JPH02236873A - Magnetic disk and magnetic disk device - Google Patents

Abstract

PURPOSE:To preclude malfunction by forming an area where data indicating that a servo data storage area has a defect is stored adjacently to the servo data storage area and providing a means which inhibits position control over a magnetic head at the time of reading the data indicating the defect. CONSTITUTION:Data sectors 4 and servo sectors 5 are provided in a storage area on a data surface, i.e. between concentric circles 2 and 3, recording information is recorded in the sectors 4, and position signal information is recorded in the sectors 5. The position signal information on the servo sectors 5 is used as a reference signal when the magnetic head is positioned in a corresponding track. When a defect is found by inspection after the servo sector position information signal is written, specific defect signals 10a and 10b are recorded in erasure zones 9a and 9b of servo sectors 5a on its recording track. When a servo sector signal is reproduced and the signals 10a and 10b are detected, a servo circuit is not operated with the position information signal. Malfunction due to the defect of a servo sector is evaded by this constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic disk and a magnetic disk device used in information processing.

2. Description of the Related Art In recent years, magnetic disk drives have increased in capacity, and a so-called sector servo method, in which each data track is divided and a position reference signal is recorded, has begun to be used as a head positioning method. (For example, Japanese Patent Laid-Open No. 51-81603) In this method, servo signals are not recorded only on the servo surface as in the past, but servo sectors are also provided on all data surfaces, and position signals read from the servo surface are recorded. The head positioning control is performed by superimposing the position signal of the servo sector on the data track.

FIG. 3 shows the data surface of a magnetic disk using the sector servo system. Recording area on the data surface, i.e. concentric circle 2 shown in the diagram
and 3 consists of data sector 4 and servo sector 5,
Recorded information is recorded in the data sector 4, and position signal information is recorded in the servo sector 5. This position signal information of the servo sector 5 is used as a reference signal when positioning the magnetic head on the corresponding recording track. Note that 5a indicates a defective servo sector, which will be described later, and 5b indicates a normal servo sector.

FIG. 2 is an enlarged view of the broken line area of the recording area of the disk 1 shown in FIG. On the other hand, the recording tracks 6 and 7 move in the direction of the arrow shown. Data sector 4 and servo sector 5 have
Information data and position information signals are recorded.

Problems to be Solved by the Invention In this case, as shown in FIG. 2, if a certain servo sector 5a has a defect 8, the reference position indicated by the position information signal in that servo sector may not be the actual center of the recording track 7. This causes the servo system to operate as if there was a positioning error in the magnetic head.
Off-track occurs, making it impossible to ensure the reliability of recorded and reproduced data. Normally, sector servo signals are recorded after the magnetic disk is fixed to the rotating shaft, so if a defect is found in the servo sector, it will be necessary to rewrite the sector servo signal or replace the magnetic disk itself, which will reduce productivity. do. That is, since servo signals are recorded not only on the servo surface but also on the data surface, all data surfaces are required to have the same signal quality as the servo surface, and specifications for defects become stricter.

Means for Solving the Problem In order to solve this problem, the present invention provides a magnetic disk with an area adjacent to the servo data storage area for storing data indicating that the servo data storage area has a defect. The magnetic disk device includes a control means that prevents position control of the magnetic head when data indicating that the servo data storage area has a defect is read.

With this configuration, even if there is a defect in the servo data storage area, the servo data read therefrom is invalidated to prevent malfunction.

Embodiment A magnetic disk and a magnetic disk device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 2, a plan view showing the data sector and servo sector described above, if a defect 8 is found in the inspection after writing the servo sector position information signal, a specific Defect indication signals 10a and 10b are recorded. Then, when reproducing the servo sector signal, this defect indication signal 10a
1 or 10b is detected, malfunctions due to defects in the servo sector can be avoided by, for example, preventing the servo circuit from operating with the position information signal from the servo sector.

FIG. 1 is a configuration diagram illustrating a magnetic disk device according to an embodiment of the present invention. In FIG. 1, a servo signal read from the servo surface of a magnetic disk by a servo head 102 is amplified by a servo amplifier 21, converted into a servo surface position deviation signal 22a by a servo surface position signal detection circuit 22, and a clock signal 23b is separated.

The timing generation circuit 14 outputs a timing signal 14c to the defective sector detection circuit 13 for detecting the defect indication signals of the erase zones 9a and 9b in FIG. A timing signal 14d for position information detection is sent to the data surface position signal detection circuit 12. On the other hand, data head 1
The data signal read from the data surface of the magnetic disk by 01 is amplified by the data amplifier 1l and sent to the data surface position signal detection circuit 12, defective sector detection circuit 13, and data processing circuit (not shown). In the data surface position signal detection circuit 12, the position information signal from the data surface is
The output of the timing generation circuit 14d is converted into a position signal proportional to the amount of positional deviation of the data head, and the data surface A/
The signal is sent to the D converter 15. The data surface A/D converter 15 converts the analog positional deviation signal obtained by the data surface position signal detection circuit 12 into a digital signal, and sends data surface positional deviation information 15e to the processing circuit 16.

The defective sector detection circuit 13 includes a timing generation circuit 14c.
, the defect indication signals 10a . 10b is detected and a signal 13 indicating the presence or absence of a defect is detected.
f is output to the processing circuit 16.

Further, the servo surface position deviation signal 22a detected by the servo surface position signal detection circuit 22 is transmitted to the servo surface A/D converter 24.
Then, the analog servo surface position deviation signal becomes digital signal 2.
4g and input to the processing circuit 16. The processing circuit 16 reads the output signal 13f of the defective sector detection circuit 13, and if it is not a defective sector, reads the servo surface position deviation signal 24g of the servo surface A/D converter 24 and the data surface A/D.
The data plane positional deviation signal 15e of the converter 15 is subtracted, and a relative positional deviation signal 16h is sent to the D/A converter 25. The D/A converter 25 converts the digital signal of the relative positional deviation signal 16h between the data surface and the servo surface position information into an analog signal, and outputs the analog signal to the adder 26. The adder 26 outputs the servo surface position deviation signal 22a and the relative position deviation signal 1.
6h is added to the servo circuit section 27 including position compensation, etc.
positioning control is performed by driving the voice coil motor 28.

Here, when the data head 101 passes the defective sector 5a, the processing circuit 16 reads the output signal 13f of the defective sector detection circuit 13, and if it detects that it is a defective sector, the data surface is detected by the position signal of the data surface due to the defect. The relative positional deviation signal 16h between position information and servo surface position information is not output.

In this way, there is no risk that the voice coil motor 28 will be erroneously driven by the data plane position information signal from the defective servo sector, and correct positioning can be performed.

In this embodiment, a microcomputer is used as the processing circuit, but it goes without saying that a configuration using only hardware is possible. In addition, although two defective data storage areas 9a and 9b are used for the defective sector, it is possible to detect it if there is at least one of them, but considering the size of the defect, etc., this embodiment is more effective. It is. Moreover, the defect indication signal 10a. If 10b is a signal pattern that does not occur in the recording/reproduction data pattern, defective sectors can also be detected by creating a signal pattern detection circuit using a data processing circuit.

Effects of the Invention As explained above, according to the present invention, when a defect is found in a servo sector section, it is recorded that there is a defect in the sector servo signal section, and when the defective signal is detected at the time of reading, the servo sector is Since the position information signal from the controller is disabled and operation caused by defective servo sectors is prevented, it is no longer necessary to rewrite servo sectors or replace magnetic disks as in the past, improving productivity of magnetic disks and reducing manufacturing costs. It is possible to provide a magnetic disk and a magnetic disk device, which has great practical effects. Further, since data indicating that the sector is defective is stored adjacent to the defective sector, recognition of the sector to be invalidated becomes more reliable than when the sector is not adjacent to the defective sector.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a magnetic disk device according to the present invention, FIG. 2 is a plan view showing a data sector and servo sector of a magnetic disk, and FIG. 3 is a plan view showing a data surface of a magnetic disk. 1...Magnetic disk, 4...Data sector, 5...
・Servo sector, 5a...Defective servo sector, 6, 7
. . . recording track, 8 . . . defective part, 9 . . . erase zone, 10 . ...Timing generation circuit, 22...Servo surface position signal detection circuit. Figure Figure 1 ---f' 4 people

Claims (1)

[Scope of Claims] 1) a data storage area that is divided into a plurality of sectors and stores data; a servo data storage area that is provided between sectors of the data storage area and stores servo data; A magnetic disk provided between the data storage area and the servo data storage area, wherein the adjacent servo data storage area has a defect. 2) A magnetic disk according to claim 1), a magnetic head that reads data stored on the magnetic disk, and a position control of the magnetic head according to servo data read from the magnetic head. a position control means; when the data read from the magnetic head is data indicating that the servo data storage area has a defect;
A magnetic disk device comprising: control means for inhibiting position control by the position control means.