JPH10233003A - Magnetic disk drive - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In particular, a magnetic disk device incorporated in a system performs following and idle seek even in a state other than a signal recording / reproducing operation, so that a sense current is always supplied to an MR head. There was a problem that it had to be washed away. In a magnetic disk device equipped with a plurality of magnetic heads and magnetic disks, an MR head is used as a read head, and the head used as the device is arbitrarily limited according to the characteristics of the magnetic head. In other words, a magnetic disk device having at least one head (spare head) not used as a device, and in a state other than recording / reproducing of a signal, the sense current of the MR head is supplied to the registered spare head to follow up. Or by performing an idle seek.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive having or capable of having a spare head.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a magnetic disk device, which is an external storage device of a computer, to be reduced in size, capacity, and cost. Under such circumstances, the necessity of using an MR head as a read head has been increasing. However, when an MR head is used, some magnetic heads and magnetic disks cannot be used due to variations due to the characteristics of the MR head and defects in the magnetic disk. In particular, for variations in the characteristics and defects of magnetic heads and magnetic disks mounted in a plurality of magnetic disk devices, even if the magnetic heads and magnetic disks have good single-piece characteristics, when considering the variations, when mounted on the device It is difficult for all magnetic heads to obtain good performance. Therefore, there is a problem that a magnetic head which does not satisfy the performance appears in a test after assembling the device, which results in a defective device, thereby lowering the yield of the device. In such a case, it is necessary to repair the device as NG, but this requires time and labor. As a method of overcoming this problem, among the plurality of magnetic heads mounted, a magnetic head having inferior characteristics is used as a spare head that is not used on the device, and the yield is improved while ensuring device performance and reliability. .

When an MR head is used, it is necessary to keep the apparatus in a following or idle seek state by energizing the MR head even in a state other than a signal recording / reproducing operation and a signal recording / reproducing operation. However, M
There is a problem that the life of the R head is shortened.

[0004] When a spare head is used, it is necessary to record spare head information indicating which head is to be selected as the spare head. This includes:
As shown in US Pat. No. 5,216,655, there is a method in which information of a spare head is written and recorded on a magnetic disk by a magnetic head. As another method, there is a method of recording in a P / K for servo control or read / write control.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic disk drive incorporated in a system, particularly, for performing a follow-up operation or an idle seek operation in a state other than a signal recording / reproducing operation. Must always supply a sense current. Therefore, if the sense current is continuously supplied to the MR head, the life of the MR head may be shortened accordingly.

When a spare head is used, it is necessary to record spare head information indicating which head is to be selected as the spare head. As this method, U
As shown in SP-5216655, there is a method in which information of a spare head is written and recorded on a magnetic disk by a magnetic head. With this method, it is necessary to determine at the time of initialization which head is to be the spare head, which means that the information of the spare head needs to be written to the magnetic disk before deciding which head is to be the spare head. Therefore, writing the information to a magnetic disk that should be used as a spare head occurs. As another method, there is a method of recording information of a spare head as to which head is selected as a spare head in a P / K for servo control or read / write control of a magnetic disk device. However, the spare head information is
Since it differs for each A, it must always be integrated with the HDA. Therefore, according to this method, if the servo control or read / write control P / K is defective during maintenance, if the maintenance control of only the servo control or read / write control P / K is performed, the spare head information recorded there will be recorded. May be lost, so servo control and read / write control P
It becomes impossible to replace only / K. Therefore, it is necessary to solve the above-mentioned problem by changing the method of recording the information of the spare head, which head is selected as the spare head.

[0007]

A means for achieving the above object is to provide a magnetic disk device having a function of performing a follow-up or idle seek with a spare head in a state other than a signal recording / reproducing operation. It is. As a result, the time for energizing the MR head for signal recording / reproducing operation can be reduced, and the life of the MR head for signal recording / reproducing operation can be extended.

The information of the spare head is stored in the FP in the HDA.
The magnetic disk device has a structure including a circuit / part capable of recording on an information recording P / K of an IC on a spare head or a spare head, or a structure in which a jumper pin for spare head selection is attached to a side surface of the HDA. As a result, maintenance and replacement of only the servo control and the read / write control P / K can be performed.

[0009]

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

In FIG. 1, the first group is a head, the 2 is a spare head, the 10 is an IC (flash memory or the like) on an FPC, and the 11 is a P / K for servo control and read / write control.

Normal recording / reproduction is performed using a group of heads. As for a head in a following state immediately after recording / reproduction or a seek operation for recording / reproduction, a head for recording / reproduction in a group is selected and used. When there is no recording / reproducing command for a certain period of time, a command for selecting the spare head 2 is given. Then, the spare head 2 is set to a state in which the following or idle seek is performed, and a sense current is not supplied to the MR heads of the group of heads 1 for performing normal recording and reproduction. Then, when a command to perform recording / reproduction is received, the head is switched to a group of heads for recording / reproduction and seeks to a cylinder for recording / reproduction, thereby performing recording / reproduction.

FIG. 1 shows information on a spare head, which head is selected as a spare head, in an IC on an FPC.
(Spare head control circuit) shows a method of storing the data in the spare head control circuit 10. This can be recorded by using a flash memory or the like. This eliminates the need to write the information of the spare head to the magnetic disk by the magnetic head. Further, it is not necessary to store the information of the spare head in the servo control or read / write control P / K 11. In addition, a method of storing the information of the spare head in an IC in the information recording P / K of the spare head attached to the side surface of the HDA may be used. This P / K may be outside the HDA or inside the HDA. Alternatively, a structure in which a jumper pin for a spare head select is attached to the side of the HDA may be used.

[0013]

According to the present invention, when the sense current supplied to the MR head is followed or idle-seeked by the spare head in a state other than the signal recording / reproducing operation, another MR for recording / reproducing is performed. The life of the head can be kept long.

The information of the spare head is stored in an IC in a P / K for servo control and read / write control of the magnetic disk drive.
Because it is not recorded in the servo control or read / write control P
/ K can be replaced by maintenance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a magnetic disk drive of the present invention.

[Explanation of symbols]

1 ... magnetic head group, 2 ... spare head, 3 ...
-Magnetic disk, 4-Carriage, 5-Spindle, 10-Spare head control circuit, 11-P / K for servo control, read / write control

Continued on the front page (72) Inventor Shigehisa Shimizu 2880 Kozu, Odawara City, Kanagawa Prefecture Hitachi Computer Equipment Co., Ltd. (72) Inventor Masami Miyatake 2880 Kozu, Kokuzu, Odawara City, Kanagawa Prefecture Storage Systems Division, Hitachi, Ltd. (72) Inventor Tsuyoshi Nakazawa 2880 Kozu, Odawara City, Kanagawa Prefecture Hitachi, Ltd. Storage Systems Division

Claims (2)

[Claims] In a magnetic disk drive on which a plurality of magnetic heads and magnetic disks are mounted, an MR head is used as a read head, and the head used as the device is arbitrarily limited according to the characteristics of the magnetic head. In other words, a magnetic disk device having at least one head (spare head) not used as a device, and in a state other than recording / reproducing of a signal, a sense current of the MR head is supplied to the registered spare head to follow up. A magnetic disk drive characterized by performing an idle seek. 2. A magnetic disk drive having at least one spare head, wherein information of the spare head is taken into an IC on an FPC in a magnetic disk or a dedicated P / K attached to a side surface of the magnetic disk drive. , H
A magnetic disk drive having a structure in which a jumper pin for spare head select is attached to the side of DA.