[Beowulf] Re: Interesting

Robert G. Brown rgb at phy.duke.edu
Fri Oct 29 11:59:03 EDT 2010


On Fri, 29 Oct 2010, Ellis H. Wilson III wrote:

> Interestingly, I found "Keeping Bits Safe: How Hard Can It Be?" by David 
> Rosenthal in the November Communications of the ACM just released.
>
> It does discuss data retention at the centuries level, but unfortunately does 
> not consider the moon-based strategy proposed by Rob.  Nonetheless is a good 
> read for any out there who are now interested in this area. However, I do 
> wish flash (or any technology besides normal 3.5in hard drives) was 
> considered.  I would expect dormant flash-based technology to last quite a 
> while at controlled temperatures.

IIRC flash has serious bitlevel problems in its read-write cycle,
although this is improving.  But fundamentally, what we're dealing with
is the good old second law of thermodynamics and microscopic statistical
mechanics.  The smaller one makes "bits" in any kind of storage system,
the more susceptible they are to "random" (thermal or non-thermal)
processes that erase their contents -- cosmic rays or other radiation,
pure thermal day, quantum decay, physical accidents or electronic
accidents.  In order to prevent this sort of progressive diffusion of
disinformation, one has to a) lower the temperature of the storage
medium to as low as one can make it.  Pluto would therefore make a great
repository, if it weren't for the possibility of a gravitational
resonance that might one day send it e.g. crashing into Neptune or the
Sun (something we cannot predict as it is a many body problem with
unknown masses and chaotic solutions:-); and b) use large objects with
lots of atoms in them in highly stable and non-reactive configurations
to store the information.

Cunieform on carefully stored, thick, baked clay tablets stored in a dry
environment that rarely experiences frost -- a good way to make it
through 6000 years.  Fossil imprints buried deep in the earth in
not-particularly-geologically-active rock layers in dry, thermally
stable mountainsides are pretty good out to a few hundred million years,
with a lot of degradation of course.

Not much is good out to a billion years.

But as for electronic storage -- well, that's pretty much a joke.  Not
only are the media themselves cheap mass produced pieces of crap, but
the technologies that underlie them have the expected lifetime of a
love-sick moth trapped in a box full of lit candles.  A decade or
perhaps two, tops.  At that point the very interface they depend on is
likely to go away, and go away forever.  Do they even MAKE floppy
controllers any more, on motherboards?  In a few more years, will they
even make motherboards and desktop computers with ROOM for a floppy
drive?  And then, is the information saved on those "lifetime" verbatim
floppy disks still there, or have cosmic rays erased key bits so that it
is no longer accessible if you HAD a controller?

This may change.  In fact, there is room for an entrepreneurial thing,
here.  Really Long Term storage is valuable.  But it ain't available
yet.

    rgb

>
> ellis
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Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu


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