CDs,+DVDs,+HD+DVD+and+Blu-ray


 * CD
 * 700 MB on one side of the disk.
 * Inexpensive
 * Slower
 * Compact disk
 * DVD
 * Digital Versatile Disc
 * 4.7 GB on one side.
 * Dual layer DVD can hold up to 18 GB.
 * Types
 * CD-ROM // DVD-ROM
 * Permanent data.
 * CD-R // DVD-R
 * Written only once.
 * RW
 * Re-written around 1000 times.
 * RAM
 * Rewritten over 100000 times.
 * Lasts 30 years.
 * HD DVD
 * Optical disk format.
 * High capacity.
 * Blu-ray
 * Up to 50 GB.
 * Likely to replace DVDs.