Disk drive self-servo writing includes transferring a reference pattern by
magnetic printing onto a reference disk, wherein the resulting printed
reference pattern includes embedded servo information that provides servo
timing and head position information, installing the reference disk and a
head into the disk drive, reading the printed reference pattern using the
head to generate a readback signal, sampling the readback signal at a
sampling rate to generate a sampled signal, processing the sampled signal
waveform spectrum to generate a recovered signal including the embedded
servo information and fundamental and higher harmonics of the sampled
signal, using the embedded servo information from the recovered signal to
precisely position and maintain the head at concentric tracks of the
reference disk, and self-writing servo patterns onto the tracks with the
head.