A particular laser beam shape for erasing and recording in single media rotation.
The domain is created by the phase change recording. In order to make the domain by single rotation of the media, One Beam Overwrite and Mark Edge Recording is utilized.The different laser power corresponding to read, erase, and write, and the comb like shaped laser pulse can make the complete domains.

A particular data mark shape for high density recording°GMark Edge
As an innovative recording method, Mark Edge Recording uses both edges of a recording mark as the signal positions to increase pit density and boost recording capacity.
Recording can hold the data at the every edge of the domain. Mark Position Recording, on the other hand, can hold the data at the center of the domain. Therefore, Mark Edge Recording can avoid the intruption by the nighboring, leading or following domains and can improve recording density on the media.