8.1.3 Recordability, rewritability, erasability and accessibility

8.1.3.1  CD-R, DVD-R and DVD+R discs are dye-based recordable (write once) discs, but not erasable. CD-RW, DVD-RW and DVD+RW discs are phase-change based repeatedly rewritable discs permitting erasure of earlier data and recording of new data in the same location on the disc. DVD-RAM discs are phase-change rewritable discs formatted for random access, much like a computer hard disc.