[ale] OT- Re: Cd-r life

[Greg Freemyer]

On Mon, Oct 4, 2010 at 9:44 AM, Paul Cartwright <ale at pcartwright.com> wrote:
> On Mon October 4 2010, Richard Faulkner wrote:
>> This is an issue which I'm starting to wrestle with for the long-term care
>>  and preservation of data and photographic archives for the 34th PRS
>>  website and project.  At this point all archival is done on CD-R and HDD
>>  with new archives coming to long-term (gold) optical media.  Most all of
>>  what we have in storage at this point is (green) media -- likely part of
>> the reason why they have lasted so long.    ----R
>
> got any links to some of this archive media?? gold CDs?

I haven't been reading this thread so this may have already been said:

Kodak sells (used to sell?) CDs with Gold used as the recording media.

This is done because a CD is a plastic-metal-plastic sandwich.  The
metal is protected from oxidation (rust) by the plastic to plastic
seal on the outer and inner circumference of the CD.  (You can easily
see the plastic to plastic area if you just look at the back of a CD.)
 If this seal breaks, then air gets to the metal and you eventually
have data loss due to oxidation.

Since gold does not oxidize, it is used by Kodak to protect the metal
layer from oxidation when the plastic/plastic seal breaks.  I seem to
recall Kodak claiming 30yr lifetime for their gold CDs.

fyi: aiui, the longest term storage media is microfiche.  100+ yrs.
(possibly centuries).

Greg