High Density Servo Track Writing Using Two-Stage Configuration

In order to increase the track density of hard disk drives, it is essential to develop new technologies for media level servo track writers that support writing of qualified servo patterns at high track density. This paper describes essential servo control requirements for the servo track writing that can support high number of tracks per inch (TPI). Servo systems for conventional servo track writing, media level servo track writing and self servo track writing are reviewed. A hybrid servo for media level servo track writing using a two-stage configuration is proposed and experimentally verified. Experimental results show that the proposed method can minimize the effects of all relative vibrations existing between the head and the media and hence increase the track density from 142 kTPI to 362 kTPI.