16 Mar
2005
16 Mar
'05
11:51 p.m.
On Thu, 17 Mar 2005, Tom Jennings wrote:
On Wed, 16 Mar 2005, Dwight K. Elvey wrote:
Your experience may differ, and you make very valid points and I dispute
none of them. However, I find that media is much more sturdy than these
discussions would indicate. We tend to gripe very loudly (and rightly so)
when poor quality backup media takes our data with it. But what about all
those times we go back to our old backups and thankfully find what we
need?
I consistently read lots of data with nary a problem: 20-30 year old
floppy disks (5.25" and 8"), 20-30 year old mag tapes, even 20 year old
VHS tapes. And of course the punch cards don't count ;)
I wouldn't doubt that newer media like CD-R has problems, but as long as
you make incremental backups and also do as Tom says and keep your data
"live" you should be fine. It also helps immensely in how you store your
media. In a safe, dry, dark place that doesn't get wild temperature or
humidity fluctuations: good deal. In a barn: not so good.
--
Sellam Ismail Vintage Computer Festival
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This does require regular reading of the archived
disk. This
is not necessarily an easy thing to do.
I'd like to offer that there is no such thing as archival computer
media. None.
Dwight's comment is succinct; all offline storage needs to be
checked. Literally all of it is rotting on the shelf.
(For short-term backup, eg. data loss prevention, this logic
doesn't apply so directly.)
It's a lot of work to check archival data; nearly no one does it
right, and it mostly amounts to spot checks (a valid method
certainly but in itself an admission of the scope of the problem).
I don't do "backups" per se; I keep everything on rotating
spindles, aka hard disks in running systems. If you pause to
consider what this means as a long-term solution, it sounds really
precarious, because it is; but in fact it's *less precarious* than
any form of offline storage because it is essentially 100%
continuously monitored, embedded in a live computer.
I have five computers in four physically distinct locations (three
are >> 100 miles apart) with enough storage to hold literally all
the computer-readable data I own.
If you somehow think that tapes stored in a controlled vault is
more reliable, or less susceptible to bit rot than rotating
spindles, I believe you are wrong (and my every experience and
observation says otherwise). Only fiche and paper are statically
reliable.