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The Myth Of The 100-Year CD-Rom
Toshito writes "Are we putting too much faith in the ubiquitous "recordable CD", or CD-R? A lot of manufacturer claims 100 years of shelf life for a CD-R. But in real life, it can be much less. Expect failure after only 5 years... Personnaly I just discovered 6 audio cassettes with the voice of my late grandfather, talking about old times. These tapes are copies of reel to reel recorded in 1971, and they are still in excellent shape.
I was thinking about digitizing everything, do a little noise reduction, and burning this on CD's, for my childrens and great grand-childrens enjoyment, but it seems that old analog tech from the '70 is more reliable than digital. The full story at Rense. Other links about the subject: Practical PC, Mscience, and an excellent reasearch by the Library of Congress (warning! PDF): Study of CD longevity, html version (google):Study html."
The danger in "old" storage formats is lack of machines to read them. Those tapes may be in good shape, and so might the data on an 8" floppy I have, but the 8" floppy is effectively lost to me because I don't have easy access to a drive that can read it anymore! The paper tape programs I "printed" out from a VAX PDP-11 are probably good (if I hadn't lost them years ago) but I can't get to a tape reader, etc.
You almost have to make dozens of copies of data on a modern cheap format, and keep moving it forward.
How do you know there is no loss with analog?
Analog quality loss is acceptable, because it results in static. Digital loss isn't acceptable, because (at least practically) it is a binary property...the CD works or it doesn't. Scratch the hell out of a record, and at least you still have something.
We could build acceptable redundancy into digital backups, its just that most people think of it as wasteful. You know what though?... I have everything worthy of backup "backed up" in at least 3 places, one of which is always CD stored somewhere out of reach. Digital is better. Once you convert to digital, you can have zero quality loss with near 100% efficiency, you just have to want it that bad.
Whether CDs last a long time or not is really missing the point. The benefit of going digital is that the data can be backed up.
If you're oriented on the media you're forever on the upgrade path. Should you move the collection to DVDs? But wait, blue light DVDs are right around the corner. It will never end.
120Gbyte hard disks are getting cheap. This trend will continue. What you store something on will literally become unimportant. The only important thing that will remain is still: how well is it backed up?
What happens when the amount time it takes to transfer all the data from one medium to another is longer than the life time of the media on which it currently resides?
Then obviously you couldn't have copied all the data to the "current" medium in the first place.