Last minute Gift Cards @ Best Buy.
Storage: Do burned CDs and DVDs have a shelf life?
- 2/13/09 2:55 PM
they don't last for ever, you can buy archival quality media
by Raccoon1400 - 1/30/09 6:44 PM In reply to: Do burned CDs and DVDs have a shelf life? by Lee Koo (ADMIN)
Since burned CDs use a dye to record data instead of having the data pressed into glass matter, they will wear out eventually. I have a sony CD that I backed up files onto a few years ago, and now it shows up as blank.
From what I've heard, 5 years is the maximum life expectancy for burned CDs.
However, for not that much more, you can get archival quality media that will last much much longer.
But, if you are just doing backup, would you ever need the data on the 5 year old disks?
I keep a running backup
by easytimes455 - 1/30/09 6:51 PM In reply to: Do burned CDs and DVDs have a shelf life? by Lee Koo (ADMIN)
Short answer goes, yes, burned CDs and DVDs have a shelf life. While factory made disks are pressed with the information, burned disks are made from a chemical/dye being burned/etched by the drive. I have heard anything from five to ten years as the expected life of the disks. It's up to you how often you renew your valuable backups... but if you're like me, some of the high value backups can change over the years. Family pictures seem to be the only truly sustained value backups.
I am taking for granted that the disks most likely to burn properly are the disks that will last the longest, so I use Taiyo Yuden disks. Taiyo Yuden makes disks for various better known names, but the list of names changes over time, so I just buy the originals online, rather than squinting at the disks trying to see the various code numbers denoting Taiyo Yuden manufacture.
If you choose to buy this brand, you can find vendors online by simply searching with that name. The vendor I have used for years is there, among the others. I also purchase during special sales, and buy 8x inkjet printables to keep the price lower... usually they fall into the 29-34 cent per disk range. When I backup the disks I print a folder view screen capture as the label with a dated title, so I can identify the contents without having to put the disk in the drive.
So far, I have been using optical media for backups since about 1998 and I have only had a small handful of disks, less than ten out of over a thousand, become unreadable. Back then I used media that wasn't as good as what I use, now. I also never use RW media, after having some problems with it becoming unusable after a few additions.
Since I do a lot of DVD videos, I gravitated towards DVD-R rather than DVD+R, so I just use that for all my uses, even data backup. So far, it works very well, and I have used them to repopulate my recent computer builds with programs and other files, since I purchase a number of downloaded programs.
Not so short of an answer, but hopefully it helps.
Yes, we switched to Taiyo Yuden
by daeby - 2/10/09 7:38 AM In reply to: I keep a running backup by easytimes455Yes, 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.
Taiyo Yuden
by poaol - 2/14/09 4:59 AM In reply to: I keep a running backup by easytimes455can you share the code numbers that let you know TY is the manufacturer?
CD and DVD life
by Alain Martel1 - 1/30/09 6:51 PM In reply to: Do burned CDs and DVDs have a shelf life? by Lee Koo (ADMIN)
They do have limited but prety long life expectency.
If you store them away from the sun and heat sources, in a dry and relatively cool place, they can last over a century. We don't know yet what the maximum life expectancy of those disks can be...
What can shorten their life expectency are:
Direct, or almost diredt, sun light. The UV can degrade the dyes used, so can the heat from the IR.
To much heat can, over a prolonged period, cause a reaction similar to that used while writing them.
To much humidity can allow some mold to devlop, ruining the media. A real problem in some areas of the world. It can also affect manufactured CD and DVD, not just writable ones.
Obviously, friction against dust and sand is deadly to any disk.
Glued on labels have been known to peel off CDs lifting the back layer. The CDs back layer is where the information is burned. DVDs are made diferently, and are imune to that particular problem.
DVDs are made from 2 plastic layers and the recording material is between those. Dual layers have 3 plastic layers and 2 recording layers.
Flexing a DVD can cause the layers to separate, ruining the DVD. So, you want to never bend or flex any DVD. Even the non writable ones.
So, to get maximum life and reliability from recorded medias, you should:
- Protect them from dust.
- Protect them from bending.
- Store them in a cool and dry place.
- NEVER write on them with anything other than a felt tip pen.
- Don't let them fall.
- Always hold them by the center hole and the edge. Never put your fingers over the surface.
In short, follow the storage and handling recomendations that are shown on the packaging.
Among the archivists, actualy, the bigest concern is not the media's life, but, the long term availability of the hardware that can access it and that of the software needed... And they think in therm of century.
Data arent written/stored in the back labal or coating
by wjunwei - 1/30/09 8:36 PM In reply to: CD and DVD life by Alain Martel1Data 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.
Not correct as regards CDs
by Watzman - 2/13/09 6:37 PM In reply to: Data arent written/stored in the back labal or coating by wjunweiYour 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.
Label Side
by Hforman - 2/15/09 1:14 PM In reply to: Not correct as regards CDs by WatzmanI 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.
data is NOT written IN the plastic, but ON the aluminum
by Culebra - 2/13/09 8:43 PM In reply to: Data arent written/stored in the back labal or coating by wjunweiyou 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.
CD Shelf Life
by ttarqjr - 1/30/09 6:52 PM In reply to: Do burned CDs and DVDs have a shelf life? by Lee Koo (ADMIN)
All present media has a shelf life. However with CD and DVD media it is well beyond the life expectancy of anyone that would be recording on them today. The bigger question would be, "What is the "life" of the hardware on which it could be read?"
Think back only 30 years. How much data on 8" floppy, or even 5-1/4" floppy for that matter is accessible today? We have seen 8 track tape disappear, audio cassettes, and recently VHS tape. So it is not a question of how long the media will last. If we have anything in archives it is more important to keep bringing it forward to the newer technology lest it be relegated to the "unreadable" dust heap.
Reading old floppy disks ....
by Watzman - 2/13/09 6:46 PM In reply to: CD Shelf Life by ttarqjrRe: "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).
apples (magnetic) and oranges (optical)
by Culebra - 2/13/09 8:45 PM In reply to: Reading old floppy disks .... by Watzmanobservations about magnetic media have nothing to do with CD or DVD media.
apples (magnetic) and oranges (optical)
by ArtieNorway - 2/14/09 2:46 AM In reply to: apples (magnetic) and oranges (optical) by CulebraI 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
nothing 'wrong' with it -- just not the same issue
by Culebra - 2/14/09 12:30 PM In reply to: apples (magnetic) and oranges (optical) by ArtieNorwayHow 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.
disc rot
by austinbarry - 2/13/09 9:19 PM In reply to: CD Shelf Life by ttarqjrI 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.
| Forum legend: | |
 |
Locked thread |
 |
Moderator |
 |
CNET staff |
 |
Samsung staff |
 |
Norton Authorized Support team |
 |
AVG staff |
 |
Windows Outreach team |
 |
Dell staff |
 |
Intel staff |
