Phase change Dual

Phase-Change Dual (PD) is a rewritable optical disc format introduced by Panasonic in 1995. Much like CD-RW, PD uses a phase change layer that can be overwritten in a single pass of the read/write head. A PD disc has a capacity of 650 MB, can be rewritten 500,000 times and is enclosed in a protective cartridge. PD discs are compatible with PD drives and first generation Panasonic DVD-RAM drives while PD drives can read and write PD discs as well as read CD-ROMs.