Optical Disks
CD (Compact Disc)
CD-ROM: can read it, but cannot write to it
CD-R: can write, but cannot erase
CD-RW: can write and erase multiple times
DVD (Digital Versatile Disc or Digital Video Disc)
DVD-ROM: regular movies are on DVDs (can read, but not write to them), need a DVD-ROM player (these also play CDs)
Blue-Ray
more expensive, better quality
CD-ROM: can read it, but cannot write to it
CD-R: can write, but cannot erase
CD-RW: can write and erase multiple times
DVD (Digital Versatile Disc or Digital Video Disc)
DVD-ROM: regular movies are on DVDs (can read, but not write to them), need a DVD-ROM player (these also play CDs)
Blue-Ray
more expensive, better quality