An optical data/information storage medium comprises a disk-shaped substrate with a data/information encoded surface having a plurality of concentric, radially spaced-apart data tracks formed therein, each of said data tracks comprising a plurality of spaced-apart, nano-dimensioned data pits or marks with different angular orientations with respect to a down-track direction of each data track. Each of the data tracks further comprises a plurality of spaced-apart, nano-dimensioned servo tracking pits or marks with a preselected angular orientation with respect to the down-track direction for use in obtaining radial error (RE) signals of a read-out head by means of radial push-pull (PP) or differential phase detection (DPD) tracking.