[CentOS] OT: cheap DVD-RAM media?

Bryan J. Smith

b.j.smith at ieee.org
Fri Aug 5 19:07:00 UTC 2005


On Fri, 2005-08-05 at 14:42 -0400, Peter Arremann wrote:
> Hmm - MO needs a magnetic read head... I guess the technology you 
> guys mean is PD as the base for DVD-+RW... 

DVD-RW and DVD+RW are Phase Change, not Phase Dual IIRC.
DVD-RAM, like PD-CD before it, is a MO variant called Phase Dual.

> Phase Change media (no matter what kind) do have a high error rate... 
> MO media do not.

Actually, MO can without write-after-verify correction.
But yes, I oversimplified by referring to everything as MO.
Sorry about that.

> The biggest customer for those is the US government... 
> it is common for a MO disk to have a 40+ year warrenty. 

Typical expected lifetime is 30+ years, although that assumes you have
other mitigating features (e.g., cartridge).

DVD-RAM is just the DVD Consortium's standard for rewritable.
It was introduced early on because it was inexpensive, and created a
real standard for optical archiving in a sea of proprietary MO formats.

DVD-RW was more of a consumer answer to DVD+RW.

BTW, from my understanding, DVD+R is more of a WORM implementation of
DVD+RW, than a single groove record like CD-R and DVD-R.

-- 
Bryan J. Smith     b.j.smith at ieee.org     http://thebs413.blogspot.com
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