DVD-R+ and DVD-R-

• Both DVD-R + and - do the same thing -- burn information to DVDs via a recorder. You can do this on a computer's recordable disc drive. These discs can only be recorded onto once. The differences between these discs is the manufacturers. They each hold 4.7GB of data and can be played on most home DVD players.
  
  

DVD-RW and DVD+RW

• These discs can be written and rewritten on thousands of times before the disc will show any degradation. They can be used only in DVD recorders and burners that give support for DVD-RW and multi-format recording. Like the DVD-R, they also holds 4.7GB of data.
  
  

Types and Companies

• Panasonic, Toshiba, Apple, Hitachi, NEC, Pioneer, Samsung and Sharp use the DVD-R and DVD-RW, while Philips, Sony, Hewlett-Packard, Dell, Ricoh and Yamaha use the DVD+R and DVD+RW.
  
  

Dual layer DVDs

• Dual-layer DVDs do the same job as most recordable DVDs, but they hold twice as much data, 8.5GB as opposed to 4.7GB. They can only be recorded on once, and can only play on double- or dual-layer DVD players.