hase change D
ual disc) An earlier rewritable optical disc from Panasonic that used phase change technology. Introduced in 1995, its 5.25" cartridges held 650MB and withstood 500,000 rewrites. The PD drive also read CD-ROMs, but not Panasonic's prior phase change (PCR) disks. See phase change disc
and optical disc
The PD cartridges looked like and used the same technology as DVD-RAM discs. Panasonic DVD-RAM drives could also read PD discs.