A magnetic data storage medium is provided that has a substrate surface with regularly spaced, continuous ridges and grooves thereby to enhance the magnetic layer crystallization orientation. Data storage tracks extend longitudinally along the ridges, the grooves between adjacent ridges providing separation between data tracks on either side of each ridge. To form the substrate surface a focused laser beam is continuously applied to the substrate in a path of generally circumferential direction on the disk surface between inner and outer radii of a data storage zone while the substrate is rotated at a relatively constant first speed and the focused beam is moved radially at a relatively constant second speed.