Bill Kearney wrote:
He called to say he has recently compiled a 2 DVD set

Are these stamped DVDs or just burned ones? Anyone can download and burn
their own DVDs these days. But burned DVDs are proving notoriously
unreliable. Stamped DVDs (like CDs) are far more reliable. If he's just
selling free data onto burned DVDs it's hardly worth paying anything for
them. Just download and burn 'em yourself.


Why are burned DVD's notoriously unreliable? I know there are problems
with DVD+ and DVD- and people trying to "burn" protected DVD's, but if
it is in the correct format and the orginal is not protected, why are
they having problems? I really have not had any problems with viewing
burned DVD's, is it just because I am lucky?

"Reginald P. Smithers III" wrote in message
. ..
Bill Kearney wrote:
He called to say he has recently compiled a 2 DVD set

Are these stamped DVDs or just burned ones? Anyone can download and burn
their own DVDs these days. But burned DVDs are proving notoriously
unreliable. Stamped DVDs (like CDs) are far more reliable. If he's just
selling free data onto burned DVDs it's hardly worth paying anything for
them. Just download and burn 'em yourself.


Why are burned DVD's notoriously unreliable? I know there are problems
with DVD+ and DVD- and people trying to "burn" protected DVD's, but if it
is in the correct format and the orginal is not protected, why are they
having problems? I really have not had any problems with viewing burned
DVD's, is it just because I am lucky?


Burned CD's can change. The reason being the construction. The critical
part of a CD is not the clear side but the shiny side. A pressed CD has the
dimples pressed in and then the coating is applied, and the distance from
the surface to the reflective coating does not change. A burned CD,
diffuses an internal material. If heat and chemistry happen, that diffusion
can grow or change. The reason a CD works is the light source is reflected
from the shiny coating or the diffused internal area. The diffused or
dimple is 1/2 wave length in depth, so you get a cancellation of light. A
dark spot. If there is damage to the reflective surface, then bad data.

"Calif Bill" wrote in message
link.net...



Burned CD's can change. The reason being the construction. The critical
part of a CD is not the clear side but the shiny side. A pressed CD has
the dimples pressed in and then the coating is applied, and the distance
from the surface to the reflective coating does not change. A burned CD,
diffuses an internal material. If heat and chemistry happen, that
diffusion can grow or change. The reason a CD works is the light source
is reflected from the shiny coating or the diffused internal area. The
diffused or dimple is 1/2 wave length in depth, so you get a cancellation
of light. A dark spot. If there is damage to the reflective surface,
then bad data.



I read at some point in time:

A burned CD has an approximate storage life of only 3 years before it can
start having data errors simply due to aging. They are not recommended for
long term storage of important documents or files.

Interestingly, magnetic media (tapes) have an estimated data storage life of
approximately 100 years.

Eisboch

Why are burned DVD's notoriously unreliable? I know there are problems
with DVD+ and DVD- and people trying to "burn" protected DVD's, but if
it is in the correct format and the orginal is not protected, why are
they having problems? I really have not had any problems with viewing
burned DVD's, is it just because I am lucky?

Burned DVD video seems far more tolerant of errors. I've had HORRENDOUSLY
bad reliability problems with burned DVD media. This being from several
different brand discs, different burners, software, PCs and even locations.
Seems a good many discs just don't want to let you record multi-gig files
onto them. Well, they'll let you RECORD but you're screwed if you want to
read them back whole. And I'm talking about storage intervals of sometimes
less than ONE MONTH! This in a controlled temp/humidity environment. It's
bad enough that I've gone back to TAPE.

Note, I'm talking about DVDs here, not CDs. I've had better luck with CD-R
media, but they're not large enough to hold the files involved (large
..tar.bz archives of XML data)

-Bill Kearney

"Bill Kearney" wrote in message
...
Why are burned DVD's notoriously unreliable? I know there are problems
with DVD+ and DVD- and people trying to "burn" protected DVD's, but if
it is in the correct format and the orginal is not protected, why are
they having problems? I really have not had any problems with viewing
burned DVD's, is it just because I am lucky?

Burned DVD video seems far more tolerant of errors. I've had HORRENDOUSLY
bad reliability problems with burned DVD media. This being from several
different brand discs, different burners, software, PCs and even
locations.
Seems a good many discs just don't want to let you record multi-gig files
onto them. Well, they'll let you RECORD but you're screwed if you want to
read them back whole. And I'm talking about storage intervals of
sometimes
less than ONE MONTH! This in a controlled temp/humidity environment.
It's
bad enough that I've gone back to TAPE.

Note, I'm talking about DVDs here, not CDs. I've had better luck with
CD-R
media, but they're not large enough to hold the files involved (large
.tar.bz archives of XML data)

-Bill Kearney


Density. The DVD format is much more dense, so any bleeding of the dyes in
the media, and you can easily be beyond the error correcting code facility.