Seamless and untrimmed primary servo burst with multiple secondary servo bursts

Abstract

A disk storage system having servo data stored thereon for accurate head position control over a magnetic or other storage medium. The servo data is seamless and untrimmed and consists of a primary servo burst set (AB burst) in which the difference defines the desired tract pitch for the surface. Multiple secondary servo burst sets (e.g., CD burst and EF burst) are written at the desired track pitch but radially offset from the primary burst set. In one embodiment, two secondary servo burst sets are used, but alternatively, any number of secondary servo burst sets could be used. In this exemplary embodiment having two secondary servo burst sets, the CD servo burst set is offset by ⅓ of the track pitch from the primary servo burst set. Also in this embodiment, the EF servo burst set is offset by ⅔ of the track pitch from the primary servo burst set. There are six bursts per set. The servo data is written in multiple servo sectors around the surface of the medium. From the servo data, three PES (position error signals) are generated, A−B, C−D and E−F, for providing linear position sensitivity information to the head position control logic. The resulting PES is more linear for smaller head sizes.