A rewritable optical disc. First used in drives by Panasonic in the late 1980s, the phase change technology was subsequently employed in all major optical drives, including CD-RW, DVD-RW ...
CD-R - meaning CD-Recordable, the user can write data to the CD once or fill it over time using multi-session (writing to the same disc on separate occasions). CD-RW - meaning CD-ReWritable ...