| 摘要 |
PURPOSE:To enable the light protection of high reliability strong even for a soft error by providing the information showing a ROM part, RAM part and one part of the zone range on an optical disk and prohibiting the rewriting of the ROM part. CONSTITUTION:A ROM part 5 and RAM part 6 are provided on an optical disk 1, the information showing the one part of the zone range thereof is provided as well and this information is read by an optical pickup head 10 and fed to a disk controller 12 via a signal reading circuit 11. It is then compared by a comparison part 22 with the storage contents of a boundary position storing part 21 and the erasing and writing by the head 10 are prohibited for the ROM part 5 via a laser driver 13. With this prohibition by hardware, the light protection of high reliability strong even for soft errors can be executed. |
