By Kire Terzievski, RMIT Test Labs
June 18th, 2002.
DVD+RW and DVD+R
(Write and rewrite speed: 2.4x; this has the same data throughput as a 20x CD writer.)DVD+RW is well suited to applications where data may need to be freely overwritten in everyday use, such as for storing data or making DVD-Videos, and can be used for almost all applications. We should also note that you can easily append data to a DVD+RW disc, making it highly suitable for backups. DVD+RW technology was also introduced before DVD+R. However, most DVD+RW drives now extend their capabilities by being able to write to -write once" only discs.
DVD+R has been developed for those instances where important data should never be erased, or data is to be distributed or exchanged, and compatibility is extremely important. While keeping data from being erased or overwritten, the discs share a high level of compatibility because of the format's physical specifications that are basically the same as DVD-ROM discs.
DVD+RW Video is encoded in MPEG2 with a variable bit-rate, providing high bit-rates where necessary while no storage capacity is wasted in scenes with less movement. This means that under some circumstances, much longer recording times can be achieved with the same disc capacity.
DVD-RW and DVD-R
(Write speed: 2x, rewrite speed 1x)
DVD-RW is suited to applications where data is to be overwritten each time. One problem with this format is that the software that comes with these drives cannot record multiple sessions. While DVD-R was also developed for instances where data should not be erased. DVD-R discs are also more compatible than DVD-RW discs.
DVD-RAM
(Write speed 1x)
DVD-RAM media are housed in cartridges and were initially limited to a 2.6GB capacity. Now there are discs that store 2.6G4.7GB, 5.2GB, and 9.4GB. The main problem with these discs is that no other drive besides a DVD-RAM drive can read DVD-RAM discs.
How many times can a DVD+RW disc be overwritten?
A DVD+RW disc is very similar to a CD-RW disc in terms of the number of times that it can be re-written to. Tests have proven a re-recording capability of over 1000 times. DVD-RAM is re-writeable up to 50,000 times.
8%
1%
