Monitoring of phenomena indicative of PTP in a hard disk and controlling the burnishing of heads

A system for identifying and correcting undesired pole top protrusion (PTP) of a write portion of a read/write head that is configured to transfer data to and from a disk media in a hard disk, the system comprising:

• a high fly write monitoring circuit that monitors for occurrence of a high fly write (HFW) condition of the read/write head, wherein the high fly write monitoring circuit comprises a low pass filter that filters a read signal from the read/write head reading the disk media so as to remove high frequency signals unrelated to air bearing frequency resonance and generate a filtered read signal;
• a PTP determining circuit that determines based on the filtered read signal when occurrence of a HFW condition monitored by the monitoring circuit is indicative of an undesired PTP condition;
• and
• a corrective action assembly that comprises a pole tip burnisher and is configured to correct undesired PTP of the write portion of the read/write head using the pole tip burnisher in response to the PTP determining circuit determining occurrence of an undesired PTP condition, wherein the PTP determining circuit comprises a threshold detector that detects when the low frequency signals of the filtered read signal related to air bearing frequency resonance reach a defined threshold that is indicative of an undesired PTP condition.

A system for identifying and correcting undesired pole top protrusion (PTP) of a write portion of a read/write head that is configured to transfer data to and from a disk media in a hard disk, the system comprising:

• a high fly write monitoring circuit that monitors for occurrence of a high fly write (HFW) condition of the read/write head;
• a PTP determining circuit that determines when occurrence of a HFW condition monitored by the monitoring circuit is indicative of an undesired PTP condition;
• a corrective action assembly that comprises a pole tip burnisher and is configured to correct undesired PTP of the write portion of the read/write head using the pole tip burnisher in response to the PTP determining circuit determining occurrence of an undesired PTP condition;
• and
• a mechanism configured to write to the disk media through the write portion of the read/write head during a PTP test write cycle, wherein the high fly write monitoring circuit monitors for occurrence of a HFW condition of the read/write head shortly after conclusion of the PTP test write cycle, wherein during the PTP test write cycle the mechanism is configured to continuously write to the disk media through the write portion of the read/write head for a predetermined period of time in a portion of the disk media at a data rate that is higher than a data rate used to write data in the portion of the disk media when not in the PTP test write cycle.

A method of making a hard disk, the method comprising:

• monitoring occurrence of a high fly write (HFW) condition of a read/write head in the hard disk by reading a disk media in the hard disk to generate a read signal, low pass filtering the read signal to remove high frequency signals unrelated to air bearing frequency resonance and generate a filtered read signal, and monitoring the filtered read signal for occurrence of a HFW condition;
• determining based on the filtered read signal when a monitored occurrence of a HFW condition is indicative of an undesired pole tip protrusion (PTP) condition of a write portion of the read/write head;
• and
• burnishing the write portion of the read/write head with a pole tip burnisher in response to determining that an occurrence of the HFW condition is indicative of an undesired PTP condition, wherein said determining comprises detecting with a threshold detector when the low frequency signals of the filtered read signal related to air bearing frequency resonance reaches a defined threshold that is indicative of an undesired PTP condition.

A method of making a hard disk, the method comprising:

• monitoring occurrence of a high fly write (HFW) condition of a read/write head in the hard disk:
• determining when a monitored occurrence of a HFW condition is indicative of an undesired pole tip protrusion (PTP) condition of a write portion of the read/write head;
• burnishing the write portion of the read/write head with a pole tip burnisher in response to determining that an occurrence of the HFW condition is indicative of an undesired PTP condition;
• and
• writing data on a disk media in the hard disk during a PTP test write cycle wherein monitoring occurrence of a HFW condition of the read/write head is carried out shortly after conclusion of the PTP test write cycle, wherein writing data on the disk media during the PTP test write cycle comprises writing the data continuously through the write portion of the read/write head for a predetermined period of time in a portion of the disk media at a data rate that is higher than a data rate used to write data in the portion of the disk media when not in the PTP test write cycle.