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samintx wrote:
Does this mean the media is going bad?
Yep.
Back 'em up.
Keep your DVDs away from heat and humidity and they might be good for more than 10 years. Key-word: "might."
There's no optical media available at the moment that's rated to last much longer than that.
freeradical wrote:
The funny thing is that it's the discs that I put a label on that have problems.
Yeah. There are solvents in the glue on some labels that can eat through the laminate over time.
freeradical wrote:
Now I just scribble on them with a laundry pen
Use a water-based marker designed for writing on optical media and they might last a little longer.
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How about humidity, does that cause this?
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Doc wrote:
[quote=samintx]
Does this mean the media is going bad?
Yep.
Back 'em up.
Keep your DVDs away from heat and humidity and they might be good for more than 10 years. Key-word: "might."
There's no optical media available at the moment that's rated to last much longer than that.
Mitsui/Mam-A Pthalocyanine dye gold reflective layer CDs have a 200 year shelf life. I have hundreds that are 15 years old. Not sure about DVD blanks though. CDs ARE still optical media .......
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Racer X wrote:
Mitsui/Mam-A Pthalocyanine dye gold reflective layer CDs have a 200 year shelf life.
http://www.thexlab.com/faqs/opticalmedialongevity.html
How reliable are manufacturers' longevity estimates?
While some manufacturers have used accelerated life testing to support estimated life expectancy claims ranging from 20 to 200 years, how manufacturers interpret those tests to estimate longevity is often unclear. [5]
Tests involving only a single stress, such as temperature, may yield a greater estimated longevity than if the same media had been exposed to multiple stresses — temperature, relative humidity, and exposure to simulated sunlight — depending on the media's characteristics.
The measurements selected as end-of-life indicators can significantly affect the interpretation of life expectancy from test results. A number of published manufacturers' reports employ BLER as the sole end-of-life measurement [6, 7], but tests conducted by Media Sciences, Inc. have shown that BLER alone is an unreliable indicator of failure. [8, 9, 10]
Unless a manufacturer can provide their accelerated life testing results for a given recordable optical media product, any longevity claims for that product should be regarded as suspect.
http://www.clir.org/pubs/reports/pub121/sec4.html
...it is not always clear how a manufacturer interprets its measurements for determining a disc's end of life. Among the manufacturers that have done testing, there is consensus that, under recommended storage conditions, CD-R, DVD-R, and DVD+R discs should have a life expectancy of 100 to 200 years or more; CD-RW, DVD-RW, DVD+RW, and DVD-RAM discs should have a life expectancy of 25 years or more. Little information is available for CD-ROM and DVD-ROM discs (including audio and video), resulting in an increased level of uncertainty for their life expectancy. Expectations vary from 20 to 100 years for these discs.
... R discs use a dye-based layer (organic dye) for recording data. These are "write-once" discs and cannot be erased by CD or DVD drives. The organic dye used in the data layer of R discs degrades naturally but slowly over time. High temperatures and humidity will accelerate the process. Prolonged exposure to UV light can degrade the dye properties and eventually make the data unreadable. Heat buildup within the disc, caused by sunlight or close proximity to heated light sources, will also accelerate dye degradation.
...Flexing (bending) the disc by any means, such as removing it from a jewel case or sitting on it, may harm the disc by causing stresses. The disc should be stored in its case and placed vertically, like a book, on a shelf. Long-term horizontal storage, particularly in a heated environment, can cause the disc to become permanently bowed. While the data may still be intact, the disc may not operate properly in the drive or permit the laser to follow the track. The maximum degree of flex (bend) or number of times a disc can be flexed before it incurs damage is not known. To minimize the risk of damage, it is better to avoid flexing discs.
http://chnm.gmu.edu/digitalhistory/preserving/1.php
A recent report by NIST researcher Fred R. Byers notes that estimates vary from 20 to 200 years for popular media such as the CD and DVD, and even the low end of these estimates may be possible only under ideal environmental conditions that few historians are likely to reproduce in their homes or offices. Anecdotal evidence shows that the imperfect way most people store digital media leads to much faster losses. For example, a significant fraction of collections from the 1980s of audio CDs, one of the first digital formats to become widely available to the public, may already be unplayable. The Library of Congress, which holds roughly 150,000 audio CDs in conditions almost certainly far better than those of personal collections, estimates that between 1 and 10 percent of the discs in their collection already contain serious data errors.
Good reading.
Yeah. Maybe the discs will last 20 years.
...If you keep 'em in the fridge.
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