How long is a CD going to last?

My Grandmother is a Historian. She has huge amounts of information on our area’s heritage and past filed away. This information needs to be kept safe.

I would like to back up her files by scanning and burning them to CD, but I’m worried.

CD’s have not been around all that long. Do they have a reasonable life expectancy?

The Monks have done well keeping re-printed texts alive, but i’m hoping there might be a better way to preserve all this hard work.

I believe normal audio CD’s are expected to last on average about 20 years. CD-R and CD-RW will probably last for less time though.

Ha ha! Hee hee… ahem. :slight_smile:

Okay, the information of this century isn’t gonna last very long at all. Thousands of years ago you had people carving stuff into stone and making pottery and pyramids and things. They stuck around. Then paper came along, and that disintegrates, but if well kept lasts centuries itself. Todays media lasts/will last… decades, mostly.

Even if you avoid the problems of a certain company making apps that can’t open stuff saved with last year’s version, CDs themselves aren’t as good long term storage devices as some might think. Even the commercially pressed ones can have problems - I don’t have a cite, but a researcher somewhere had some disks where the media layer was flaking off, and found the substrate was “infected” with an aluminum eating bacteria or fungus or something. (Rare, but still)

CDRs and CDRWs are even worse, with some brands being unreadable within a year or two. (Can’t find that cite either :()

So now I have to be helpful - Good CDs are expected to last over 50 years if kept properly (some stats) The brand and manufacturing method matter a lot in this area. Try searching for life span “cd media” or the like.
You might be interested in the BBCs experiences with a long-term data storage project. The data was unusable within a decade, and was recently re-built with considerable effort. I’m assuming their current version will last a lot longer given what they’ve learned. - http://www.domesday.org.uk/

Other interesting links:
The NIST (National Institute of Standards and Tech.) wants to have specs for long-term CD and DVD media: http://slashdot.org/article.pl?sid=03/09/11/0351214&mode=nested&tid=137&tid=185&tid=198
I didn’t read much, so I’m not sure where they are on that, but it might be just what you’re looking for.

This conversation on media decay (not the one I was looking for, but anyhow) http://ask.slashdot.org/article.pl?sid=00/01/22/1924250&mode=nested&tid=126

Can you not have them microfiched? Or is this very expensive?

I have had to ditch a couple of CD’s as they just would not play, the silver finish had changed very slightly to having a merest tinges of brown in it.
They were 15 years old.

It is possible that the chemicals in the paper used to make the CD notes caused it.

Copied from the internet:

*The common, off-the shelf CD’s you find at Walmart or CompUSA or other large retailer may last one year or 20 years, but you are taking a major risk using them for anything other than temporary storage.

Also, do not trust any form of magnetic storage such as disks or tapes – they are not archival media because the magnetic signal is subject to corruption and will decline in strength over time.

Go with Mitsui Gold CD’s. They cost a little more, but you have the peace of mind that you will be able to pass your valuable pictures along to your great-grand children, and beyond.The common, off-the shelf CD’s you find at Walmart or CompUSA or other large retailer may last one year or 20 years, but you are taking a major risk using them for anything other than temporary storage. *

I have a Sony CD camera for almost 2 years. I have had no CD that became unreadable but have read about some people that have. I think I will get some Gold CD’s for storage of my best pictures.

Keep in mind that even a gold CD will be readable only by a very specialized piece of hardware. Much of the data from the early days of digital storage is unreadable on today’s standard equipment.

Think Betamax, or 8 tracks. How many people do you know who could access the information on either of those nowadays?

If you want it TRULY archivable, for centuries, no matter what unforeseen technological standards arise, then put it on acid free paper and inside a fireproof box. The hardware needed for reading words on paper will (hopefully) never become obsolete.

Yep, I think the basic issue is not “how long will the media last”, but “will the hardware/software still be able to read it”. Just look at how the media has changed in the last twenty years or so. First you had those big ol’ 8" floppies like Matthew Broderick used in “War Games”, then they got down to 5.25", then there were the 3.5" diskettes. Now CDs & DVDs. Plus how many different varieties of tape, magneto-optical disk, etc. over the years. It’s not the media itself so much as having still-functioning hardware that can read it.

Just as an aside, I’ve got my dad’s old late-70’s-vintage Osborne 1 and I fire it up every once in a while just to see if it still runs. It always boots up just fine, there doesn’t appear to be any degradation from the diskettes sitting around unused for extended periods of time.

The Master Speaks.

I trade in Betamaxes and have several working ones right now. I expect to have working Betamaxes longer than VHS machines. 8 track tape players are easy to get at any thrift store, even (vintage) tapes. I also know where to get blank 8-tracks cheap and could make new tapes if I wanted.

In short, you need a better metaphor.

My oldest CDRs are over 6 years old and still readable. But those were much better quality than the free-after-rebates ones most people get now.

Shoeless hits the real nail on the head. But there is a solution. In a year or two copy all the CDs to DVDxRs. Then a couple years after that to blue light DVDxRs, etc. Note that with each generation you get higher density, faster access etc.

The hard part is getting it digital in the first place. Once digital, you just have to be periodically responsible and make a new dupe.

Plan ahead, that’s all it takes.

If its any consolation, NASA lost almost 75% of the data from the Viking missions because of magnetic tape degradation.

Do the smart thing- put it on CD’s, lock them in a very dry very dark place, and make hard copies too.

Wow, stuff to think about. Worrisome stuff to think about.

Does anyone know how the life of a good hard drive will stack up against this? Future compatibility problems aside, would it make more sense for us just to save it and let it be once it’s been scanned?

Perhaps you could photocopy them on acid free paper and store them in a cool, dry, fireproof environment apart from the originals. That will take care of the readability and durability issues.

At the archives conferences I have attended, they always recommend reformating things when new mediums come along… like ftg said to do.

Going back to the OP, the definitive answer is not hard to find. A a substantial number of rigorous scientific and industrial tests, and years of field trials, all point to the same conclusion: a CD is a near-perfectly reliable, rock-solid and dependable data storage medium, virtually indestructible and offering perfect digital fidelity to the data source.

Unless you really, really need the data on it, there’s an “it’s the only backup we’ve got” crisis, and your job is on the line. At which point the CD will develop a fatal corruption error, and your precious data will resemble chalk drawings on the sidewalk in heavy rain.

I’m interested in knowing more about this too, since I’ve taken over my family tree of ~1000 known individuals, half of which include high quality photos and other information. I scanned many of these photos myself from my mother’s and cousins’ albums and couldn’t stand to lose them, and would like to pass them on to future generations.

Currently I make backup CD-Rs every 4-6 months with CD-RWs every 2 months to backup my own photos (I’m following ftg’s plan) and store some of the important photos on my family tree website (but at reduced quality). But I’ve been thinking, would a Firewire external hard drive be better/safer/more reliable? Should I do both CD-Rs and an external hard drive? Would it be best to just print all the photos at Walmart and try to preserve them that way? Could I just edit all the .JPGs with Notepad, print up that weird information, and try to conserve the printed text so my great great grandchildren can scan that in to convert it back to images?

I wonder if a coating can be added to a CD so it stays free from oxidation.

I don’t mean on the read side, but on the lreverse or label side.

Seems to me that any degradation has to take this route, sealing the foil would possibly counter this ?

Mitsui Gold CD-R’s would solve your problem.