 The layer jump is a switch (jump) between the layer closer to the laser head (referred as L0) to the farther layer (referred as L1), or vice versa.Jumping layers is already necessary for reading multiple layer optical media (so far market released products are limited to two layers despite some research prototypes having up to eight layers), as well as for recording them with Sequential Recording.However the layer jump during the recording occurs only once, at the position called Middle Area, during a Sequential Recording, while it may occur multiple times with Layer Jump Recording.