Active control of a read/write head
The invention generally relates to hard disk drives with a disk and a read/write head, and methods for preventing contact between the disk and the read/write head. The hard disk drive includes a z-axis actuator configured to control movement of the read/write head, and to prevent contact between the read/write head and the disk, based on signals from a controller that indicate when the distance between the read/write head and the disk are outside a predetermined range, such as between 0 and 10.0 nm.
1. A hard disk drive comprising:
a disk comprising a magnetic data recording and reading surface;
a read/write head for reading data from and writing data to the disk surface;
a z-axis actuator coupled to the head and for controlling movement of the head in a substantially orthogonal direction relative to the disk surface; and
a controller for monitoring a distance of the head relative to the disk surface and for maintaining the distance within a predetermined range, the controller employing robust control to ensure the head and the disk surface are prevented from coming into contact;
wherein one or both of the disk surface and the head is devoid of any overcoat or lubricant layer.
2. The hard disk drive of claim 1 wherein the robust control actively controls the head within a tolerance of between 1.0 nm and 10.0 nm.
3. The hard disk drive of claim 1 wherein the robust control comprises monitoring head-media spacing (HMS) between the head and the disk surface and also transmitting signals to the z-axis actuator to cause movement of the head.
4. The hard disk drive of claim 1 wherein the robust control comprises a servomechanism with error-sensing negative feedback to maintain the head within a range of 1.0 nm and 10.0 nm.
5. The hard disk drive of claim 1 wherein the z-axis actuator is rigidly coupled to the head.