General discussion

1/27/06 How long do burned CD-Rs and CD-RWs last?

Jan 25, 2006 9:54AM PST
Question:

I recently read an article by a data storage expert who claimed that burned CD-Rs and CD-RWs can be expected to last only two to five years and not a whole lot more. I personally have commercially pressed CDs from the 1980s that still play fine, but I have begun to notice that some of my burned CD-Rs are beginning to skip, or not start (player shows "no disc"), or have a strange echo that was not on the original. This sounds serious! The expert suggests that for secure long-term storage, high -quality magnetic tape is the way to go. Are any of your readers beginning to notice this problem with their burned CDs, and are there other opinions about how to combat it? Are some burnable CDs of higher quality than others? What are the best storage methods for the discs that will make them last longest?

Submitted by: Carl N. of Cottonwood, Arizona

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Answer:


Factory-pressed CDs are totally different from recordable CDs. In a pressed CD, the data is literally "molded into" (actually pressed into) the media and will not disappear unless the CD is physically damaged. Recordable CDs use a dye that changes color or reflectivity when heated. There are different dye types commonly used in recordable CDs--phthalocyanine, azo, and cyanine, in particular--and they do not all have the same life expectancy and stability.

All of the studies that I have seen except one suggest that properly burned one-time media (-R media, but not -RW media; see below) has an expected life of decades to possibly even centuries. There was a study by NIST (a U.S. government agency, used to be the National Bureau of Standards) on the relative stability of different media here:

http://www.itl.nist.gov/div895/gipwog/StabilityStudy.pdf

You can see some comparisons in the NIST study of the different dye types. But this study did not attempt to extrapolate the data to a life expectancy, although it did provide data about the relative stability of the different dyes and reflection layers behind them.

However, opinions still differ as to how long such media will last. The OSTA (Optical Storage Technology Association), in a report here:

http://www.osta.org/technology/cdqa13.htm

suggests that optical recordable media will last 50 to 200 years. This observation is backed by quite a number of studies that I have seen done both by the media makers and others. However, some storage experts suggest numbers more in line with your question, for example the expert in this report suggests a life of only 2 to 5 years:

http://blog.eogn.com/eastmans_online_genealogy/2006/01/life_expectancy.html (I have a suspicion that this is the article that you read).

The bottom line is that you are not going to get one single answer that everyone agrees on, although I personally am confident that properly recorded CD-R media can last decades if not a century or two. These 3 articles provide a good starting point for understanding some of the variables involved, which include:

-Dye type
-Physical construction of the media
-Storage conditions (temperature, humidity, light exposure, mechanical stress, chemical exposure and air quality)
-Manufacturing conditions (can vary from batch to batch in otherwise identical media of the same brand)

Now let?s mention some other things that are relevant and important:

-The quality of the burner. A borderline defective burner can ?under expose? the media to the laser beam, producing a seemingly good recording (at the time of burning) that will ?fade? over time (failing weeks, months, years or decades sooner than it should have had the laser beam intensity been correct)
-Recording speed. Fast burns (52X) are probably less stable than somewhat slower burns (say 16x to 32x), but you can burn media too slowly also. There is a very good analogy here to photographic film and exposure levels. The dyes on a given media have a certain range of acceptable ?exposures? and outside of that range, you can either under or over expose the media to the laser beam. However, mechanical jitter and certain other variables (largely a function of the quality of the drive) generally will be unconditionally worse at faster speeds.
-Your own handling and storage practices. On a CD, the data ?exists? in a dye layer on the label side of the media. This can be scratched from the back (from the label side), which will literally and directly destroy the data. The front side is clear plastic but can also be scratched. While front side damage may make the data less readable or completely unreadable, the data is still intact and undamaged on the label side, and the scratches on the front can normally be removed by polishing the plastic. On recordable DVDs, the data is on a layer ?inside? the media, but the media is a laminate of several layers and can delaminate, destroying the data. Flexing ? even VERY minor flexing ? is particularly bad at causing such damage. And, also, recordable DVDs tend to fail from the outside in, so you can increase your success rate and decrease the incidence of failures by not recording such media beyond 80% to 90% of capacity, leaving the outside edge, where the failure rate is greatest and failure occurs first, blank anyway.

-Labeling: The glues in adhesive labels, or the solvents in pen-type markers, both applied to the label side (the side containing the data) can SLOWLY penetrate the reflective backing and dye layers and destroy the data. Therefore, for archival media, the safest policy is to not label the CD or DVD itself at all. If you do label it, with either a label or a pen, you are, at best, taking a chance with your data (hint: it is safe to write on the clear inner hub (where there is no data at all) with a suitable pen that won?t rub off).

And, finally, I would be remiss if I did not mention one other factor which is really huge: Eraseable ?RW? media is FAR less stable than one-time (?R?) media and should absolutely not be used for any permanent recordings of any kind whatsoever. There is no question that RW media can and does ?fade?. Although I?ve never seen failure of ?R? media that I could attribute with absolute certainty to dye instability, I routinely see ?RW? recordings that are unreadable after periods of months to a year or two when there is really no other explanation for the failure. I see this both on CD-RW and DVD+/-RW media, and I advise people in the strongest possible terms not to use ?RW? media for anything that they want to consider permanent. Since RW media is also both more expensive (a lot more expensive) and slower, from my perspective the decision to never even buy RW media at all is an easy one from my perspective.

Submitted by: Barry W. of North Canton, OH

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Comments
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CD-R Burning photos
Feb 17, 2006 1:11AM PST

I burned about 250 jpegs onto a CD-R and when I checked them out, all the jpegs were read only. Any comments are appreciated.

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files burned to a CD are always Read-Only- 1 exception - UDF
Feb 17, 2006 7:58AM PST

When you burn files to a cd they are most always going to be read-only. There is only 1 exception to this. Files will be read/write only when saved to a CD formatted in UDF (universal drive format) which enables DLA (drive letter access)packet writing ability.

You can format all CD-R, CD-RW, DVD

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all files copied to a CD-r are marked read-only
Jan 7, 2007 1:19AM PST

Hi,

That is only logical, as you would not have been able to write to a CD-r with the CD-r drives that were available at the time that CD-r disks and drives were introduced.

Best regards,

Hans

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HOW ABOUT ARCHIVAL GOLD CDs?
Jul 13, 2006 2:44AM PDT

I am looking at an ad for Archival Gold CDs & DVDs. Has anyone checked these out?
cpmdave

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Life of Cds & DVDs
Aug 23, 2006 5:34AM PDT

Congratulations! Very good article. i learned a lot.

emets2@yahoo.com

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Can I recover faded CD's?
Sep 26, 2006 2:25PM PDT

Last night I tried to review some of the old digital pictures and to my desperation I discovered I can not reads CD?s from 2002 and 2003. I tried on 4 different CD_ROM drives (including the one used to burn the CD?s in the first place) and the result was the same: I could read the directory structure but not individual .jpg files. Then I attempted to copy the files on the HD but XP reported CRC error. I even tried to copy the files with old mighty DOS and still it fails for every single file.
Is there any hope I could recover some of the files on those CD?s?
The home burnt CD that last a ?life time? is just a myth !
Do we really have any other alternative but burning the CD/DVD collection every 2 years?

Submitted by Ovidiu M. of Melbourne, Australia

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Transfering from RW media to R media
Dec 22, 2006 3:54AM PST

If I record my movies on my Sony Handicam on to a RW disk and then copy and burn to R disk will this make my movies less vulnerable to degredation due to age?

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Sharpie Permanent Marker a no no for labeleling cd's????
Dec 22, 2006 4:02AM PST

After reading all the comments on degredation. I should I assume that using a Sharpie Permanent Marker to label my cd's is a big no, no?

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How long do burned CD-Rs and CD-RWs last
Dec 23, 2006 6:04AM PST

I can only offer an untechnical observation but I have found that many of my CDs of all types burned on a variety of burners frequently fail in as little as 2 years. Sometimes I can 'resurrect' one using a ripper or persevering with another reader but overall I find them totally unreliable - even less so than floppy disks!
None of these tecnologies has been properly tested and refined because the manufacturers are all hell bent on getting the next generation medium out to reap yet more profits and hang the quality.
Keith T

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REPLY TO cebuBill
Jan 7, 2007 8:32AM PST

Yup! You are spot on, but I've noticed that labelling with them thar printable sticky label type identifiers screw up the disks, I have found that simple small marker type pen does the trick!
I have disks that are several years old, the ones with the labels start to misread after about 2-3 years, whereas the marker pen ones perform o.k without any problems!

NOW, MY QUESTION IS, IF I STORE FILES ON A U.S.B FLASH DRIVE, HOW LONG WILL THE FILE LAST IF YOU LOADED THEM ON, LEFT THEM IN A DARKENED DRY DRAW (WITHOUT BUNGING THE DRIVE BACK INTO A U.S.B PORT), HOW LONG WILL WILL THEY BE VIABLE/READABLE?......COME ON YOU BRAINY GUYS AND GALS OUT THERE,YOU MUST HAVE SOME SORT OF INKLING?

PS.IN A FORMER POST I SUGGESTED THAT MAYBE OLD EDISON WILL HAVE THE LAST LAUGH AS VINYL/SHELLAC RECORDINGS WILL LAST VIRTUALLY FOR A LIFETIME IF THEY ARE STORED IN A REASONABLE WAY!

I HAVE NOW DISCOVERED THAT INDEED YOU CAN BUY A LASER READER TURNTABLE FOR YOUR OLD VINYL/SHELLAC RECORDS, SO THERE IS NO NEEDLE/STYLUS WEAR AT ALL!!! IT COST'S AN ARM AND A LEG THOUGH!
SO, WHO'S GONNA BE THE MANUFACTURER THAT BRINGS OUT A READ/WRITE TYPE VINYL/SHELLAC RECORDER THAT BURNS THE MEDIA IN A DIGITAL FORM,.....BET YER *** SOMEONE SOMEWHERE IS WORKING ON IT?

RGARDS,

GERONIMO.

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How long do burned cds last?
Feb 11, 2008 2:31AM PST

There is a lot of discussion and differing views regarding what labeling methods corrupt data on discs and what methods doesn't. There seems to be two camps here. Those who say that discs can be corrupted by labeling methods and those that say they have never experienced any data corruption. Fine. Both are correct but may I suggest that where there is smoke there is fire? Obviously certain inks and adhesives can cause data loss in certain discs under certain conditions. Why take a chance and why press your luck? If something was worth burning and labeling to begin with why not do everything you can to protect your discs? When playing Russian Roulette you have an 83% chance of not having your head blown off. Still those are tough odds when so much is at stake. Why not swallow your pride and just label your discs with an unquestionably safe method? I use a DiscPainter to label my discs. It prints on printable discs which offer an extra layer of protection against data corruption. The ink used is water based and not solvent based. I don't know about you but I would rather play Sicilian Roulette. That's a game where you know you will always win.

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Don't forget redundancy
May 20, 2008 2:32AM PDT

Even though nothing lasts forever but surely things can last very long. The same thing should apply to CD/DVD-Rs. The question is how. I myself made a lot of backups on DVD-Rs, and yes some of them, after awhile, are not flawless in terms of pefect readibiliy. Some bytes will eventually become unreadable, rendering files that contain them unusable. However from my experience, I learn several tips (some of which were also mentioned somewhere in the other posts).

1. Do not use the full capacity of the disk (especially for DVDs). A single layer DVD can hold up to 4.7GB. Use around 4 GB only. As you will notice, usually (if not most of the times) unreadable bytes take place in the outer part of the disc (near the edge). Unreadable bytes not only happen because of the physical factor (scratch, etc) but also happen because of weak laser. Some old drives have difficulty reading data on the outer part of the disc. This also suggest to never use the overburn feature.

2. Do not write with maximum speed. Although I can't prove it scientifically, I believe that writing with medium speed results with better writing on the media.

3. Despite of the brands, careful handling and storage of the media is crucial. Basic known facts are to keep them in a cool, dark place. What I can add is, use silica gell to control humidity in the storage place.

4. Do not use the backup CDs for daily data retrieval. The more often the CDRs are used, the bigger chance they can be corrupted by many factors. So, just backup (and make sure it is written successfully) and keep them. Do not use it for daily purpose, but only in times of emergency (like data restore).

5. Always prepare to create a new set of backups after every period of time. As for me, I check my CDs every year. So far, even four-year old DVDr are still okay (I started using DVD-Rs about 4 years ago). For CDs, some of mine are already over ten years old and they're all practically okay.

Having said that, don't forget redundancy. Having multiple sets of backup discs that contain the same data won't hurt. Even though the data are still perfectly intact in the media, after a period of time you might want to create a new set of backups. After along time, you will have several sets. In case of unreadable bytes, no two CDs would lose bytes on the same spot, so, having multiple sets will help to restore broken files.

So, backing up to CD/DVD-r? Why not!

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