> >>However, I hear CD-ROM is unreliable even over 12 months, so that's
> >>out.
> >
> > I have heard this too. Does anyone know the physical mechanism
> > responsible for the deterioration? ...
>
> Exposure to light and excessive heat can deteriorate the dye layer on
> CD-R and CD-RW media.
Ah, so the problem is perhaps initial quality rather than an
inherent shortcoming of the principle.
Given a moderate environment (such as a safe deposit box), the "high
quality" CDROM might be the best archival storage available to the SOHO
user. Magnetic tapes print-through. I don't trust the small vertical
domains of the super-high density hard drives for long term storage.
(An older disk might be better!)
Shielding from light is easy. Temperature is the problem. One could
store the archive CDs in the refrigerator, as we have done with
photographic film for years.
The question is, how do you detect a bad CD batch before losing the
data. Since higher temperature would accelerate the loss of contrast
in the dye, a simple test at high temperature might sort the good
manufacturers or production runs from the bad.
A 1 hour stay in an environmental chamber at successive temperatures
30C 40C 50C 60C and 70C with reading tests between should at some point
fail all types. The archival-ness could be judged by the temperatures
at which the errors appeared. I will have to try that. There should
be some cheap CDs at the stationary stores. I have Memorex, but
perhaps I can find some Fuji and Taiyo Yuden to include in the test.
Jim Kuzdrall
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