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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."
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.
Record it to your HDD in an non-lossy format and store copies of it on various friends' and family members' computers. Back up frequently and your recordings won't suffer from the kind of decay and generation loss that analog tape does.
The story about the Rot of Death seems to come up every once and a while. My fun strategies for longevity:
- If you can rub the top of a CD and have your finger come back silver, that's a bad sign. I avoid cheap CD-Rs. Sorry, CompUSA.
- I burn at 2x, always, unless I am burning something that I don't care about. Someone showed me the difference in color, I was convinced.
- Sticker on top = CD death.
- Take care of your media. Had a friend who left a CD on the windowsill and forgot about it. Many months later, you could see right through it. Nice corrosion.
I find it weird that anyone can stick a 100 year lifespan on a product that hasn't been around that long. I know that they have processes that supposedly accelerate the process and give you a rough estimate, but I am skeptical. Maybe they really are that durable, and people are just careless/cheapskates. You know what they say about malice and idiocy.
Auto-reply to ACs: "Truly, you have a dizzying intellect."
The 100 year CD-ROM becomes a 27 million year CD-ROM, and they plan to have their copyrights extended that far.
Store them on a series of floppy diskettes. They have proven to be VERY reliable. ;)
Factor that in with the project the BBC did in the mid-1980s (A digital Domesday book, designed to be a snapshot of life at that particular moment of time) that was unreadable withing 20 years because of the fast pace of technology and no way will CDs last 100 years.
HAH! I just wasted a second of your life making you read this, but I wasted a minute of mine thinking it up. DAMN.
Blank CDs in bulk are cheap. For archival stuff I make a new copy every 5 years. I have a bunch of scanned photos I don't want to lose, so I re-copied them all onto new CDs.
You aren't supposed to write on the CDs either but I've not had any trouble with that, probably because I'm not trying to keep them very long.
Rename the MP3s of your grandfather's voice to coors_twins_baby_oil.mpg and put it on Kazaa.
Repeat every year with the current cover girls of Maxim, Stuff, or whatever men's mag suits your fancy.
Guarantee you'll never be at a loss for a copy of dear old granddad.
3D Printing Tips and Tricks at Zheng3.com
I know lots of people that have "worn out" cd's. The first time I heard that, I thought they were kidding, but no... even if you take super great care of say, an audio cd, it will eventually wear out. It's especially bad if you keep it in the original plastic jewel case, and take it out each time -- my friend's rare Pearl Jam CD's are nearly scratched beyond playability, but he was able to extract the digital information before it got lost. What makes CD's better than tapes is that the 0's and 1's will always "be the same" logically, unfortunately the physical media wears out quickly with use. I prefer to think of CD's as a temporary storage mechanism for a permanent idea, like a sketch on newsprint. Once the newsprint disintegrates, you'd better hope you made something good with the idea... it doesn't mean the idea is gone, but the medium isn't like stone.
stuff |
But be sure to use blanks from different manufacturers. Otherwise your failures won't be independent, so the odds of all your copies going bad at roughly the same time (i.e., before you notice the first one has failed) is high.
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.
It's not exactly a fair comparison between CD-R and analog tape for audio. The audio tape isn't "more reliable." It just degrades differently.
As the tape ages, the quality of the audio signal degrades dramatically, but because it is an analogue signal, it can still be deciphered by or ears.
With digital medium, the audio never gets worse. As the media degrades, it just reaches a point where it isn't able to be deciphered as audio data.
If you want to compare the mediums (magnetic tape vs. CR-R), data is probably a better place to do so. You can easily measure the amount of readable/unreadable data in bytes and make a fair, quantifiable comparison.
In the wrong conditions, such as sunlight, humidity and upper surface damage, your CD-R will slowly turn into a coaster. "CD-Rs should never be left lying in sunlight as there's an element of light sensitivity, certainly in the poor quality media," says Stevenson. "I wouldn't rely on CD-Rs for long-term storage unless you're prepared to deal with them as recommended."
Surely storing cd's correctly is the key, if the dye on a cdr fades after being kept in a jewel case at a room temperature fr 2 years then that is obviously very bad (and there could be some lawsuits in the future).
The first link is to rense.com, a website that promulgates the theory that the US government is experimenting on us with "chem trails" emitted by otherwise innocuous-looking aircraft flying overhead. The webmaster at that site obviously has a very low threshold for rubbish, and no critical thinking ability!
What's the deal? This same article with a slightly different look shows up every 6 months, it seems.
Besides the fact that CDs DON'T have a 100 year shelf life, we've also discussed the CD eating fungus several times here, which for people in hot and humid environments (particularly, it seems, Mexico, Central, and South America) can reduce a CDs lifespan to months or a couple of years.
And then you have the fact that rewriteables have an even shorter lifespan.
One thing that's rarely mentioned is the fact that most CDs are defectively manufactured. I say this because the metalic layer between the plastic is supposed to be sealed. But the fact that the aforementioned CD eating fungus enters through the two layers of plastic says to me that CDs are generally defective in that they fail to properly seal this layer.
I personally lost about 25% of my CD collection to this fungus over a 2 year period in Mexico, so I speak with some experience. These CDs were not abused. Most were in plastic cases, some were in sleeved carriers.
I don't get this obsession with hoping to keep media for 100 years. Technically punch cards are forever. Do you still use them ? No, because their storage capacity is ridiculous by today's standard. In five years you will store your data probably on your solid-state 200 g key-chain.... move with the times..
The BBC Library still uses vinyl records for long term audio storage. For some items they cut a lacquer master, plate the metal stampers on the lacquer and leave the metal stampers attached to the lacquer.
They believe that this will preserve the audio for about 300 years and they say that vinyl is the only storage medium with a real and predictable life span.
Audio processing technology will get better. Don't ruin your grandkids' heirloom recordings by using today's technology to permanently alter them.
Make working copies and filter those as much as you want, but keep those masters pristine! Maybe somewhere in the background you can hear your grandma yelling at dear ol' grandpa to put that thing away and paint the house, and a clumsy run with an agressive low-pass filter will throw that data away forever. You have something really valuable; please take care of it for the future.
Dewey, what part of this looks like authorities should be involved?
Now, you can enjoy your CDs for a long time...
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I'm sure what I'll say has already been said, but I can certainly attest to the shorter-than-advertised longevity of CDR media. I recently had to pull some long lost files off of CD's I burned back in the college days, probably 5 years ago or so. These consisted of several types of media, both cheap and expensive, green and blue dye, sticker and no sticker. Basically the dye color has little effect, and stickers really do call for the early death of the media. But most of all, I think it was the early CD burning software or the actual CD-Rec drive that I used. Some earlier CD's, that I know I burned at work (using the latest software at the time) were near flawless. But a batch burned later, on a friend's computer using some lesser known software, was completely corrupt (TOC and CRC errors abound). I now make sure I get decent CDR's like TDK's (not the cheap CompUSA stuff), don't use stickers, always keep them in a multi-CD case, and run a bit-for-bit check on the archive after burning with Nero. I have yet to have a problem since I started this practice at least 2 years ago...although time will certainly tell.
Sometimes I doubt your commitment to Sparkle Motion.
Although it seems like burning at a slower speed means that your data lasts longer, for some newer CDs burning at 2x might actually cause your data to be less secure. Most CDs sold nowadays are optimized for faster burns, say at 48x. The "fast" media doesn't handle slow burn speeds quite as well as older media optimized for 2x would.
Pressed CDs shouldn't be as vulnerable to bit rot as burned CD-Rs. But I can't understand how the discs would lose quality. One either gets a valid frame of redbook audio or not. I can understand that some of the frames might go bad (even to the point where the built-in error correction can't help) and lead to audio defects, but I don't see how the whole disc would sound different than before.
Ita erat quando hic adveni.
that's why I bought the Unreal Tournament 2004 Special Punchcard Edition.
a /U T04-PunchCard.gif
http://img53.photobucket.com/albums/v162/Cordat
As long as I keep them in a dark and dry place, it's going to last forever!
So i guess someone was paying attention in Stats class ;)
That does it. I'm converting all my mp3 collection to 8-track tapes. Does anyone know of a good 8-track tape recorder that mounts in a typical tower 5.25" drive bay to make this easy?
Don't blame Durga. I voted for Centauri.
"Real men don't use backups, they post their stuff on a public ftp server and let the rest of the world make copies." - Linus Torvalds
The National Institute of Standards and Technology also has an extensive guide, Care and Handling Guide for the Preservation of CDs and DVDs, including a one-page Do-and-Don't Quick Reference.
This means that if you have a 2X recorder, writing at 2X is *much* better than 1X. If you have a 32X recorder, writing at 32X will produce measurably better discs than writing at 4X, 2X or 1X. This has been true since around 1998 or so. It is quite true that you could get better results with some early 4X recorders when writing at 1X than 4X. However, none of those devices are current any longer.
The "writing slower is better" story is a myth. Please don't spread it further. And yes, if you want more information about disc testing Media Sciences is a company that is dedicated to disc quality and testing. I do not work for them.
... if you know what you're doing. First of all, there are specialty CD-Rs intended for archival purposes. These will inherently last longer than normal CDs for numerous reasons, assuming the manufacturers are not full of crap. To find these CD-Rs, check a photography store, as photographers tend to have a need for both archival and mass storage thanks to digital cameras. You will likely find some there.
Second, the biggest mistake most people make in CD archival is to write on the CDs with magic marker -- DO NOT DO THIS. The ink will, given several years, leach through the extremely thin plastic on the labelled side of the CD and pollute the optical layer, resulting in a ruined CD. Adhesive stickers, I'm told, are not much better. There are special CD-labelling markers out there, I don't know if they work well as I haven't tried them, but I doubt they're worse than a magic marker. I have found that writing very lightly with a soft, dark graphite pencil works well. If you're very paranoid, you might consider not labelling the CD at all and just be meticulous in returing it to its (properly labelled) case when you're done.
Additionally, store the CDs properly. Somewhere reasonable. Not in direct sunlight. Safely stowed in their jewel cases.
Of course, even doing all this, no one can tell you that your CDs will still work in 100 years. It hasn't even been 100 years since we invented the damn things, how do we know how long they will last? Still, these are steps that should allow your CDs to last for at least as long as a magnetic tape, and with perfect accuracy, as opposed to the slow degradation of audio tapes.
What we really need is something similar to the S.M.A.R.T. technology in harddrives nowadays, to alert you that "Listen, I'm getting close to reaching the limit of my error-correction techniques here. This media probably isn't going to last a whole lot longer. You may want to do something about that." Currently, there's really no way to tell until it's too late.
Random and weird software I've written.
Really, what do you expect when most people pick up spindles that all some from the crappy Ritek or Princo plants in Taiwan because they can get them for $9 a spindle? I've had those go blank on my shelf too, and now I know better.
Want a long lasting CD-R? Search the spindles to find the ones that are made in Japan. Sometimes these will be on the same shelf with the Taiwan ones, wearing the same packaging, and for the same price (if you're lucky). Usually these are made by Taiyo-Yuden, a high-quality CD-R manufacturer (and one of the co-developers of CD-R technology). Look for a frosted hub for positive ID.
For archival quality, you'll need to spend a couple of bucks a disc on media that has a gold reflective layer. The standard here has always been Mitsui (now branded as MAM-A). Even their silver discs are a cut above in quality.
Oh, while I'm here. In 1996 I scribbled all over a burned CD-R with various colored Sharpies, then last year cleaned it all off with carb cleaner. It hadn't migrated into the disc at all, and cleaned off without a trace. The data was fine. Anyway, I mention this because I hear people claim Sharpies kill CD-Rs all the time, and think it's nonsense. These people probably bought the cheap-o discs and are looking for something other than their own cheapness to blame it on. Oh, BTW, the scribble disc was a Sony, made by Taiyo-Yuden.
pronoblem
(2004/02/17) in CD-Recordable FAQ:
CD-RWs are expected to last about 25 years under ideal conditions (i.e. you write it once and then leave it alone). Repeated rewrites will ccelerate
this. In general, CD-RW media isn't recommended for long-term backups or archives of valuable data.
The rest of this section applies to CD-R.
The manufacturers claim 75 years (cyanine dye, used in "green" discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years
("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has been written. The shelf life of an unrecorded disc has been estimated at
between 5 and 10 years. There is no standard agreed-upon way to test discs for lifetime viability. Accelerated aging tests have been done, but they may not provide a meaningful analogue to real-world aging.
Exposing the disc to excessive heat, humidity, or to direct sunlight will greatly reduce the lifetime. In general, CD-Rs are far less tolerant of environmental conditions than pressed CDs, and should be treated with greater care. The easiest way to make a CD-R unusable is to scratch the
top surface. Find a CD-R you don't want anymore, and try to scratch the top (label side) with your fingernail, a ballpoint pen, a paper clip, and
anything else you have handy. The results may surprise you.
Keep them in a cool, dark, dry place, and they will probably live longer than you do (emphasis on "probably"). Some newsgroup reports have complained of discs becoming unreadable in as little as three years, but without knowing how the discs were handled and stored such anecdotes are
useless. Try to keep a little perspective on the situation: a disc that degrades very little over 100 years is useless if it can't be read in your
CD-ROM drive today.
One user reported that very inexpensive CD-Rs deteriorated in a mere six weeks, despite careful storage. Some discs are better than others.
An interesting article by Fred Langa (of http://www.langa.com/) on http://www.informationweek.com/story/showArticle.j html?articleID=15800263&pgno=1
describes how to detect bad discs, and discusses whether putting an adhesive label on the disc causes them to fail more quickly.
By some estimates, pressed CD-ROMs may only last for 10 to 25 years, because the aluminum reflective layer starts to corrode after a while.
One user was told by Blaupunkt that CD-R discs shouldn't be left in car CD players, because if it gets too hot in the car the CD-R will emit a gas that can blind the laser optics. However, CD-Rs are constructed much the same way and with mostly the same materials as pressed CDs, and the temperatures required to cause such an emission from the materials that are exposed would
melt much of the car's interior. The dye layer is sealed into the disc, and should not present any danger to drive optics even if overheated.
Even so, leaving a CD-R in a hot car isn't good for the disc, and will probably shorten its useful life.
See also http://www.cd-info.com/CDIC/Technology/CD-R/Media/ Longevity.html,
especially http://www.cd-info.com/CDIC/Industry/news/media-ch ronology.html about some inaccurate reporting in the news media.
See "Do gold CD-R discs have better longevity than green discs?" on http://www.mscience.com/faq53.html.
Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
The number of things that can go wrong with old magnetic media is so long I won't even go there. If nothign else, the magnetic tape will get old and brittle. It also stretches slightly when you play it, which could leave granddad sounding like James Earl Jones in a few years. Certain types of mildew love it. AAAAAA! Make a copy! Make a copy!
Add to that the cost of replacing r2r tech, and you've got a scary situation. I agree with the parent. CD may not be the answer, but digital sure as hell is. I'd be super paranoid having anything I cared about stuck on old tape.
ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
AFAICT, reading all the available literature from Mitsui on their gold MAM-A discs, the reflective metallized layer _is not actually gold_. It's aluminum.
Mitsui is claiming their _special dye_ is what makes their MAM-A discs last so long, and the dye is what gives their discs their gold color. Not the metallized layer.
And really when you think about it, it doesnt matter how long-lived the reflective layer is, if your dye deteriorates. Since you're recording your data onto the dye layer -- not the reflective layer.
Umm... what literature would that be? There is a white paper which explicitly states that the reflective later is 24k gold.
Real men write stuff that the rest of the world wants to copy.
We burn about 200K CD-R's here per month. We have found, unequivocally, that you can burn data CD-R's at 40x, but the best we can do for audio is 12x. We don't really know why, but we think it has more to do with the error correction capabilities that the data format has. That's the theory, anyway. Of course, we use only the best drives and media.
No, the cassette was just changing to reflect the current Jackson.
The only reason we have the rights we have is that people just like us died to gain those rights. -- Cheerio Boy
Is that I can still read data from Iomega Zip disks that are 6 years old, yet can't read CD's I burned 6 months ago. For some reason, the perils of magnetic media and Zip drives never came true for me.
What really irks me is that CD-R was sold to the public as a way of _permanently_ archiving data. Once written, it was supposed to be permanent. The non-magnetic, non-rewritable nature of the media was supposed to prevent accidental overwrites and erasures from magnetic fields.
Top Ten reasons to love CD-R/CD-RW:
* - yes, these are the recommendations that came with a 2004 Toshiba laptop regarding making CD's.
The society for a thought-free internet welcomes you.
I was one of the original developers for Magneto Optic for MaxOptics and Pinnacle Micro Systems approx 20 years ago. I still have media recorded back then on truly rewritable optical media that is 100% flawless to this day. And all this is on Plastic Media. I never did understand why magneto optic didn't catch on more. The Glass Media units I'm sure would go to 100+ years and were tested in Europe for the telephone and data companys 20 years ago, and the last I heard they still hadn't seen a single cartridge with glass media go bad.