JP2927234B2 - Servo pattern writing method for magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sector servo technique for a magnetic disk drive, and more particularly to a sector servo technique for a magnetic disk drive using a combined thin film head and MR head.

[0002]

2. Description of the Related Art As shown in FIG. 10, a magnetic disk drive comprises a magnetic disk 101 having a magnetic surface and supported on a spindle (not shown) for rotation, and at least a movable disk relative to the disk surface. One magnetic head 10
3 and a spindle motor 10 for driving the spindle
4, a head support mechanism 105 coupled to the magnetic head 103, and the magnetic head 1 along the magnetic disk surface.
And an actuator 106 for moving the head support mechanism 105 formed to move the magnetic head 1 and servo information recorded on the magnetic disk surface.
And a servo system 107 for controlling the actuator 106 by reading at 03 and moving the position of the magnetic head 103 to a target position or holding the magnetic head 103 at a target position.

A recent magnetic disk device generally performs positioning of a magnetic head, that is, tracking control by a so-called sector servo system.

In this sector servo system, as shown in FIG. 10, about 30 to 100 servo sectors 102 are arranged in one round so as to cross a plurality of concentric data recording tracks on a magnetic disk 101 at equal time intervals. .
Here, the servo sectors 102 are not linearly arranged in the radial direction but are curved because the movement locus of the head is not a straight line but an arc centered on the pivot.

In the typical example, the servo area 102 includes an AGC section 110 and a coarse position information section (cylinder address information section) 111 in order of time (in the circumferential direction of the disk) passing under the head as shown in FIG. And servo burst A11
2, servo burst B113, servo burst C11
4, and a precise position information section composed of four servo bursts D115. Each servo burst is a repetition of a single frequency signal (eg, 10 cycles). The radial width of each servo burst is the data track pitch Tp
The burst pattern is repeated in the radial direction at a cycle of 2 cylinder widths across an erase portion (no signal portion) having a data track pitch width in the radial direction. Further, each burst of A, B, C, and D is radially separated from each other by 1/1 of the data track pitch Tp.
They are arranged offset by an integer multiple of two. In FIG. 11, B is offset by Tp with respect to A, and C is Tp /
Two offsets and D are arranged at 3/2 Tp offset (or Tp / 2 offset in the opposite direction to C in another expression).

The sector servo pattern is written by a precision equipment called a servo track writer (STW) using the magnetic head 103 itself for reading and writing data. The write head width is the data track pitch Tp
Since it is narrower, writing a servo pattern with a one-track pitch width requires writing over. A servo pattern is formed by rewriting at a position shifted by 1/2 of the data track pitch Tp, and the width of extra writing is further reduced by 1/2 of Tp.
DC erase is performed at the offset position. Therefore, when observing the pattern of one track width by the Bitter method or the like, it is understood that there is a narrow erase band formed when the pattern is rewritten at the center. (FIG. 11 omits the writing splicing.) For the positioning control, the position is detected, and the actuator is controlled so that the difference is smaller than the target position.
The position detection is performed as follows. First, the cylinder address is recognized by decoding the code of the coarse position information section. Next, the four bursts A, B, C,
Detect the amplitudes Sa, Sb, Sc, and Sd of D. Since the output amplitude of the magnetic head 103 is almost proportional to the width of the recording pattern passing immediately below the magnetic head 103, when the magnetic head 103 is on the line of the track center Tc, Sa, S
It is easily understood from FIG. 10 that b is about half of the maximum value, Sc is maximum, and Sd is minimum (substantially zero). So Figure 1
As shown in FIG. 1, Sa-Sb and Sc-Sd are used as position error signals 120 and 121 to obtain a precise position within one cylinder.

Here, two position signals are generated because the linearity of the position signal is lost near the maximum and minimum of one position signal, the sensitivity of the position is reduced, and a dead zone is generated. In that case, accurate position information can be obtained by using another position signal. The cause of the dead zone is that the read width Tr of the magnetic head 103 is smaller than the recorded burst pattern width Tp. When the burst amplitude is near the maximum value, even if the head is offset by a small amount (± (Tp-Tr) / 2 or less) to the left and right (in the cross-track direction), the output amplitude hardly changes because there is a recording pattern right under the head. Even if the offset is small in the vicinity of the minimum burst amplitude as well, the area immediately below the head is the erase portion and the amplitude remains almost zero.

When the magnetic head 103 is off-track by 1/2 Tp from the track center Tc, the position signal (Sa-S)
b) Since a dead zone is formed at 120, the position error signal (Sc-Sd) 121 is obtained at a position off-tracked by 1/4 Tp.
, The position error signal corresponding to the position is output from the magnetic head 103 regardless of the position of the magnetic head 103, and the magnetic head 103 can be positioned.

Nowadays, the amplitude detection output Sa of the servo burst A and that Sb of the servo burst B are respectively converted to AD.
After conversion, the microprocessor performs an operation (Sa-S
b) is often calculated, and the position error signal does not always exist as an analog signal.

[0010]

The recording density of magnetic disk devices has been rapidly increasing year by year, and MR heads having high read sensitivity have been used to achieve high recording densities. Since the MR head is read-only, writing uses a thin film head (TF head) as in the past. Therefore, the magnetic head is a combination of the thin film head and the MR head.

A problem with the conventional servo pattern is that when a composite head having a read-only MR head is used, a position error signal (Sa-S) generated from a servo burst signal is used.
b). When the linearity region of (Sc-Sd) becomes narrow and the dead zone becomes large, it cannot be stably and accurately positioned at an arbitrary position, for example, a 1/4 off-track position.

One of the reasons is that in the case of the TF-MR composite head, the track width of the TF and the MR is changed to reduce the reading error for off-track, and the head is designed for wide write / narrow read. Since it is narrower than the writing / reading combined TFH, the dead zone is widened.

Another reason is that in the reproducing MR head, the off-track sensitivity characteristic is non-linear, and the skirt and shoulder of the off-track profile deviate from a straight line.

Still another reason is that the MR head is essentially asymmetric in the left and right off-track characteristics.

For these reasons, the position error signals (Sa-Sb) and (Sc-Sd) generated by the burst reproduction output.
And it is difficult to maintain the ratio of the linear area to the data track pitch Tp at 50% (± １ ／ Tp), and it is difficult to secure the linear area by switching at the position where the track is off by オ フ cylinder. Positioning control becomes difficult.

FIG. 6 shows the basic arrangement of the servo burst pattern. FIG. 7 shows a relative positional relationship between the burst pattern and the reproducing MR head. FIG. 8 shows the result of the off-track profile when the reproducing MR head is off-tracked in FIG.

Considering a trapezoid formed by a straight line obtained by linearly approximating a slope portion of a profile, a line with a normalized output Y = 0, and a line with a normalized output Y = 1, the lower left and upper right corners of the profile are rounded and distorted. I have. FIG. 9 shows the reproduction MR head having the off-track profile shown in FIG. 8 and the amplitude S of the two bursts A12 and B13 in the arrangement of FIG.
The profile when a and Sb are extracted and a position error signal (Sa-Sb) is created is shown. The position error signal (Sa-
The interval between the points P and Q where Sb) = 0 is the burst A in FIG.
12, a burst B13 interval. Position error signal (S
a-Sb) = 0 at the center, the linear region is the reproduction MR
Only about 80% of the reproducing track width of the head can be secured. This is due to the fact that the reproducing MR head has a reduced sensitivity distribution in the track width direction.

When the relationship between the track width Tr and the reproduction track width Rw of the reproduction MR head is ＴｒTr> 0.8 × Rw (1), a position error signal (場合) when the servo burst pattern is offset by ＴｒTr. Sa-Sb), (Sc
−Sd), a dead zone that cannot be positioned is created.

However, as described above, generally, reproduction M
The R head has a reduced reproduction track width to secure a margin during data recording and reproduction. If the reproduction track width is 70% of the track width Tr, there is no problem from the above equation (1).
When it becomes 0%, the track width is １ ／ from the relation of the above equation (1).
Positioning is difficult with an offset servo burst pattern.

As a countermeasure, servo bursts A, B,
There is a method to increase the number of servo bursts to 6 or 8 to increase the number of bursts to 8 or more, and to use no nonlinear part.
Then, the data area for the increased servo burst is reduced, and the data use efficiency is reduced. In addition, the number of channels and the processing time of the AD converter are increased, which leads to an increase in cost and performance.

An object of the present invention is to provide a servo pattern suitable for a composite head of a wide write narrow read system. According to the present invention, it is possible to increase the recording length of the servo information and improve the accuracy of the position information without deteriorating the use efficiency of the data surface, and to stably perform accurate positioning at an arbitrary position with the same detection circuit as before. It becomes possible.

The radial width of each burst is set to 2/3 of the data track width, and the servo bursts are arranged offset by 1/3 of the data track width in the radial direction. In this case, the width of the MR head is relatively larger than the width of the servo burst information with respect to the width of the MR head, and the basic idea is that a dead zone can be avoided.

By setting the burst pattern width to 2/3 data track pitch, the pattern cycle can be doubled to 4 Cyl in the same four servo bursts and the linearity can be improved.

[0024]

A magnetic disk drive according to the present invention has a magnetic surface and a magnetic disk supported on a spindle for rotation, and at least one magnetic head movable with respect to the surface of the magnetic disk. A spindle motor that drives the spindle, a head support mechanism that supports the magnetic head and operates to move the head along a disk surface, an actuator for moving the head support mechanism, A servo system that reads servo information recorded on a disk surface with the magnetic head, controls the actuator to move the position of the magnetic head to a target position, and holds the magnetic head at the target position. Wherein the servo information includes coarse position information indicating a rough position of the head and precise position information. The precise position information includes four position information patterns A, B, C, and D. Each position information pattern includes at least two magnetization reversals and is sequentially recorded in the track direction. Each position information pattern has a width of about 2/3 of the data track pitch in the cross-track direction, that is, every 4/3 of the data track pitch across a portion where there is no magnetization reversal. The four pieces of position information A, B, C, and D are recorded at positions shifted from each other by 1/3, 2/3, or 1 times the data track pitch in the cross-track direction. It is characterized by having.

In the magnetic disk drive of the present invention, the coarse position information includes cylinder address information, and one recording end of the cylinder address information in the track cross direction is any one of four patterns of the fine position information. It is characterized by being arranged so as to be on the same radius as.

According to the servo pattern writing method of the present invention,
3. A method of writing a sector servo pattern including coarse position information and precise position information on the magnetic disk of the magnetic disk device according to claim 1 by a servo track writer, and writing the sector servo pattern for one round by １ ／ of the data track pitch. By repeating the operation of shifting and writing again by the pitch, the coarse position information and the fine position information are successively written according to the timing information generated by the clock head synchronized with the rotation of the magnetic disk. When writing with a shift in pitch, the coarse position information is written in the same pattern continuously every three times, and the precise position information is divided into four pieces of the position information A, B, C, and D. The information pattern is written twice consecutively, and the DC erase operation is repeated twice. Position of the track transverse to write is characterized to keep shifting one time feed pitch of the head or twice or three times to each other at their four position information.

According to the servo pattern writing method of the present invention,
3. A method of writing a sector servo pattern including coarse position information and precise position information on the magnetic disk of the magnetic disk device according to claim 1 by a servo track writer, and writing the sector servo pattern for one round by １ ／ of the data track pitch. By repeating the operation of shifting and writing again by the pitch, the coarse position information and the fine position information are successively written according to the timing information generated by the clock head synchronized with the rotation of the magnetic disk. When writing at a pitch shift, the coarse position information is written once and then the write date is closed twice so as not to overwrite, and the fine position information is the four pieces of position information A, When the position information pattern is divided into B, C, and D, and the position information pattern is written once for each of the position information, The write gate is closed to prevent overwriting, the next one is performed by DC erasing, and the next one is performed by repeating the operation of DC erasing or closing the write gate, and the precise position information is written. The writing position in the transverse direction of the track is characterized by being shifted by one, two or three times the head feed pitch from each other based on the four pieces of position information.

According to the position detecting method of the present invention, when utilizing the coarse position information and the precise position information in the magnetic disk device according to the second aspect, the four pieces of precise position information overlap each other in the radial direction of the disk. Are selected, and the difference between the two position signal amplitudes belonging to each pair is defined as the first position error information and the second position error information, and the absolute value of the first position error information and the second position error information is selected. Is used as the position error information, the position error information and the maximum or minimum of the four precision position information,
Alternatively, the position is detected by using the polarity of the larger absolute value of the first position error information and the second position error information and the cylinder address information of the position information as a reference for determining the approximate position within one track. It is characterized by.

As shown in FIG. 1, the servo pattern has a repetition of four track cycles of N, N + 1, N + 2, and N + 3, and the magnetic head receives a position error signal (Sa-Sb),
By switching the position error signal (Sc-Sd) as shown in FIG. 4, the usable range of the slope of one position error signal can be made ± 1/6 cylinder width, so that ± 1/4 of the conventional pattern is used. Since it is narrower than the cylinder width, the dead zone due to the position error signal can be eliminated, and a continuous linear region can be secured to perform positioning.

[0030]

Next, an embodiment of the present invention will be described in detail with reference to FIGS.

The structure of the magnetic disk drive is the same as the conventional one and is as shown in FIG. FIG. 1 shows the configuration of the coarse position information and the precise position information of the sector servo of the magnetic disk drive of the present invention. The servo sector 102 of FIG. 10 includes the position information of FIG.

In FIG. 1, 1 is an AGC section and a coarse position information section (address section), 2 to 5 are precision position information sections, 2 is a servo burst A, 3 is a servo burst B, 4 is a servo burst C, and 5 is a servo burst. Burst D. The width of the coarse position information section is substantially equal to the track pitch Tp. On the other hand, the width of each burst in the precision information section is 2/3 Tp, and blank portions on the left and right of each burst are in a DC erase (erasing) state. As is clear from FIG. 1, the pattern arrangements of N to N + 3 are all different. Focusing only on the precise position information section, the burst pattern is a repetition of a 4/3 Tp cycle, but the relationship between the boundary of the coarse position information section and the burst pattern is 4 / 3Tp.
The p and 8/3 Tp destinations are different, and 12/3 Tp = 4
It returns to the same arrangement only after Tp. Therefore, it is possible to determine which part in the adjacent four cylinders is located from the value of the lower two bits of the address information (coarse position information) and the magnitude relationship between the four bursts.

FIGS. 2 and 3 show two methods of writing the servo pattern having the arrangement shown in FIG. FIG. 2 shows a standard writing method. Some kind of writing is performed on the entire servo sector at every 1/3 Tp pitch. The width of the coarse position information is Tp, and the same pattern is written three times. Therefore, two narrow erase bands can be formed within the width of Tp due to the spread of the magnetic field at the edge portion of the writing head.
It is to be noted that the timing of magnetization reversal must be aligned at the time of writing, and for this purpose, the servo track writer uses a clock head separately from the write head to obtain a reference clock synchronized with rotation.

FIG. 3 shows a writing method that does not cause a writing splice in a written pattern. After positioning the write head at the NCyl position using a laser tracker or the like with a servo track writer, the data specified at the servo pattern write timing of N in FIG. 3 is written. If N, AGC + coarse position information and servo burst A are written, and servo burst B is DC erased. At this time, the gate is closed and passed without writing at the timing of the servo bursts C and D. Next, the write head is moved to 1/3 of the data track pitch and positioned at N + 1/3, and N
Data is written at a servo pattern write timing of + ／. In N + ／, servo burst C is written and servo burst D is DC erased. The other areas close the gate and allow it to pass. Next, the write head is moved to 1/3 of the data track pitch, positioned at N + 2/3, and data is written at a servo burst write timing of N + 2/3. In N + 2/3, servo burst A is DC erased and servo burst B is written. Otherwise, the area closes and allows the gate to pass. Further, the write head is positioned at 1/3 feed N + 1 of the data track pitch, AGC + coarse position information and servo burst D are written, and servo burst C is DC erased.

As described above, the gate is controlled at the write timing shown in FIG. 3, and the write head is sent from N to N + 3 + 2/3 by the 1/3 data track pitch to write the designated data, whereby AGC + coarse position information, servo burst The servo pattern has no erase band due to rewriting, the four servo burst radial widths are set to 2/3 of the data track pitch, and the servo bursts are radially offset by 1/3 of the data track pitch. Then, a 2/3 track pitch burst pattern is created.

The magnetic head (reproduction MR head) 6
Positioning is performed using a position error signal generated by using the servo bursts.

FIGS. 4 and 5 show a method of processing position information by the servo burst pattern.

When the servo burst pattern shown in FIG. 1 is read out by the reproducing MR head 6 having a narrow track width, and a position error signal (Sa-Sb) 7 and a position error signal (Sc-Sd) 8 are generated from the difference in amplitude. It looks like 4.

FIG. 5 shows a position error signal to be used depending on the position of the magnetic head in the track cross direction in each track. The position signal to be used is switched according to the zone where the head is located. Thus, a dead zone caused by the position error signal is eliminated, a continuous linear region is secured, and accurate position information can be obtained regardless of the position of the magnetic head (reproduced MR head) 6 on the track.

[0040] It should be noted that is not to detect the actual to the position from the position information, we do not know is located in advance anywhere in the zone. In this case, the position can be obtained by realizing the use of the position error signal shown in FIG. 5 as follows.

When the position X is expressed with reference to the O thin shader, X
= Tp (4N + m-f) + KθS. Here, Tp is the track pitch, 4N + m is the cylinder address, and m is the lower 2 bits of the cylinder address and is 0-3. f is the offset of the center line of the position error signal from the track center, -1/2, -1.6, +1.6, + 1 /
Two. S is Sa-Sb, Sc-Sd,
Either Sb-Sa or Sd-Sc. Kθ is the sensitivity (distance / voltage) of the position error signal. The selection of f and S is determined as shown in the following table according to the magnitude relationship between m and Sa-Sb, Sc-Sd. If | Sa-Sb |> | Sc-Sd | and Sa-Sb> 0, then S = Sc-Sdf; if m = 0, then -1/6; if m = 1, +1/6, m
= + 2 if m = 3, f = -1 / 2 if m = 3 | Sa-Sb |> | Sc-Sd | and Sa-Sb <0, S = Sd-Scf If m = 0, then +1/2 , M = 1 -1/2, m
= −− １, m == 3, f = + 1/6 | Sa−Sb | <| Sc−Sd | and Sc−Sd> 0, S = Sa−Sb f, and m = 0, + 1 / 6, m = 1, +1/2, m
= −2 if m == 3, f = −1 / 6 if | Sa−Sb | <| Sc−Sd | and Sc−Sd <0, then S = Sb−Saf and if m = 0 then − If 1/2, m = 1, -1.6 m
= + 2 if m == 3 and f = + 1/2 if m == 3 | Sa-Sb |> | Sc-Sd | and Sa-Sb>
0 means that burst A is maximum, or burst B
Is equivalent to the minimum value of Sa, Sb, Sc,
The maximum or minimum of Sd may be obtained, and S and f may be selected.

[0042]

As described above, by using the servo pattern of 2/3 track width of the present invention, the reproduction M
In order to position the R head, position error signals (Sa-Sb),-(Sa-Sb), (Sc-
By switching and using Sd) and-(Sc-Sd), a dead zone of the position error signal can be eliminated and a continuous linear region can be secured.

As a result, positioning can be performed even when the reproducing track width of the reproducing MR head is about 60% of the track width.

Further, the conventional burst pattern having one track width can be reduced to a half of the conventional one-fourth track pitch and eight times the conventional one.
The same effect can be obtained by using a plurality of servo patterns, but there is a disadvantage that the length of the burst pattern is doubled, the occupancy of the data recording surface of the servo information is increased, and the data recording capacity is reduced. Further, compared to the present invention, the processing time of a servo track writer, which is an expensive facility, is increased because a servo pattern is written at a fine pitch, resulting in poor productivity. As described above, there is an effect that the utilization efficiency and the production efficiency of the data surface are superior to the simple extension of the conventional technique.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a servo pattern showing one embodiment of a servo signal writing system and a positioning system of the present invention.

FIG. 2 is a timing chart of writing a servo pattern according to FIG. 1;

FIG. 3 is a timing chart of a servo pattern that does not cause writing to be repeated.

FIG. 4 is a waveform diagram of a position error signal composed of a servo pattern according to FIG. 1;

FIG. 5 is a diagram showing the relationship between the position of a magnetic head (reproduced MR head) and a position error signal to be used.

FIG. 6 is a schematic diagram of a servo pattern.

FIG. 7 is a diagram showing a relative positional relationship between a reproduction MR head and a recording pattern.

FIG. 8 is a reproduction MR output profile diagram for an off-track position.

FIG. 9 is a profile diagram of a position error signal (AB).

FIG. 10 is an external view of a conventional magnetic disk drive.

FIG. 11 is a configuration diagram showing a conventional servo pattern.

FIG. 12 is a waveform diagram of a position error signal composed of a conventional servo pattern.

[Explanation of symbols]

 Reference Signs List 1 AGC + coarse position information 2 Servo burst A 3 Servo burst B 4 Servo burst C 5 Servo burst D 6 Magnetic head (reproducing MR head) 7 Position error signal (Sa-Sb) 8 Position error signal (Sc-Sd) 11 MR head Reproduction track width 12 Burst A 13 Burst B 14 Burst 101 Magnetic disk 102 Servo sector 103 Magnetic head 104 Spindle and spindle motor 105 Head support mechanism 106 Actuator 107 Servo system 110 AGC section 111 Coarse position information section 112 Servo burst A 113 Servo burst B 114 Servo burst C 115 Servo burst D 120 Position error signal (Sa-Sb) 121 Position error signal (Sc-Sd)

Claims (4)

(57) [Claims] 1. A magnetic surface having a magnetic surface on a spindle for rotation.
A supported magnetic disk, and at least movable with respect to the surface of the magnetic disk.
A magnetic head, a spindle motor for driving the spindle, and a support for the magnetic head;
A head support mechanism that operates to move the head support mechanism, an actuator for moving the head support mechanism, and servo information recorded on the magnetic disk surface.
Read by the head to control the actuator.
Moves the position of the magnetic head to a target position.
And a magnetic system including a servo system to hold it in the desired position
A disk device, wherein the servo information is coarse position information indicating an approximate position of a head.
And precise position information, wherein the precise position information includes four position information patterns A, B,
C and D, each position information pattern includes at least two magnetization reversals.
Recording is performed sequentially in the track direction, and the recording width in the cross-track direction is equal to the data track pitch.
Elsewhere a 2/3, each position information pattern data tracks across the tracks
Erased part with width about 2/3 of the pitch
Of the data track pitch across the part without magnetization reversal
It is arranged to repeat every 4/3 , and the four position information of A, B, C, D is
1/3 times the data track pitch or 2 /
A magnetic disk recorded at a position shifted by three times or
Coarse position information and precise position information
Servo track write
In the method of writing the data, 1/3 peak data track pitch after writing one revolution
To repeat the operation of shifting and writing again
A clock head synchronized with the rotation of the magnetic disk.
The coarse adjustment according to the timing information generated by the
The position information and the precise position information are successively written, and when writing by shifting by 1/3 pitch ,
The same position information is written continuously every three times, and the precise position information is the four position information A, B, C, D
And the position information pattern is written twice consecutively,
The position in the track cross direction where the writing is performed by repeating the operation of DC erasing one time and the precise position information is written is as follows.
The head feed pitch is once with each of these four position information
It is characterized in that it is shifted for 2 or 2 or 3 times
Servo pattern writing method. 2. A magnetic surface having a magnetic surface on a spindle for rotation.
A supported magnetic disk, and at least movable with respect to the surface of the magnetic disk.
A magnetic head, a spindle motor for driving the spindle, and a support for the magnetic head;
A head support mechanism that operates to move the head support mechanism, an actuator for moving the head support mechanism, and servo information recorded on the magnetic disk surface.
Read by the head to control the actuator.
Moves the position of the magnetic head to a target position.
And a magnetic system including a servo system to hold it in the desired position
A disk device, wherein the servo information is coarse position information indicating an approximate position of a head.
And precise position information, wherein the precise position information includes four position information patterns A, B,
C and D, each position information pattern includes at least two magnetization reversals.
Recording is performed sequentially in the track direction, and the recording width in the cross-track direction is equal to the data track pitch.
Elsewhere a 2/3, each position information pattern data tracks across the tracks
Erased part with width about 2/3 of the pitch
Of the data track pitch across the part without magnetization reversal
It is arranged to repeat every 4/3 , and the four position information of A, B, C, D is
1/3 times the data track pitch or 2 /
The coarse position information includes cylinder address information, and is recorded at a position shifted by 3 times or 1 time, and one of the cylinder address information in the track cross direction.
The recording end is one of the four patterns of precise position information
A magnetic disk arranged so as to be on the same radius as the recording end
Coarse position information and precise position information
Servo track write
In the method of writing the data, 1/3 peak data track pitch after writing one revolution
To repeat the operation of shifting and writing again
A clock head synchronized with the rotation of the magnetic disk.
The coarse adjustment according to the timing information generated by the
The position information and the precise position information are successively written, and when writing by shifting by 1/3 pitch ,
The same position information is written continuously every three times, and the precise position information is the four position information A, B, C, D
And the position information pattern is written twice consecutively,
The position in the track cross direction where the writing is performed by repeating the operation of DC erasing one time and the precise position information is written is as follows.
The head feed pitch is once with each of these four position information
It is characterized in that it is shifted for 2 or 2 or 3 times
Servo pattern writing method. 3. A spindle having a magnetic surface on a spindle for rotation.
A supported magnetic disk, and at least movable with respect to the surface of the magnetic disk.
A magnetic head, a spindle motor for driving the spindle, and a support for the magnetic head;
A head support mechanism that operates to move the head support mechanism, an actuator for moving the head support mechanism, and servo information recorded on the magnetic disk surface.
Read by the head to control the actuator.
Wherein the position moves of the desired position of the magnetic head by a
And a magnetic system including a servo system to hold it in the desired position
A disk device, wherein the servo information is coarse position information indicating an approximate position of a head.
And precise position information, wherein the precise position information includes four position information patterns A, B,
C and D, each position information pattern includes at least two magnetization reversals.
Recording is performed sequentially in the track direction, and the recording width in the cross-track direction is equal to the data track pitch.
Elsewhere a 2/3, each position information pattern data tracks across the tracks
Erased part with width about 2/3 of the pitch
Of the data track pitch across the part without magnetization reversal
It is arranged to repeat every 4/3 , and the four position information of A, B, C, D is
1/3 times the data track pitch or 2 /
A magnetic disk recorded at a position shifted by three times or
Coarse position information and precise position information
Servo track write
In the method of writing the data, 1/3 peak data track pitch after writing one revolution
To repeat the operation of shifting and writing again
A clock head synchronized with the rotation of the magnetic disk.
The coarse adjustment according to the timing information generated by the
The position information and the precise position information are successively written, and when writing by shifting by 1/3 pitch ,
Once the pattern is written, the pattern is written once
The position information is closed to prevent overwriting, and the precise position information is composed of four pieces of the position information A, B, C, and D.
And, for each of the position information, the position information pattern
Write one time, then close the light gate the next time
Do not overwrite, the next one is DC erase
The next time, DC erase or light
The position in the cross direction of the track where the writing is performed by repeating the operation of closing the
The head feed pitch is once with each of these four position information
It is characterized in that it is shifted for 2 or 2 or 3 times
Servo pattern writing method. 4. A magnetic surface having a magnetic surface on a spindle for rotation.
A supported magnetic disk, and at least movable with respect to the surface of the magnetic disk.
A magnetic head, a spindle motor for driving the spindle, and a support for the magnetic head;
A head support mechanism that operates to move the head support mechanism, an actuator for moving the head support mechanism, and servo information recorded on the magnetic disk surface.
Read by the head to control the actuator.
Moves the position of the magnetic head to a target position.
And a magnetic system including a servo system to hold it in the desired position
A disk device, wherein the servo information is coarse position information indicating an approximate position of a head.
And precise position information, wherein the precise position information includes four position information patterns A, B,
C and D, each position information pattern includes at least two magnetization reversals.
Recording is performed sequentially in the track direction, and the recording width in the cross-track direction is equal to the data track pitch.
Elsewhere a 2/3, each position information pattern data tracks across the tracks
Erased part with width about 2/3 of the pitch
Of the data track pitch across the part without magnetization reversal
It is arranged to repeat every 4/3 , and the four position information of A, B, C, D is
1/3 times the data track pitch or 2 /
The coarse position information includes cylinder address information, and is recorded at a position shifted by 3 times or 1 time, and one of the cylinder address information in the track cross direction.
The recording end is one of the four patterns of precise position information
A magnetic disk arranged so as to be on the same radius as the recording end
Coarse position information and precise position information
Servo track write
In the method of writing the data, 1/3 peak data track pitch after writing one revolution
To repeat the operation of shifting and writing again
A clock head synchronized with the rotation of the magnetic disk.
The coarse adjustment according to the timing information generated by the
The position information and the precise position information are successively written, and when writing by shifting by 1/3 pitch ,
Once the pattern is written, the pattern is written once
The position information is closed to prevent overwriting, and the precise position information is composed of four pieces of the position information A, B, C, and D.
And, for each of the position information, the position information pattern
Write one time, then close the light gate the next time
Do not overwrite, the next one is DC erase
The next time, DC erase or light
The position in the cross direction of the track where the writing is performed by repeating the operation of closing the
The head feed pitch is once with each of these four position information
It is characterized in that it is shifted for 2 or 2 or 3 times
Servo pattern writing method.