Posted by JimK on 05/16/06 15:52

On Fri, 12 May 2006 03:00:06 +0200 (CEST), Nomen Nescio
<nobody@dizum.com> wrote:

>I've got some +R discs that were recorded about a year ago starting to go
>bad. The DVDR that recorded them doesn't even recognize them anymore. A
>separate player machine reads some of them but not others.
>
>What's going on here? I thought these discs were supposed to last 100
>years. Maybe the plastic substrate will, but the image emulsion doesn't
>seem to hold the data, at least on my discs. Is this an inherent defective
>technology? I've never had trouble with CD-R discs but DVD has been a big
>headache and I'm ready to throw in the towel after a lot of money and time
>wasted.

Unless you know and have the error (PEI,PIF) scans of the DVD when it
was first recorded, a kind of hard to speculate why that dvd became
unreadable after 1 year. If your first burn had lots of errors and the
disc quality was marginal at best, it doesn't take much, (a scratch,
thumb print) to add enough read errors to make the dvd unreadable.
Light, temperature change, and how the dvd's are stored increases the
error rate of the disc over time. Use grade 'A' media to start with
helps

Bad Dvd. First 2.5GB work fine now, in a year, I very much doubt it.
http://img89.imageshack.us/my.php?image=cdspeed5bad7xe.jpg

A good burn will have
PI Errors Maximum of 10 total 10,000
PI Failures Maximum of 1-2 total 300

A disc will still be readable with
PI Errors up to 280
PI Failures up to 4 (single PIF spikes above 4 are ok if not in a
cluster and grouped together.)

PI Failures start at above 400 on a newly burnt disc and any PIF spike
above 4, I don't think that disc going last 1oo years.

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