JPH0349082A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To perform rerecording or re-reproducing without turning off a power source at the time of failing in positioning a magnetic head by letting a microcomputer execute a program for restoring the magnetic head to an initial position at the time of turning on the power source in the case of the magnetic head positioning through an actuator fails. CONSTITUTION:The magnetic head 2 is controlled to move by the microcomputer CPU 8 through an actuator control circuit 7, etc., in accordance with the detection output of a rotating speed and position and velocity detecting circuit 6 to position the head 2 on a target track. In the case of failing in positioning, the CPU 8 executes the specified program in a ROM 9 so as to restore the head 2 to the initial position at the time of turning on the power source. As a result, a magnetic disk device in which the head is moved and rerecording or re-reproducing is performed without turning off the power source and whose throughput is high is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk drive having an actuator that performs random access, and particularly to one having a recovery mechanism in the event of a failure in positioning the magnetic head.

[Prior Art] FIG. 3 is a block diagram showing a partial plan view of a conventional magnetic disk device disclosed in Japanese Unexamined Patent Publication No. 62-75969.

In FIG. 3, (1) is a magnetic disk, (2) is a magnetic head that reads servo information from the magnetic disk (1),
(3) is an access arm that supports the magnetic head (2);
(4) is an actuator supported by a device board (not shown) and connected to the access arm (3), here a voice coil motor; (5) is a voice coil motor (4);
(6) is a rotation speed/position/speed detection circuit connected to the magnetic head (2); (7) is a voice coil whose input side is connected to the rotation speed/position/speed detection circuit (6); Actuator IIJ control circuit whose output side is connected to the coil (5), (10) a rotation speed check circuit connected to the rotation speed/position/speed detection circuit (6), (11)
) is a switch connected to the rotation speed check circuit (10), (12) is a power source that supplies electrical energy to the entire device connected to the switch (11), (13g), (13
b) is the runaway damper provided at both ends of the voice coil motor (4), (14) is the servo data area on the magnetic disk (1), and (15) is the servo data area (1).
4) a first guard band region adjacent to the outside of (16
) is a second guard band area adjacent to the inside of the servo data area (14).

Next, the operation will be explained. The magnetic head (2) is located on the servo data area (14) or the first
When the second guard band area (15) or the second guard band area (16) is located, the servo information is read out and the rotational speed of the magnetic disk (1) is accurately detected.

However, if the magnetic head (2) swings significantly due to vibration or the like as it moves (seeks), the access arm (3) may hit the runaway damper (13g) or (13b). If the magnetic head (2) is strongly hit, the magnetic head (2) will come off the first guard band area (15) or the second guard band area (16).

Then, the servo information becomes unreadable, so the rotational speed check circuit (10) operates the switch (11) to cut off the power supply (12).

[Problems to be Solved by the Invention] When the conventional magnetic disk device fails to position the magnetic head (2) due to the inability to read servo information as described above, the power supply (12) is turned off by the switch (11). Since the magnetic disk drive is configured to be disconnected, the power supply (12) must be turned on in order to operate the magnetic disk drive again, which poses a problem in that the throughput of the magnetic disk drive decreases. .

Therefore, there is a problem that the above problems must be solved.

This invention was made to solve the problem,
When the magnetic head (2) fails in positioning, the power supply (1)
2) It is an object of the present invention to provide a magnetic disk device that can record and reproduce information again without cutting the magnetic disk.

[Means for Solving the Problems] A magnetic disk device according to the present invention includes a recording unit for a program that controls an actuator control circuit to move the magnetic head to the initial position immediately after power is turned on when the magnetic head fails in positioning. It has the following.

[Function] In the magnetic disk device of the present invention, when the magnetic head fails in positioning, the actuator control circuit is controlled by a program using the CPU, the magnetic head is moved to the initial position, and the magnetic head is restarted without turning off the power. It enables the movement of the magnetic head or the recording/reproduction of information.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing one embodiment of the present invention.
) is a magnetic disk, (2) is a magnetic head, (3) is an access arm that supports the magnetic head (2), (-4) is an actuator connected to the access arm (3), and in this example is a voice coil motor. , (5) is the voice coil in the voice coil motor (4), and (6) is the magnetic head (2).
), a rotational speed/position/speed detection circuit connected to (7)
is an actuator control circuit that controls the voice coil motor (4), (8) is a CPU connected to the actuator control circuit (7), (9) is a storage means, and in this embodiment, RO
FIG. 2 is a flowchart of the program stored in the ROM (9).

Next, the operation will be explained according to the flowchart shown in FIG.

First, immediately after the power is turned on, initial values regarding the RAM, output port, etc. of the CPU (8) are set (Pl).

Next, a variable EC that counts the number of times positioning has failed.
Set an integer n (n≧2) in NT (Pl). This n
is the number of times positioning is performed again in response to a positioning failure.

Next, a spindle motor (not shown) is driven to rotate the magnetic disk (1) (P3), and the rotation speed of the magnetic disk is detected by the rotation speed/position/speed detection circuit (6). When the rotation speed reaches the specified value (P4), the magnetic head (
2) is moved (first seek) to the initial position (usually this position because the θ-th cylinder of the magnetic disk is the outermost position) (P5). Next, positioning for the first seek is determined (P6). If positioning fails, ECNT is decreased by 1 (PI).

The process ends if ECNT becomes equal to 0, and if not, it repeats from (P5) until ECNT becomes 0 (P8
). As a result, the process ends when positioning cannot be achieved by seeking n times.

If the positioning is successful, wait for a pulse (step pulse) about the head movement direction and head movement track number to be output from the host device (not shown) (P9), and if the step pulse is output, seek will be started. (PIO).

Next, positioning determination corresponding to this step pulse is performed (pH).

When positioning is successful, information is recorded and reproduced (Pl
2) Waiting for step pulse input (P9).

When positioning fails, the head is moved to an initial position away from the magnetic disk that is unrelated to recording and reproducing information before the power is turned on (PI 3), and ECNT is decreased by 1 (
Pl4).

Next, ECNT is determined (Pl5). When ECNT is O, the program ends and the magnetic disk drive stops.

When ECNT is not 0, after performing the initial setting (Pl6) similar to the initial setting (Pl) again, (P3) to (Pl5
)repeat.

Therefore, the same operation as when the power is turned on can be performed, and predetermined positioning can be performed again. Then, change this operation to n
The power is turned off only if the predetermined positioning cannot be achieved even after repeating the process several times.

[Effects of the Invention] As described above, according to the present invention, even if the magnetic head (2) fails in positioning, it can perform recording again without cutting off the power.
Since playback is possible, the trouble of turning the power on again can be saved, and the throughput of the magnetic disk device can also be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a partial plan view of a magnetic disk device according to an embodiment of the present invention, and FIG. 2 is a flowchart of a control program used in the magnetic disk device according to an embodiment of the present invention. FIG. 3 is a block diagram showing a partial plan view of a conventional magnetic disk device. In the figure, (1) is a magnetic disk, (2) is a magnetic head, (3) is an access arm, (4) is a voice coil motor (actuator), (5) is a voice coil, and (6) is a voice coil motor (actuator).
) is a rotation speed/position/speed detection circuit, (7) is an actuator control circuit, (8) is a microcomputer, (9
) is a storage means, here ROM, (10) is a rotational speed detection circuit, (11) is a switch, (12) is a 'rls source,
(13a) and (13b) are runaway dampers (14)
is a servo data area, (1q) is a first guard band area, and (16) is a second guard band area. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A magnetic disk that records information, a magnetic head that is positioned at a predetermined position by a servo mechanism and records and reproduces information on the magnetic disk, an actuator that moves the magnetic head, and an actuator that controls the operation of the actuator. In a magnetic disk drive equipped with a control circuit and a microcomputer that controls the actuator control circuit, the microcomputer includes program means for moving the magnetic head to an initial position when the power is turned on when positioning of the magnetic head fails. What is claimed is: 1. A magnetic disk device comprising: a magnetic disk device, wherein a program in the program means is executed when a positioning failure of a magnetic head occurs.