Optical Storage (CD and DVD)
Optical media are today's most important software distribution method, for both computer programs and entertainment such as music and videos. Add writing capabilities, and your optical drive can also back up your hard disk or make discs to send files to friends or production houses. You can even make your own CDs for your stereo system or turn home movies into private-label DVDs. And a read/write optical drive can even substitute as your primary mass storage system should your hard disk fail and you have patience even a saint would envy. When the new Mount Rainier system makes its way into operating systems, your CD drive will likely fully take over the role formerly assigned to floppy disks.
Although the CD and DVD are often treated as two different systems, they share a common heritage and technology. The DVD is really only the second generation of optical disc storage for computers. The major technical differences are a result of improvements in technology over the nearly two-decade history of the CD medium. No revolutionary changes separate the two. In fact, the biggest changes only reflect new formats created to take advantage of the larger capacity the technical refinements permit.