writing really small

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Alexander Rose
Wed, 11 Feb 1998 16:43:11 -0800


Here are some specs on CD ROMs from the 3M corp around 1993 published in
"Preservation of Electronic Formats" distributed by the Society of
American Archivists.

The tracks are .5 microns thick and from .85 to 3.5 microns long and are
on 1.6 micron centers.

This is all done with cheap desktop technology. Potentially we could
write actual text at this same resolution with similar technology.

About longevity...

3M actually has a 25 year Warranty on their media. They generated this
through accellerated aging techniques. The failures seemt o come mostly
from a breech in the undercoating protecting the metal disc. this
corrolates with the other finding sI have found such as
http://www.phlab.missouri.edu/~ccgreg/tapes.html. Actually they seem to
think that they will last about 100-300 years under good storage
conditions and therefore assume the worst and give a 25 year Warranty.
(what they plan to give you for your lost data in this case is probably
just your money back for the CD of course, not the cost of regenerating
the data, and I have a feeling that they know no one will even remember
a warranty 25 years from now.)

--
Alexander Rose                                     
(Executive Director)

The Long Now Foundation 415.561.6582 "fostering long term responsibility" FAX.561.6297

http://www.longnow.org