JP2639064B2 - Magnetic disk and magnetic disk device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk and a magnetic disk device used for performing information processing.

2. Description of the Related Art In recent years, a magnetic disk device has been increased in capacity, and a so-called sector servo system in which each data track is divided and a position reference signal is recorded as a head positioning system has begun to be used. According to this method, servo signals are not recorded only on the servo surface as in the prior art, but servo sectors are provided on all data surfaces, and position signals read from the servo surface are provided. To
The positioning control of the head is performed by superimposing the position signal of the servo sector on the data track.

FIG. 3 shows a data surface of a magnetic disk using the sector servo method. The recording area on the data surface, that is, between the concentric circles 2 and 3 shown in the figure, is composed of a data sector 4 and a servo sector 5. The position signal information of the servo sector 5 is used as a reference signal when positioning the magnetic head on the corresponding recording track. 5a indicates a defective servo sector described later, and 5b indicates a normal servo sector.

FIG. 2 is an enlarged view of a broken line portion of the recording area of the disk 1 shown in FIG. 1, and shows data and servo magnetic heads (not shown) fixed by rotation of the magnetic disk. On the other hand, the recording tracks 6 and 7 move in the direction indicated by the arrow. Information data and a position information signal are recorded in the data sector 4 and the servo sector 5.

However, in this case, as shown in FIG. 2, if there is a defect 8 in a certain servo sector 5a, the reference position indicated by the position information signal in that servo sector is the actual center of the recording track 7. It deviates from the position, and the servo system operates as if a positioning error has occurred in the magnetic head.
Off-track occurs, and the reliability of the recorded / reproduced data cannot be ensured. Normally, the sector servo signal is recorded after the magnetic disk is fixed to the rotating shaft, so if a defect is found in the servo sector, the sector servo signal must be rewritten or the magnetic disk itself needs to be replaced, reducing productivity. I do. That is, since the servo signal is recorded not only on the servo surface but also on the data surface, the same signal quality is required on the entire data surface as on the servo surface, and the specification for defects becomes strict.

Means for Solving the Problems In order to solve this problem, the present invention provides a magnetic disk in which, when a defect occurs in a servo data storage area, a data storage area adjacent to the defective servo data storage area is provided. A defect indication signal was recorded between sectors. Also,
When the magnetic disk device reads the defect instruction signal,
There is control means for preventing position control of the magnetic head.

Operation With this configuration, even if there is a defect in the servo data storage area, the existence of the defect can be quickly recognized,
In addition, the servo data read from the defective servo data can be invalidated to prevent malfunction.

Hereinafter, a magnetic disk and a magnetic disk device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
In FIG. 2 which is a plan view showing the data sector and the servo sector already described, if a defect 8 is found in the inspection after writing the servo sector position information signal, the erase zone 9a, 9b of the servo sector 5a on the recording track 7 is recorded. The specific defect indication signals 10a and 10b are recorded. Next, when reproducing the servo sector signal, the defect indication signal 10a or 10b
Is detected, a malfunction due to a defect in the servo sector can be avoided by, for example, disabling the servo circuit with the position information signal from the servo sector.

FIG. 1 is a configuration diagram illustrating a magnetic disk drive according to one embodiment of the present invention. In FIG. 1, a servo signal read from a servo surface of a magnetic disk by a servo head 102 is amplified by a servo amplifier 21 and converted into a servo surface position deviation signal 22a by a servo surface position signal detection circuit 22. The signal 23b is separated. The timing generation circuit 14 outputs to the defective sector detection circuit 13 a timing signal 14c for detecting a defect instruction signal of the erasing zone 9a, 9b in FIG. 2 from the clock signal 23b, and outputs the timing signal 14c of FIG. A timing signal 14d for detecting position information is sent to the data plane position signal detection circuit 12. On the other hand, the data signal read from the data surface of the magnetic disk by the data head 101 is amplified by the data amplifier 11 and sent to the data surface position signal detection circuit 12, the defective sector detection circuit 13, and the data processing circuit (not shown). You.
In the data plane position detection circuit 12, the position information signal from the data plane is converted into a position signal proportional to the amount of displacement of the data head at the output of the timing generation circuit 14d and sent to the data plane A / D converter 15. Is done. Data plane A / D converter 15
Converts the analog displacement signal obtained by the data plane position signal detection circuit 12 into a digital signal, and sends the data plane displacement information 15e to the processing circuit 16.

The defective sector detection circuit 13 outputs a defect indication signal 10a, 1 in the area of the erase zone 9a, 9b by the output of the timing generation circuit 14c.
0b is detected, and a signal 13f indicating the presence or absence of a defect is output to the processing circuit 16.

Further, the servo surface position shift signal 22a detected by the servo surface position signal detection circuit 22 is converted into an analog servo surface position shift signal into a digital signal 24g by a servo surface A / D converter 24, and is sent to the processing circuit 16. Is entered. The processing circuit 16 reads the output signal 13f of the defective sector detection circuit 13, and if it is not a defective sector, the servo surface position deviation signal 24g of the servo surface A / D converter 24 and the data of the data surface A / D converter 15 Subtracts the surface displacement signal 15e and converts the relative displacement signal 16h to the D / A converter 2
Send to 5. The D / A converter 25 converts the digital signal of the relative position shift signal 16h between the data surface and the servo surface position information into an analog signal, and outputs the analog signal to the adder. In the adder 26, the servo surface position shift signal 22a and the relative position shift signal 16h are added and sent to a servo circuit unit 27 including position compensation and the like, and the voice coil motor 28 is driven to perform positioning control.

Here, when the data head 101 passes through the defective sector 5a, the processing circuit 16 outputs the output signal 13 of the defective sector detection circuit 13.
When f is read and a defect sector is detected, the relative position shift signal 16h between the data surface position information and the servo surface position information based on the data surface position signal due to the defect is not output. Thus, there is no possibility that the voice coil motor 28 is erroneously driven by the data surface position information signal from the defective servo sector, and correct positioning can be performed.

In this embodiment, the microcomputer is used as the processing circuit. However, it goes without saying that the configuration can be made only by hardware. Although two defective data storage areas 9a and 9b are used for the defective sector, at least one of them can be detected, but the present embodiment is more effective in consideration of the size of the defect and the like. . Also, the defect indication signal 10
If a and 10b are signal patterns that do not occur in the recording / reproducing data pattern, a defective sector can be detected by creating a signal pattern detection circuit in the data processing circuit.

Effect of the Invention As described above, according to the present invention, when a defect has occurred in a servo data storage area, a defect indication signal is recorded between the servo data storage area having the defect and an adjacent data storage area. As a result, the servo data storage area having the defect can be reliably and promptly recognized, and the servo control can be reliably performed. Further, it is not necessary to rewrite the servo data or replace the magnetic disk as in the related art, thereby improving the productivity of the magnetic disk and reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of a magnetic disk device according to the present invention, FIG. 2 is a plan view showing data sectors and servo sectors of the magnetic disk, and FIG. 3 is a plan view showing a data surface of the magnetic disk. 1 ... magnetic disk, 4 ... data sector, 5 ... servo sector, 5a ... defect servo sector, 6, 7 ... recording track, 8 ... defect part, 9 ... erasing zone, 10 ... defect indication signal, 12 ... Data surface position signal detection circuit, 13 ... Defective sector detection circuit, 14 ... Timing generation circuit, 22 ... Servo surface position signal detection circuit.

Claims (2)

(57) [Claims] 1. A magnetic storage device comprising: a data storage area divided into a plurality of sectors and storing data; and a servo data storage area provided between the sectors of the data storage area and storing servo data. A magnetic disk, wherein when a defect is present in a servo data storage area, a defect indication signal is recorded between a servo data storage area having the defect and a sector of an adjacent data storage area. . 2. A magnetic disk according to claim 1), a magnetic head for reading data stored on said magnetic disk, and a position of said magnetic head according to servo data read from said magnetic head. A magnetic disk drive comprising: position control means for performing control; and control means for preventing position control by the position control means when a defect instruction signal is read from the magnetic head.