JPH03181077A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To reduce the off track on a data write face without extending a servo information write area by estimating the track position of each recording medium face based on first and second servo information to position a head. CONSTITUTION:If a revolving shaft 1a is inclined by thermal deformation or the like, first servo information read by a head 12b is corrected with second servo information read from the upper face of a recording medium 2 by a head 8a. In the case of a head 11b, the positioning position of the head 12b is corrected to satisfy aXd+bXc=0 where (a), (b), (c), and (d) are the off track detected by the head 12b, the off track detected by the head 8a, the distance between heads 11b and 12b, and the distance between heads 11b and 8a respectively. Consequently, the head 11b is placed in the center of the track. Thus, the off track on the data write face is reduced without extending the servo information write area.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic disk device for recording and reproducing various information such as image information, audio information, and code information.

BACKGROUND OF THE INVENTION Conventionally, as track density increases, this type of magnetic disk drive positions the head at the center of the track based on servo information written on the recording medium to prevent off-track due to thermal deformation. .

However, in order to obtain sufficient servo gain, a lot of servo information must be written, which reduces the original data writing area. Therefore, among multiple recording media, which are magnetic disks attached to the rotating shaft of the disk motor, one side is dedicated to writing servo information, and the servo information is used to apply the servo. The other surface of the medium and the upper and lower surfaces of all other recording media are used as data writing areas.

Problems to be Solved by the Invention However, in the conventional magnetic disk drive described above, head positioning is performed only on the servo information writing surface, so the rotation shaft of the disk motor and the rotation shaft of the rotary head actuator are exposed to heat. If it is tilted due to deformation or the like, there is a problem in that the data writing surface that is distant in the axial direction from the surface on which servo information is written will be off-track.

The present invention solves these conventional problems, and provides a high-capacity, highly stable disk that can reduce off-track on data writing surfaces other than the servo information writing surface without increasing the servo information writing area. Its purpose is to provide magnetic disks.

Means for Solving the Problems In order to achieve the above object, the present invention provides first servo information written on the entire surface of one side of one of a plurality of recording media and data on a certain side of the other recording medium. The head is positioned by estimating the track position on each recording medium surface based on the second servo information written discretely in between.

Therefore, according to the present invention, off-track caused by thermal deformation of the rotating shaft of the disk motor can be reliably removed without increasing the writing area of servo information, and any head can be reliably positioned at the center of the track. can.

2 to 6 are magnetic disks attached at regular intervals to the rotating shaft 1a of the disk motor 1, and 7 is a recording medium that supports the heads 8a to 12a and 8b to 12b. The heads 8a to 12a each support the recording medium 2.
The heads 8b to 12b are attached to the head support stand 8 via support arms 13a to 17a so as to be in contact with the upper surfaces of recording media 2 to 6, respectively, and the heads 8b to 12b are attached to the head support base 8 via support arms 13b to 17b so as to be in contact with the lower surfaces of recording media 2 to 6, respectively. It is attached to a head support stand 8.

18 is the base of the drive, and 20 is the head 8a to 12a s 8 b via the head support base 7, as described later.
This is a circuit that controls 12b.

On the lower surface of the recording medium 6 that the head 12b is in contact with,
Only the first servo information, which is a two-phase signal, is written, and on the surface of the recording medium 2 that is in contact with the head 8a that is farthest from the head 12b in the axial direction of the rotating shaft 1a, the second servo information is written between the data. servo information is written discretely. Servo information is not written on the upper and lower surfaces of the recording media 2-6, which are in contact with the other heads 9a-12a and 8b-llb, but only data is written thereon.

Next, the operation of the above embodiment will be explained. head 12a
A two-phase signal is written as servo information on the lower surface of the recording medium 6 which is in contact with the recording medium 6, and this servo information enables positioning not only to the center of the track but also to any desired track position.

Normally, when the head 12b is positioned at the track center using the first servo information read from the bottom surface of the recording medium 6, the other heads 8a to 12a, 8b to llb
will also be positioned at the center of the track.

However, if the rotating shaft 1a is tilted due to thermal deformation or the like, the above relationship cannot be obtained. Therefore, the first servo information read by the head 12b is corrected with the second servo information read from the top surface of the recording medium 2 by the head 8a.

For example, in the case of head llb, the off-track detected by head 12b is a1, the off-track detected by head 8a is b1, the distance between head llb and head 12b is C1, and the distance between head llb and head 8a is d. Then,
Head 12 so that the formula aXd+bXc=0 holds.
If the positioning position b is corrected, the head 11b will also be located at the center of the track.

Effects of the Invention As is clear from the above embodiments, the present invention has the following effects.

(1) Since only the first servo information is written on the entire surface of one side of the recording medium, it is resistant to external disturbances and the off-track main component can be reliably removed.

(2) Even if an off-track occurs that cannot be removed using (1) above due to inclination due to thermal deformation of the rotation axis of the disk motor or the rotation axis of the rotary actuator, the recording medium (one surface other than the servo surface) It can be corrected and removed using the data and second servo information written discretely.

(3) For the surface of the recording medium on which servo information is not written, interpolation is performed using the first and second servo information.
There is no need to write servo information, and all sides of the recording medium except for the two sides on which servo information is written can be used as data areas, resulting in a large capacity.

FIG.

DESCRIPTION OF SYMBOLS 1... Disk motor, 2-6... Recording medium, head support stand, 8a-12a, 8b-12 head, 20
...Control circuit.

7... b...

Claims (1)

[Scope of Claims] A plurality of recording media including a recording medium in which first servo information is written on the entire surface of one side and a recording medium in which second servo information is written discretely between the data on one side; A plurality of heads installed on each surface of each recording medium, and means for estimating a track position on each recording medium surface based on the first and second servo information and positioning the head. Magnetic disk device.