Rob Danielson wrote
At 9:04 AM -0700 5/29/10, umashankar wrote:
re:
>dvd back ups look promising but if one disk out
>of ten fails in a few years (and they do),..
About 5-6 years ago, I started following the
suggestions in a study produced US Library of
Congress and National Institute of Standards and
Technology http://tinyurl.com/2bve9d8 (pdf) to
use discs with phthalocyanine dye on a silver and
gold alloy reflective layer and to burn the media
at no more than 2X rate. I was able to find a
Block Error Rate (BLER) study on line that used
conforming Mitsui and Taiyo Yuden Silver Silver
DVD-R media and rated current CD/DVD burners
(2004). I bought a Pioneer model 107D which
scored high and, so far, none of the 2000+
DVD-R's I've burned with this device/media has
failed to mount or restore data.
Thanks, that is very "real World" encouraging practical experience.
I have (circa 1998-2004) used a Plextor CD burner & a range of supposedly
hi- end CDR's eg Verbatim, & Traxdata, plus I always checked every "burn"
is bit perfect & find about 10% of my back-ups have errors, when I checked=
them about 3 years after creating them.
As it happens I had the DAT media from which they came so I re-digitised
then re-edited the lot. [yes, very laborious but as it happens ultimately
better results were had]
Thus far my more recent DVD+R backups seem fine, (intuitively I feel the
more data that gets recorded on a disk the more likely it will F*** up, my=
CDR's {low density) experience is not good, so DVD & more so Blu-ray seem
frightening) yes it is a worry.
IE the suggested 200 year archival life of my original CDR-data back-ups is=
clearly a bad joke!. And yes they were not in cardboard sleeves that may
have chemically degenerative qualities & they were kept in the dark at
reasonably low and stable temperatures..
John L
Out of the 600
disc orders, I track the number of discs that do
not verify after burning and the maximum number
has been 4. My cost is less than 10 cents/GB
including plastic sleeves and storage cases. I
store my media in light tight cases from 62-72
degrees at 50% humidity.
Studies estimate disc longevity for the
phthalocyanine/metal combination under proper
storage conditions from 30-250 years. Today, one
can buy gold DVD-R media with phthalocyanine dye
which some reports suggest is a more stable
combination.
In support of umashankar's observation, I have
received quite a few DVD and CD's of other types
burned with other burners fail to mount,
including burners that came in brand new Macs and
PC's.
The last time I looked for a similar Block Error
Rate (BLER) tests for current burners/media, I
didn't come-up with much. If I we're getting
started with DVD-R archiving right now, finding a
good BLER study is where I'd start. Plextor and
Pioneer had consistently higher scores in
2004-2005; I'm not sure what the state of burners
is right now. Once you find a confirmed
burner/media combination, I'd consider buying two
or more of the burners. Rob D.
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