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NIST Releases Study Of CD/DVD Longevity
dirkin writes "The National Institute of Standards and Technology has released a preliminary study of the potential lifespan of CD-Rs and DVD-Rs. The PDF study is here. A good starting point for deciding what type of media to purchase to keep those backups and photos kicking around longer. (You DID buy the silver/gold alloy phthalocyanine CDs, didn't you?)"
the speed in which the CDR is burned sometimes it makes a difference, for the highest reliability I think 1x is the best.
My pr0n my precious precious prOn!
Take multiple backups and atleast have one backup on high quality CD-Rss not the 25c a piece ones.
Keep upgrading your Harddisk from time to time and backup data from old HD to new one.
for the last time people, I am "frodo from middle eaRTH", not "middle eaST".
Lots and lots and lots and lots and lots and lots of floppies.
Jonahweb.com has stuff.
Well - if you recall tape drives were the "big thing" in backup about 5-10 years ago. I have looked at 10 year old tape backups & they work just fine. Maybe we need to trust good old reliable tapes. Or the other (faster) solution would be external hard drive backups.
===> An eye for an eye makes everyone blind - MG
Just do what I do : buy a rack, install in front of your machine (under the DVD or CD-RW or somewhere) and back up all your important data (or your entire harddrive) to a separate harddisk. Prices on smaller models (40-60 gigs) aren't all that steep, and most people I know have trouble just filling up their 'small' 20 or 30 gig drives. A spare 60 gigger rackdisk will keep you satifsied for a long time... Alternatively you could also just buy an external fire-wire or USB harddisk, although I don't really have all that much experience with those kind of devices.
Simply buy twice the number of drives you need, and do an rsync between the two sets now and again. For added safety, get a friend with broadband and store the second box there. Then you are safe from fire, theft, drive crashes etc, with minimal effort to keep the backup up to date.
I've got a whole load of burned CD's that I created up to about 5 years ago.. and on varying quality of media, and a lot of them aren't any problem.
I suppose storage is the key thing, keep them in a dark cool place will help them last just that bit longer (unless you have a case of those little bugs that like eating the data layer).
Although they are of a similar tech, what about DVD recordable disks? I've got plenty of those now... but if I keep doing what i've been doing over the years and backup my backups onto newer media then I'm not too worried.
Just my $0.02
Are you local? There's nothing for you here!
This doesn't tell us much. It's almost a teaser. "Are you going to die tomorrow? The answer may surprise you. Stay tuned for News at 11." I have some CDRs that stopped working within days and others that have lasted over 4 years now--same brand from the same spindle even. I wonder if the full Dutch article gives specifics or if they found _any_ CDs that were still working fine after twenty months. The teaser seems to suggest that they're all terrible. I do know that I get fewer duds now that I use Toast than I did when I used "Easy CD Creator." Beyond that, I don't know anything that makes a difference. CDRs stop working. DVD-Rs are crazy fragile. Hard drives fail. Paper burns. Maybe my data wasn't supposed to last forever. Alex.
>treat them like a mushroom and keep them in the dark.
RTFA. That's what they did; they kept them in a closed cabinet for two years in their original packaging. Some brands were toast after two years.
The fact that your CD-R discs appear to be readable after 4-5 years isn't a useful data point. These guys used CD analyzer hardware (CDA-3000) to check the quality of the discs. CD's have error checking and the damage may not yet be noticeable to the end user until later.
Or, rather literally translated into English: "Our sample shows that there is a lot of junk on the market. We have found cd-rs that should never have been for sale. Possibly it concerns rejected batches." Which suggests to me that the correct heading of this article should be: CD-Rs are like everything else: you get what you pay for.
What speed was used to write the CDs?
Were they all stored in the same place?
Were they all burned by the same CD burner?
Were they all burned from the same source (a single CD, hard drive, network, etc.)?
30 CDs sounds like an epidemic, but since they were all burned at the same time twenty months ago, there could be a lot of other reasons why all of these discs would go bad. If they were all burned at the same time, then they're effectively talking about one batch, regardless of how many different CD-R brands were used in that single batch.
Does the Dutch article cover this or is this just a scare story?
Take now into account earth's rotation and its magnetic field. It induces an albeit very slow movement of the molecules - the data layer degradation. The same effect causes btw certain currents in the Pacific oceans. While the movement is very slow and in the case of the ocean not very important, it does cause damage after a certain amount of time in the case of a CD-R. You should remember that the scale of the information storage units on a CD-R is in the nanometer range. The information is just "washed away" in an entropy-like effect.
However, you can slow this movement down. The molecular movement in the data layer is directed. So it can be reversed to a certain degree just be placing the CD-R the other way around. So, all you have to do is to mark the position of the CD-R in your rack exactly. And reverse it's position every month or so. This can increase to the lifetime of a CD-R about 150 percent. More can't achieved (in normal environment) because electric machines like your computer etc. create their own electro-magnetic fields. And the effects of these varing fields are much more difficult to negate.
BTW: the 100 percent wrong place to store your CD-Rs is on the top of your CRT.
Owner of a Mensa membership card.
Or put it in your Kazaa folder and give the filesi maginative names like "horny young teen sex party.mpg", etc... You need to maintain a porn name real name table though in case you'll need the backups again. :-)
Beware: In C++, your friends can see your privates!
Don't forget to have one or more off-site backups (encrypted in case they are stolen). I keep one off-site backup (on CD-RW) in town, at a friend's place, and swap it for a fresh backup every time I visit him. (Be sure to offer to do the same for your friends.) An out-of-state backup gets refreshed every time I visit my folks.
It's peace of mind knowing that if, heavens forbid, anything catastrophic were to happen to your place of residence, or if burglars were to take your computers and disks/tapes, then you would at least not have completely lost all of your critical data.
FWIW, I can't remember having a single CD-R go bad. I've had some scrathed ones which took a while to read because the reading drive slowed to a crawl, but I got the data nonetheless. I even recently found what must have been one of the first CD-Rs I've ever burned. Must have been from around '96 or '97, it had my backup copy of Duke Nukem 3D on it, among other stuff, and everything read fine (the disc was a Sony CDQ-74CN).
Did you know you can fertilize your lawn with used motor oil?
Back in the eighties, when regular CD's were first introduced that could be read by a standard computer (pc, mac, etc), the discs were fairly thick, and consisted of (iirc) from top down:
disc label
protective coating
data layer (usually pressed)
protective coating
Then at the end of the eighties, I don't recall exactly what year, but it was adopted by various cd makers till eventually all, the price of CD's dropped dramatically, almost in half.
The reason for this was the fact that the top protective layer was removed from the manufacturing process, leaving just the thin disc label and it's material to protect the data layer, barely.
I want to clarify that I'm talking about regular PRESSED cd's manufactured in bulk, and not dye layered ones, but the point is the same in both cases. By removing the top protective layer, it allowed manufacturing of CD's to drop in price dramatically.
I'm positive there have been other cost cutting measures used for dye layer CD's that the manufacturers have adopted over the years, such as cheper dyes that are affected faster due to exposure to sunlight, and so on.
It's not just about scratches or dye, but about the overall picture here. The manufacturers WANT to have built in obselesance. This gives them a nice steady flow of income when one has to contually burn his media archive every 2 years.
Food for thought anyhow. I thought I'd post about what I saw in the eighties, in case it was relevant.
user@host$ diff
I used to work for a company in Austin, TX whose speciality was optical drives (not CDs, but WORM mostly), and one of our customers was the National Archives. This was when CD-Rs were just coming out, and the NA was interested in a cost/benefit analysis of whether or not they could replace their expensive 14" WORM systems with cheap CD-Rs.
The first thing to understand is that WORM systems, true WORM systems, not the Magnetic-Optical pseudo-WORM systems, are built on ablation of material in the disc itself. In other words, you burn holes in the disc revealing a lower layer that is reflective. In the case of most discs, and Kodak especially, they were gold on the reflective layer for long-term stability. Various tests of accelerated degradation were performed in both climate stabilized and non-stabilized situations, and at worst, the discs were stable for 100 years before any error correction was necessary.
We decided to perform the same kind of evaluation of CD-Rs, and found that brand varied greatly. The best were stable for 3-4 years, the worst only 6-8 months if the climate changed dramatically. In addition, UV exposure had a radical impact on the life-span of the disc. Further research found out that the problem was the natural instability of the organic dyes that were used in the disc layers.
Basically, if the disc wasn't perfectly sealed (look at the work done in the referenced article, and how it starts at the edges), oxygen would get in and react with the dye, which would change it's characteristics relatively quickly. It doesn't take much before the dye structure collapses, and data becomes unreadable after a short period. While I suspect the dyes have gotten better over time, they're still organic last I knew, and still subject to degradation by contact with air. Quality control is the only thing that will get you anything here, and I suspect even the best dye-based discs can't make it past 20 years unless exposure to UV is totally eliminated.
What Kodak had developed was what they called "Century Discs", which were basically scaled down WORM discs, but in CD-ROM format. They were gold inside, non-reactive, and well made. They did, however, require a very expensive writer because they needed more power than a CD-R drive could ever hope to provide to force the burn away the spots. They were, however, readable in a normal drive.
That's just my experience, but everytime I've seen an organization talking about "archiving" on CD-R, I have issues with it. It's fine for "backup," where the data cycle is shorter, but true archival purposes (for example, financial data), it won't cut it. You either need to use WORM, or tape. Tape is, however, subject to problems over the cycles as well, witness the failing properties of 9-track tapes written by NASA in the 1970s (heard first hand, not sure where to find it written up). Linear-write systems are better than helical.
Just a few thoughts, but this is not an easy issue. You have to understand what you're storing, and how long it has to be readable before you consider an actual medium for storage.
used to include a study of glove compartment temperature cycles for their high end discs...
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
You DID buy the silver/gold alloy phthalocyanine CDs, didn't you?
No, I've not ever ran across them, and it's not like they print the reflective layer and dye compositions on the side of the package. Mine are always green-ish.
(fp?)
"Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
Mine will be kept on a real Hard Disk. What I have now is a 120GB, 7,200 rpm Maxtor HD, which has never disappointed me at all.
Discerning pr0n collectors choose silver/gold alloy phthalocyanine CDs.
Lawrence Person (lawrencepersonh@gmailh.com (remove all "h"s to mail)
http://www.lawrenceperson.com/
I still think that corn CDs are the best idea... you'll just need to reburn every once in a while.
It only becomes a problem if you're a big nacho fan...
actually, I was going through my legally obtained mpeg-4 backup CDs earlier this week, and found a number of Discs had irrecoverable errors on them, despite having been kept at room temperature, in cd sleeves, and having no scratches. The longevity of cheap to medium grade CD media is not nearly as high as you'd think.
that buying cheap crappy CD-Rs meant that your data died faster, but I had no idea how the degredation worked. What about the "armored" DVD-Rs from places like Datawrite? They're supposedly almost impossible to destroy. How well do they stand up?
With the study subjecting discs to extremes to cause them to fail, they've shown relative tolerance to certain conditions, but we still don't have "burn to these CDs and keep temp between 60 and 80, RH between 10% and 50%, and light to a minimum and they're good for 10 years" kind of numbers...
500GB of disk, 5TB of transfer, $5.95/mo
I have some Kodak Gold CD-Rs stashed away for archival masters. I have no idea how long the DVD+Rs and DVD+RWs will last.
Mea navis aericumbens anguillis abundat
I just write mine down as ones and zeros on paper. It takes me a few months to do a full system backup, but it would take the government years to accomplish the same task. I figure I'll be saved by the statute of limitations by the time they figure out what I've been doing.
...I guess I'm the oddball here. I've never thought of any of these media as permanent storage. In fact, I learned quickly very early on that all are susceptible to wear, damage or degradation. CDR/W and related tech are more a bandwidth-saving item or convenience item than anything else to me. The things that I need to save, I move to newer formats, usually multiple copies if it's important stuff.
I've yet to lose data to media degradation, however I once lost some important accounting data to a hard drive crash, followed by two ZIP disk backups that were killed by "click-death". One in a billion shot, I guess. Well, I didn't exactly lose the data, I had hard copies on paper, apparently the only semi-permanent storage media that's trustworthy.
Fred
"A fool and his freedom are soon parted"
-RMS
I wish they would test the Memorex black cd's. If you scratch the non-readable side of them, they are actually gold. I've been using these for the past year or two. The price is good on them, and I've had no problems.
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It doesn't matter whether holographic storage is here now, or ever. I have a large collection of CDs on spindles that will surely go bad within the next 3-5 years, but I'm not going to sweat it. If you figure that at least 50 CDs fit onto a single high-capacity DVD (e.g. blu-ray), there's no way I'm going to worry about it.
However, the same doesn't apply for everyone. Many information-intensive companies are constantly struggling to keep up with the latest technology, spending big $$ on data retrieval. Thousands of tape backups aren't quite as easy to read and consolidate as a bunch of personal CDs. I guess the story here is that most people think CDs are a permanent storage medium.
As others have noted, the technologies used in the media are never printed on the packaging. Furthe, like many commodity items, the wrapper has nothing to do with who actually made the media. One spindle of Brand Y disks can be made by Manufacturer A, and the spindle twice its size, with the same labelling, also from Brand Y- will be made by Manufacturer Z. It is extremely difficult to be an educated consumer under these conditions.
It happens in lots of other places- gasolene is not "made" by Mobil; Mobil, Hess, Shell, Sunoco etc contract to area distributors. The distributors buy from whoever is the cheapest or distributes to their area; they slosh-mix any company-specific additives, if any, on the way to the station. Milk? Guess what- federal law requires that the bottling plant's registration number be printed on every bottle of milk. Next time you're in the store, notice how the brand name and generic store brand milk have the same prefix on that stamped number? Notice the brand name milk is pretty expensive compared to the store brand stuff? Dirty little secret of the milk industry, in plain view.
When I need CD-R/DVD-R media, I don't want to have to spend an hour sitting on some webforum reading posts to find out what the most reliable media looks like this week and where to buy it. I want to walk into a store, see "gold type cyno-whatever", see it's $2 more for a spindle of 20 than the other stuff, and walk out.
Though I'm sure there is collusion among manufacturers at the moment, it's only a matter of time before one manufacturer realizes they can market their product based on media type/chemistry thanks to this report educating buyers (the major PC mags will probably pick this up in an issue or two).
What bugs me is how bad my DVD-R disks SMELL. I have to hold the spindle at arm's length when I open the cakebox, and leave the room until the disk is done, because it reeks. I want to know what the hell makes it smell so bad...or, then again, maybe I don't...
Please help metamoderate.
Mitsui licensed the process to Kodak, and still sells the Gold/Silver CD-Rs under either the Mitsui or MAM-A trade names.
Older discussion: Say Goodbye To Your CD-Rs In Two Years?
afterdawn had a discussion on CD-R brands a while back. In short, go with Taiyo Yuden. And to identify Taiyo Yuden?
The biggest issue IMO isn't the media, but the readers. So what if your CD-RW is still readable in 20 years if you can't even find a CD-ROM around to read them with?
I still have tons of 5" floppy disks around, and I'm sure the data on them is usable, but getting it off is another story.
did you ever go to the store and pick up a cheapo blank and a super high grade? you can feel the weight difference. you can also tell with older movies that are sold for under $10... they always weigh nothing. VHS tape is magnetic media (like audio tape)... generally speaking the heavier it is the better the quality. the higher quality ones also will last through more playings/recordings. i am not sure if either are better for archiving though.
with CD-R media i have heard some claims that the black ones are good (look like a playstation game) if they will go to people that have a tendency to leave disks all over their desk... the black plastic lens keeps harmful light off the media surface.
test brands yourself... leave a few on your dashboard through the summer and see what the sun and temperature swings do to them.
(NOT a joke post)
Is it true with many things that reflect light, that the less light it throws back, the more it ABSORBS?
--meaning here probably, that absorbation is what degrades the medium.
I mean, I've had both "dull" and "blinding" discs, (some light-green one's that basically didn't shine at all once "shone on",) and the EXTREMELY reflective one's, that would practically blind you, to some extent.. --I mean, when angled towards a tungsten bulb, or flashlight, whatever..
-Get the drift? --Maybe this is of some importance, don't ask me.. I always go for 'the shiny' one's; as I've suspected them to be "better"..
A horse can't be sick, you know, even if he wants to.
Only problem is, the message gets corrupted really, really fast. Witness the Religious Right in America. Or medieval Europe. Or the tail end of the Roman Empire.
"Hardly used" will not fetch you a better price for your brain.
I store all my data in FBI digital case files. The government will obviously never have a system in place that can read them, so I'm safe.
I'm Rick James with mod points biatch!
Is the data really gone, or is it simply the reader that can no longer handle the tolerances? Are the dots truly gone, or just harder to read? It could be that archivists and the rest of us need more tolerant, but slower-reading devices for when we have flaky discs.
Really, the big advantage stone tablets have is huge amounts of redundancy, but a very small amount of actual data. DVDs could have multiple repetitions of the data on different parts of the disc for fault tolerance.
Ooh, a sarcasm detector. Oh, that's a real useful invention.
That's what makes it such a great archival medium. Centuries from now, holographic storage will still be "almost here", so you never have to worry about it becoming obsolete.
Useful info on a few of the manufacturers, thx. But seriously, are you really attempting to describe the performance of a digital storage medium with terms used to describe the way the stored data sounds? "bright", "good and neutral", "richer, 'tube' toned"?
The terms you use correlate to accuracy of reproduction of various frequency of audio. Audio stored on a CD (I"m not talking about CD with mp3 files on it) is stored as a sequence of samples... that is to say strictly as a time-domain function.
I can't think of any possible way that the performance of the medium could have an effect on the sound of the audio that could be remotely described by the terms you've used.
I have several old Kodak gold CDs recorded on an HP 4x burner about five years ago (about US$400 -- top of the line at the time) which have died. They were stored in an airtight plastic camera box with dessicant and rarely removed. Now the dead ones seem to have some sort of dull, milky film on the shiny surface. Cause of death is unknown. Their neighbors (the exact same gold discs in the same box) are still OK, but I am making backups while I can. You can't necessarily trust gold either :-(