6.4 Overview of CD-RW and DVD
6.4.5 Recordable DVD
Consumer demand for greater amounts of removable storage options has prompted the industry to develop methods of recording DVDs. Currently, there are four different methods of DVD recording. Each of these technologies is vying to be the standard for recordable DVD:
  • DVD-R – DVD-R (recordable) is similar to CD-R technology in that it allows the media to be written one time only. This method is most often used for DVD authoring and is not very practical for consumers due to the price of drives (U.S. $2000 or more) and media (U.S. $20 per disc). Even though price is a drawback for this technology, compatibility is not. Most DVDROM drives and stand-alone players can read DVD-R discs. DVD-R discs can hold 4.7GB of data per side.
  • DVD-RAM – Using the Random Access Memory (RAM) technology allows users to write and overwrite discs 100,000 times. DVD-RAM uses phase-change technology similar to CD-RW drives and stores 4.7GB of information on each side of the disc. DVD-RAM drives are priced below U.S. $1000 with media costs of U.S. $15 per disc. Compatibility is an issue with DVD-RAM drives and most of these drives require the use of a cartridge-based disc while recording.
  • DVD-RW – The DVD-RW (re-writable) is a technology designed to address compatibility and re-recording issues. Geared more towards general-use than authoring, DVD-RW uses a "caddy less" system and allows users to rewrite information on the media to approximately 1000 times. The media is compatible with most DVD-ROM drives and stand-alone players on the market today. The drive uses a sequential recording technology used primarily for streaming media. DVD-RW is capable of writing 4.7GB of information to each side of a disc.
  • DVD+RW – DVD+RW is the latest DVD recording technology. Many major corporations including Hewlett-Packard back DVD+RW. As with DVD-RW, the technology is both compatible with existing hardware and is easily written to multiple times. The major advantage of DVD+RW is the ability to use a variable bit-rate when encoding certain types of media (such as streaming video). The major industry backing of this format coupled with the affordability of the drive (less than U.S. $600) should find DVD+RW as the standard DVD recording format in the near future.