Patent ID: 7027383

Claim:
An optical data storage medium ( 1 ), having an optically readable information layer, with a first optical reflectivity, said layer having an annular zone ( 12 ), with an inner periphery ( 3 ) and an outer periphery ( 4 ), outside the user data recording area ( 2 ), said annular zone ( 12 ) having at least one first type ( 5 ) of sector extending from said inner periphery to said outer periphery provided with a permanent information mark ( 7 ), having a second optical reflectivity different from the first optical reflectivity, characterized in that the annular zone ( 12 ) has at least one second type ( 6 ) of sector extending from said inner periphery to said outer periphery provided with a recordable identification mark ( 8 ), having a third optical reflectivity different from the first optical reflectivity; thereby creating a hybrid annular zone ( 12 ) containing both the permanent information mark and the recordable identification mark to save radial space, wherein the recordable identification mark ( 8 ) has a physical format and a spatial bit-cell ( 31 ) density, which are substantially equal to the physical format and the spatial bit-cell ( 31 ) density of the permanent information mark ( 7 ).