Archival storage

[der Mouse]

> [M]y state's historical archiving group [] are back to the issue of
> digital archiving for a new reason, space.  They would like to have
> some form of high density storage (higher than paper)

Paper may actually not be totally out of the question.  With decent
printing technology you can get about 75dpi with fairly clear
readability.  If you put 8x10.5 inches of data on an 8.5x11 inch page,
that gives you 8*10.5*75*75 or 472500 bits, 59062.5 bytes, per page
(or, actually, per page side).

You'd want to keep a few pages describing the encoding used in English,
but they're overhead and can be amortized over many pages of data.
With sufficient patience and a magnifier (and proper encoding algorithm
description) it could even be unpacked by hand.

> Does anyone know if there are optical formats that can reliably
> deliver 10 year shelf-life?

Ummm...do pressed CDs count?  (As opposed to CD-Rs and CD-RWs.)  Not
many collections of data are worth doing a one-off pressed CD, but it
may not be out of the question for some data.

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