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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?)"
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
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.
I've always wondered if this is actually true or not.. I have yet to see any actual evidence to back up this claim.
It doesn't really matter how fast the reading laser moves along the media, so why would it matter how fast the recording laser moves?
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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?
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.
I found it odd, though, as they said they couldn't tell the public their findings. This point stuck with me, but I forget the exact reason. Perhaps it is simply that it would influence the market? Wouldn't make sense to me: the taxpayer probably put up the funds for the tests and the public and the market would both benefit from the results. Maybe NIST got some industry money to do the test with the condition that the results be kept secret.
Anyway, it would seem they probably have done the same for CD-Rs.
That's because you're using hastily slapped together plastic/aluminium/dye sandwiches from the infamous Coaster Manufacturing Company - CMC Magnetics, and the other shit brands. They're cheap for a reason folks - the same thing happened with floppies.
Try decent discs. Two words: Taiyo Yuden - the very best there is. When you absolutely, positively got to be able to read the data in five years - accept no substitute.
Don't believe me? Track some down. Burn on them. Put them side by side with a crappy CD-R. Spot the difference. Test them. Notice that with many drives you'll get zero C1 errors. Test them in a week. A month. A year. Notice that if kept right, and they don't deteriorate suddenly, they should still be C2 free in twenty years.
Crappy media has crappy quality control, and thus tends to fail quickly. This isn't news, it's just the way it is.
So instead of worrying sbout the CD falling apart, you have to worry about mechanical failure. Unfortunately, that can happen from just sitting around, especially in something so fragile as a hard disk drive.
01101001 01100001 01101101 01101110 01101111 01110100 01100001 01101100 01100001 01110111 01111001 01100101 01110010
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
Yes, but corners weren't being cut to keep production costs to the bare minimum.
Ph-nglui mglw'nafh Gates M'dna wgah'nagl fhtagn.
I know I shouldn't feed the trolls, but...Wow, that's mature. It is an open standard, with free (both open and closed source) readers for virtually every platform in existence. The paper contains images, charts, and so on. PDF is a perfectly acceptable choice, particularly if it was a report which was not originally designed for the web.
Unfortunately, seems they slightly missed the point- the charts and other line art...well...aren't. They're screen-resolution bitmaps. Oh well.
Please help metamoderate.
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 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
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.
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.
In fact, if I had enough space, I would back up my commerically manufactured CDs and DVDs, given the horror stories I've heard about their crappy longevity. The MP/RIAA wants you to re-purchase all the content they've sold you every 5-6 years. Screw 'em.
Computers are useless. They can only give you answers.
-- Pablo Picasso
There are two kids of Maxtor users - those that have lost data, and those that are about to...
JON
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.
For backups and archiving, I use hard drives, period.
I change hard drives every few years, since there's a constant attrition rate, anyhow. Plus they just keep getting BIGER and CHEAPER every year.
to me, optical media are for sending data to others, not for gathering dust.
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.
I personally believe tapes and tape drives are a big con-job nowadays.
They may not be great for home backups (they never really were) but tape is definitly NOT a con-job. LTO-3 is 800GB per ~$150 tape, disk can't touch that, and they backup at up to 160MB/s, again a single drive can't touch that. The only reasonable solutions to backing up LOTS of data are tape or farms and farms of drives which are offsite with a VERY high speed network connection and which are write protected while not being backed up to. The latter can be done but it generally makes tape look cheap. Again for home use there probably isn't a lot of use for tape (I backup my machine by HDD as well), but for my clients I can't imagine using anything other than tape as an offsite/archival solution.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Umm, 'scuse me a sec..
I have a 133 megabyte full height 5.25 Maxtor that is 20 years old, and a 44 megabyte miniscribe that is 22 years old. I saved them back from the days when they were GOLD to me.
Like a moron, I traded a 100mhz dual trace Tektronix scope for the 133 meg drive. Now it sits on the floor in the closet. But guess what?
The drive STILL boots and runs. Yep, it's loaded with IBM DOS 3.1 and I can still play some of my old Sierra games on it.
It's worth squat. But after 20 years of banging around on the floor as I moved several times, it still boots and runs.
I can't say that for CDR's I burned two years ago. Most of them over 2 years old are riddled with holes, like moths eating wool..
I DO NOT trust CD or DVD media for long term storage. Piss poor media if you ask me. I wish they had never invented the damn things, I put lots of important data on them over the years just to go back later and find it ruined and gone forever.
CD and DVD is a BAD technology. It's time to abandon it and reinvent the wheel..
My understanding is that CD-RW and DVD-RW doesn't use an "organic" dye, but relies on some physical property of an alloy to determine a one/zero. Are CDRW even more or less susceptible to aging?
I recently starting going through some of my old CDR's and I noticed that 3 of my 4 CDROM drives had trouble reading a certain disc. I try a 4th drive (DVD+RW), and it reads it just fine. My guess is this means that the disc is starting to die, and now would be a good time to back it up again.
Several people have suggested the idea of storing media in the fridge or freezer. This is not something to be done lightly. Yes, the colder temperatures would, all other things being equal, reduce the rate of chemical reactions. But in the real world, the fridge or freezer is a magnet for condensation and frost. If you put the disks in a freezer with auto defrost, then they can also be subjected to thermal cycling which is very bad. I am also dubious about a fridge/freezers suggested ability to survive fire given that they are often insulated with petrochemical foams that could be highly combustable or outgas harmful materials in a fire.
The humidity/moisture environment in a fridge/freezer is a complicated thing. On the one hand, water will condense on the evaporator coils which leads to a desicating effect. On the other hand, new moisture enters the compartment every time you open the door and through leaky gaskets. Sometimes the system desicates the contents of the compartment and sometimes it desicates the room only to condense or drip on the contents. And if the fridge is also used for food there can be vinegar drips from fermented food, mold, and other nasties. Each time the door opens, the contents are subjected to some degree of thermal cycling. When you remove a disk, it is also exposed to condensation.
The odds could be improved by putting the disks in a sealed container with some desicant, using a dedicated fridge, and maintaining the gaskets and drain.
I have encountered several people in the audio business describe the "Sound" of different types of CDs (as you do with "bright", "neutral", etc). However, I have yet to have a single one explain to me how a media type that simply describes waveforms through a binary series (1s and 0s) could possibly influence the sound produced, assuming the binary series is stored reliably in all of them. What impact would the media have on the waveforms? And WHY?
The only audible result from different brand of media, from what I understand, would be the vibration due to poor balancing, thickness, or other physical determinates of the vibrations of actual CD as it spins.
In most of those cases though if you really needed the data, you could go to a data retrieval service and get it back, probably all of it in fact. I doubt you could get as much back from a CD-R mainly because once the dye fades I don't see much you could do. I'm sure these companies could try to work some magic but its not like the data is necessarily gone from the HD there's just no way to access it. Using CDs or DVDs to permanently back up important information is suicide, not to mention that its much more expensive. When I could buy a good 160 GB from Maxtor for $80, I don't see much point of using CDs and DVDs for anything other than short term backups and for using as actual CDs and DVDs.
From the article:
Do not be mislead by the numbers presented--they have little relevance to how CD-Rs are typically stored.
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