SPUG: Re: [SLL] Remote Backup

[Gareth Beale]

The whole issue of long term storage is about much more than what kind of 
media you are using. As an aside, CDROMs and other optical media may
have a very long physical lifetime, but will the drives and associated
software be around 50 years from now? I'm sure we've got 7-track reel
-to-reel tapes somewhere here at Boeing, but no drives to read them.
Anyone got backups on any 5-1/4 inch floppies still? You can probably
find a drive to read them, but it's getting harder.

Tapes do have the advantage of capacity for now, and under the right
storage conditions, have an acceptably long shelf life (~ 10-20 years).

However, chances are that if you want to keep it that long, you'll be 
refreshing it periodically anyway. For anything other than text files, 
the application that created the file may be superseded many times over
a period of years. e.g. Word processing or spreadsheet files, program 
binaries, etc.

For REALLY important stuff, make more than one copy, maybe on more than
one media type, and don't keep them all in one place. Maybe at least one
in a safe deposit box or somthing like that. We send copies of our 
backups east of the mountains, out of the earthquake zone.

Gareth

----- Begin Included Message -----

Your question didn't come off as a challenge, but I couldn't resist the
opportunity to raise the issue that the medium itself is of critical
importance, being the substrate that stores the data!  Sorry if I 
sounded like a wise-guy (that would be the first time, I assure you 8-} )

Tape is about the most unreliable offline medium, next to paper,
due to its sensitivity to temperature and humidity fluctuatinos, and
the associated problems of stretching and loss of iron oxide (causing
"dropouts").  I'm not an expert on the latest and greatest options, but my
guess would be that for maximal stability of the stored data over time,
you'd have to go with writeable CD-ROMS or DVDs, or something similar.
However, for non-critical work (like I do at home, but unlike what the
Pentagon is supposed to be doing), you might be willing to compromise the
ability to store the data for 50 years to save some money!  Personally,
I use tapes, and have been pretty lucky with them so far, but for really
important stuff, I'd be looking for a more durable medium.
 

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