JPH0689546A - Controller for positioning magnetic head - Google Patents

Abstract

PURPOSE:To stably read data even when an off track exists by offsetting forcedly a head when the off track exixts, reading out an ID part, storing a sector address and detecting the sector based on stored data. CONSTITUTION:When the read of the ID part becomes difficult due to the off track, a control part 19 supplys magnetic head positional deviation information, a magnetic head positional deviation control part 18 makes the magnetic head 11 forcedly offset, and the read of the ID part is made possible. Then, the sector address of the ID part is stored in an ID judgment part 16, and the forced offset of the head 11 is released. Meanwhile, by a counter 15, the number of sector pulse is counter, and a target sector is detected, and the data from the sector is read out through a read-out part 12. Then, when the off track exists, the data is read out stably, and the reliability of the device is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head positioning control device used in a magnetic disk device for positioning a magnetic head when reading information written in a storage medium.

[0002]

2. Description of the Related Art When a magnetic disk (storage medium) is initialized, a magnetic disk device has address information for each sector (referred to as an ID section) for each data block unit (this is called a sector) of the storage medium. Write).

When reading the information written in the storage medium, the conventional magnetic disk device first searches for the target ID section, confirms that the read ID section is the target ID section, and then reads the data. Is being read.

[0004]

In the conventional magnetic disk drive as described above, when the desired ID portion is searched for, the magnetic head is positioned and the position where the ID portion is actually written. If there is a positional deviation of the storage medium in the radial direction (this is referred to as off-track), it becomes difficult for the magnetic head to stably read the ID part, so that even if the data is normal, there is no positional deviation. Even if it is written in such a state, it has a drawback that a problem occurs in the data read operation.

Also, by forcibly shifting (offseting) the magnetic head in the radial direction of the storage medium, I
Even if the D section is read, it is difficult to stably read the data in the offset magnetic head because off-track occurs in the subsequent data section. In such a state, if the data necessary for starting up the host device of the magnetic disk device is written in the ID part and the data part, there is a high risk that the host device cannot be started up. There is a problem.

The object of the present invention is to solve the drawbacks of the conventional magnetic disk drive as described above, and to find the desired ID section even when the ID section cannot be read due to the off-track of the magnetic head. It is to provide means for surely reading the subsequent data section.

[0007]

A magnetic head positioning control device of the present invention is a magnetic head positioning control section for controlling the positioning operation of a magnetic head, and a magnetic head forcibly shifting the magnetic head in the radial direction of a storage medium. A misregistration control unit, a reading unit that reads information written in the storage medium, a sector pulse detection circuit that detects a sector pulse from the reading unit, and an index pulse from the reading unit. Index pulse detection circuit,
A counter that counts the sector pulse signal from the sector pulse detection circuit according to the index detection signal from the index pulse detection circuit, and an ID section determination unit that determines the ID section information input from the reading section based on the signal from the counter. The operation of the magnetic head positioning control unit is controlled by the information from the ID unit determination unit to read data from a target sector and when there is an offset, the operation of the magnetic head position shift control unit is controlled to control the operation. And a control unit for performing an off-track operation of the magnetic head.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan view showing a storage medium read in the embodiment of FIG. 1, and FIG. 3 is a format diagram showing details of a portion A of FIG. is there.

In the embodiment shown in FIG. 1, a magnetic head 11, a reading section 12, a sector pulse detecting section 13, an index detecting section 14, a counter 15, an ID section determining section 16 are provided.
A magnetic head positioning controller 17, a magnetic head position shift controller 18, and a controller 19 are provided.

The magnetic head 11 is connected to the reading section 12, the magnetic head positioning control section 17 and the magnetic head position shift control section 18. The reading unit 12 is connected to the sector pulse detection unit 13, the index detection unit 14, the ID unit determination unit 16, and the control unit 19.
Sector pulse detector 13 and index detector 14
Are connected to the counter 15. The counter 15
It is connected to the ID section determination section 16. ID section determination section 16
The magnetic head positioning controller 17 and the magnetic head position deviation controller 18 are connected to the controller 19.

Next, the operation of the magnetic head positioning control device constructed as described above will be described.

As shown in FIGS. 2 and 3, when the storage medium 21 is initialized (formatted), the magnetic disk device makes address information for each sector for each data block unit (sector) of the storage medium 21. (ID part)
Write 24/27.

When a data write command is sent from the host device to the magnetic disk device, the control unit 19 causes the magnetic head positioning information 11 regarding the ID portion of the sector to write the data.
6 is sent to the magnetic head positioning controller 17.
The magnetic head positioning control unit 17 thereby sends the magnetic head positioning signal 117 to the magnetic head 11, and positions the magnetic head 11 with respect to the sector having the intended ID portion of the storage medium 21. Magnetic head 11
When the positioning operation is completed, the control section 19 confirms that the ID section of the sector is the target ID section, and then the data section 25 that follows the ID sections 24 and 27.
・ Write in 28.

At the time of this write operation, the data portion 25 is I
When the data is written in the D section 24 in the radial direction of the storage medium 21 (off-track), the host device writes the data written in the data section 25 of the sector having the ID section 24 to the magnetic disk device. When the read command is issued, it is difficult to stably read the ID section 24 because of the off-track, and thus it is difficult to read the data of the data section 25.

When it becomes difficult to read the ID section 24 due to off-track, the control section 19 sends the appropriate magnetic head position deviation information 1 to the magnetic head position deviation control section 18.
14, the magnetic head position shift control unit 18 sends the magnetic head position shift signal 115 to the magnetic head 1.
The magnetic head 11 is forcibly offset. As a result, the magnetic head 11 has the ID section 24.
Can be read. The ID section 24 read by the magnetic head 11 is stored in the ID section information 1 by the reading section 12.
The data is converted into 10 and sent to the ID section judgment section 16, and the ID section judgment section 16 judges whether the sector having the target ID section is replaced by another sector due to a scratch or the like. If it is replaced, the ID section determination section 16
Stores the information of the ID part of the substitution destination. If not replaced, the information of the current ID part is stored. In any case, from the information of the ID part, the number of the target sector (sector address) from the index detection signal 22 is determined and stored.

Next, the control unit 19 cancels the offset of the magnetic head 11. This makes it impossible to stably read the ID section, but since the sector pulse signal 111 from the sector pulse detection section 13 and the index detection signal 112 from the index detection section 14 are input to the counter 15, 15 is an index detection signal 1
The sector pulse signal 111 is counted by 12. ID
The section determination section 16 notifies the control section 19 of the sector address that matches this count value, and the control section 19 reads the data 113 of the data section of the sector having the sector address via the reading section 12.

[0018]

As described above, the magnetic head positioning control device of the present invention forcibly offsets the magnetic head to read the ID portion and store the sector address when there is an off-track. By detecting the target sector by counting the sector pulse signals and reading the data from the sector, it is possible to stably read the data even when there is an off-track. Therefore, there is an effect that a highly reliable magnetic disk device can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a plan view showing a storage medium read in the embodiment of FIG.

FIG. 3 is a format diagram showing details of a portion A in FIG.

[Explanation of symbols]

 11 magnetic head 12 read-out unit 13 sector pulse detection unit 14 index detection unit 15 counter 16 ID unit determination unit 17 magnetic head positioning control unit 18 magnetic head position deviation control unit 19 control unit 21 storage medium 22 index detection signal 24/27 ID unit 25/28 data section 110 ID section information 111 sector pulse signal 112 index detection signal 112 113 data 114 magnetic head position deviation information 115 magnetic head position deviation signal 116 magnetic head positioning information 117 magnetic head positioning signal

Claims (1)

[Claims] 1. A magnetic head positioning control unit for controlling a positioning operation of a magnetic head, a magnetic head position shift control unit for forcibly shifting the magnetic head in a radial direction of a storage medium, and a magnetic head position control unit for writing the data on the storage medium. Read information, a sector pulse detecting circuit for detecting a sector pulse from the reading unit, an index pulse detecting circuit for detecting an index pulse from the reading unit, and an index from the index pulse detecting circuit. A counter that counts the sector pulse signal from the sector pulse detection circuit based on a detection signal, an ID section determination section that determines the ID section information input from the reading section based on a signal from the counter, and an ID section determination section. From the target sector by controlling the operation of the magnetic head positioning controller with information A magnetic head positioning control device comprising: a control unit that controls the operation of the magnetic head position shift control unit when data is read and there is an offset to perform an off-track operation of the magnetic head.