What are CD-ROM/WR and DVD-ROM+/-WR?

CD-ROM (compact disk read only memory) is removable media drive that hold 750+ megabyte of data.CD-RW (compact disk re-readable re-writable) is extension of CD-ROM that allows data to be erased and write again.DVD (digital versatile disk) store close to 10GB for single layer and 17GB for dual-layer disk. DVD can store movies with high graphic and sound quality and data.DVD+/-RW (DVD re-readable re-writable) is extension of DVD-ROM that allows data to be erased and write again.