What is the life expectancy of physical media? CD-R/DVD-R, etc

[Engineering]

I been told DVD's and CD's wear out after several years. Verbatim and Taiyo-yuden included.

Is that so? Are they not immortal?

In a closed container, protected from cold and heat and UV and physical damage...

How long can the burnt data last without corrupting or becoming inaccessible thus forever lost?

Edited February 28, 2011 by Engineering

[cdob]

42

[Glenn9999]

Now for a serious answer.

I been told DVD's and CD's wear out after several years. Verbatim and Taiyo-yuden included.

Is that so? Are they not immortal?

Plastic is not immortal?

Yes, writable optical media wears out. If you Google you'll find out that it's not plastic, but a malleable dye (varies based on brand and kind) that the laser on your drive can etch without much problem. This is what degrades.

How long can the burnt data last without corrupting or becoming inaccessible thus forever lost?

The estimate is 5-10 years for most brands in ideal conditions, though some of the more poorly made brands can go much sooner. Also, they can go in much shorter time (a couple of weeks) if conditions are less than ideal. Using RW disks moves this estimate downward. Personally I give most disks a maximum of a year or two. Given this problem (which I've run into on some data with particularly), I tend to burn a file of MD5 hashes of the other files on the disk to that disk so they can be checked if suspicion of corruption arises.

Edited February 28, 2011 by Glenn9999

[allen2]

Are you looking for something like this: http://www.digitaltrends.com/computing/cranberry-diamonddiscs-offer-1000-year-dvd-shelf-life/

[pointertovoid]

Wear-out of writeable optical disks is not much a matter of time but of ultra-violet light. The UV light that writes the disk's thin data-holding layer at the laser also "overwrites" it. The brand can't help radically here.

UV comes from Sunlight (it's powerful!) and from fluorescent bulbs as well, which includes the energy-saving lamps - they're nothing else than a fluorescent tube folded into a compact shape.

Same story for plain plastics, which get destroyed mainly by UV, though the polycarbonate making the thickness of optical disks is rather stable to it. Much more observable at old polyethylene plastic bags for instance.

So the basic precaution with writeable optical disks is to protect them from light, both before they're written and after, by keeping them all the time in an opaque box.

You may also consider copying your data after 5 years for instance, instead of forgetting it.

But the, why should your data stay on optical disks? A hard disk drive has only advantages for that use.