[RndTbl] Optical media longevity warning

Trevor Cordes trevor at tecnopolis.ca
Wed Oct 27 23:54:31 CDT 2021

On 2021-10-23 Adam Thompson wrote:
> ...so here's a periodic reminder that the centuries your optical
> discs were supposed to last?  Let's call that *highly optimistic at
> best*.
> I know several people reading this who back up to optical media, but
> only one (maybe two) who plan for media longevity.

Funny, I recently did a little study of my own and was going to make an
article about it or something.  Still probably will.

I've been backing up to CD-R and DVD-R for about 15 years.  So I took
the oldest 500 discs a while back and started running checksums on the
all to see if any had problems (and compare against original checksums
I still have).

So far I have 1 CD that seems to be having issues.  Out of hundreds.
And since my backup system breaks things up into 10-20 chunks per disc,
my loss of 1 file is only about 50MB.  I am still trying to figure out
if anything else might be going on (i.e. physical damage).

All in all they seem to hold up even better than I had expected.

On 2021-10-24 Hartmut W Sager wrote:
> It was pointed out that, longevity aside, you need compatible reading
> hardware later to read the discs.  For both reasons, I re-write (copy
> to elsewhere) everything every 2-3 years.  I no longer use CD-R/DVD-R

Funny, that's exactly what I do.  My program is currently set to
rewrite every 5 years.  I started at 2 years, but as I went on without
issues I kept upping it to save media.  I use a mix of cheapo and
datalife plus.  So far there doesn't seem to be much difference in
reliability to be honest.

Optical media: the only backups that will survive an EMP!  :-)

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