On Thu, 26 Feb 2004 23:01:07 -0800 (PST), David Dyer-Bennet
<dd-b.TakeThisOut@dd-b.net> wrote:
>"Ron Andrews" <randrew1.TakeThisOut@rochesterDOTrr.com> writes:
>
>> "Don" <nospam.TakeThisOut@please.org> wrote in message
>> news:103mtncafv5ao1a@corp.supernews.com...
>>> I don't agree with the premise that digital files will not survive 20
>>> years - or 50 or 100 years for that matter. I does take some care and
>>> maintenance, of course.
>
>> Agreed. With care and maintenance, digital files will last
>> indefinitely. Since you are committed to maintain them, they will last you a
You have a far more optimistic outlook on this than does the industry.
We, and I used that advisedly as I recently retired from the computer
industry, figure a high quality CD can be reliably stored for about 10
years. Now that is figuring archival data integrity.
I think you would have to go a long way to find someone who actually
works in the industry that would trust data on a CD to be reliable
much beyond that. Yes, they may last far longer, but the material on
which the data is stored will deteriorate. Even CDs properly stored
in a temperature and humidity controlled room require periodic
replacement.
>> lifetime. Will your children and grand children be as committed? If my
>> grandfathers slides (40-50 years old) had been digital images, they might
I have lots of slides that are that old and in good shape. I have
others that are far newer that are not.
>> have survived in our family. The photo of my great great grandfather shot in
>> 1855 was neglected in a box for many decades. It would not still be here if
>> it was digital. Image archive experts recommend that for maximum life,
>> images should be in human readable form.
Most of those images have lasted far longer than the industry believes
their products will remain viable.
>
>A CD left in a box has non-trivial chances of still being around in
>150 years (in the sense of the information being recoverable).
Industry figures just do not substantiate that. Certainly there is a
"probability" that a particular CD will still be around in 150 years,
but they do deteriorate and I currently know of none that claim a
lifetime of any where near that. CDs are fragile and they definitely
are not robust when it comes to deteriorate.
>Furthermore, there could be many copies of that CD floating around (in
>various branches of the family, say).
IF there are many copies AND those copies have been updated often
enough, then yes. but given ten CDs that have a predicted useful life
of 20 years the likely hood of any of them exceeding the predicted
life by 7500% (7 1/2 times) is stretching things more than a little.
Some of the newer CDs *may* and I emphasize the "may" have much longer
lifetimes than they current batch, but we just don't have enough hard
data to prove it. We only have claims and claims have not proven to be
very reliable in the past.
>
>150 years from now, I figure I can put the CD in the atomic scanner,
>point it at the Red Book spec (or whatever one defines CDs), and have
>it figure out what the data means, even if I don't have a CD drive.
Again, there is nothing to indicate the computing industry would even
try to maintain that kind of backward compatibility. It goes against
the industry history and would require a complete change of
philosophy.
For one, the number of people wanting to read obsolete data file
formats would most likely be small, which would make it a niche market
at best. That means the specialized equipment would be expensive.
Very expensive. That is not to say there wouldn't be businesses that
specialized in "Ancient data recovery" as they already exist.
I recently purchased a Nikon LS 5000 slide and film scanner with the
automated slide feeder. My computers have close to a terabyte of
storage between them and several will soon be going to 800 Gig each.
I use high speed R/W drives for both CDs and DVDs.
Yes, I back up the data on CDs and DVDs with the expectation that one
or the other format will be useable in the future. Still with
hundreds of CDs and DVDs storage and organization of the archival data
becomes a non trivial problem.
OTOH I have no illusions that future generations will widely share my
desire to preserve all the family history. Those CDs and DVDs will
eventually end up in the equivalent of a shoe box stuck in some one's
attic or basement. Because there as so many they more than likely
will end up in some future dump.
To expect CDs to remain readable much beyond their expected lifetime
is, based on my experience, fantasizing.
Now I can Hope, and I do, that the technology will soon be available
that will make archiving large amounts of digital data inexpensive and
reliable for long periods. Just remember that no material is
impervious to decay in one form or another.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
<a style='text-decoration: underline;' href="http://www.rogerhalstead.com" target="_blank">www.rogerhalstead.com</a><!-- ~MESSAGE_AFTER~ -->
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