JPS5984382A - Magnetic disk device controlling system - Google Patents

Abstract

PURPOSE:To enable stable operation by changing the inversion interval of a position bit signal of servo information according to change of angle made by the track and head on a magnetic disk. CONSTITUTION:A positioning mechanism 30 positions a head 7 at a specified track on a magnetic disk 1 from a microprocessor 36 through a controlling mechanism 32. The program of the processor 36 is stored in a main memory 39, and operation is performed according to the program. Radial position on the disk 1 and the corresponding optimum magnetizing inversion width are stored in a pair in an ROM35. When the optimum magnetizing inversion width of position bit corresponding to a position at a time when the head 7 is positioned at some point on inner periphery - outer periphery on the magnetic disk 1 is read out from the ROM35 and the position bit is read, writing is made by this value. Consequently, gain of positional signal does not change even when the position of the head changes, and stable operation can be effected.

Description

[Detailed description of the invention] [Field of application of the invention] What is the invention? The present invention relates to a control method for a magnetic disk device, and particularly to a control method suitable for a magnetic disk device having a rotary actuator.

[Prior art]

A rotary actuator (also referred to as a rotary actuator) is easier to miniaturize than a so-called linear actuator that moves in a straight line, and has recently become widely used in small magnetic disk drives.

Figure 1 shows the rotary actuator il! , (, is a plan view showing the main points. The head par 5 moves 161 around the two-piece rotary actuator pivot center 3 to move the magnetic head (hereinafter simply referred to as "head") 7 to a desired track on the magnetic disk 1. The rotator is controlled by a voice fill motor consisting of a poiscoy A/4 integrated with the head par 5 and a magnet 6.

The movement of the head 7 draws an arc centered on the pivot center 5, as shown by the broken line in FIG. Therefore, the angle (Y) between the track on the magnetic disk 1 and the gap between the head 7
AW angle) changes depending on the position of the head 7.

FIGS. 2 and 3 show this situation, and FIG. 2 shows the case where the head 7 is near the outer periphery of the magnetic disk 1.
FIG. 3 is an enlarged view showing the case where the head 7 is located at the inner peripheral portion of the magnetic disk l. As is clear from both figures,
The angle (YAW angle) 10 formed between the track 13 on the magnetic disk 1 and the gap 12 of the head 7 changes greatly depending on the position of the head 7, and as a result, the track width as seen from the head 7 changes greatly.

Next, let's clarify a little bit about servo information.

FIG. 4 shows conventionally used servo information.

Servo information is generally used to synchronize demodulation circuits.
It consists of an information 5YNC bit (hereinafter simply referred to as rsYNc bit) 21 and a position bit representing position information. Also, the servo track is ODD (odd number)
It is composed of a track 40 and an EVEN (even number) track 41, and an ODD position bit 20 and an EVEN position bit 23 are recorded on each track.

If the head 22 is located astride the ODD trunk 40 and the EVEN rack 41 as shown in FIG.
4. That is, 5YNC Biy)
21. ODD position hit 2o.

This is a signal consisting of EVEN position bits 23.

5YNC pin) 21 is used to synchronize the above-mentioned θ1t<, recovery circuit. Specifically, P L L (ph
aFIeLock: [, oop) Synchronize the circuit to 5YNC bit 21, ODD position bits 20 to 0
DI) ODD gate pulse 2 to obtain position information 27
5 and an EVEN gate pulse 20 for obtaining an EVEN position information meter 28 from the EVEN position bit 23. 0DI) Location information 27. The EVEN position tlJ information 28 is obtained by peak-holding the values when each gate is open. Servo head 22 digit 1
(2) The signal 29 is obtained by taking the difference between the ODD position information 27 and the EVEN position information 28. The servo control system controls the position signal 29 to be O when positioning the head on the track.

The problem with the magnetic disk device control method described above is that the YAW of the head inside and on the outer periphery of the magnetic disk is
This is a change in the successive signal due to a change in the track width due to a change in the angle, and a change in the flying height of the head based on the difference in JfJ speed between the inside and the outer circumference of the magnetic disk. Since the former is generally a non-linear change and the latter is a linear change, the change in the readout signal based on a combination of both changes is also generally a non-linear change. In the case of a normal linear actuator, only the above-mentioned linear change occurs, and the position signal 29 when the 5EEK operation is performed has a trapezoidal shape where the outer periphery is small and the inner periphery is large, as shown in FIG. This causes a problem in that the gain differs between the inner and outer circumferences, making it difficult to control the positioning of the head.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-mentioned problems in the conventional rotary actuator type magnetic disk drive control system, and to prevent the position signal from changing even when the head position changes. An object of the present invention is to provide a magnetic disk device control method that allows stable operation without changing the gain of the magnetic disk device.

[Summary of the invention]

The gist of the present invention is that in a magnetic disk drive rt that has a rotary actuator that controls the positioning operation of a head using servo information recorded on a servo surface, a The present invention is characterized in that the inversion interval of the position bit signal of the servo information is changed.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 7(2), a3) shows an embodiment of the present invention, and FIG.
DD or EVEN position bits are written on the same outer periphery, and (2) in FIG. 7 shows ODD or EVEN position bits. The optimum magnetization reversal width 50A of the positive control bit on the inner circumference is that of the position bit on the outer circumference 50B
Although it is larger, it is distinctive in that it does not increase linearly from the outer circumference to the inner circumference.

As mentioned above, FIG. 6 shows the optimum magnetization reversal II of the position bit depending on the radial position on the magnetic disk 1! f11
FIG. 2 is a configuration diagram showing an embodiment of a servo information writing device that writes data by changing the servo information. In the figure, 30 is a positioning circuit; 32 is a positioning control circuit; 34 is a recording/reproducing circuit for the head 7;
36 is Micro Pro Seven, 35 is ROM, and 39
is the main memory at position 0 (6) The determining mechanism 30 is controlled by the microprocessor 36 via the positioning control circuit 32 to position the head 7 at a predetermined track on the magnetic disk 1. - The regeneration circuit 34 is also controlled by the microprocessor 36.

The program of the front Ht microprocessor 36 is stored in the main memory 39, and operates according to the program. The ROM 35 stores pairs of radial positions on the magnetic disk 1 and the corresponding optimum magnetization reversal widths.

The operation of the present embodiment apparatus performed as described above is such that when the head 7 is positioned anywhere from the inner circumference to the outer circumference on the magnetic disk l, the optimum position bit corresponding to that position is determined. The magnetization reversal width is successively read out from the ROM 35, and when writing position bits, writing is performed according to this value.

It goes without saying that the values of ir:f and suitable magnetization reversal width to be written in the ROM 35 may be either calculated values or measured values.

〔Effect of the invention〕

As described above, according to the present invention, the head positioning operation is controlled by the servo information recorded on the rib surface.
In a magnetic disk device equipped with a rotary actuator that performs ++, the inversion gap of the position bits of the servo information is changed according to the change in the angle between the track of the magnetic disk and the head. This has the remarkable effect that it is possible to realize a magnetic disk drive control system that does not change the gain of the position signal even if the head position changes and allows stable operation.

[Brief explanation of the drawing]

Figure 1 is a plan view showing an overview of the rotary actuator, Figures 2 and 3 are diagrams explaining changes in the YAW angle, Figure 4 is a diagram without servo information, and Figures 5 and 6 are diagrams showing changes in the YAW angle. A diagram showing a continuous output signal corresponding to FIG. 4, No. 7 (1) and (2) are diagrams showing an embodiment of the present invention, and FIG. 8 is a diagram showing an embodiment of a servo information writing device. 1: Magnetic disk, 7: Head, 10: YAW angle,
13 Nidrak, 20.23: Position bit, 2
1: 5YNC bit, 30: Positioning lever L52: Positioning control circuit, 35=ROM, 36: Microprocessor, 39: Main memory. Agent Patent Attorney Masaru Isomura
(,. Figure 1 Figure 2 Figure 6 Figure 8 Figure 0, -10 0.-1°→ →
size leaf size →zu
tun

Claims (1)

[Claims] In a magnetic disk drive having a rotary actuator that controls the positioning operation of a magnetic head using servo information recorded on a servo surface, the position of the servo information is adjusted according to changes in the angle between the track on the magnetic disk and the magnetic head. A magnetic disk device control method characterized by changing the inversion interval of a bit signal.