Physical Layer

The physical layer of the LVDD handles startup and termination of the physical request. The physical layer calls a physical disk device driver's ddstrategy entry point with a list of buf structures linked together. In turn, the physical layer is called by the iodone kernel service when each physical request is completed.

This layer also performs bad-block relocation and detection/correction of bad blocks, when necessary. These details are hidden from the other two layers.