Jitter raising mechanisms for compact disk (CD)-rewritable at quadruple CDvelocity

A disk designed for compact disk (CD) 2X is employed to test its performanc e at CD 4X. The eras ability at CD 4X is poorer than that at CD 2X. A sharp increase in jitter after overwriting for CD 4X was observed as a result of the existence of two different amorphous mark shapes. One of them is of no rmal shape and the other is extended with a tail in the trailing part. For overwriting more than 50 times, only one type of amorphous mark with tiny s harp tail was observed. This singular amorphous mark shape gives rise to a decrease in jitter. For much higher overwriting cycles, the jitter will inc rease with the amount of pinholes present.