Disk drive integration issues for perpendicular recording

In addition to achieving high areal density, recording with perpendicular m edia must be compatible with other elements of disk drive recording. These include use of rotary actuation, the need for offtrack capability, stray fi eld immunity, and servo control of the head position. Rotary actuation impl ies writing and reading with the head skewed at substantial angles relative to the track, while servo requires dean track edges. A soft magnetic under layer, while improving the perpendicular write efficiency, exacerbates prob lems with head skew and stray fields. We have performed experiments related to drive integration, at the component level and by building drives incorp orating perpendicular media. We report on the effect of head skew on the dr ive, particularly for servo and data recovery. We report on a beveled probe head design which minimizes the effect of skew on the servo pattern and tr ack squeeze. In a 20 Gbit/in(2) drive, perpendicular media yields comparabl e servo and nearly equal areal density performance to longitudinal recordin g.