JPS63173220A - Method and device for magnetic recording and reproduction - Google Patents

Abstract

PURPOSE:To realize high track density by recording a data signal in a surface layer part of a magnetic layer, recording a track position signal in a deep layer part of the magnetic layer, obtaining a track position error signal, positioning, the track based thereon, and executing the recording and reproduction. CONSTITUTION:When a gate circuit 11 is switching and connecting a coil 5 of a first head part 2 to an amplifier 13, a reproduced signal is inputted to the amplifier 13, and the amplifier 13 is amplified, and inputted to a servo- pattern detector 14. The servo-pattern detector 14 detects a servo-pattern of a servo-signal, inputs the servo-pattern to a gate circuit 15, and the gate circuit 15 prepares a gate for reproducing each pattern which is shifted by half track each alternately, from its time point. By holding the peak of the respective servo-patterns by this gate, and delaying the peak of the preceding servo-pattern, absolute values of both of them are compared, and a position error signal is generated by a position error signal generator 16. By such a position error signal, a magnetic head 1 is positioned correctly. In such a way, high track density can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing method and apparatus that enable high recording density and high track density using a magnetic recording medium.

[Conventional technology]

With the improvement of recording density in magnetic recording, in the so-called longitudinal recording method in which magnetization is recorded parallel to the film surface of the conventional magnetic recording medium, in order to reduce the influence of the 'l'i Tn field, the magnetic recording medium is made into a thin film. Various methods have been used, such as increasing the coercive force of the magnetic recording medium or increasing the coercive force of the magnetic recording medium.

From the viewpoint of wear resistance and reliability, for high-density recording and reproducing, there are currently only a few heads with playback output values other than heads made of Mn-Zn ring-shaped cores or Ni-Zn ring-shaped cores. There are no heads that fully satisfy the standard values. The biggest problem when using the above head is that the coercive force of the magnetic recording medium has been increased in order to increase the recording density, making saturation recording difficult.
Reducing the gap length of the ring head (which is an essential factor for improving recording density) deteriorates the superimposition recording characteristics and causes an increase in the error rate.

Recently, a pre-erase head 21 shown in FIG. 3 has been proposed as a head that achieves sufficient overlapping recording characteristics even in unsaturated recording and even when the recording/reproducing gap length is small. This is configured such that the erase gap 22 is followed by the recording/reproducing gap 23 in the medium movement direction, and data is first erased in the wide erase gap 22 and then data is recorded in the recording/reproducing gap 23. This is what we do. Both are magnetically separated by non-magnetic N24.

On the other hand, as another method of increasing storage capacity, methods of increasing track density are also being actively researched. For example, in a conventional magnetic recording/reproducing device that uses a flexible magnetic disk as a magnetic recording medium,
As described in detail in Japanese Patent No. 669, if a tracking servo is not used, the track density will be 100 TPI (100 tracks per inch) due to a chucking error when loading the medium into the device or due to temperature and humidity expansion of the medium. ) was considered to be the limit. Recently, as the diameter of flexible magnetic disks has become smaller, the above-mentioned thermal and humidity expansion has been reduced, and devices with track densities of 135T P I have become commercially available due to improvements in the base film, etc., and reduction in chucking errors due to the center hub. It became so. Also, some companies have proposed the possibility of a track density of 200 TPI, but this has not actually been commercialized.

In order to achieve a high track density of 200 TPI or more in a magnetic recording/reproducing device using a flexible magnetic disk, it is necessary to implement a servo system that detects a track position error signal and correctly positions the recording/reproducing head on a desired track. be.

[Problem that the invention seeks to solve]

The above-mentioned conventional magnetic recording and reproducing devices, for example, flexible magnetic disk devices that use flexible magnetic disks as magnetic recording media, use a servo surface servo method similar to that used in hard disk devices due to the interchangeability of flexible magnetic disks. cannot be adopted, so the so-called data surface servo method, that is, the sector servo method is the easiest method to implement.

In this sector servo method, servo information is recorded at the beginning or end of each sector, and this is reproduced by a recording/reproducing head to generate a track position error signal.Based on this, the applied voltage to the head drive actuator or Control the current to follow the desired track.

However, in a floppy disk device, the rotation speed is slow and the number of sectors is not so large, so the number of samples of the track position error signal obtained is small. Furthermore, the number of data bytes per sector needs to be variable depending on the operating system (O8) used.
The sector servo method, which obtains a track position error signal for each sector, has a problem in that the servo tracking characteristics deteriorate as the number of sectors decreases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording/reproducing method and apparatus which eliminates such drawbacks and enables high track density.

[Means for Solving the Problems] The magnetic recording and reproducing method of the present invention records data signals in the surface layer of the magnetic layer of a magnetic recording medium, and records track position signals in the deep layer of the magnetic layer of the magnetic recording medium. The data signal is recorded, a track position error signal is obtained from the track position signal, and the track position is determined based on the track position error signal, while the data signal is recorded and reproduced.

The magnetic recording and reproducing apparatus of the present invention includes a first magnetic recording apparatus that reproduces a track position signal recorded in a deep layer of a magnetic layer of a magnetic recording medium, and erases a data signal recorded in a surface layer of a magnetic layer of the magnetic recording medium. and a second head section that records data signals on the surface layer of the magnetic layer of the magnetic recording medium and reproduces the recorded data signals; and the first head section. error signal detection means for obtaining a track position error signal from the reproduced track position signal; positioning means for positioning the magnetic head on a predetermined track of the magnetic recording medium based on the track position error signal; The present invention is characterized by comprising a recording/reproducing means for recording data signals on the surface layer portion of the magnetic layer of the magnetic recording medium and reproducing the data signals from the surface layer portion through the head portion No. 2.

[Effect]

When increasing the recording density of data signals, the gap length of the head is made smaller in accordance with the recording density, so that the leakage magnetic field does not allow saturation recording to the deep part of the magnetic layer. Therefore, as the recording density increases, data signals are recorded only on the surface layer of the magnetic layer of the magnetic recording medium. From this, it can be seen that if a servo signal, which is a track position signal, is recorded in the deep part of the magnetic layer using a head with a wide gap length, it will not be affected by the recording and reproduction of data signals. Therefore, if data signals are recorded in the surface layer of the magnetic layer of a magnetic recording medium and servo signals are recorded in the deep layer, each sector of the data signal recording layer, which is the surface layer of the magnetic layer of the magnetic recording medium, can be recorded. Unlike the conventional sector servo method in which servo signals are recorded in the servo signal recording layer, which is a deep part of the magnetic layer, the formatting rate is improved.

Further, according to the present invention, the preceding erase head having both the erase head and the recording/reproducing head described above is used as the magnetic head, but since the data portion of each sector is first erased by the erase head, this portion is It is difficult to record servo signals.

However, since servo signals can be recorded in the data section of each sector other than the section to be erased,
The amount of information regarding track position deviation increases. Therefore,
Track following characteristics can also be improved.

〔Example〕

Next, embodiments of the magnetic recording/reproducing method and apparatus according to the present invention will be described.

FIG. 1 is a partial sectional view of a flexible magnetic recording medium for explaining an embodiment of the magnetic recording and reproducing method according to the present invention. In the magnetic recording and reproducing method according to the present invention, first, a servo signal is recorded in a servo signal recording layer 34, which is a deep layer of a magnetic layer 32 of a flexible magnetic disk 31, which is a magnetic recording medium, using a head with a wide gap length. . In the figure, arrow al+a! indicates the magnetization direction of the servo signal.

On the other hand, data signals are recorded and reproduced in a data signal recording layer 33 that is a surface layer of the magnetic layer 32 of the flexible magnetic disk 31. In the figure, arrow bl.

bz, b:+, b4. bs indicates the magnetization direction due to the data signal.

When recording and reproducing data signals, a track position error signal is obtained from the servo signal, and the track position error signal is used to determine the track position while recording and reproducing the data signal.

Next, embodiments of the magnetic recording/reproducing apparatus according to the present invention will be described with reference to the drawings.

FIG. 2 is a configuration diagram showing an embodiment of the present invention. This magnetic recording/reproducing apparatus includes a magnetic head 1 having the same structure as the preceding erase head. This magnetic head consists of a first head section 2 which corresponds to an erase head, and a second head section 3 which corresponds to a recording/reproducing head. The first head part 2 includes a ring-shaped core 4 and a coil 5 made of a high magnetic permeability material.
The second head portion 3 is constructed of a ring-shaped core 6 made of a high magnetic permeability material and a coil 7. 2
The two ring-shaped cores 4 and 6 are arranged on the same track in a direction parallel to the moving direction of the magnetic recording medium with a sufficient distance therebetween, and are magnetically insulated by a non-magnetic layer 8. The gap 9 of the ring-shaped core 4 has a wider gap length than the gap 10 of the ring-shaped core 6, and is set so as to obtain sufficient overlapping recording characteristics.

In the magnetic head l having the above configuration, the first head section 2 is used not only for erasing data signals but also for reproducing servo signals, and the second head section 3 is used for erasing data signals. Used for recording and playback.

The magnetic recording and reproducing apparatus of this embodiment further includes a gate circuit 11 that switches the circuit connected to the coil 5 of the first head section 2, and an erase circuit 12 that sends an erase signal to the coil 5 of the first head section 2. an amplifier 13 that amplifies the signal from the first head section 2; a servo pattern detector 14 that detects a servo pattern from the signal from the amplifier 13; a gate circuit 15 that creates a gate; a position error signal generator 16 that generates a position error signal according to the signal;
, a controller 17 that generates a control signal from a position error signal, a head actuator 18 that operates based on the control signal, and a recording and reproducing circuit that is connected to the coil 7 of the second head section 3 and that records and reproduces data signals. It is equipped with 19.

The flexible magnetic disk 31, which is a magnetic recording medium in the figure, is, for example, a Ba-ferrite floppy disk.

Next, the operation of this magnetic recording/reproducing device will be explained.

In the flexible magnetic disk 31, a servo signal having a servo pattern is recorded in advance in a servo signal recording layer 34, which is a deep layer of the flexible magnetic disk 31, as shown in FIG. It is assumed that each servo pattern is recorded alternately at positions shifted by half a track.

When the gate circuit 11 switches and connects the coil 5 of the first head section 2 to the amplifier 13, the signal reproduced by the head section 2 is input to the amplifier 13.

The amplifier 13 amplifies this signal and inputs it to the servo pattern detector 14. The servo pattern detector 14 detects a servo pattern of a servo signal. This detection is performed, for example, by the usual method of recognizing the address mark as a missing pit, or by forming a DCO and recognizing it to detect that it is a servo pattern. Then, the servo pattern detector 14 inputs the detected servo pattern to the gate circuit 15. The gate circuit 15 has a servo pattern detected by the servo pattern detector 14.
Gates are created for reproducing each pattern alternately shifted by half a track from the point detected in . This gate holds the peak of each servo pattern, delays the peak of the preceding servo pattern, compares the absolute values of the two, and generates a position error signal in the position error signal generator 16.

Based on this position error signal, the controller 17 drives the head actuator 18 to correctly position the magnetic head 1 on a desired track.

Data recording and reproduction can be performed using the head section 3 of the magnetic head 1 and the recording and reproduction circuit 19.

When the first head section 2 is used as an erase head to erase data signals, the gate circuit 11 is connected to the coil 5.
is switched and connected to the erase circuit 12.

Furthermore, as a servo pattern, in addition to comparing the absolute value by holding the peak value of the output of the servo pattern detector,
It is also possible to use a method of alternately arranging servo patterns with different frequencies, detecting both using bandpass filters corresponding to the respective frequencies, and performing peak hold and comparing to create a position error signal.

〔Effect of the invention〕

As explained above, the present invention improves the formatting rate because the servo signal is recorded deep in the magnetic recording medium, compared to the conventional technology that detects the servo pattern with a recording/reproducing head to obtain a track position error signal. can.

In addition, since the track position error signal is obtained from the servo signal using a circuit system that is completely separate from the recording/reproducing head, the track position error signal is always obtained even when seeking, and the magnetic head can be positioned on the desired track. It is also possible to improve credibility.

Further, according to the present invention, track following can be performed without interfering with the erase function of the first head section.

Furthermore, the present invention has made it possible to further improve the performance of the servo and to realize a magnetic recording/reproducing device with high recording density and high track density.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a flexible magnetic disk for explaining an embodiment of the magnetic recording/reproducing method according to the present invention; FIG. 2 is a configuration diagram showing an embodiment of the magnetic recording/reproducing apparatus according to the present invention; FIG. 3 is a schematic diagram of the advance erase head. 1... Magnetic head 2... First head section 3... Second head section 4.6... Ring-shaped core 5.7... Coil 8... ...Nonmagnetic layer 9.10...Gap 11...Gate circuit 12...Erasing circuit 13...Amplifier 14...Servo pattern detector 15...・Gate circuit 16...Position error signal generator 17...Controller 18...Hend actuator 19...Recording/reproducing circuit 31...Flexible magnetic disk 32... ...
・Magnetic layer 33... Data signal recording layer 34... Servo signal recording layer Agent Patent attorney Yoshiyuki Iwasa Figure 1 % 2 Figure 11-Chi Moving direction of the beam body Figure 3

Claims (2)

[Claims] (1) recording a data signal in the surface layer of the magnetic layer of a magnetic recording medium, recording a track position signal in the deep layer of the magnetic layer of the magnetic recording medium, and obtaining a track position error signal from the track position signal; A magnetic recording and reproducing method for recording and reproducing the data signal while performing track positioning based on this track position error signal. (2) a first head unit that reproduces a track position signal recorded in a deep layer of a magnetic layer of a magnetic recording medium and erases a data signal recorded in a surface layer of a magnetic layer of said magnetic recording medium; a magnetic head that records a data signal on a surface layer of a magnetic layer of a magnetic recording medium and a second head section that reproduces the recorded data signal; and the track position that is reproduced by the first head section. error signal detection means for obtaining a track position error signal from the signal; positioning means for positioning the magnetic head on a predetermined track of the magnetic recording medium based on the track position error signal; A magnetic recording/reproducing device comprising: recording/reproducing means for recording data signals on a surface layer portion of a magnetic layer of the magnetic recording medium and reproducing data signals from the surface layer portion.