On Sun, Nov 26, 2023 at 04:36:43PM -0500, Geoff Steckel wrote: > On 2023-11-24, Crystal Kolipe <kolip...@exoticsilicon.com> wrote: > >>At the end of last year, I did a comprehensive write-up about using blu-ray > >>recordable on OpenBSD, and as part of that I checked around 100 BD-R discs > >>that had been written about 10 years previously and verified as good at the > >>time. Ten years laster, I found exactly ZERO bad discs. All data was > >>readable from every single disc, (and returned the correct checksums).
> Do you have any data about blu-ray double layer lifetime? Most of the discs in that test that I mentioned were single layer, I think there were probably six or eight that were dual layer. But out of that small sample, I had no issues with reading them several years later. Dual layer recording _is_ more picky and error prone in general. I have had more difficulty finding good combinations of drive and brand of media when using BR-R DL than with single layer. But almost always, any problems are repeatable with the same combination of drive and brand of media, whereas other known good combinations work fine the vast majority of the time. Reading and writing BD-R DL is somewhat slower than single layer, so for smaller datasets I've generally preferred the 25 Gb discs. Just to be clear: these are discs that verified successfully when first written. What I'm saying is that I've not seen degradation _over time_. Those that read correctly the first time have never given me problems years later, which is very different to my experiences with CD-R and DVD-R.
