JPH0495272A - Magnetic disk medium - Google Patents

Abstract

PURPOSE:To execute the sector servo-system and to enhance the efficiency of recording density by providing a dead track on a boundary of a zone of a zone bit recording system. CONSTITUTION:Between tracks whose bit rate is varied by a zone bit recording system, a dead track for recording no data is provided. That is, servo-sector 11 is constituted of servo-IDs (4a-c,5a-c) and servo-data (6a-c,7a-c), and in a boundary of a zone, a dead track 1 is provided. Also, as for the tracks for placing the dead track 1 between, since the arrangement of sectors is changed, a position of the servo-sector is shifted. Accordingly, the servo-IDs 4a, 5a and the servo-data 6c, 7a being adjacent to the dead track 1 are protruded by half onto the dead track 1. In such a way, an output of the servo-data is read, and a position of the head is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk medium, and particularly to a format of a magnetic disk medium using a zone bit recording method and sector servo.

[Conventional technology]

Generally, in a magnetic disk drive, a magnetic head performs recording and reproduction on a magnetic disk medium that rotates at a constant rotational speed. Since the bit rate of recording and reproduction by this magnetic head is constant, the recording density is inevitably higher on the inner tracks of the medium than on the outer tracks. In magnetic tape media, the higher the recording density, the greater the capacity, so recording is performed at as high a recording density as possible. Therefore, if the recording density at the innermost circumference is set to the French limit value, the recording density at the outermost circumference will be quite similar. In other words, since the recording density is set according to the innermost circumference, even though the outer circumference has a large capacity, it is used at a low recording density, resulting in a loss in capacity.

For this reason, a method called a zone bit l recording method has been proposed in recent years. This method is a method in which the recording and reproduction, particularly the recording bit rate, is made stepwise higher on the outer circumference than on the inner circumference, thereby increasing the recording density on the outer circumference and increasing the storage capacity.

[Problem to be solved by the invention]

Although the above-described zone pit recording method basically poses no problem in practice, a problem occurs when the sector servo method is used as positioning means by closed-loop control of the head. That is, in the sector servo system, a servo sector is provided on a track, servo data is formed there by a method such as shifting the rack pitch by 1'/2), and positional deviation is detected from a monitor signal from a magnetic head. In the conventional general recording method, sectors are connected from the inner track to the outer track, and lost servo data can be linked from the inner track to the outer track. However, in the zone pit recording method, if the bit rates of adjacent tracks change, the positional relationship of the sectors will be distorted. Therefore, the servo data of one track may protrude into the data sector of the adjacent track.

[Means to solve the problem]

In order to solve the above problems, the magnetic disk drive of the present invention uses a zone pit recording method to provide dead tracks on which no data is recorded between tracks where the bit rate changes.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

The magnetic tape medium of this embodiment will be explained with reference to FIG. This medium 10 is divided into four saws 7 so that the bit rate can be changed in four stages. The shaded area is the servo sector 11 in which servo data is recorded. A data section 12 is formed in areas other than the servo sector 11.

Next, features of the present invention will be explained with reference to FIG. 2, which is an enlarged view of section A in FIG. 1.

Servo sector 11 has servo ID (4a"c, 5a"
-c) and servo data (6a''-c, 7a
"-c). A chit track l is provided at the boundary of the zone. This dead track has no data section at all, and its width is the same as a normal track. Since the arrangement of sectors in the tracks on both sides has been changed, the position of the servo sector is shifted.Therefore, the servo sector I adjacent to the dead track l
Half of D4a, 5a and servo data 6c, 7a protrude above dead track 1.

FIG. 3 is an enlarged view of the vicinity of track n-12a. Head 8 reads servo ID4a and servo ID4b, detects servo information, takes timing from it, and outputs each output data of servo data 2 6b and servo data 3 6c ■2
・Read V3.

By calculating the calculation formula on the vertical axis in FIG. 4 and referring to the graph 7, it is possible to know how far the position of the head 8 deviates from the track n-12a, and by correcting the position, the head 8 can be moved to the track n-12a. - Can be placed correctly on 12a. Head 8 position is 0 towards dead track
．． If there is a deviation of 5 tracks or more, servo data 2 6
Output (2) of b is zero, but since half of the servo data 6C is projected to dead track 1, output (2) of servo data 36c can be read, and the position of the head 8 can be corrected.

This operation is the same as the positioning operation of the conventional sector servo, but since there is a dead track 1 in the present invention, when the head 8 is on track with this track 1, different processing is required. In other words, if there is a head 8 as shown in FIG. 5, the head 8 will receive the servo ID 4a and the servo ID 5a, so it cannot determine which of the servo cheater c and the servo data 7a should be referred to.

In this embodiment, identification is performed by changing the frequency of the servo ID between adjacent saws 7. That is, track 2
When positioning at point a, the frequency used in servo D4a=c is recognized as the servo ID. In order to control in this way, the head 8 does not recognize the servo ID'5a as a servo ID even if it receives it, but recognizes the servo ID4a as a regular servo ID, receives the servo data 6c, and positions it on the track 2a.

Furthermore, with the provision of the chit track 1, one more process is required. In general, magnetic disk drives perform positioning by using a combination of coarse positioning using an oven loop and fine positioning using a closed loop.

The processing described above is related to fine positioning, and the processing related to coarse positioning will be described here.

Generally, in coarse positioning, in order to move the head from the current track to the target track, the distance is determined by increasing the track pitch to the difference between the current track number and the target track number. Therefore, in the configuration of the present invention, it is necessary to take Ted tracks into consideration. In other words, in order to move across two zones, it is controlled to move an additional one track, and in three zones, it is controlled to move an additional two tracks. In this embodiment, since the width of the dead track is the same as that of a normal track, control is easy because it can be realized by simply adding an integer to the number of moving tracks. However, since the width of this dead track is to prevent the protruding servo information from protruding into the data area of the adjacent track, it does not need to be the width of one track.

C Effects of the Invention As explained above, the present invention enables the sector servo method in the zone pit recording method by providing a ted track at the boundary of the sawn in the zone pit recording method.
This has the effect of increasing the efficiency of recording density.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a magnetic tissue media according to an embodiment of the present invention, FIG. 2 is an enlarged view of section A in FIG. 1, and FIG. 3 is an operational explanatory diagram showing the positions of the magnetic tissue media and the head. Fig. 4 is a graph showing the correlation between the head position and the processed signal, and Fig.
The figure is an explanatory diagram of the operation when the head is on a dead track. 1...Dead track, 2a~c, 3a~C・
...Truck, 4a-c, 5a-C...
Servo ID, 6a-c, 7a-C...Servo data. Figure M1 Figure V3 Figure 4 Figure S

Claims (1)

[Claims] A magnetic disk medium having a plurality of zones recorded at different bit rates on the medium and servo information formed in sectors, the magnetic disk medium having a data-free track between the plurality of zones. .