Abstract: A data storage device is disclosed comprising a first disk comprising first servo sectors A0-AN distributed around a circumference of the first disk, and a second disk comprising second servo sectors B0-BN distributed around a circumference of the second disk, wherein the second servo sectors B0-BN are offset circumferentially from the first servo sectors A0-AN. While the first and second disks are rotating second servo information is transmitted from a second servo channel to a first servo channel. One of the first servo sectors Ai is read to generate first servo information, and a first command value is generated based on the first servo information and the second servo information, wherein a first actuator is controlled based on the first command value.

Abstract: A reader failover system and method are described for a data storage system. At least two reader systems, including a first reader element and a second reader element, situated on the same head, are employed to read a magnetic storage medium. In an aspect, the head is a two-dimensional magnetic recording (TDMR) head. Control circuitry detects when the first reader system provides less than a predetermined performance or fails, and thereafter causes the second reader system, but not the first reader system, to read the magnetic storage medium. In an aspect, a buffer stores a first reader element signal until the control circuitry detects whether or not the first reader element provides less than a predetermined performance or fails. In an aspect, when a reader element fails, data recovery is performed, and all of, or a majority of, the media continues to be readable, improving the data storage system robustness.