High Density DVD's

[carpedick]

Ok, my question isn't really video related, mostly media. I'm looking for a high capacity DVD for backing up data as opposed to tape backups. The only thing I was able to find was what was listed in this sites DVD FAQ's about DVD-18, ability to hold 15 DS/DL. I have also found another site which details a "Blu-Ray High-Density DVD" that can hold up to 27 gigabytes SS/SL.

Does anyone know which of these technologies is available and where?

[lattedfw]

DVD-R/RW and DVD+R/RW are only single-layer media. Each layer holds 4.3GB of data (advertised as 4.7GB but that's 1000-byte kilobytes not 1024-bytes). There are dual-sided DVD-writable media, but not dual-layer. There will probably never be dual-layer recordable DVD (reason for this addressed in several posts). The BlueRay technology won't be available for a few years.

[carpedick]

So, if I understand you correctly, there are double layer DVD's that are available for reading but not for writing.

[Thorn]

Dual layer DVDs have to be pressed (i.e. commercial discs). Theoretically the DVD spec allows up to 4 layers on the same side, but that hasn't been implemented in commercial players.