For anything
important, I wouldn't trust just optical media.
External hard drives are so inexpensive with such a large capacity.
Storing important things on a couple instances of magnetic media,
perhaps in additional to optical, might be a safer way to preserve
them. (A couple big external drives, stored in a couple of safe,
offsite, locations etc).
And you leave them some years without turning on, the heads glue to
the disk surface and bye bye.
Why would you leave them turned off for any more time than absolutely
necessary?
Pat
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Purdue University Research Computing ---