Developed by Panasonic, PD is a new type of removable media drive that combines an optical disk drive with a quad speed CD reader, essentially giving you two drives in one. A PD drive alternately accepts standard CDs and PD rewritable optical disks into a front loading tray. When the media is inserted into the drive, a micro-optical head inside the PD drive automatically senses which type of media has been inserted.
PD media is a new form of optical disk, which uses a 120mm diameter, single-sided, phase change disk enclosed in a protective cartridge storing up to 650MB of data. The drive can read, write, and erase the PD media.