| 摘要 |
<p>This invention relates to an optical disk, in which part of the sectors are reproduction-only sectors (11A, 11B; 14A, 14B) and remaining sectors are recording-reproduction sectors (12, 15). Data and first error correcting codes for the data are recorded in advance in the reproduction-only sectors, and second error correcting codes for data over a plurality of reproduction-only sectors are recorded in advance in other reproduction-only sectors. At data reproduction, only sectors which are unrecoverable by the first error correction codes undergo error correction by the second error correcting codes, and the corrected data with the first error correcting codes being appended are recorded in the recording-reproduction sectors. Later on, when data in sectors unrecoverable by the first error correcting codes are needed, the above-mentioned recorded sectors are read out. Data storage about twice the capacity of the data recording areas is made possible by adopting the PWM (pulse width modulation) recording for the data reproduction-only area and the PPM (pulse position modulation) recording for the recording-reproduction area.</p> |
