Method and system for detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk

A method, comprising:

• detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk, the change being caused by head-disk contact;
• and
• detecting bounce of the head along the disk, and processing signals correlating to the change in rotational velocity and detection of bounce together for detecting head-disk contact,
• wherein detecting the change in the rotational velocity includes measuring a change in a current applied to a motor driving the spindle to maintain about a constant rotational velocity thereof.

A method for detecting head-disk contact, comprising:

• measuring a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk;
• detecting a change in the rotational velocity, the change being caused by head-disk contact;
• detecting bounce of the head along the disk, and processing signals correlating to the change in rotational velocity and detection of bounce together for detecting head-disk contact;
• and
• correlating the change in rotational velocity with the head-disk contact.

A method for setting a head-disk clearance spacing, the method comprising:

• inducing a head-disk contact;
• measuring a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk;
• detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk, the change being caused by the head-disk contact;
• detecting bounce of the head along the disk, and processing signals correlating to the change in rotational velocity and detection of bounce together for detecting the head-disk contact;
• and
• determining a condition to avoid prolonged head-disk contact;
• wherein the condition includes a rotational velocity of the disk relative to the head.