[Leica] Re: DVD failure

[lrzeitlin at optonline.net (Lawrence Zeitlin)]

In early 2004, NIST (National Institute of Standards and Technology)  
looked at CDs and DVDs to see how long digital information recorded  
on to them would survive. They concluded that most CDs and DVDs will  
last 30 years or more if handled with care, but many factors can  
slash their longevity. Direct exposure to sunlight can do a great  
deal of damage both from the sun's ultraviolet rays and the heat.  
Indeed, any rapid significant change in temperature or humidity can  
stress the materials. Discs last longest when stored in plastic cases  
in a cool, dark, dry environment. Because gravity can gradually bend  
the disc, storing it upright like a book is best for long-term  
storage. The study also found that fingerprints and smudges  
frequently do more damage than scratches, and recommends handling  
discs by the outer edge or the center hole.

If the data is extremely important put the files on two different  
discs and physically separate them. If you have a fireproof safe or  
safety deposit box is an excellent place to store one set of vital  
discs. At the office or at home, place the other disc copies flat on  
the lowest shelf of a cabinet possible.

Remember you can?t rely on hard drives. Despite the fact that the  
cost/GB is extremely attractive, drives do have a relatively high  
failure rate ? compared to CDs/DVDs ? and should you lose a drive you  
are likely to lose everything that hasn?t been backed up someplace  
else. A 500 GB drive will hold the contents of 100 DVDs but if a DVD  
becomes unreadable, you lose only 1% of the total stored data. If the  
hard drive fails, you lose 100%.

The best advice ? buy smart, test what you record then protect/handle  
critical discs as best as you can.

So If I can get 30 years life from a DVD (or even 10 years), that  
will suit me fine. The good images will be transfered to whatever new  
storage technology comes along, perhaps even holographic storage in  
crystals, the bad images discarded. By that time I should have enough  
perspective to tell me which is which. The side benefit is that I  
will have an unlimited supply of drink coasters.

Larry Z