Chapter 14 - Off-track performance

Abstract

When a track of information is written on a magnetic medium, it has a certain width that is determined by the geometry of the write bubble along the cross-track direction. The certain width of magnetic medium enclosed by the write bubble is successfully written with magnetic transitions, resulting in a magnetic data track as the disk spins. At larger distances from the track center, the head field decreases below the medium coercivity and is not enough to write magnetic transitions. In theory, the read/write heads are more or less on-track―the head and data track are aligned properly. The on-track performance of a magnetic recording system determines how close data bits can be packed and transferred. In reality, however, the read/write head is often off-track. Therefore, it is essential to consider how the off-track position of the read/write head affects the performance of magnetic disk drives and how the data track configuration can be best designed. The off-track performance of a magnetic recording system is extremely important, because it determines how close data tracks may be written on disk surfaces.