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CDs, DVDs Eyed For Long-Term Archival Use
Alien54 writes "Computer scientists at the National Institute of Standards and Technology (NIST) are launching an effort to develop specifications for 'archival quality' CD and DVD media that agencies could use to ensure the procurement of sufficiently robust media for their long-term archiving needs (i.e., 50 years and longer). See the press release at the NIST site." The research involves "...enclosed chambers that use temperature and humidity changes to artificially age the media some 20 years in only six weeks."
It's cool to create media that can hold information for an extended period of time. But - do not forget that you need to have a device that can read the media. I've saved some of my earliest work from the 70's on a paper strip with holes in it, and from the 80's on a 12" floppy disk. Both look like mint condition, and I'm sure they work. But - I haven't got any hardware that can read them.
So - if you plan to store digital information for decades, you need to store the player as well. That means, you need to make hardware that will work after, say, 100 years. This makes me think if we should strive after something that's human readable (microfilm or plain old paper) instead of something that require a computer. This is by far an easy problem to solve. My humble suggestion is to save information on todays media and prepare to copy it to a new media every 10 years.
50 years is not long, 500 years is what we should be talking about.
Books, if looked after properly, last for centuries. OK: many modern paperbacks are printed on paper that has not been properly stabilised (still contain acid), but there are plenty of very old books.
In case you think that I am over the top: have you never looked at an old family album with pictures going back to the start of the last century? What will future generations think of us if none of that sort of material survives because we had the lack of foresight to put it onto good media?
For a start.
A typical backup tape will handle 120Gb to 200Gb these days.
Then you have the problem with getting hardware which will read the disks in 20 years or 50 years.
The real solution to archiving is the ability to move to new formats as they appear and become cheaper than the existing technology, it's an ongoing process, not a product. The hardware itself should be irrelevant.
Government of the people, by corporate executives, for corporate profits.
I see a lot of people saying that the short CD lifespan is not a problem .. you just copy from one generation of media to the next as you approach the optimum time.
Well that doesn't really cut it for two main reasons
1/ You have now decided that the only information you will hand down to the future is that the stuff that you care about now. As soon as you stop caring about that data, or your descendants stop caring, then that data will lost.
2/ It will only need a skip of roughly 2 generations of technology before you won't be able to recover any digital data that you (or someone else) accidently re-discovers.
If this doesn't seem important, look at what historians and archeologists are finding/learning from poking around things that have survived millenia, compared with the despair of knowing what huge gaps exists from records/items that have been irretrievably lost.
So how do you want to judge the concept of "archival"? As something that is accessible as long as the item is whole, or as something that requires active intervention to maintain its integrity?
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Many people have talked about older methods of storage as the gold standard. Paper, vellum, papryrus, clay tablets - some documents written on these media have survived thousands of years.
BUT, they have not survived that amount of time without degradation. The reason we can still read them is because of their low information density. Documents can fade - a 1 inch square portion of a document could flake away, leaving the original text still readable. Why? Because 1 square inch of most documents doesn't contain all that much information.
As physical objects I suspect that quality CDs or DVDs would degrade less over 1000 years than just about any of the other media I've previously mentionned. The problem is that we are trying to cram so much data onto them that even the slightest bit of degradation leads to data loss.
So what's the answer? Massive redundancy. Replicate data in 100 different ways across the surfaces of the CD or DVD - this might dramatically decrease the storage capacity, but even 10 MB on the surface area of a CD is a massive improvement over the storage density of vellum. Now you have a chance of lasting 1000 years. Even if the CD is shattered and all some future archeologist can find is a shard, there is a good chance that the entire data set is contained within that shard, perhaps even multiple copies.
Even further, one could imagine using file formats that are resistant to file errors, perhaps uncompressed raster images. Easy for future scientists to decode, and wonderfully resistant to degradation. This is just another way to decrease density.
-josh