-=> Jay Emrie said to Greg Mayman
 -=> about "MESSAGE EDITING" on 12-24-02  22:38.....

 JE> But that is the problem - it will not stay in one piece.

Quite a few of the early movies were copied onto more stable
stock which was around from the early 1930's IIRC. But movies
made as late as the 1960's are deteriorating fast due to fading
of the dyes, and I believe there are a large number that have
been lost to that effect.

I saw an excellent documentary a few years ago about the "repair"
of 'My Fair Lady'.

 GM>But how long will CDs and DVDs last? Does anyone know?

 JE> I believe it is projected to be many many years - which
 JE> seems logical considering the way the CDs are made and the
 JE> way data is recorded on them.

Since the surface of the CD or DVD is covered with a layer of
clear plastic, diffusion in the plastic or surface crazing could
easily make them unusable.

 GM>And if the technology changes would anyone be able to duplicate
 GM>it to play them in, say, 100 years time?

 JE> Only if those "anyones" had enough foresight to do the
 JE> equivalent to what we are now doing with home movies, VCR
 JE> tapes, etc.

Quite often there is stuff stored away, maybe forgotten for
years, to be later discovered. And that is where the problem
lies.

There are a lot of books detailing the techniques for making and
replaying movies on film, the same with disk recordings, and the
descriptions are comprehensive enough so that anyone with some
technical skill and a reasonable workshop -- even a home one --
could make a player for either medium.

I venture to say that someone could build a magnetic tape
reproducer for reel-to-reel or cassette merely from a description
in a book.

Even examining the recording medium either directly or with
simple equipment would tell a lot about how it was to be
reproduced, and a reasonably skilfull person could re-invent the
equipment to play it.

But the same cannot be said of video tapes, and even less of CDs
and DVDs. A description in a book would get you absolutely
NOWHERE in resurrecting the technology required to play those
media. For someone who had never seen one before, looking at the
medium with a high powered microscope MIGHT tell them something
about how it is to be replayed, but I doubt that it would help
much.
 
 JE> No, they just bundled up ALL the tapes - which included
 JE> quite a number of National Geographic and other purchased
 JE> tapes - mostly for our grand kids viewing when they come
 JE> over..

Strange. They don't usually go to that much trouble. they usually
just take whatever seems immediately to be attractive to them,
usually stuff that has a known resale value.

From Greg Mayman, in beautiful Adelaide, South Australia

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