JP2002008302A - Magnetic disk device and method for controlling servo detection timing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the on time of a reading circuit by predicting a next servo sector start position from monitor information by a timer in such an idle state which selects and controls the minimum necessary servo information without using the servo information of the entire sector in order to reduce electric power consumption. SOLUTION: There is a need for sufficiently assuring the timing margin for reading servo information by taking the fluctuation in the rotation of a spindle motor when the servo information is read by selecting the servo information at every other one sector or two sectors in an idle state for electric power saving. In order to avoid the same, the start positions of the servo sectors are monitored at every sector or every other one sector and the next servo sector start position is predicted and the timing for reading the servo information is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sector servo type magnetic disk drive for performing head positioning control based on servo information arranged in each sector, and more particularly, to monitor the start position of a servo sector during idle. The present invention relates to a magnetic disk device that corrects timing for reading servo information and a control method thereof.

[0002]

2. Description of the Related Art In a magnetic disk device, especially in a small magnetic disk device, in order to reduce power consumption, in a state of waiting for a command from a host computer, the power of a read circuit system is turned on only in the servo sector of each sector, and A method of turning off the data sector is used.

[0003]

However, in order to read the servo sector of each sector, the starting time from when the power of the reading circuit system is turned on to when the servo circuit operates normally, and the start of the servo sector due to the rotation fluctuation of the spindle motor, etc. To read the servo sector every one or two or more sectors, it is necessary to turn on the power of the reading circuit system for a long time with respect to the length of the servo sector. was there.

Therefore, in the present invention, the start position of the servo sector is monitored by a timer for each sector or every other sector or more, so that the time required to turn on the power of the reading circuit system is minimized, and the consumption of the magnetic disk drive is reduced. Reduce power.

[0005]

In the magnetic disk drive of the sector servo system, the servo information includes a track number, digital servo information indicating a sector number, and analog servo information indicating an offset amount from a track center. When the SERVO GATE signal is turned on to read the servo information, the power supply of the reading circuit system is turned on. The SERVO GATE signal needs to be turned on before the servo sector starts. According to the present invention, the time for turning on the SERVO GATE signal can be set short by counting the start position of the servo sector by a timer and correcting the deviation of the servo sector start position.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 5 denotes a magnetic disk.
A plurality of tracks are arranged concentrically on the magnetic disk 5. As shown in FIG. 2, the magnetic disk 5 is further formed with 60 sectors radially. In each sector, servo information 7 is written at the head, and a data area is secured thereafter. The servo information 7 includes digital servo information indicating a track number and analog servo information indicating an offset amount from the track center.

[0008] The servo information 7 is read by the head 4, amplified by the RWIC 3, converted to digital information by the RW channel 2, and sent to the CPU 1 by digital servo information indicating a track number.

The CPU 1 recognizes a specific pattern written at the head of digital servo information, and recognizes a start position of servo data. When recognizing the servo data start position, the CPU 1 starts counting, turns on the power control signal SERVO GATE just before the next servo data start position, and starts reading the servo data. The counting is performed until the specific pattern is found. When the specific pattern is found, the CPU 1 detects a deviation of the servo data start position, turns off the SERVO GATE, and starts counting again. The start of reading the next servo data is performed at a timing at which the detected servo data start position deviation is corrected.

[0010]

According to the present invention, since the start position of a servo sector is corrected, the accuracy of reading servo information is improved.

Further, the time required to turn on the power supply of the electric circuit for reading the servo information can be minimized, so that the power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a model diagram of a magnetic disk drive in which only necessary parts for describing the present invention are shown.

FIG. 2 is a schematic diagram of a servo data format on DISK.

FIG. 3 is a diagram showing a case where servo detection timing correction is performed;
It is a timing chart of an ERVO GATE signal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... read / write channel, 3 ... read / write IC, 4 ... magnetic head, 5 ... disk, 6 ... spindle motor.

Claims (1)

[Claims] In a magnetic disk drive adopting a sector servo method for positioning a head based on servo information arranged in each sector, a specific state other than a write or read operation in an operation mode is identified, and the specific state is determined. And a control method for the magnetic disk device, characterized by comprising means for correcting the timing of servo information processing.