User Panel
Posted: 1/3/2006 6:56:37 PM EDT
If I store data on DVDs or CDs, how long am I guaranteed the data will stay there if the disks are stored in hard containers, out of sunlight, and are properly cared for?
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The figure I've heard is approx. 10-15 years, provided they're kept somewhere around room temp. I have pressed music CD's from 1990 that are still fine, but I haven't tried testing the longevity of burned CDs.
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If no scratches and kept properly, they will last indefinantly (sp?)
Found this... Normal DVD's/CD's can last 100-200 years. Rewritable around 25 years. |
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IIRC, the gubment was using CDs back in the middle 80's for data backup and found that early CDs had corrosion problems and the data would become unreadable. As for now, I would like to know also. |
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Nothing lasts forever. With that fact in mind manufaturers have rated their disks longevity from between 5 to 100 years. I would say that if kept in a climate controled enviroment and out of sunlight I would bet that you could get a good 20 years out of them mabey more. Its the quality of the disk material itself and how rapidly it degrades over time that is the key factor. Here is a link with more info.Cd Life span
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Some of the manufacturers will claim 100 years, but...
They haven't really been around long enough to test any of the claims the manufacturers have made. |
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I have had many last less than a week
they delaminate aound the hub and form little bubbles or it oxidizes, or whatever, and they die - I had that problem several times with our backup systems at the office - so we tossed them all and went with super large removable hard drive backups (faster than DVD, tape, etc) |
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To add... I wouldnt buy cheap media no matter what they say. If your wanting it to last, get the good stuff.
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Gold CD-R, with logo in bulk 100 pack, 74 min Thanks to Mitsui's patented organic Phthalocyanine dye, the most technically advanced dye in the world and to the Gold reflective layer, MAM Gold CD-R gives an optimum recording quality and an unequaled precision. These characteristics make MAM Gold the ideal professional CD-R for mastering and professional archiving. Unlike CD-Rs containing Cyanine, which lose their characteristics more quickly from exposure to light and heat, MAM Gold CD-Rs ensure stability, exceptional longevity and durability as well as added protection from the reinforced Diamond Coat protection layer. Accelerated aging tests show that MAM Gold can be used as a reliable storage media for more than 300 years. All of the main components in the MAM Gold CD-R are very stable in the environment; plastic (polycarbonate), Phthalocyanine dye and gold (it NEVER oxidizes). MAM-A Part# 40191 Price: $135.00 |
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If I need backups longer than that..... |
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A few years ago, I read that music CD's in South America were being contaminated by mildew and fungus due to the humidity.
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It apparently depends entirely on the media. I have seen reports of cheaper media not reliably lasting more that 3-5 years.
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I called the Sony tech center on this question, on the DVD's they are rated for at least 25 years.
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What cheapass Chinese burners are you using? I have a CD-R from 3 years ago that was literally used as a coaster at one point and it still works fine. |
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CD-RW media supposedly holds up longer than -R media. Something about how the "phase change" works.
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I've got CD-Rs that I burned 11 or 12 years ago that run just fine.
The CD-Rs cost about $10 a piece and the burners ran about $1200 to $1500 a piece. |
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If it will make you feel better, just reburn them after a few years...
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Alright then, what is the most guaranteed way of storing data digitally?
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Mitsui Gold media? IIRC, the stuff used a very thin sheet of real gold as the reflector. The reflector was also not the top surface of the CD-R, it was under a layer of plastic. Since two of the main failure modes are the reflector getting corroded or scratched, the Mitsui media was (har har) the gold standard. As far as what's best nowadays? I'd say keeping multiple copies in multiple locations -- anything you really want to keep, keep one copy in your bank's safety deposit box, another copy in a safety deposit box somewhere far, far away, and another in a closet at home for easy access. Refresh the copies every couple of years. |
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I wonder what would be the reaction of the archeologist when they did up my house 1000 years later and find my stash of DVD porn.
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the .gov will not use DVD or CD media for important data. Early CD's suffered from "cd rot" which was an internal breakdown of the media rendering them useless over time. The issue was supposedly resolved with a different manufacturing technique several years ago and i have not seen the problem in the last 5-6 yeras or more.
As for DVD's.... in theory yes they should last a long time properly stored. that said i'd have more than one copy. |
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+1 my cheap ones often last a year or two but start to make chirps and noises then eventually wont play. If you want it to last buy the good stuff |
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Some of the cheap disks can lose data in as little as two weeks. The better ones might go a few months. If you store it in perfect conditions it might last two years. Maybe not though. Some disks seem to last longer, but it is more a matter of luck of the draw so cannot be relied upon for critical data.
So what to do? Maxell CD-R Pro disks are still made of archival quality dyes. They are very hard to find but actually still say archival on the box. You can also search the internet for the original testing program cdrid163.zip I just searched Goggle and it is here today http://fido.okclub.org/cgi-bin/bbs2html?area=windows You can also download Liteon SmartBurn (it may or may not work on your CD/DVD burner depending on brand, but works for several I have). The downside is it does not spell out archival long term vs short term dyes so you have to learn the dye types. www.liteonit.com/ODD/English/e_downloads/e_utility.asp The downside of these programs is they read the original master type (the die) so what the disk is made of may vary depending on whether they used the “die” for they type of disk it was designed for or not. They at least help, so I still use them. My most critical data is backed up hard drives, on CDs in several locations, as well as being stored online as encrypted files. |
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A largish RAID array. |
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+1 - as long as it isn't RAID 0 |
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I was just thinking, we have books and the like that are several hundred years old.
Wouldnt it be some shit if someday everyone went to CD/DVD type media only, TEOTWAKI happens, and a couple hundred years later all of our history is lost. Maybe thats what happened to those ancient civillizations like Atlantis. |
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The only problem with longgggg term storage is the avaliability of devices able to read the format, not the format being able to retain the data.
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a true stamped CD will last a loooooong time.
However a CDR/RW on average will last 2-5 years depending on quality/stoarge cond. After that its a gamble. Like voting, backup early and backup often. |
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Not only willl the Gov't not use CDs for data storage, but neither will Proctor and Gamble, General Electric or any pharmaceutical companies that I am aware of.
You can't guarantee, even under ideal conditions, that most will last longer than 2 years. The solution that most companies use is to store data on SCSI RAID systems. |
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When you absolutely, positively have to be able to access data, the best storage is analogue. Paper. Security Deposit Box. Stored redundantly in at least two places. |
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There was just an article where a scientist w/IBM was saying that burned CDs will last about 2 years--5 years at the most. Pressed/stamped CD should last 25 years
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It is my uderstanding that good CDs will last at least 10 years and probably quite a bit longer, but DVDs will not last nearly as long. A bigger problem will be finding a computer/program that will be able to read your data.
www.cdrfaq.org/faq07.html#S7-5
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The figure I've heard is 10-20 years for HIGH QUALITY CDs recoreded at relatively slow speeds and stored in controlled environments. High quality CDs means you choose the dye chemistry and reflective layer properly. The longer-lasting dyes with gold reflective layer will be fairly reliable; cheap dyes with aluminum reflecting surfaces will, of course, not last as long. A recent study found that 10-20 years is optomistic, and that you should count on no more than about 5 years, average. Same study recommended using quality magneitc tape for long-term storage. Data archival is a strange area of study now. Up to mid-1900s, you were merely discussing paper and ink chemistry and storage techniques, and at the far reaches you were discussing language evolution. Now, you have to consider technological obsolescence--even if your 8" floppy discs are in perfect working condition, where will you find a CP/M machine with a working 8" drive to read them and transfer the data? With my own data and program archives, I've moved them from one storage format to another. All of my 5.25" disks with anything important on them were copied to 3.5" disks years ago. Most of my 3.5" discs have been burned to CD-RW discs, as I believe the phase change alloys in the CD-RWs might be a better long-term solution than the dye layers on CD-Rs. I'm now looking at DVD formats and various drives to consider what the next step is for my long-term data storage. One also has to consider other technological advances. People have figured out how to SCAN a vinyl record with a flatbed scanner, and extract the audio from the vinyl record's tracks. Who knows what we might be able to do with a deteriorated CD-R in 30 years? Jim |
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This is a very, very serious potential problem. Not necessarily the TEOTWAWKI issue, but the loss of information, especially the kind of communications information that historians use for their research. Jim |
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Pressed CDs probably have a much greater longevity than burned CDs, assuming they are not attacked by microbes or airborne chemicals. Audio CDs can survive much longer than data CDs, because audio CDs can withstand a significant amount of 'bit rot' where data CDs become unusable with even a minimal amount of rot. Jim |
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Soooooooooooooooooooooooo, scanning family pictures and saving them on CD-RW so I can pitch the hard copies is not a good plan.
(Yes, I already did that with one box of them). |
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Yeah, I'd keep the hard copies somewhere. Scanning them is a great idea if you want to distribute to other family members without the expense of making paper copies. Jim |
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Just reburn a copy every five years. |
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To hell with the media i have files that are less than 10 years old that are suffering from s/w obsolescence already. Granted most of them were done in Wordperfect but 10 years ago that was a viable alternative to MS Word.
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