On Thu, 10 Sep 1998 08:10, Pauls0627@xxxxxxx wrote:
>In a message dated 9/10/98 12:54:09 AM Eastern Daylight Time,
>msparks@xxxxxxxxxxxx writes:
> Dan, I agree with your concerns about the impermanece of many forms of
> digital storage, and could even add a few of my own. But I think
> including modern optical disks in this odd lot is premature. Their mass
> acceptance worldwide is a phenomenon that I'd compare to the invention
> of the printing press. The loss of digital history would require a
> fairly catasrophic interruption in human civiization. >>
>I agree with Morgan. One of the key features of digital imaging is the ability
>to create an EXACT duplicate of the original. While specific storage
>technologies may become outdated, it is a relatively simple matter to copy the
>data to newer technologies. I was recently involved in a project where
>engineering drawings for nuclear submarines, which had been stored for 10
>years on 12" glass WORM (Write Once Read Many) disks were copied to newer,
>5-1/4" platters, specifically because the 12" versions had become obsolete.
>I'm sure the 5-1/4" platters will last us at least another 10 years, at which
>time we'll migrate to something newer and better.
But that was just my point: you have to keep copying the data every
few years if you want to preserve it. On the other hand, if the
data is kept on a medium that does not obsolete in a few years, then
you don't have to keep copying it (for all practical purposes, all
medium will preserve the data for decades, if not centuries). The
carvings of ancient Egypt can still be read today, the same with the
menuscripts of the middle ages, and the printed books of the previous
centuries. The pictures taken 75-100 years ago can still be seen,
and the photographs taken 50 years ago can still be reprinted from the
negatives -- all this without copying every few years.
Going back to my previous example, if the information I have on the
punched cards is important enough, I am sure I can build a card reader
that can recover the information. And if I had the forethought to
preserve that data, I would have copied it to mag tape when cards
seemed obsolete, and then from mag tape to 8" floppies, and then to
5.25" floppies, and then to cartridge tape, and then to ... But on
the other hand, if I have a printout of the data on paper, I can still
read it today.
Granted, a copy of digital information is more accurate than an analog
copy, but how many of us amatures can afford to keep copying ALL the
digital pictures we have taken every few years? And if we limit the
discussion to digital pictures, don't forget that the picture started
out as a digital approximation of an analog image, captured via an
digitizing device. So an EXACT copy of an approximation is still an
approximation. The difference between digital archive and film+paper
archive is that digital requires active preservation (re-copy once
every few years to new medium), while film+paper is passive (file
it away in a drawer and forget it).
>I've also noticed that the industry is getting better at making the technology
>backward compatible. The 2.6GB 5-1/4" optical drives we put in can read both
>the earlier 1.3GB and 650MB platters. The new DVD drives can also read older
>CDs. So maybe we're making some progress...
This is true, but unfortunately when the technology completely changes,
there is no chance for backwards compatibility. The CD to DVD change is
an evolution of the technology, but the next change may be a revolution
with completely different medium. The change from 360K 5.25" floppies
to 1.2M was evolutionary, and it provided backwards compatibility, but
the change from 5.25" to 3.5" was revolutionary with no compatibility
possible.
Personally, I think the world will lose a lot of significant historical
knowledge when everything is digital.
-Dan
>Paul Schings
>Coventry, RI
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