sequence for moving the total error according to the degree of adjustment. After moving the magnetic head to the outermost circumferential track that serves as a reference via the control l108, the magnetic head is moved to a specified track on the alignment disk 1 on which the adjustment signal is recorded. In this track, the adjustment signal is regenerated, converted into a DC voltage containing ripples by a rectifier circuit 3, and removed by a filter 4 to remove high frequency ripples.

The output of this filter 4 is digitized by an A/D converter 5, and the data is taken into the memory of the personal computer 7 via a step 106. Thereafter, values such as off-track amount, index timing, azimuth, etc. are calculated based on the data in the memory. Next, the magnetic head is moved further to the inner circumference of the alignment disk 1 and the same process is performed. After data is similarly captured in the remaining tracks, the direction of movement is changed again, the magnetic head is moved from the inner circumference to the outer circumference, and the same processing is performed. When the data capture and processing of a predetermined track is completed, the vertical displacement of the magnetic head is displayed on the screen of the personal computer 7.

The static angle error of the STM 25, the hysteresis error due to the rotation direction of the STM, the cumulative error due to the transmission system, etc. are displayed.

As a result, if the total error exceeds the tolerance value,
Although the mounting position of the STM 25 is adjusted, precise adjustment is possible by retaking the adjustment signal in accordance with the movement of the STM 25 and moving the total error of the processed result on the screen of the personal computer 7. An example of the alignment disk 1 to be removed is shown in FIG. On the adjustment track center 14 of the alignment disk 1, a track diameter adjustment signal 16 is provided as a pair of inner circumference side signals 17 and outer circumference side signals 18 extending geometrically alternately from the adjustment track 14 to the inner circumference side and the outer circumference side. A total of eight pairs are provided symmetrically with respect to the rotation center axis 9.

Also as an index timing adjustment signal 22.

It is placed on the adjustment track 14 after a specified time T from the index timing detection point (IDX) 23. Furthermore, as the azimuth adjustment signal 19, the adjustment track center 14
A Cw signal 2o written by a signal writing head (not shown) adjusted to have prescribed intersecting angles α, α' clockwise with a radius line Ω extending from the rotation center 9 above, and C
The Cw signal 21 is arranged as one block pair and alternately arranged with the track diameter adjustment signal 16. In addition to the adjustment tracks 14, on the alignment disk 1, track diameter adjustment signals 16 ( The index timing adjustment signal 22 and the azimuth adjustment signal 20 and 21 are not arranged. It is located at .15. Furthermore, the same signal as above is written on the back side of the alignment disk 1. Next, the magnetic disk drive device 2 is adjusted and verified using the alignment disk 1.
The structure and operation of will be explained with reference to FIG. The magnetic disk 24 is connected to a rotation bearing portion 34 of a direct drive motor (hereinafter abbreviated as DD motor) 33 by means of a first knot 32.
and is rotated at a constant speed by the DD motor 33. Carriage 28 equipped with magnetic head 29
can be moved in the track radial direction by 57M25,
After being positioned to the target track, data is recorded and reproduced on the magnetic disk 24.

Here, to explain the head positioning mechanism, first, the rotation angle of the 57M25 fixed to a chassis (not shown) changes in a stepwise manner according to a control signal.

Therefore, the carriage 28 is linearly moved along the rail 35 via the steel belt 26 wound α around the pulley 27. Therefore, the magnetic head 2 mounted on the carriage 28
9 also performs linear motion at regular intervals on the magnetic disk 24 in response to the rotation of 57M25. By setting this interval to the interval between tracks, the magnetic head 29 is positioned at the position of the track. Further, the index direction, which is the direction of rotation of the magnetic disk 24, is determined by the index timing light receiving section 31. By the way, by moving the fixed position of the 57M25 fixed to a chassis (not shown) back and forth, the magnetic head 29 also moves in the track radial direction, so that fine off-track adjustment is possible. Furthermore, the index timing can be adjusted by changing the mounting position of the index timing light emitting section 30 or the index timing light receiving section 31. Positioning error factors caused by such a magnetic head positioning mechanism include: (1) 57M25 static angle error and hysteresis error that changes with load in the rotational direction.

(2) Accumulated errors caused by the roundness of the pulley 27, the way the steel belt 26 is wrapped around the steel belt 26, etc.

(3) Chucking error, which is an error due to eccentric components that occurs when chucking the magnetic disk 24.

etc. are possible. Here, as shown in Fig. 4, the static angle error of the 57M25 appears as an error curve with one period having the same number of steps as the number of phases of the 57M25 (4 phases in this example), and the error at the same phase is small. Generally known.

In FIG. 4, each phase is indicated by ○, X, and △2 symbols.

Therefore, in order to find the resting angle of 57M25, it is necessary to
4 may be arranged corresponding to each phase of 57M25. In this embodiment, tracks 16, 19, and 22°25 are set. Furthermore, Fig. 5 shows the amount of off-track when the 57M25 shown in Fig. 4 is actually incorporated into a magnetic disk drive.
The trends in the static angle error and cumulative error of 57M25 do not change minutely.

The center 10.15 of the adjustment track of the alignment disk 1 shown in FIG.
The cumulative error is obtained by linearly approximating the slope from the off-track amount on one of the adjustment tracks. In this embodiment, in order to distinguish it from the static angle error of 57M25, the tracks Nα1 and 37 that are in phase with the track Nα25 are
I set this adjustment track center to .

Next, when verifying the adjustment of the magnetic disk drive device using the alignment disk 1, for example, the magnetic head 29 reproduces 1/8 of each adjustment signal on the track Nc 25 corresponding to the adjustment track 14, and The output of filter 4 in FIG. 1 is shown in FIG.

Here, (a) shows the reproduced signal of the upper head, (b) shows the filter output signal of the upper head, (c,) shows the reproduced signal of the lower head, and (d) shows the filter output signal of the lower head. Symbols (T1. T2, VRU^, etc.) are the first
This corresponds to the value or address taken into the personal computer 7 by the A/D converter 5 shown in the figure.

(1) The track diameter direction is determined by the output ratio of the inner circumference side signal 17 and the outer circumference side signal 18 of the track diameter adjustment signal 16.
The off-track amount can be determined from the relationship between A/V RLB and V RLIA/VRUB.

(2) In the index timing direction, set the time interval for A/D conversion to a constant value, start A/D conversion from the IDX point, store it in the memory of the personal computer 7 in order, and start the index timing adjustment signal 22 at the rising edge of the index timing adjustment signal 22. T□ by multiplying the memory address corresponding to the previous step by the time I'jff interval for A/D conversion and displaying the result on the screen.

It can be adjusted and verified so that T2 falls within the allowable value of the specified time T.

(3) The azimuth direction is the Cw signal 20 of the azimuth adjustment signal 19. Vot, Δ/VO, which is the output ratio of the CCw signal 21
From the relationship between LB and VOUA/VOUB, magnetic head 2
It is possible to adjust and verify whether the azimuth angles of the upper and lower head R/W gaps of 9 are within the allowable values.

As the next example, in track Nα1 near the outermost circumference,
FIG. 7 shows a waveform obtained by filtering the adjustment signal reproduced by the magnetic head 29 through the filter 4 shown in FIG. The upper side shows the waveform of the upper head of the magnetic head 29, and the lower side shows the waveform of the lower head.

(1) Off-track amount ΔL, ΔU is 8 pairs (VRL
A)i / (VRLB)i and (VRIJA)j
/ (VRLIB)j value and R of the magnetic head 29
/W gap width W can be expressed as follows. Therefore, the static angle error of STM25 and the hysteresis error due to the feed direction.

It is possible to display and verify the assembly error of the upper and lower parts of the magnetic head 29.

(2) Tracks Nα1, Nα25, and Nα37, which are the same excitation phase of STM25, are set to Δ1°Δ25.
Assuming Δ37, the cumulative error is equal to the amount of linear approximation, so if the slopes of the straight line connecting Δ37 and Δ25 and the straight line connecting Δ25 and Δ] are in the same direction, then 1Δ37 - Δ11 ・The straight line connecting Δ37 and Δ25 and Δ・If the slopes of the straight lines connecting 25 and Δ1 are in different directions, which one of 1Δ25−Δ1[is the larger value.

It can be expressed as Therefore, it is also possible to display and verify cumulative errors.

(3) 8 pairs per circumference of the magnetic head 29 + 71 (VRLA)
i / (VRLB) i or (Vr+u^)j /
(VRU8) From the difference between the maximum and minimum ratios of j, the chucking error α, which is the error of the eccentric component that occurs when chucking the magnetic disk 24, can also be determined as follows.

Next, an example in which the errors described above are collectively displayed on the CRT of the personal computer 7 in FIG. 1 will be explained based on FIG. 8.

In the figure, a1 to aδ are tracks Nα16°19.2
It represents the off-track at 2.25, and a1 to a
4 indicates the error of the lower head, and a15 to as indicate the error of the upper head. Here, the left part Ql of each diamond represents the error when moving in the inner circumferential direction, and the right part Q2 represents the error when moving in the outer circumferential direction. That is, the hysteresis error is expressed by the difference Q3 between Ql and Qz, and the chucking error 2α is expressed by the length of Ql or Qz. Further, the vertical assembly error of the magnetic head 29 can be understood from the difference between al and aδ of the same track, for example Nα16, and the variation in the static angle error due to the excitation phase of the STM is a
It can be understood from the positional relationship of 1 to a4. Finally, a9 is used to indicate the sum of the cumulative error and the track radial position error. Here, flB represents the total off-track in the four tracks shown on the right side of Figure 1, a4 and Q6 are the cumulative errors determined by the track Nα1.25.37, and Ql and 06 are the 1Δ37−Δ251 and Δ251, respectively. 1Δ2
5-Δ11. That is, the result of adding up the sizes of numbers α to QB indicates the total off-track of the magnetic disk drive device 2 determined by the alignment disk 1. This value can be used to verify whether the position adjustment of the head carriage drive unit is within the allowable range.

Next, a case where adjustment is performed when the off-track does not fall within the allowable value as a result of the above operations will be described with reference to FIGS. 8 and 9. At this time, first, as shown in FIG. 8, points c1 and 02 representing the maximum and minimum off-track values of the magnetic disk drive device 2 are displayed on the screen. Next, the magnetic head 29 is moved one track toward the outer circumference and one track toward the inner circumference, centering on a specific track on which the track diameter adjustment signal is recorded (track Nα16 in FIG. 9).
When the vehicle returns, the track diameter adjustment signal is read again and off-track is calculated. The value at this point b should originally be the same as the ρ work of diamond a1 in Figure 8, but ST
Since M is finely adjusted in the track radial direction, only that adjustment device causes deviation.

Incidentally, even if fine adjustment is performed and the off-track feed value of the entire magnetic disk device changes, the width does not change. The off-track point at this point is a.

If so, the overall off-track will also deviate by the average value of ao and al, that is, the deviation X of the static angle error. Therefore, by moving the maximum value Ql and the minimum value c2 by X and displaying them, the current degree of adjustment can be determined. Adjustment can be easily made by repeating this operation until the off-track falls within the allowable range. Further, index timing and azimuth adjustment will be explained based on FIG. 10.

The magnetic head 29 is moved to the center 14 of the adjustment track where the index timing adjustment signal 22 and the azimuth adjustment signal 19 are recorded in FIG.
9 to play. If the index timing is not within the allowable value, adjust it by changing the positions of the index timing issuing unit 30 and index timing light receiving unit 31 shown in FIG. This is done by changing.

Highly accurate adjustment is possible by reading the adjustment signal each time the alignment disk 1 rotates once, and calculating and displaying the difference from the specified value as shown in FIG. In the figure, O indicates the difference from the specified value for the upper head, and Δ indicates the difference from the specified value for the lower head.6 According to this embodiment, (1) Position adjustment accuracy (2) STM static angle error and hysteresis error.

Accumulated errors in the transmission system (3) The chucking error of the magnetic disk and the assembly error of the upper and lower magnetic heads can be displayed all at once on the screen, and the accuracy of each component, such as a magnetic disk drive device, has reached its limit.

By verifying products that are designed considering the required accuracy based on probability distribution at the assembly level, the position adjustment error of the head carriage drive unit can be found for each magnetic disk drive, and if it does not fall within the tolerance, it can be confirmed. displays the position adjustment error according to the degree of adjustment, so you only need to adjust with the necessary and sufficient accuracy, eliminating the need for unnecessary adjustment time. It is possible to determine whether a component is defective or a defective assembly, and it can be displayed in accordance with the index timing and the degree of azimuth adjustment, which has the effect of improving productivity and reliability.

〔Effect of the invention〕

According to the present invention, the reference adjustment signal reproduced by the magnetic head can be converted into a digital signal by the conversion means, the converted digital signal is stored in the storage means, and the calculation means is based on the digital memory address data of the storage means. The adjustment amount calculated and generated can be displayed on an adjustment amount display means, and the off-track amount is moved in the radial direction by a control means that outputs an adjustment amount control signal for the magnetic disk drive device based on the adjustment amount signal. Since it can be ascertained, which component of the magnetic disk drive device is not within the adjustment tolerance or has a defective assembly can be found on the adjustment amount display screen, improving productivity and reliability during reassembly. Also, there is an excellent effect that the accuracy of position adjustment of the carriage can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a tracking adjustment device for a magnetic disk drive according to the present invention, FIG. 2 is a diagram of an alignment disk, FIG. 3 is a configuration diagram of a magnetic disk, FIG. 4 is a diagram showing static angle errors of STM, and FIG. 5 is a diagram showing the off-track amount when the STM is incorporated into a magnetic disk drive device, Figures 6 and 7 are reproduction output diagrams of alignment disk adjustment signals, and Figure 8 is a diagram showing the amount of off-track when the STM is incorporated into a magnetic disk drive. Figure 9 is a diagram showing an example of calculating the variation during off-track adjustment, Figure 10 is a diagram showing an example of display during index timing and azimuth adjustment, and Figure 11 is a diagram showing the conventional alignment disk. An example diagram, FIG. 12, is a diagram showing a conventional example of a tracking adjustment device. 2... Magnetic disk drive device, 3... Rectifier circuit, 4
...Filter, 5...A/D converter, 6,8...
Engineering/○, 1st (211 78--So7ru)/I: 1-ta rod 20 □ "-"l'/'1% toyy7 fIL; thing 4 figure rod 13 m 5IDE0 5IDE1 9th m child 10 O 11th m 120th

Claims (1)

[Claims] 1. A magnetic head for recording data on a magnetic recording medium and reproducing the data; a carriage for mounting the magnetic head;
A magnetic disk drive comprising: a drive device for moving the carriage in a track radial direction on the magnetic recording medium; a display device for displaying in analog form a reference adjustment signal input to the magnetic head; In the tracking adjustment device of the device, a conversion means is provided for inputting the reference adjustment signal from the magnetic head, digitally converting it, and outputting a digital signal, and the display device is provided with a storage means for storing the digital signal, and the storage means calculation means for calculating and generating an adjustment amount signal for the drive device based on the digital signal stored in the controller; adjustment amount display means for displaying the adjustment amount based on the adjustment amount signal; and adjustment amount display means for displaying the adjustment amount based on the adjustment amount signal; A tracking adjustment device for a magnetic disk drive device, comprising: a control means for outputting a device adjustment amount control signal. 2. The control means moves the carriage in a radial direction to reproduce the reference adjustment signal stored in the track corresponding to the excitation phase of the stepping motor of the drive device. A tracking adjustment device for a magnetic disk drive according to scope 1. 3. A claim characterized in that the control means moves the carriage in a radial direction to reproduce the reference adjustment signal stored in at least one of the vicinity of the outermost circumference and the vicinity of the innermost circumference of a predetermined track. A tracking adjustment device for a magnetic disk drive device according to item 1 or 2. 4. When the adjustment amount displayed by the adjustment amount display means is a magnetic head adjustment amount signal indicating the adjustment amount of the magnetic head, the process of change in the magnetic head adjustment amount is determined based on the magnetic head adjustment amount signal. The magnetic disk drive according to any one of claims 1, 2, and 3, characterized in that the inclination of the magnetic head is adjusted by continuously displaying it on the adjustment amount display means. Device tracking adjustment device. 5. When the adjustment amount signal in the adjustment amount display means is a signal indicating the adjustment amount of the magnetic head, based on the adjustment amount of the magnetic head, corresponding to the adjustment amount of the rotational direction position of the magnetic head, The magnetic disk drive according to any one of claims 1, 2, 3, or 4, wherein the adjustment amount signal of the magnetic head is displayed on the adjustment amount display means. Device tracking adjustment device. 6. The adjustment amount signal in the adjustment amount display means includes a vertical error of the magnetic head, a static error of the drive device, a hysteresis error due to the moving direction of the carriage, and a cumulative error accumulated at each step from the inner circumference to the outer circumference. , eccentricity error during magnetic disk chucking, the error adjustment amount signal indicates the adjustment amount of one or more of the following: an eccentricity error during magnetic disk chucking. Claims 1, 2, 3, 4, or 5, characterized in that the total value of each of the errors based on the quantity signal is displayed on the adjustment amount display device. A tracking adjustment device for a magnetic disk drive according to any one of the above.