| 摘要 |
An optical writing and reading method and apparatus for writing data on a recording medium. To prevent an over-writing of data, a mark is written to indicate that data is already written. Before writing data, a mark is written on a mark recording region. Simultaneously with the writing of the mark, the light quantity reflected from the mark recording region is detected. When the reflected light quantity indicates that data is already written, subsequent data writing is inhibited. |
