The invention is directed to a magnetic storage medium recorded with an amplitude-based servo pattern in which one or more first servo windows positioned above a centerline of a servo track have a different width than one or more second servo windows positioned below the centerline. The first servo windows may be larger or smaller than the second servo windows. In either case, by detecting the widths of the servo windows and detecting signal amplitude as a servo head passes relative to the servo track, servo tracking can be achieved without the use or need for additional synchronization marks in the servo pattern.