I wonder, with the concern about the longevity of various kinds
of storage media if we aren't overlooking the value of the web as
a means of preserving material.  Take MMD, as an example.  While it
is important for the owners to make their backups, many subscribers,
myself included, have archives on our PCs (in my case going back to
about 1999) that can be called on for disaster recovery.  These live
on my hard disk, get backed up to a second disk, and occasionally get
written to DVDs.

Hard disk to hard disk transfer is fast and easy, my copies are now on
about the fourth different computer since I subscribed.  The copy on my
work computer is not only there, but also backed up to archival tapes
that get stored in a salt mine somewhere.  Similarly, I've downloaded
and kept all of Terry Smyth's roll scans, so if his computer were to
die he could get them back from me, or, I would guess, hundreds of
other people.

The key to preservation of valuable materials, I would suggest is
publication.  Once information is made freely available, hundreds to
thousands of people will make and keep copies, and propagate them as
long as they retain value.  As "online" storage continues to drop in
price, I suspect there will be less and less need for "archival" media.
Information is increasingly being kept "live" in highly redundant
copies, distributed around the world, as long as it is published.  Only
the private treasure troves are in danger of being lost.

Roger Wiegand
Wayland, Massachusetts, USA