Chuck Guzis wrote: While I'd like to believe that DVD-R media has the
same permanence, my problems with DVD players successfully reading
movies and such makes me suspicious. It could be that DVD is just
"pushing" the technology a bit.
Storage for CD-Rs in stlil in styrene jewel cases. We'll
occasionally use PVC cases as mailers (they survive the rigors of the
USPS better), but we advise customers to use traditional styrene
cases for storage. From what I've read on the archivists' list, some
PVC material has been found to outgas chlorine.
Cheers,
Chuck
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I never quite know how to take all the disk bashing that seems to come up
periodically on this list. One point that seems to be missed is that the
DVD play back is influenced by the reliability of the laser diode. And that
diode is subjected to thermal stresses far beyond those of the CD-ROM laser
diodes. At the junction temperatures used in DVD burners, the life of the
diode is a small fraction of the CD-ROM diodes. It also deteriorates in
performance from the junction breaking down.
Consequently the playback life of the player is significantly reduced. Yet
it is always the media that takes the hit.
Everybody else seems to have lots of horror stories about media. I don't.
I want to again state that I have seen CD's burned in the 1976-77 time
period that can still be read. And I've seen DVDs from the early 90's that
can also still be read. Reliably.
But the moves to cut the cost of the players to sub-$50 means that many
companies are using substandard laser parts, or parts with shorter rated
life (which are a lot cheaper.)
Every study I have seen shows that CDs and DVDs have a much longer life span
than magnetic media, especially floppies.
Another point made that I do agree with - because of all the music CDs made,
the players will not go away. All the major players in CDs and DVDs have
tried for many years to force to another form factor. Those mostly empty
5.25" chasses are really offensive to design engineers trying to push the
state of the art. And how can you resell the same music again, if you don't
change form factor or format?
But the customer base won't budge. They don't want to render obsolete their
sizeable investment in CDs. (Last year I have data for shows annual
production of CDs in the billions world wide!) Legacy demands will keep the
5.25" form factor around for the rest of my life. Can't speak for you
youngsters. But say another 25 years minimum.
Shame really - I saw some lovely little Blu Ray 20mm disks that held as much
video as the current DVD. Gives you a DVD player that could be built into a
cell phone or toy. But every customer survey showed massive resistance to
change from 5.25".
PVC does outgas Chlorine - and other volatiles. Does nasty stuff to the
reflective films in DVDs. Most jewel cases are better. But oddly enough,
the self cleaning paper sleeves caused the least affects - except for shock
events.
Billy