No abstract

A generalized analysis has been presented for describing the influence of overwrite (or reverse overwrite) interferences on the spectra of readback signal, which extends the previous theory in describing the spectra characteristics caused by the hard–easy transition shift. Interestingly, it also suggests that the residual signal from the overwritten data pattern could be periodic as well. Essentially, an imprint effect arising from old data pattern could also create an amplitude-modulated signal that generates sidebands around the fundamental and odd harmonics of the overwriting signal.

An effort has been made to evaluate disk drive components at high data rates. Fully functional write-head/media components to 2.6 Gbit/s have been demonstrated in spin-stand testing and magnetic force microscopy characterizations. In addition, the drive front-end electronics examined possess complete functionality up to 4.0 Gbit/s without significant performance degradation, which is consistent with electric modeling results. Furthermore, our experimental data clearly indicate that the pre-amp’s performance at high frequency is becoming a limiting factor to achieving an ultrahigh data rate in present write-head/media designs. The magnetic moment on write gap edges for certain recording heads shows signs of becoming insensitive to following the write current switching speed at ultrahigh frequency.