JPH0778434A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To write servo information having sufficiently high density and quality even under a bad environment by writing necessary servo information after a magnetic disk where preservo information is written is incorporated and the position of a reproducing head is decided. CONSTITUTION:The preservo information is accurately written in a magnetic disk unit at a stage before it is incorporated into the magnetic disk device. At this time the preservo information is provided with high and low frequency patterns 27 and 28 and written alternatively among respective tracks and so that the phases of the patterns are made coincident between the adjacent tracks. The magnetic disk having the patterns 27 and 28 written thereon is incorporated into the magnetic disk device, a spindle motor is rotated and the preservo information is read by a reproducing gap 26. At this time the frequensies of the patterns 27 and 28 are separated and a voice coil motor is deriven so as to decide a position where the signal amplitudes of both are made equal. Then, when write of the servo information is over, current is flown to the voice coil motor in a direction where a recording and reproducing separate type head is moved inside and movement is made to a next track position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo information writing system for recording and reproducing servo information such as positioning information and track information on a magnetic disk laminated in a magnetic disk device. A magnetic disk device incorporating this servo information writing method and a magnetic disk device incorporating a magnetic disk as an information recording medium and a recording / reproducing separated type head for recording / reproducing information on / from the information recording medium. Regarding

[0002]

2. Description of the Related Art FIG. 5 is a block diagram of a conventional servo information writing apparatus for a small hard disk drive.
In FIG. 1A, the servo information writing device includes a clamper (not shown) for fixing the casing 1 of the magnetic disk device, a reference signal read / write head 10 inserted from the outside of the magnetic disk device, and a magnetic head 4. A drive plate 12 for moving to an arbitrary position, and the drive plate 12 and the carriage arm.
Drive pin 11 for contacting the drive unit 6, step motor 13 for driving the drive plate 12, and this step motor
A rack and pinion 14 for converting the linear displacement generated by the motor 13 into a rotational displacement, an encoder 15 for detecting the amount of movement when the drive plate 12 is driven, a spindle motor 3, a voice coil motor. A cable 9 for transmitting and receiving signals for operating the data output device 7 and the head amplifier 8 to and from the magnetic disk device, a drive system control circuit (not shown), and a servo information recording / reproducing system control circuit. Has been done.

The magnetic disk drive is fixed on a clamper (not shown) so that the center of rotation of the drive plate 12, the rack and pinion 14, and the encoder 15 coincides with the center of rotation of the carriage arm 6. .

The reference signal read / write head 10 is inserted from the outside of the magnetic disk drive so as to be positioned at an arbitrary position on the outer peripheral side of the magnetic disk 2 other than the data area. The drive pin 11 is in line contact with a part of the carriage arm 6, and the drive plate 12 is driven to freely move the magnetic head 4 of the magnetic disk apparatus main body to an arbitrary position on the magnetic disk 2. Can be made. Drive pin 11
Is a cutout window 35 provided in the top cover 34 of the magnetic disk drive or in a part of the top cover.
In the state of being inserted from above, it contacts a part of the carriage arm that supports the magnetic head facing any magnetic disk 2.

FIG. 1B is a partially enlarged view showing the positional relationship between the carriage arm 6 and the drive pin 11. When determining the contact position between the drive pin 11 and the carriage arm 6, in order to accurately position the magnetic head 4 at an arbitrary position on the magnetic disk 2, the magnetic head 4, the suspension 5, and the carriage arm 6 are arranged. Among these, the contact position is selected such that the amount of positional deviation from the tip of the magnetic head is minimized in the portion of the carriage arm 6 having the highest rigidity.

FIG. 1C shows a conventional servo information writing apparatus of a type in which a cutout window is provided in a part of a magnetic disk device, and a drive pin 11 and a reference signal read / write head 10 are inserted through the cutout window. It is an external view of a magnetic disk device when used. In Figure (c), the drive pin is on the top cover 34.
There is an insertion window 35 of 11 and a reference signal read / write head insertion window 36 on the right side facing the paper, but if the above-mentioned conventional servo information writing device is used, such a servo will be placed somewhere in the enclosure. There is an insertion window from the information writing device. These windows are one of the major causes of dust contamination inside the enclosure.

Next, a method of writing the servo information will be described with reference to FIGS. 5 and 6. First, power is applied to the spindle motor 3 and the head amplifier 8 from the cable 9, a current is supplied to the voice coil motor 7 to drive the carriage arm 6, and the magnetic head 4 is moved to the inner circumference of the magnetic disk 2. Generates a force in the direction of movement. Then, the reference signal 17 is supplied from a reference signal generation circuit (not shown) to the magnetic disk device specification via the reference signal read / write head 10 inserted at an arbitrary position on the outer peripheral side outside the data area 16 of the magnetic disk 2. Write only the number designed based on. At that time, not only the even numbers of the reference signals 17 are matched, but writing is continued until the phase of each reference signal 17 and the phase of the start and end of writing of the reference signal 17 match.

Next, the step motor 13 is driven and the carriage arm 6 is moved by the rack and pinion 14 to position the magnetic head 4 on the outermost track of the data area.
The position at this time is monitored by the encoder 15, and the drive system is controlled by a drive control circuit (not shown) so that the magnetic head 4 is positioned at a predetermined position.

After the positioning of the magnetic head 4 is completed, the reference signal 17 read by the reference signal read / write head 10 is read.
Is counted by an address counter 18 based on an index signal (not shown), and a pattern memory 19 in which servo information is previously stored from a host computer (not shown).
Is converted into the address code of the pattern memory 19 and the corresponding address on the pattern memory 19 is selected. The servo information 20 read from the pattern memory 19 is written as a part of a concentric track on the magnetic disk 2 via the magnetic head 4 of the magnetic disk apparatus main body by a storage / reproduction system control circuit (not shown). Be done. The area divided by the servo information 20 written on the track is called a sector 21, and such a servo information writing method is generally called a sector servo method. As described above, in the conventional servo information writing apparatus using the sector servo method, normally, when writing the servo information, the magnetic head incorporated in the magnetic disk apparatus main body is positioned at a predetermined track position. A stepping motor 13, a rack and pinion 14, an encoder 15, a drive plate 12, and a drive pin 11, which are magnetic head positioning means outside the magnetic disk device, are used.

When the writing of the servo information 20 for one track is thus completed, the positioning method described above
The magnetic head 4 is moved to the next track. that time,
The driving amount of the step motor 13 is calculated in advance, and the magnetic head 4 can be moved at an accurate pitch according to a command from the host computer.

By repeating the above-described series of servo information writing operations for a required number of tracks, the magnetic disk 1
Writing the surface servo information is complete. By the way, the vibration force generated by driving the step motor 13 and the rack and pinion 14 affects the behavior of the magnetic head 4 from the contact position between the drive pin 11 and the carriage arm 6. Further, the rotational vibration component generated by the rotation of the spindle motor 3 also affects the behavior of the magnetic head 4. As a result, the vibration component at the time of writing the servo information is recorded in the servo information 20 through the magnetic head 4, and the magnetic information for positioning using the servo information thus written is used. In the disk device, this is a major cause of deterioration in the positioning accuracy. this is,
Since the drive pin 11 for positioning the magnetic head 4 is only in contact with the carriage arm 6, the behavior of the magnetic head 4 for writing the servo information 20 directly on the magnetic disk 2 cannot be controlled. Inability to increase the rigidity of the writing device to infinity, and variations in characteristics of individual magnetic disk devices when the magnetic disk device is fixed to the servo information writing device and compatibility with the servo information writing device to cause. This is because even if the servo information writing device is made to have a high rigidity and the magnetic disk device housing is made to be a high rigidity, the servo information writing device is used to make a magnetic disk of the magnetic disk device. This is an unavoidable problem as long as the conventional servo information writing method such as writing the servo information is adopted.
Further, in the conventional servo information writing method, one servo information writing device is occupied to complete the writing of the servo information 20 of one magnetic disk device. Information of one magnetic disk unit
To complete the writing of 20, it is necessary to write multiple servo information writing devices, or it is necessary to write the servo information one by one over the time required for multiple writing. From these facts, in the conventional servo information writing apparatus and servo information writing method, the higher the track density of the magnetic disk device, the more accurate the servo information writing accuracy with respect to the track pitch of the servo information. Deteriorates and
This will increase the time to write the information, which will have a bad effect on increasing the density of the magnetic disk device. Moreover, the place where the information writing device is installed must be clean and quiet. Therefore, it is a very big obstacle to the improvement of the productivity of the magnetic disk device.

Particularly in recent years, in order to meet the demand for a large capacity of a small magnetic disk device, the track density has been improved and the life of the product has been shortened. Along with this, it is necessary to develop a servo information writing device capable of writing high quality servo information. In this case, the vibration source by the servo information writing device itself,
When the track density is increased by the positioning accuracy of the magnetic head positioning means, the vibration force generated by the interaction between the magnetic head positioning means and the magnetic disk device body, etc., the above-mentioned influence is large with respect to the track pitch. Not only does it significantly reduce the quality of the servo information,
It is necessary to fully consider the environment in which the writing of servo information is enforced.

As described above, in a magnetic disk device aiming at high track density, how to write servo information accurately and efficiently on the magnetic disk is a very important problem. .

[0014]

As described above,
When writing servo information using a conventional servo information writing device, the vibration component that is the source of vibration of the servo information writing device itself, the positioning accuracy of the magnetic head positioning means, and the spindle model of the magnetic disk device. -The rotational vibration component generated by the rotation of the spindle motor, and the vibration component generated by the excitation force generated by the rotation of the spindle motor shakes the casing of the magnetic disk device body, which significantly deteriorates the quality of the servo information. , Has hindered the increase in track pitch. In addition, it is very costly to develop a highly rigid servo information writing device with few vibration sources by providing a highly accurate positioning control mechanism, and furthermore, writing servo information for each magnetic disk device model. The productivity is very poor because the device must be developed and the environment for writing the servo information must be developed.

Therefore, in the present invention, when the servo information is written on the magnetic disk of the magnetic disk device, even if the track density is improved or the spindle motor of the magnetic disk device contains a rotational vibration component. , Again, spindle mode
The magnetic disk drive adopts the servo information writing method that can write the servo information of sufficiently high density and high quality even under the adverse environment even if the excitation force is generated by the rotation of the rotor. The purpose is to provide.

[0016]

In order to achieve the above object, the present invention provides a magnetic disk device with pre-servo information which allows the reproducing head of the magnetic disk device to perform only positioning in advance, rather than complicated servo information. A magnetic disk in which is written, the reproducing head is positioned by the positioning system according to claim 2 by using the pre-servo information, and thereafter, the self-recording of the servo information originally necessary for the magnetic disk device is performed by the recording head. It is characterized by having a self-servo light means for writing.

[0017]

The present invention has the following advantageous effects due to the above-mentioned structure. First, by self-flighting the servo information, the conventional servo information writing device is not required, so that it is possible to eliminate the vibration source by the servo information writing device. Further, there is no excitation force generated between the servo information writing device and the magnetic disk device. As a result, the servo information that is self-flighted by each magnetic disk device is the same as the above
Very high quality service as it does not contain seed vibration components
It is possible to obtain information about BO.

By using the recording / reproducing separated type head mounted on the magnetic disk device and capable of recording and reproducing at the same time, and by using the pre-servo information and positioning, the actually used servo information is used. In order to perform the self-servo write method, the sector servo method in actual use that considers the format effect of the magnetic disk drive is used.
Positioning can be performed with a servo that is much higher than the servo band, and as a result, the playback head can sufficiently follow the rotational vibration component of the spindle motor and the vibration component of the environment where the magnetic disk performs self-servo writing. Becomes possible,
Extremely high quality servo information can be written without being affected by the vibration source at the time of writing the information.

Since a servo information writing device is not particularly required and self-servo writing is possible, it is not necessary to consider the environment at the time of writing the servo information, and the servo information is individually recorded in each magnetic disk device. Can be written,
A development cost of the servo information writing device is low, and a magnetic disk device having excellent productivity can be obtained.

Since the servo information can be written in the magnetic disk device in actual use, there is no deformation at the time of fastening the casing top cover, and the reference signal read / write head can be inserted when writing the servo information. Since there is no insert from the outside of the magnetic disk device, it is possible to suppress the mixture of dust inside the magnetic disk device to the utmost.

[0021]

Embodiments of the present invention will be described in detail with reference to the drawings. First Embodiment FIG. 1, FIG. 2 and FIG. 3 are schematic views showing an embodiment of a self-survey type magnetic disk device according to the present invention.
In each drawing shown below, the same parts as those of the magnetic disk device shown in FIG.

In the self-servolite type magnetic disk device according to the present embodiment, as shown in FIG. 1A, the pre-servo information 22 is laminated on the entire surface of the magnetic disk or on a part of the magnetic disk. The magnetic head has a recording / reproducing separated head 23 in which a reproducing gap 26 and a recording gap 25 are arranged in the order shown in FIG. 2B with respect to the rotating direction of the magnetic disk. Further, as shown in FIG. 1 (b), since servo information can be written with the top cover fastened, a drive window and a cutout window for inserting the reference signal read / write head are required. There is no unnecessary cutout window in the magnetic disk device casing like the magnetic disk device when the conventional servo information writing device is used.

Further, the magnetic disk device body has a servo information storage means (not shown) for storing servo information to be written on the magnetic disk. First, the writing pattern of the preservo information 22 will be described.

The pre-servo information 22 is accurately written on the magnetic disk unit before being incorporated in the magnetic disk device. The pre-servo information at this time has a high-frequency pattern 27 and a low-frequency pattern 28, and is written alternately for each track so that the phases of the patterns match between adjacent tracks. . FIG. 2 (a) is a partially enlarged view of the magnetization pattern showing that the high frequency pattern 27 and the low frequency pattern 28 are in phase with each other between the tracks.

Next, regarding the structure of the sector information written by the self-servo write, the structure of the sector information when the servo write method of the present invention is applied to the conventional type servo information is based on FIG. Explained. Sector 21 has servo information 20 and data section 24, and servo information 20 is AG
C burst section 29, sector index detection erase section
30, address code 31, positioning burst part 32, server
It is composed of the body information and the data division part 33.

Next, a self-surveillance method in the self-servolite type magnetic disk device will be described. First, a method of positioning the reproducing head will be described.

Regarding the preserver information 22, a high frequency pattern
In the magnetic disk device incorporating the magnetic disk 2 in which the high frequency pattern 27 and the low frequency pattern 28 are alternately written, the spindle motor 3 is rotated and the pre-servo information 22 is read in the reproduction gap 26. At this time, the high frequency pattern 27 and the low frequency pattern 28 are frequency-separated, and the voice coil motor 7 is driven so as to be positioned at a position where the signal amplitudes of both are equal. After that, when the writing of the servo information is completed, a current is applied to the voice coil motor in the direction in which the recording / reproducing separated head 23 moves to the inner peripheral side, and the voice coil motor moves to the next track position. Therefore, if the pre-servo information is written with a track width that is half the actual track width, in FIG.
The track positions to be positioned are P-1, P, P + 1, P
The position becomes +2, and the Wov portion overlaps between adjacent tracks.

By repeating the above process for each track, the servo information 20 necessary for the magnetic disk device can be written from the outer circumference side to the inner circumference side.
The process of writing the servo information is performed from the outer peripheral side to the inner peripheral side, but it is also possible to perform the same process from the inner peripheral side to the outer peripheral side.

As described above, if the preservo information 22 is read in the reproduction gap 26 and the positioning is performed by using the preservo information, the self-servo light type positioning method according to the present invention is used. Sampling higher than the sampling frequency Fss for obtaining the servo information necessary for actually using the magnetic disk device as shown in the equation (1) because the pre-servo information can be obtained continuously. Since the positioning can be performed at the frequency Fps, the spindle motor rotation vibration frequency Fnrro at the time of writing servo information, which is included in the servo information that becomes a problem when actually using the magnetic disk device, and the magnetic disk When actually using the device, when positioning the magnetic head with Fss, this occurs when writing servo information that adversely affects the positioning accuracy. With respect to the unnecessary vibration frequency component Fetc, Fps can be set within the range given by the equation (2), and the vibration component generated at the time of writing the servo information can be sufficiently tracked. Therefore, the self-servo write writes the servo information in the positioning state using the pre-servo information, so that an unnecessary vibration component that adversely affects the positioning accuracy is actually used when the magnetic disk device is actually used. It is possible to obtain the servo information of very high quality, which does not exist in the body information.

Fps> Fss (Fss: number of sectors × spindle motor rotation speed) (1) Fps / 2> MAX (Fnrro, Fetc) (2) (MAX (*, *) is the frequency of the two. Then, the method of writing the servo information will be described.

FIG. 3 is a magnetization recording pattern when the conventional servo information in the sector servo system is recorded by the self-servo system according to the present invention.
It shows a schematic diagram of the

In the figure, pre-servo information is written at a half pitch of the track pitch. The boundary between the high-frequency pattern 27 and the low-frequency pattern 28 corresponds to the track center. The reproduction gap 26 reads the pre-servo information by the above-mentioned positioning method and is positioned at the track center. In this state, a recording magnetic field is generated from the recording gap 25, and AGC burst signal 29, erase signal 30, address code 31, positioning burst signal which are servo information necessary for the magnetic disk device. 32, write the delimiter signal 33. Sector
In the BO system, AGC burst 2 for each track
9. The erase signal 30 and the delimiter signal 33 are continuous signals having the same phase, and the address code 31 must continuously change for each track. However, it is known that when the gap width Wg of the recording gap 25 is Wg and the track pitch is Tp, Wg is in the range shown in the equation (3).

Tp / 2 <Wg <Tp (3) Further, the conventional servo information requires four-phase positioning burst signals A, B, C and D. In order to satisfy these two points, in order to perform the servo write in the self-servo write type magnetic disk device according to the present invention, the positioning based on the pre-servo information must be performed at Tp / 2. As a result, the pre-servo information is left in at least two areas a to h shown in FIG. 3 depending on the order of the servo write of each track. The width of this region δ
Is given by equation (4), where F is the total amount of bleeding on both sides of the gap width during recording and E is the total amount of erase.

Δ = (Tp−Wg−E−F) (4) Further, when the self-servo write ends, δ / 2 or more on the outermost track and the innermost track of the track in which the servo information is written. Preservation information will remain.

By the way, normally, in a sector servo type magnetic disk apparatus, not only positioning information but also track address information is required as servo information. On this occasion,
If a phase shift occurs in the magnetization pattern of servo information between adjacent tracks, the track address signal may be erroneously detected. Therefore, in the conventional servo information writing apparatus, in order to prevent this phase shift, the reference signal read / write head 10 is externally inserted and the reference signal is written in a part of the magnetic disk. This reference signal is reproduced by the reference signal read / write head, a reference clock generation circuit generates an appropriate clock signal of an amount capable of correcting the phase shift between adjacent tracks, and the servo information is written using this. At that time, complicated signal control is performed such as correcting the appropriate phase amount and writing servo information so that the phase shift does not occur. Therefore, it is necessary to insert a reference signal read / write head, which is essentially unnecessary, from the outside of the magnetic disk device, and vibration control and various signal controls for this head must be performed. This is cited as one of the major causes of increasing the development cost of the conventional servo information writing device.

However, in the self-servolite type magnetic disk device of the present invention, the phase of the pre-servo information is the same between the consecutive tracks, and since the recording / reproducing separated head is used, it is complicated. An appropriate phase correction amount can be easily generated by adjusting the reproduction timing to the recording timing itself or by reading the phase of the pre-servo information. -It has an excellent effect that the pattern phase between adjacent tracks of body information can be easily matched.

Further, the recording timing of the servo information in the self-servo write system according to the present invention is such that the phase alignment between the adjacent tracks is easily performed as described above.
Although it is performed at the same time as the reproduction timing of the pre-servo information, the phase adjustment between adjacent tracks is performed more efficiently than the conventional servo information writing device even if the recording and reproduction timings are shifted to reduce crosstalk. It is possible. Therefore, the self-servo light system of the present invention can be used even for the conventional inductive head in which recording and reproduction cannot be performed at the same time.

Finally, the positional relationship between the pre-servo information track and the servo information track will be described with reference to FIG. In the figure, positioning control is performed so that the reproducing gap is positioned at the center of the P + 3 track, and at the same time, the recording gap 25 is at the D bar of the P + 3 track.
Writing strike signal. When the writing of the servo information is completed in this way, N-1, N, and N + 1 correspond to the track centers in actual use of the magnetic disk device.

Second Embodiment FIG. 4 is a schematic diagram of a magnetization pattern of servo information using the self-servolite method according to the present invention.
This is an embodiment in which the body information is used as the servo information for actual use.

In this embodiment, the pre-servo information is used as the positioning burst signal in the servo information to form a two-phase burst. Self-servolite system service
The positioning method at the time of writing the information is the same as in the first embodiment. Servo information writing is done by positioning burst signal
In the 32 areas, the servo information is not written, the preservo information is left, and the preservo information is used as a positioning burst signal for the magnetic disk device in actual use.

The track positional relationship between the pre-servo information and the servo information is the same as in the first embodiment. Also in this embodiment, preservo information of δ / 2 or more remains at the beginning and end of writing the servo information, and preservo information also remains at the positioning burst signal position. Even for such a servo pattern, the self-servolite method in the present invention can be adopted.

[0042]

As described above, the self-servo type magnetic disk device according to the present invention does not require a servo information writing device, so that there is no vibration source due to the servo information writing device. , There is no excitation force generated between the servo information writing device and the magnetic disk device, there is no influence of the spindle motor rotational vibration component at the time of writing the servo information, and the track density is improved. It is possible to write very high quality servo information even with a track density of up to 50%, and various vibration sources exist even if the environment for writing servo information is not clean. However, it does not deteriorate the quality of the servo information.
Since the information can be written and the magnetic disk device casing does not need a cutout window or the like, it is possible to provide a magnetic disk device capable of preventing the mixing of dust and dust. To be

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration example of a self-servo type magnetic disk device using the present invention.

FIG. 2 is a conceptual diagram showing one configuration example of pre-servo information for adopting the self-servo light method according to the present invention.

FIG. 3 is a conceptual diagram showing a method of writing servo information when the self-servo write method according to the present invention is used for conventional servo information.

FIG. 4 is a conceptual diagram showing a method for writing servo information using a self-servo write method according to the present invention.

FIG. 5 is a conceptual configuration diagram of a servo information writing device according to a conventional example.

FIG. 6 is a schematic diagram showing a servo information writing method according to a conventional example.

[Explanation of symbols]

 1: Enclosure of magnetic disk 3: Spindle motor 7: Voice coil motor 8: Head amplifier 20: Servo information 21: Sector 22: Preservo information 23: Recording / playback separation head 24: Data part 25: recording gap 26: reproduction gap 27: high frequency pattern 28: low frequency pattern 29: AGC burst section 30: sector in disk detection erase section 31: address code 32: positioning bar -Strike part 33: Divided part

Claims (4)

[Claims] 1. The servo information is recorded together with the servo information.
At least 1 for recording or reproducing information other than information
A magnetic disk device comprising one or more magnetic disks and a magnetic head for reading servo information recorded on the magnetic disks and recording or reproducing information other than the servo information, The pre-servo information is written in the magnetic disk before the magnetic disc device is incorporated into the magnetic disc device, and by using the pre-servo information, the positioning information and the track necessary for practical use of the magnetic disc device. A magnetic disk device characterized in that servo information such as application information is written on a magnetic disk by a recording head or self-servo writing is performed to overwrite preservo information. 2. The self-servo light is positioned by the recording head at the track position where the pre-servo information is written by the reproducing head while being continuously or intermittently positioned in the circumferential direction. -The magnetic disk drive according to claim 1, wherein the information is written. 3. The magnetic disk drive according to claim 1, wherein the recording timing of the recording head is a recording / reproducing separated type head which can be performed simultaneously or independently of the reproducing timing of the reproducing head. . 4. The recording / reproducing separated type head according to claim 3, wherein the reference signal for writing the servo information does not exist on the magnetic disk surface, and there is no notch window for inserting the reference signal read / write head. 4. The magnetic disk drive according to claim 3, wherein the magnetic disk drive can function as the reference signal read / write head, and the average eccentricity and the eccentricity of each disk are different.