JPH02187972A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To enable the correction of thermal expansion and contraction of a closure without any seek operation by measuring and storing a temp. inside a disenclosure and an amplitude of a detecting signal of a gap pattern part to be outputted from a magnetic head. CONSTITUTION:A temp. sensor 15 fitted on a base plate 2 of the disk device and an amplitude detecting circuit 18 of a control circuit are connected to a microcomputer 13 to store a detected temp. value and an amplitude detecting value and to detect the occurrence of thermal off-track due to thermal expansion and contraction of a magnetic disk 3, the base plate 2 and an actuator mechanism 8, etc., owing to self-heating after a power source is turned on and an environmental temp. change. That is, whether the detecting temp. of the sensor 15 is raised or lowered as against its temp. immediately after positioning is detected, and the direction of a positional change of a magnetic head 5 and the disk 3 is detected. Thus, driving control contents on a servo motor 7 is corrected by the computer 13 in order to equalize a read amplitude with a value immediately after positioning, so that the head 5 is accurately positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device that is capable of correcting misalignment of a magnetic head caused by temperature changes.

[Prior Art] Conventionally, in preparing a small magnetic disk, a DC motor equipped with an optical encoder drives a carriage mechanism via a steel belt.

However, when it comes to the position information of optical encoders, there is a thermal off-track problem in which the position of the magnetic head deviates from the center line of the track due to differences in the expansion and contraction of the carriage/head system due to temperature changes and the base plate on which the spindle and carriage are mounted. .

For this reason, a servo track with position information recorded is provided on a part of the disk surface where data is recorded (for example, at the outermost, middle, and innermost locations), and a seek command is issued after a certain period of time has passed. When the receiver picks up the data, it detours to the servo track to detect positional deviation information, and uses that information to correct the positional deviation when positioning to the target data track.

Note that in the 5T506, which is the de facto standard interface for small magnetic disk drives, it is not possible to arbitrarily seek to a servo track in order to check the amount of positional deviation on the disk drive side.

[Problems to be solved] In the conventional positioning method for magnetic disk mounting described above, unless a seek command is issued, it is impossible to seek to the servo track without permission to check the amount of positional deviation. If the position of the magnetic head remains unchanged, there is a drawback that even if the position of the magnetic head shifts due to temperature changes, it cannot be corrected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a magnetic disk device that can correct the positional deviation of a magnetic head without requiring a seek command.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a magnetic disk that is rotated by a spindle motor, a magnetic head that reads and writes data in close proximity to the surface of the magnetic disk, and a magnetic head that reads and writes data in close proximity to the surface of the magnetic disk. an actuator mechanism that moves the magnetic disk to a target cylinder position; a servo control circuit that drives the actuator mechanism; a data read/write circuit; a signal amplitude detection circuit that detects the amplitude of the read signal; and a disk enclosure. A write-protected gap pattern section is provided at least at one location in each cylinder of the recording section on the m% disk, and the reading signal amplitude of the gap pattern section after the end of the seek is The temperature inside the disk enclosure is detected by the signal amplitude detection circuit and the temperature sensor, and the signal amplitude and temperature are repeatedly detected every preset time period, and if there is a change in the signal amplitude, the temperature is detected. The configuration includes means for determining the direction of positional deviation from the change history and correcting the positional deviation so that the signal amplitude is restored to the original amplitude.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

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

There are two magnetic disks 3 inside the disk enclosure.
is attached to a spindle motor l so as to rotate on the base plate 2. Each magnetic disk 3.3 has data recording surfaces on both the front and back surfaces, and the data recording surface is a planning surface. Each data recording surface is faced with - magnetic heads 5, respectively.

The actuator mechanism 8 for driving the magnetic head includes a carriage 6, a DC servo motor 7, and a steel belt 10 that connects the carriage 6 and the DC servo motor 7. and an optical encoder 9 directly connected to the DC servo motor 7.

It is designed to be driven by a servo control circuit 11. The magnetic head 5 is connected to a read/write circuit 16. Further, it is connected to a host device via an interface circuit 12.

A two-phase analog position signal is output from the optical encoder 9 to the servo control circuit 11.

The servo control circuit 11 has two operating modes, a positioning mode and a seek mode, and the servo control circuit 11 operates from an interface circuit 12 to a logic circuit 14 . A DC servo motor 7 is driven by a seek command outputted via the microcomputer J,3.

Then, the analog position signal from the optical encoder 9 directly connected to the DC servo motor is sent to the servo control circuit 1.
A positioning and seek servo loop is configured by feeding back to 1.

Position information is written on the magnetic disk 3 at three locations that are not data tracks. Microcomputer 1
3 is the write circuit 1 that sorts the position data of these three locations.
The microcomputer 13 calculates the error of the track position to be positioned from the position data of these three places and sends a command to the servo control circuit 11 to determine the position of the optical encoder 9. This information is corrected to ensure accurate positioning.

Also, in synchronization with the rotation of the magnetic disk 3, an index pulse is output once per rotation, or a write-protected gap pattern is created on the recording surface of the magnetic disk 3 immediately before the index pulse generation part. A section (not shown) is provided, and its signals are read out from the magnetic head 5 via a read/write circuit 16.

Also connected to the microcomputer 13 are a temperature sensor 15 that detects the temperature inside the disk enclosure, and an amplitude detection circuit 18 that detects the amplitude of the signal read immediately after accurate positioning of the magnetic head 5. The microcomputer 13 is configured to store the temperature value detected by the temperature sensor 15 and the amplitude value detected by the amplitude detection circuit 18.

Then, the magnetic disk 3. When the base plate 2, the actuator mechanism 8, etc. expand and contract thermally, the positions of the magnetic head 5 and the magnetic disk 3 change, and the read amplitude becomes smaller, it is detected that thermal off-track has occurred.

However, if the host device issues a seek command after a certain period of time has elapsed since the position data on the recording surface of the magnetic disk 3 has been captured, the position data is updated, but if the seek command is not output for a long time, the position data will be lost. will not be updated. In this case, the magnetic disk 3. The base plate 2, actuator mechanism 8, etc. expand and contract due to heat, and the position of the magnetic head 5 on the magnetic disk 3 changes.

At this time, the microcomputer 13 controls the temperature sensor 15.
It is detected that the detected temperature has increased or decreased relative to the temperature immediately after positioning, and the direction of positional change between the magnetic helad 5 and the magnetic disk 3 is determined. and microcomputer 1
3 corrects the drive control contents of the DC servo motor 7 via the servo control circuit 11 so that the read amplitude is the same as immediately after positioning, and the magnetic head 5 is correctly positioned.

In this way, the signal amplitude and detected temperature input at regular intervals are compared with the signal amplitude immediately after seek and the temperature at the previous position correction as reference values, and the correction for one positional deviation is updated.

[Effects of the Invention] As explained above, the present invention seeks thermal expansion and contraction of the disk enclosure by measuring and storing the temperature inside the disk enclosure and the amplitude of the detection signal of the gap pattern portion output from the magnetic head. This has the effect of allowing correction without any action.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 14: Logic circuit 15: Temperature sensor 16:Leet light 17: Medium surface position detection circuit 18・Amplitude detection circuit l nisbintle motor 2: Base plate 3: Disc 4 Niss spindle 5: Head 6 Carriage 7: DC servo motor 8: Actuator mechanism 9: Optical encoder lO steel belt If Servo control circuit 12・Interface circuit 13: Microcomputer

Claims (1)

[Claims] A magnetic disk rotated by a spindle motor, a magnetic head that reads and writes data close to the surface of the magnetic disk, an actuator mechanism that moves the magnetic head to a target cylinder position on the magnetic disk, and It has a servo control circuit that drives an actuator mechanism, a data read/write circuit, a signal amplitude detection circuit that detects the amplitude of the read signal, and a temperature sensor that measures the temperature inside the disk enclosure.
At least one write-protected gap pattern section is provided in each cylinder on the recording surface of the magnetic disk, and the signal amplitude detection circuit detects the read signal amplitude of the gap pattern section and the temperature inside the disk enclosure after the seek is completed. The signal amplitude and temperature are detected repeatedly at preset time intervals, and if there is a change in the signal amplitude, the direction of positional deviation is determined from the temperature change history, and the signal amplitude is detected by the temperature sensor. 1. A magnetic disk device comprising means for correcting positional deviation so that the amplitude of the magnetic disk is restored to its original amplitude.