Magnetic disk drive with a head oscillation function and the control method thereof

A magnetic disk drive comprising:

• a magnetic disk medium rotatably supported to store information;
• a magnetic head to write information to or read information from the magnetic disk medium;
• an actuator to support the magnetic head so that the magnetic head can be moved in a radial direction of the magnetic disk medium;
• a first function to oscillate the magnetic head in the radial direction in a data area of the magnetic disk medium;
• and
• a second function to process a read signal from the magnetic head during the execution of the first function.

A magnetic disk drive comprising:

• a magnetic disk medium rotatably supported to store information;
• a magnetic head to write information to or read information from the magnetic disk medium;
• an actuator to support the magnetic head so that the magnetic head can be moved in a radial direction of the magnetic disk medium;
• a first function to oscillate the magnetic head in the radial direction in a data area of the magnetic disk medium;
• a second function to process a read signal from the magnetic head during the execution of the first function;
• and
• a control circuit having a third function, the third function controlling a position of the magnetic head according to the signal processed by the second function.

A control method of a magnetic head comprising a magnetic disk medium rotatably supported to store information;

• a magnetic head to write information to or read information from the magnetic disk medium;
• an actuator to support the magnetic head so that the magnetic head can be moved in a radial direction of the magnetic disk medium;
• and a control circuit to control these, the control method comprising:
• a first step of moving the magnetic head;
• and
• a second step of oscillating the magnetic head in a data area of the magnetic disk medium.

A magnetic disk drive comprising:

• a rotatably supported magnetic disk medium having servo information for positioning a magnetic head and a data area for storing data representing user information;
• a magnetic head to write information to or read information from the magnetic disk medium;
• an actuator to support the magnetic head so that the magnetic head can be moved onto the magnetic disk medium;
• and
• a function to oscillate the magnetic head in the data area of the magnetic disk medium.

A magnetic disk drive comprising:

• a rotatably supported magnetic disk medium;
• a magnetic head to write information to or read information from the magnetic disk medium;
• a signal detection circuit to detect a read signal from the magnetic head;
• an actuator to position the magnetic head at an arbitrary position on the magnetic disk medium;
• an oscillation adding circuit to produce a signal for applying oscillations to a mechanism of the actuator;
• a position signal generation circuit to generate a position signal from outputs of the signal detection circuit and the oscillation adding circuit;
• a maneuver setting circuit to set a value for operating the actuator;
• a D/A converter circuit to convert a digital signal from the maneuver setting circuit into an analog signal;
• and
• a microprocessor connected to the position signal generation circuit and the maneuver setting circuit.

A control method of a magnetic disk drive, wherein the magnetic disk drive includes a rotatably supported magnetic disk medium having servo information for positioning a magnetic head and a data area for storing data representing user information, a magnetic head to write information to or read information from the magnetic disk medium, and an actuator to support the magnetic head so that the magnetic head can be moved onto the magnetic disk medium;

• the control method comprising:
• a first step of positioning the magnetic head at an arbitrary track on the magnetic disk medium;
• a second step of closing a write gate in the data area on the magnetic disk medium;
• and
• a third step of generating a signal for oscillating the magnetic head for a predetermined period during the second step.

A magnetic disk drive comprising:

• a magnetic disk medium having a large number of tracks formed thereon, the tracks having a data area in which to write data used by a user and a servo information area having written therein servo information for positioning a magnetic head at a target location;
• a magnetic head to read the servo information from the servo information area and write data in the data area;
• an actuator to support and move the magnetic head;
• a positioning circuit to produce a signal for driving the actuator to position the magnetic head at a target track;
• a signal adding circuit to give a signal of a predetermined frequency to the actuator to oscillate the magnetic head when the magnetic head is in the data area;
• and
• a circuit to generate a signal for correcting the position signal output from the positioning circuit according to a signal obtained by the magnetic head from the data area while the magnetic head is oscillated.

A control method of a magnetic disk drive, wherein the magnetic disk drive positions a magnetic head on a magnetic disk medium having a large number of tracks formed thereon, the tracks having a data area in which to write data used by a user and a servo information area having written therein servo information for positioning the magnetic head at a target location;

• the control method comprising:
• a first step of moving the magnetic head across the tracks toward a target track according to the servo information in the servo information area;
• a second step of causing the magnetic head to execute a track-following operation along the target track;
• a third step of applying oscillations to the magnetic head during the track-following operation;
• a fourth step of generating a new position signal based on a signal obtained from the magnetic head as a result of the oscillations;
• and
• a fifth step of positioning the magnetic head at the target track according to the new position signal.

A method of writing information to or reading information from a magnetic disk medium using a magnetic head, comprising:

• a first step of rotating a magnetic disk medium, the magnetic disk medium having a large number of tracks formed thereon, the tracks having a data area in which to write data used by a user and a servo information area having written therein servo information for positioning the magnetic head at a target location;
• a second step of moving the magnetic head across the tracks toward a target track according to the servo information in the servo information area;
• a third step of causing the magnetic head to execute a track-following operation along the target track;
• a fourth step of applying oscillations to the magnetic head during the track-following operation;
• a fifth step of generating a new position signal based on a signal obtained from the magnetic head as a result of the oscillations;
• a sixth step of positioning the magnetic head at the target track according to the new position signal;
• and
• a seventh step of writing information in or reading information from the data area of the track where the magnetic head is positioned.