A method of an embodiment of the invention rotates an optical disc having
an optically writable label side. The optical disc is radially scanned
with a laser incident to the optically writable label side, from a first
edge of the optical disc to a second edge of the optical disc. While the
laser is radially scanned from the first edge to the second edge of the
optical disc, a first radius at which markings have not been written to
the optically writable label side of the optical disc, next to a second
radius at which markings have been written to the optically writable
label side of the optical disc, is detected.