Do burned CDs and DVDs have a shelf life?

Yes, we switched to Taiyo Yuden disks because we were having production problems with another well-known brand. We have very few rejects now. We verify 100% during production, and have not heard of any disks developing problems after that. We use the white matte label disks and print directly on the disks during production.

The most important recurring theme in these comments is that you cannot depend upon one backup lasting forever. Fresh periodic backups are very important if you care about your data.

can you share the code numbers that let you know TY is the manufacturer?

Data arent written/stored in the back labal or coating. The data is still written within the plastic layer. The coating is neccessary for the reflection of laser light back into the read head.

Your are not correct, as regards CDs.

CD media (CD-R and CD-RW) is a single piece of clear plastic. EVERYTHING happens in coatings sprayed onto this plastic on the label side of the media. It is not "within" the media.

However, DVDs are a "sandwhich" of two pieces of plastic and the data IS stored "between" the two layers, e.g. "within" the media. This is why DVDs must not be bent: Bending stresses the bond of the two layers, which then can "delaminate", destroying the data.

I think you meant on the side OPPOSITE the label. If you look at a laptop CD player or burner, you will see the lense is under the disk.

you say "The coating is neccessary for the reflection of laser light back into the read head"

ummm... if the 'coating' is to reflect the laser back to the read head, and data were somehow written into the plastic below that, then the laser would never reach the data.

Re: "How much data on 8" floppy, or even 5-1/4" floppy for that matter is accessible today?"

Virtually all of it, if you have the hardware.

I am extremely active in the "classic computer" community and have multiple systems here with 8" floppy disk drives and perhaps about 2,000 8" diskettes. And I am in regular contact with about 100 other people who are similarly involved in restoring and saving 1970's hardware (names like Imsai, Altair, Processor Technology, Ohio Scientific, Heathkit, etc.) on a fairly large scale. We have NO trouble reading 8" diskettes recorded in the 1970's ... the failure rate is low single digit percentages. The problem is keeping the hardware working (rubber parts do NOT last; ask any classic computer enthusiast about platen rollers, tape drive pressure rollers, or any keyboard (like the one in the Processor Technology SOL-20) made by Keytronics that used foam rubber as an active component). But the life of magnetic media has proven to be a pleasant surprise, especially for 8" media: near perfect retention 35 years later. Sometimes, the jackets of the floppy disks are bad but then we find that if we cut the jacket open, and move the actual floppy disk to a good jacket, we can read it fine. We have more problems with 3.5" media, apparently because once the PC went "mainstream", more marginal firms entered the manufacturing process and quality standards dropped. But even there, GOOD media doesn't seem to pose a problem (again, a bigger problem may be finding good 5.25" drives that still work well).

observations about magnetic media have nothing to do with CD or DVD media.

I see nothing wrong with Watzman's post. It was an answer to ttarqjr's comment on accessibility. Hard disks and USB pen drives are also discussed here as alternatives to CD's. I personally would only trust several mirrored hard disks or USB pen drives in separate locations or online storage for very important material especially considering the price drop on USB HDs and pen drives recently. In the future solid state flash drives will probably take over for cd's.

Artie

How long information stored on magnetic media can be successfully accessed says nothing about the same question when applied to optical media, as the two media have completely different failure modes. Data on magnetic media can be lost merely by exposure to a magnetic field. Data loss on optical media comes from a completely different source: oxidation.

I have had quite a home-burned audio CDs go bad. Either they get scratched (recordable media seems to scratch much easier than prerecorded. and CD cleaners are less effective) or they develop "rot". Sometimes a little hole develops in the silver surface. This inevitably spreads (in a sort of woodgrain pattern) and the disc becomes transparent in places. Needless to say whatever tracks occupied that area are no longer playable. I've seen this happen in the middle of the disk and on the edges. I've seen it happen in car CDs (understandable) and CDs kept in cases.

Normally I regard this as an annoyance more than anything. Itunes makes you create a playlist to burn a CD, and so every CD I have corresponds to a playlist with exactly enough material for a CD, so I just burn another CD.

I've never had a DVD go bad, but then again I can't play DVDs in my car CD player. I've pretty much switched to using DVDs for backups.

I'm converting my record collection to CD's. I've read a lot of the postings here about what does and doesn't work; it seems as if the consensus here is, the better you treat your CD's, the longer they'll last. I'm keeping my CD's in either plastic-lined paper envelopes, or in jewel cases and as such, get no exposure to sunlight. Perhaps no media is capable of lasting forever, and it may be the case that the technology that was used to press records is the best of all, since the grooves are stamped into the vinyl forever and ever. I'm 54 now; all I'm asking is that my CD's last 20 or 30 years...since that's probably the time in which my own personal shelf-life will run out...

I'm 61 and have 5 1/4, 3.5, CDs, VHS. and audio tapes that I can no longer find players for. Our products and programs get dumped by the makers. Try and find a machine to run your old games and such. They don't work! I makes me mad to think the companys don't care about their oldest users. Case in point. $500. GPS, 2 Years old and no longer supported. No updates, no new maps and the marine charts no longer work. To the CO's! If you drop us, then you lose us as customers. To bad as some things were great but now are trash. Just try and get a needle for your record player. I have 78's that are worth a lot but can't be played. The Music is no longer availably unless you know the right people. Well thats my point of view. Rob Cosby

I was surprised to see your comment about your GPS's lack of support. I've got a Garmin, and I'm used to pretty decent support. I have a Street Pilot III that I purchased in 2002, and I've updated the mapping software several times, for a fee of course. They haven't had a firmware update for several years, but I was able to find a new speaker/power cable on Amazon in 2008 when my old one broke.

Speaking of Amazon and things breaking, you always need to be wary of buying anything directly *from* them that might ever break. Regardless of the manufacturer's warranty, Amazon ruthlessly enforces its own one-month warranty rule; beyond that you're entirely on your own in dealing with the manufacturer. I don't know how that would work if your purchase is really coming from a "partner" business where Amazon is just providing the listing and handling the payment, but I assume you'd be dealing with the actual seller.

No one ever said that the media was indestructable, quite the contrary, we all agree that improper handling or storage can destroy ANY media in short order.

The question, rather, is how long quality and properly recorded media that is handled and stored perfectly (or, ok, just extremely well) will last. Our question, in other words, is really how stable is the dye layers on which the data is recorded. There is no argument that whatever that answer, improper handling and/or storage can destroy the best of recordings.

By the way, one other point: People keep using the term "Shelf Life", and that is simply not what this discussion is about. "Shelf life" is the time BETWEEN MANUFACTURING AND RECORDING, and that IS limited to about 5 years. But what everyone is discussing is how long the data will last after recording, which is "ARCHIVAL LIFE", not "SHELF LIFE"

From my personal experience, they do fail.
I have literally dozens of CDs that no longer play.
I also have dozens of DVDR disks that are also unreadable.

The brand DOES make a difference, and unfortunately I can not recomend any name brands, this is due to name brands changing manufactures from batch to batch. I have had some brands that were great, and then the very next batch I buy are from a totally different factory, different dye formulation, stability unknown.
I have run several non scientific tests to determine if a disk is going to be reliable or not for my use. I make a test recording, and then expose the disk to direct sunlight, UV and infrared light sources and see how long it takes to fail. The record here for my non-scientific test is 72 hours exposure to a full spectrum sun lamp used on a coral reef aquarium. This was using very cheap non-branded media. What I have found is media rated for higher speed recording, tends to have a higher failure rate under my test setup.
This is probably due to the dye baing more sensitive in order to burn at a faster speed.
The almost silver CDR disks also have been more unreliable unde rmy tests, and the nice dark dye have held up better.

One thing I just found recently. I had been storing some older CD-R disks for a number of years, unrecorded. I finially needed a CDR to make an audio CD, and I burned one of these older disks, and it would not play back directly after burning. The media was very old 8x media, and my newer drive has 12x as it's slowest selectable speed, so this could have caused the failure.
Bottom line is I make 2 copies of everything, one copy goes into a dark closet, and the other to my library. I make backup copies every 5 years, as I have never had a failure within 5 years, but I have had many failures of 10 year old disks.
In the other hand I have video tapes going back to 1979 that still play pretty good. Signal to noise is down a little, but they play.

I warn my friends that are out buying camcorders to get a tape based model (DV or HDV) and transfer their tape to DVD or AVCHD disk. That way they still have the original tape that they can fall back on to make another copy when the DVD is either scratched or fails.
I know too many people that have HD based cameras that get dropped, or damaged, and they have lost total vacations, or other important material. At least with tape, even if the camera is totally trashed, you can buy another, and your tapes will play just fine.

Two years ago, I bought a large external drive and decided to back-up / restore about 60 back-up CD's burned from 1999-2003. The CD's were burned using a couple operating systems - Millenium and first release XP Pro, a number of burners, and a several different burner software programs.

About half the CD's I tried to back up could not be read. I received a message saying something to the effect of "disk unreadable. CD damaged". I found it hard to believe that I had that many bad disks so I began experimenting.

I first tried a couple other computers and found some of the disks could were readable. This raised my suspicion that the problem was a combination of backwards hardware / software compatibility. After trying many suggested fixes with no success, as a last step I dug through my old installation disks and found the installation CD for the original internal CD burner.

I installed the very old burner software (circa 199 and voila, all CD's were readable once again.

Just thought I would share my experience with members as another potential avenue of hope for those having trouble recovering data from seemingly destroyed disks.

What speed are you burning at. When I bought my Dell 8200, music cds burned at 16x would not play in my cd player. A Magnavox (mde ny Phillips. When I switched to 8x they played in my cd player but not in my car. When I dumped the included cd burner and installed a Plextor burner the sitiuation improved. I could now play an 8x inmy car. Just to be safe, I burn all music cds at 4x. When I create a master, I make it on Fuji and amke a backup on TDK.

this is exactly the same advice i would have given. i have lost media from using cheap disks and putting paper labels on it. i have now used litescribe for several years and would never own a computer without it. it is an awesome invention. i burn on cd/dvd-r litescribe media and then store my disks in a room with little light. i now have hundreds of disks full of photographs and so far they seem very safe on litescribe, in the cool, dark room in which i keep them. the litescribe disk were very pricey to start, but they have come down in price. they are worth the investment. i take hundreds of photos per month and have not lost one litescribe disk yet.