Spatial structure of media noise in film disks

Measurements of the spatial structure of media noise across the track direction are made using new techniques involving computer processing of digitized transient read signal waveforms. Images of media noise having spatial resolution much finer than available head widths are obtained, and are used to study the scaling of media noise with read head width. Results are presented for two types of metal film disks and a particulate disk. Uniformly DC erased media noise is found to decrease less rapidly with decreasing head width for the metal film disks than for the particulate disk, in which it scales approximately as the square root of head width. A strip of excess noise is found at the edges of written tracks on the metal film disks but not the particulate disk.