Infant mortality and longevity of DVD media?

[Jim Leonard]

Ethan Dicks wrote:
> When writing DVDs, I always do a read-verify right after burning, and
> for archival data, I tend to create recovery data with programs like
> par2, and burn two to three copies.  If it's worth my time to archive,
> it's worth spending $1 for more than one copy.

This is exactly my procedure as well, but I use QuickPar instead of 
par2.  I also burn two copies, since high-quality DVD-Rs can be had for 
less than $0.50 in bulk.

My typical process is to use Winrar with a recovery record (parity) of 
1%, then take the resulting files and use Quickpar to generate as much 
parity as necessary to fill up the DVD-R.  I then burn, ***and I make 
sure that the DVD-R also has a copy of winrar and quickpar on the 
disc*** (just in case 20 years from now someone is trying to extract my 
stuff and doesn't know what a *.par file is).

> As I said, I lost a file once.  That was with CD-Rs, and that was the
> first one out of many hundreds of discs burned (presuming they
> verified at write-time in the first place).  I _have_ had a number of
> discs that didn't verify, and that could be due to a number of causes,
> from defective media to "cosmic rays".  I have not, however, with that
> one previously mentioned exception, lost data (yet?) from disks that
> did verify.

Yes, that's been my experience as well.  If they're going to be bad, 
they're usually bad right out of the gate (ie. didn't pass Verify). 
Every year, I take my very first burnt CDR from 1995 out and try to read 
it.  It has always read.  I keep my CDRs and DVDRs in a cool dry dark 
place, though; not everyone can store them in optimal conditions.
-- 
Jim Leonard (trixter at oldskool.org)            http://www.oldskool.org/
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