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Posted by Smarty on 05/19/07 20:56
Peter,
My earliest circa 2000-2001 DVDs were made with the best Pioneer burners of
that era, using Apple. Pioneer, and Taiyo Yuden branded media. As more
generic media became available from places like Meritline, Shop4tech,
Supermediastore, etc., I bought a lot of it. My generic disks are mostly
useless, and my brand-name disks are perhaps 30% bad. The vast majority were
recorded at the slowest speeds, typically 1X or 2X, since this was all the
speed then available.
Since the formulation of the newer azo dyes and a much wider range of
improved burners, one might imagine that DVD longevity should be getting
better. This may indeed be the case. This benefit, if any, is, however, a
bit confused by the fact that much higher write speeds (as in shorter dwell
times for burning) may offset the other gains in dye stability, laser diode,
servo, and optics refinements. This is implicitly apparent in the bit error
rates and jitter shown in the phase lock loops which control the positional
servos in recent vintage drives, and recent drives usually measure worse
than older ones in this regard. The push for high write speeds ultimately
puts the user in the situation where slow burns are traded for disk
longevity whether they realize it or not. Speaking for myself, I would not
want to wait 54 minutes for 1 4.7GB burn as I did hundreds of times 7 years
ago, particularly now when the same 4.7GB can be burned in about 6
minutes.....
My personal opinion is that DVD-Rs were intended for distributing video
inexpensively and do very well in this regard. I am now highly suspicious of
any longevity claims based on accelerated aging, and know that my own
collection, stored in a relatively dark, cool, and humidity controlled
basement, is a clear exception to the manufacturers' promises.
Being "burned" by the 20 year life expectancy hype (pun intended).....I tend
to dismiss this particular media most of the time when it comes to data
backup.
Smarty
"Peter D" <please@.sk> wrote in message
news:134u8at3o8dilb6@corp.supernews.com...
> "Smarty" <nobody@nobody.com> wrote in message
> news:UOqdnfhQiMzTZNPbnZ2dnUVZ_s-rnZ2d@adelphia.com...
>> Peter,
>>
>> The newer DVD dyes may indeed be more stable, and only time will tell
>> whether they deliver better longevity than the earlier disks. The
>> definition of "archival" is not at all definitive, so the real issue is
>> whether the desired "archival" storage period exceeds the time the dye
>> remains stable. In my case, disks I made 4 years ago, claimed to have a
>> 20 year shelf life, were unplayable well before the "archival" period I
>> was expecting. Certainly if Amy only wants to backup her archival
>> materials for 2 years and the dyes remain stable for 3, then my concern
>> in not applicable to her situation.
>
> Did you consider the burner in your assessment? I have found that some
> burners, especially some early burners, were a problem, not burning a deep
> enough or strong enough signal. Also burn speeds are a factor. The
> assumption has been to burn at a low speed (2x, 4x) to get a "longer"
> burn, but evidence is mounting to indicate that DVDs designed for
> high-speed (8x, 16x) should not be burned at low speeds because it
> actually causes more errors.
>
>
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