The rewritable data storage medium (1) has a rewritable recording layer (9) provided with a tracking structure (8). Said layer (9) has a data recording area (5). An erasable identification mark is present in an identification mark area (4, 4′) other than the data recording area (5). The data recording area (5) has a first tracking structure (8′), whereas the identification mark area (4, 4′) is substantially free from a tracking structure or has a second tracking structure (8″) substantially different from the first tracking structure (8′).Thus erasure of the identification mark is practically impossible, because the location of the erasing spot of a recorder cannot be controlled precisely in radial direction.