Understanding the effect of the tape surface on the metal-particle tape medium noise

Abstract

Spacing fluctuations resulting from the head–tape interface dominate the metal-particle tape medium noise. Utilizing narrow-gap record heads, the spatial correlation of the head-medium interface has been completely and accurately characterized using a magnetic recording measurement. The measurements show that the spacing fluctuations damp with shorter wavelength, or in other words, the tape head-medium noise possesses a long spatial correlation length. In addition, the results demonstrate that the roughness-induced spacing fluctuations originate from portions of the tape surface that contact the tape, i.e., the load-bearing surface. This understanding of the head-medium noise reveals that the majority of the tape medium noise occurs during the recording process, and not during signal playback. Spatial correlation measurements on low-density (5 kfci) recordings provide verification of these conclusions. The study offers a thorough understanding of the surface roughness role on producing the head-medium noise.

Effects of structure on noise in very thin particulate data storage media

“…However, the sideband noise of the 'skirts' either side of the 2.5 MHz signal shows no variation with thickness. As sideband noise can be used as a measure of the top surface roughness [3], where the resultant variation in head-media spacing leads to amplitude modulation of the intrinsic signal, this indicates the tapes have similar contact smoothness, giving confidence in the consistency of the coating process between tape samples.…”