Vinyl LP's, carefully maintained, have a lifetime
estimated
to be 100 years or more; when played on high-quality
turntables, wear isn't really an issue.
Assuming you don't mind the $10,000 outlay, you can get a
turntable that uses an optical (laser) pickup. Then wear
*really* isn't an issue. Data density and media fragility
might be though.
Unfortunately, no mention was made of CDs using a gold
layer
which is supposed to greatly increase their durability.
Didn't Kodak discontinue their manufacture of such gold CDs a
while back due to a lack of demand for them?
I'm not sure you can rely on "Brand X" being invariant
over any substantial period of time, i.e. the media
you tested 6 months ago may well be manufactured
slightly differently (or completely differently) now.
Bulk buying may not help either - I expect that the
stuff degrades on the shelf even before it is used.
I'm not sure that worrying about the next 50 years
is appropriate anyway. We're losing a good deal of
stuff right now because it's not being archived
in the first place. Once it's digital (in some
reasonable form: HD, CD, DVD, etc.) then replicating
losslessly (assuming you have some sort of checksumming
and multiple copies for when one set of media goes
bad) is at least feasible.
Antonio
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Antonio Carlini arcarlini(a)iee.org