What is the difference between DVD-R / DVD-RW, DVD+R / DVD+RW, & DVD-RAM drives?

DVD-R - pronounced ‘DVD R” (not “DVD dash R”)

DVD-R was created by the DVD Forum (see it at http://www.dvdforum.org/forum.shtml). The most common DVD-R is a write­once 4.7gb “general purpose” disc, which is roughly equal to 120-minutes of standard playing lime.

Once recorded, a DVD-R can be played on most home DVD players. (Advertised as compatible with 90%+ of home DVD players.) General purpose DVD-R media is currently the cheapest & most common, and the newest DVD-R drives write at up to 4x. “General-purpose” discs are part of the industry’s copy-protection scheme, which employ CES scrambling to protect movies and music and game discs from being copied. These discs can be burned by “general-purpose” DVD writers such as the Pioneer DVR-A05/A04/103, Panasonic LF-D3 1 1/D321, Toshiba TSDR5002, Apple Superdrive, etc. Such drives cannot copy the playback descrambling codes on DVD movies or game discs, preventing easy duplication of commercial discs.

DVD-RW - pronounced ‘DVD R W” (not “DVD dash R W”)

DVD-RW was created by the DVD Forum (see it at http://www.dvdforum.org/forum.shtml). Generally comes in the single-sided, single layer 4.7gb capacity, which is roughly equal to 120-minutes of standard playing time.

In contrast to the write-once DVD-R types, the DVD-RW is fully re-writable or erasable up to 1,000 times. However, unlike the older DVD-RAM format, these particular erasables are NOT “random access”, meaning that you cannot erase bits and pieces of them. Instead, you have to completely erase the whole disc to reuse it The DVD-RW can be played on many home DVD players, but not as many as the DVD-Rs.

DVD+RW - pronounced ‘DVD plus R W”

This disc type was created by the “DVD+RW Alliance”. A few companies who back the DVD Forum (above) are also active in the DVD+RW Alliance, but the two standards are not compatible.

The first “plus type” DVD recording format is DVD+RW. It, like DVD-RW, is a rewriteable 4.7gb DVD disc. DVD+RW, does have a couple of technical advantages — (1) lossless linking (which enables some editing after recording without a full erasure that DVD-RW requires), (2) a special drag-and-drop file support on the desktop (otherwise known as DVD+MRW). Unfortunately, the DVD+RW disc type does not compare well with DVD-R as far as DVD playback compatibility. However, the actual level of DVD workability on players of DVD+RW is claimed to be about equal to DVD-RW.

DVD+R - pronounced ‘DVD plus R”

This disc type was created by the “DVD+RW Alliance”. A few companies who back the DVD Forum (above) are also active in the DVD+RW Alliance, but the two standards are not compatible.

The newest “plus type” format is DVD+R. It’s write-once disc is aimed at becoming more compatible with home DVD players. However, the fact is that so far it is only about as compatible as DVD-R discs are. Also, DVD+R discs are more expensive in today’s market, and are not burnable by 1st generation “plus-type” burners, which were designed only for the DVD+RW rewriteable discs. Like DVD-R “general purpose” media, DVD+R cannot copy the descrambling codes found on DVD video discs, so commercial discs cannot easily be duplicated. DVD+R drives have recently reached the same maximum recording speeds as DVD-R drives. (4x)

DVD-RAM

DVD-RAM is used for data backups and storage, and for editing of video or audio content prior to the production of a final distribution DVD. The DVD-RAM disc type is made to act a lot like a hard drive, where the disc can be formatted for Macintosh or Windows type computers. It can handle 100,000 or more erasures, and should last for many years. Of course it is not playable on most DVD players. Type 2.0 DVD-RAM discs can be removed from their cases to enable playback on the few players in which they are compatible. The newer DVD-RAM drives can handle any sized such disc, including 2.6, 5.2, 4.7 or 9.4gb discs.

Some drives support two or more of the above DVD formats. Most add support for CD-R / CD-R W burning as well. But, no currently-available drive has support for all of the D VD / CD formats.