Disk drive having a write condition detector for suspending write operations while a transducer flying height deviates from its operating flying height

An integrated circuit for use in a disk drive having a head and a recording surface, wherein the recording surface includes a track having a user data segment and a periodic reference segment, wherein the head flies above the recording surface at a fly height that varies as the head flies, wherein during a write operation the head writes data in the user data segment, and wherein during the write operation the head produces a reference signal when reading the periodic reference segment, wherein the integrated circuit comprises:

• integrator means, responsive to the reference signal, for integrating the reference signal to generate an area signal;
• peak detector means for detecting a peak in the reference signal to generate a peak signal;
• and
• means, responsive to the area signal and the peak signal, for generating a write condition signal that indicates that writing of data in the user data segment during the write operation is unsafe.

A disk drive having a head and a recording surface, wherein the recording surface includes a track having a user data segment and a periodic reference segment, wherein the head flies above the recording surface at a fly-height that varies as the head flies, wherein during a write operation the head writes data in the user data segment, and wherein during the write operation the head produces a reference signal when reading the periodic reference segment, wherein the disk drive comprises:

• an integrator for integrating the reference signal to generate an area signal;
• a peak detector for detecting a peak in the reference signal to generate a peak signal;
• and
• a write condition detector, responsive to the area signal and the peak signal, for generating a fly-height signal indicative of the fly-height of the head.

A disk drive having a head and a recording surface, wherein the recording surface includes a track having a user data segment and a periodic reference segment, wherein the head flies above the recording surface at a fly-height that varies as the head flies, wherein during a write operation the head writes data in the user data segment, and wherein during the write operation the head produces a reference signal when reading the periodic reference segment, wherein the disk drive comprises:

• a first filter for extracting a fundamental frequency component from the reference signal;
• an automatic gain control circuit, responsive to the fundamental frequency component, for controlling an amplitude of the reference signal;
• a second filter for extracting a predetermined harmonic frequency component of the reference signal;
• and
• a write condition detector for comparing the predetermined harmonic frequency component to a predetermined threshold for generating a fly-height signal indicative of the fly-height of the head.