I said

> NIST REPORT - Stability study of Optical Discs - a study of error
> rates in harsh conditions.
>         http://www.itl.nist.gov/div895/gipwg/StabilityStudy.pdf
etc

Comment below is from a friend with substantial experience in 
electronics etc.


        RM

___________________________________

I agree with essentially everything you say except (the implication 
that) it
should be possible to identify a CDR manufacturer/product which is 
better
than most and hence likely to provide longevity.

While this may be possible, there is no guarantee that one CDR of a 
given
type will perform identically to one that is ostensibly identical but
purchased at a different time/place.

We have found that Kodak CDR's from different batches performed quite
differently as far as relibaility on initial writing is concerned, and 
that
some batches were readable in a given CDROM drive while others 
(written in
the same drive at the same speed etc.) were not.

My gut feeling is that CDR (and it's descendents) is not a technology 
that
can be relied on for long-term archival of critical data. 
Unfortunately
there probably isn't an technology which combines sufficient capacity 
with
adequate longevity, and as far as I (and others) can see it is very 
likley
that the end of the 20th century will be noted as a point at which 
important
historical information began to "evaporate".

Not all of this can be blamed on flaky media of course  - there is 
also the
issue of a proliferation of media with short technology lifetimes, the
amount of transitory information which is deemed to have no 
longer-term
value (i.e much e-mail correspondence), and information which only 
ever
exists on-screen as a result of dynamic content generators 
(database-driven
applications, etc.).

As a case in point, I can read the classified ad's in a 1900-vintage 
copy of
the Herald, but I doubt anyone in 100 years time will be able to see 
what
people were buying/selling on Trademe (and at what prices).

Regards,

Ken Mardle

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