| 摘要 |
PURPOSE:To provide an optical disk suitable for densifying information by making the pitch of a pit track narrower than the pitch of a recessed or a projected groove track and providing a boundary region designating the boundary on the boundary between the region of the recessed or the projected groove track and the pit track region. CONSTITUTION:A RAM area 102 for recording/reproducing data and a ROW area 103 in which reproducing information is pre-formatted in advance are provided in an optical disk 101. The boundary between the RAM area 102 and the ROM area 103 is a boundary region 104 and provided with a sector 105 and zones 106a, 106b, 106c. The optical disk 101 is divided into plural sectors 105 per a round, is divided into plural zones 106a, b, c in the radial direction and a number of sectors in each zone per a round is constant. Two spiral shaped groove tracks of projected and recessed groove tracks 110, 111 are provided in the RAM area 102 and information is recorded in both tracks 110, 111. The track 112 in the ROM area 103 is spirally provided. |
