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Is there a source regarding M-DISC being unable to hold up to their lifetime promise? A quick google search brings up amateur-ish blog posts, and even those co

by nichch 6y ago

Is there a source regarding M-DISC being unable to hold up to their lifetime promise? A quick google search brings up amateur-ish blog posts, and even those co sign the medium.

sedatk 6y ago
Yes, French national metrology and testing laboratory LNE: https://www.lne.fr/sites/default/files/inline-files/syylex-glass-dvd-accelerated-aging-report.pdf https://www.lne.fr/sites/default/files/inline-files/syylex-g...
- nichch 6y ago
  Thank you!
- labawi 6y ago
  > The objective of this study was to investigate the behavior of the GlassMasterDisc of Syylex under extreme climatic conditions (90°C and 85% relative humidity) and to demonstrate the potential of this technology for digital archiving. > The result of this study is that the GlassMasterDisc has a much longer lifetime in accelerated aging than other available DVD±R I wouldn't draw any other conclusions on normal ageing of other tested media. They did an accelerated aging test at 90°C and 85% RH, where most discs didn't last a single test cycle (of 10 days), two discs lasted a single cycle, and only syylex lasted all 4 cycles. Quote on a brand-name DVD > This DVD model had the longest lifetime (i.e. 1500h) at 80°C and 85% RH. At 90°C, it is destroyed after the first cycle of 250 hours. For an idea of what it does to the substrate: > [for measurement] DVDs have to be taken [out] .. To prevent the formation of water droplets in the polycarbonate, it is necessary to "purify" the polycarbonate from the water that was absorbed at high temperature. OTOH, I had CDs (Verbatim, upper middle class), of which about 1-2 of 50 had issues after 20 years storage (in dark, mostly room-temperature conditions).
  - sedatk 6y ago
    Yes, they did an accelerated test, and M-DISC has performed as good as archival grade DVDs. Syylex, which promises the same lifetime as M-DISC, performed significantly better. That clearly shows either M-DISC didn't live up to their promise, or Syylex and archival grade DVDs surpassed expectations. Either is bad news for M-DISC, isn't it? What am I missing?
    - labawi 6y ago
      The "accelarated test" may not be in any way indicative of true lifetime in moderate conditions. Their own conclusion does not draw any such implications, the only other test they reference is done at 80°C (10°C lower), and the only writing on how or why this test could be indicative of archival lifetime was a generic two sentence: harsher conditions -> faster degradation (in part 4). It was a pupose-built test to see how much of X would Syylex take. It took X better than others, none of which took X well. Tests like these are very good, if you want to go with Syylex, to make sure it's not worse in some way (X, or Y, Z), which would then suggest a need for further examination. In real aging, factor X may be completely meaningless, while Y and Z are crucial, so you cannot conclude which one will last more. Why test 90°C and 85% RH, not 80°C, 50°C or 110°C, or bending, UV light, scratching, drop in acid .. whatever? For a proper accelerated lifetime test, you would need to identify (all) relevant degradation modes and model their behaviour (and interaction) in target vs. accelarated test conditions, and then extrapolate behaviour in target conditions. They didn't even write what type of degradation they are testing.
- Tepix 6y ago
  I'm not convinced. I'm no expert on aging simulation however. But heating a DVD to 90°C seems like it would do different things to the disc than normal aging at recommended temperatures, wouldn't it?

by nichch 6y ago

Is there a source regarding M-DISC being unable to hold up to their lifetime promise? A quick google search brings up amateur-ish blog posts, and even those co sign the medium.

sedatk 6y ago

Yes, French national metrology and testing laboratory LNE: https://www.lne.fr/sites/default/files/inline-files/syylex-glass-dvd-accelerated-aging-report.pdf https://www.lne.fr/sites/default/files/inline-files/syylex-g...

nichch 6y ago
Thank you!
labawi 6y ago
> The objective of this study was to investigate the behavior of the GlassMasterDisc of Syylex under extreme climatic conditions (90°C and 85% relative humidity) and to demonstrate the potential of this technology for digital archiving. > The result of this study is that the GlassMasterDisc has a much longer lifetime in accelerated aging than other available DVD±R I wouldn't draw any other conclusions on normal ageing of other tested media. They did an accelerated aging test at 90°C and 85% RH, where most discs didn't last a single test cycle (of 10 days), two discs lasted a single cycle, and only syylex lasted all 4 cycles. Quote on a brand-name DVD > This DVD model had the longest lifetime (i.e. 1500h) at 80°C and 85% RH. At 90°C, it is destroyed after the first cycle of 250 hours. For an idea of what it does to the substrate: > [for measurement] DVDs have to be taken [out] .. To prevent the formation of water droplets in the polycarbonate, it is necessary to "purify" the polycarbonate from the water that was absorbed at high temperature. OTOH, I had CDs (Verbatim, upper middle class), of which about 1-2 of 50 had issues after 20 years storage (in dark, mostly room-temperature conditions).
- sedatk 6y ago
  Yes, they did an accelerated test, and M-DISC has performed as good as archival grade DVDs. Syylex, which promises the same lifetime as M-DISC, performed significantly better. That clearly shows either M-DISC didn't live up to their promise, or Syylex and archival grade DVDs surpassed expectations. Either is bad news for M-DISC, isn't it? What am I missing?
  - labawi 6y ago
    The "accelarated test" may not be in any way indicative of true lifetime in moderate conditions. Their own conclusion does not draw any such implications, the only other test they reference is done at 80°C (10°C lower), and the only writing on how or why this test could be indicative of archival lifetime was a generic two sentence: harsher conditions -> faster degradation (in part 4). It was a pupose-built test to see how much of X would Syylex take. It took X better than others, none of which took X well. Tests like these are very good, if you want to go with Syylex, to make sure it's not worse in some way (X, or Y, Z), which would then suggest a need for further examination. In real aging, factor X may be completely meaningless, while Y and Z are crucial, so you cannot conclude which one will last more. Why test 90°C and 85% RH, not 80°C, 50°C or 110°C, or bending, UV light, scratching, drop in acid .. whatever? For a proper accelerated lifetime test, you would need to identify (all) relevant degradation modes and model their behaviour (and interaction) in target vs. accelarated test conditions, and then extrapolate behaviour in target conditions. They didn't even write what type of degradation they are testing.
Tepix 6y ago
I'm not convinced. I'm no expert on aging simulation however. But heating a DVD to 90°C seems like it would do different things to the disc than normal aging at recommended temperatures, wouldn't it?