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CD-R Lifespan - Is It The Label?
sysadmn writes "Slashdot has discussed archival lifespan of CD-R media before. Fred Langa revisits the issue with a new twist: Are glue-on labels causing premature failure? Much more common than rain forest fungus! From Fred's informative LangaList newsletter."
A co-worker turned me on to Fred's column a couple of days ago, and I've been running a few tests that may or may not have a bearing on reality...
The cheap-ass CompUSSR CD-R with and without their corporate logo were the main object of testing.
In a nutshell, the pre-printed logo CD-R survived the label removal much better than the generic no-name blank did, though you _could_ screw up the printed one just as badly with a little effort.
We're going to get everyone in the office to offer up a sacrificial CD-R of choice to conduct more tests, and I will also introduce my co-workers to the Round Table Rate-A-Record system with the office microwave...
Then we'll see what happens to DVD-R/+R...
"Eustace? Eustace? Are you there? Are you there?" = John Leeming
Of the CDs I own, the ones that've gone bad have suffered damage to the top foil part. It either rubs off, or partially becomes dislodged from the bottom part. All the review sites seem to think the dye is the weak link in the chain, but in my experience a crapy foil will go long before the dye.
AccountKiller
Kodak used to subject their CDs to "torture tests" to see how they'd stand up. Their "Gold Ultima" CDs were reported to have a 100-year archival life. Now, they're saying the same thing about the Ultima brand (now that the Gold brand is discontinued). Study results are here.
:-)
All I can say is that Kodak seems to have done a lot worse to their CDs than your friend did with just his tongue.
D.
I used to buy cheap bulk no-name CDs. However, about 1 year later, the aluminum coating was flaky and fell out of the CD... So, when you can see the light through the hole from the fell-out coating... So, the CD breaks.
In this case, coating it would have helped. I dunno whether it would end up the same way as stated in the article, though.
But, if you can spend more money on CD-Rs, you'd be better up with branded CD-Rs and apply no labels.
--
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here is an easy solution that has worked for me for years. 1. get a perm. marker 2. label your cd-r "applications cd1" or "music cd1" 3. make a text file(html format works the best) list contents of each cd-r 4. done simple as that no wasted time trying to make labels.
All media degrades. The trick is to use redundant data, and re-copy it before the media is expected to fail.
Is there a way to detect when a CD is about to fail? The CD drive will auto-correct minor errors without informing the PC - so by the time a drive returns an error code, at least one block of data is lost (if you're lucky, you can copy everything else off the CD).
I'm aware of commercial testing hardware that can report statistics like the Bit Error Rate (BER), Block Error Rate (BLER), etc. But is there any way to do this cheaply, possibly using software?
I have noticed that on some of my CDR's, burning slower results in a different color than a faster burn. I guess the dye is being changed more when it is slower. So now, for CD's that I want to keep for a few years, I write them at 4x even though I have a 48x burner. As for the labels, I don't use them.
We need to worry. REALLY. I am burning a cd right now. The data is music. Music from about 25 years ago that was on a reel to reel (older tape analogue) that had to be baked (put in an oven to recover the lost footage more here: http://www.soundsaver.com/squealingtape.htm)
If I am burning this to CD and then the CD becomes faulty, which is likely from my experience, the CD becomes useless, there is no turning back. This has happened to me, a skip becomes more and more of a skip until unplayable.
CD's are not a good way to archive anything.
I had a similar experience (or so I thought at the time). About 50% of a spindle of cheap 10x CD-RW's simply failed even after repeated attempts to blank and reburn them. Fortunately, I threw all the CD-RW's that failed into my coaster pile rather than the trash, since about a year later after I had replaced my CD burner I discovered that every single one of them worked fine.
The failing burner was a Yamaha SCSI unit that I paid about $200 for four years ago; it was (and probably still would be) quite reliable with other media, but it was only a 24x8x8x unit, which is why I replaced it. Its replacement, a Sony 48x24x48x IDE unit (rumored to be a rebadged Liteon), cost $50 on sale. It, too, seems to work with everything I throw at it -- including those CD-RW's the Yamaha couldn't deal with.
I suspect that drive/media incompatibility is more common than most people think. Some reports of failing media may be due to media that was marginally recorded to begin with due to such incompatibility.
I have a hard time believing this. I've had some CDR archived materials for 5 or more years that read fine. I think the bigger problem is clueless users (like I used to be) who mistakenly burned CDR media at a speed too high for what the media is rated for. Those discs seem to run fine at first, but then die later. I've lost several gigs due to this problem just because I know how I used to burn CD's.
Look into some sort of parity software to protect your files on the CD/DVD. They add extra files (usually 5-25% more space) that allow you to recover files that have been corrupted by the media degrading. I also create parity files for files on my hard drive (in my archive tree) because there are command line tools that will walk the directory tree and verify that all files are still clean. Take a look at QuickPar for a parity tool. For a DVD, I'd recommend setting the percentage to 10-15% (will eat up around 15-20% of the DVD with parity data).
Now for professional data, I'd recommend a few methods. First, hook up a 250Gb USB 2.0 drive and get software like rsync or SecondCopy 2000 to mirror files off to that drive daily. (SecondCopy has the ability to move deleted files to a seperate folder on the external drive, plus keep multiple revisions of changed files.) An advanced option is to get (3) drives, swap them weekly or bi-weekly, keeping the latest backup at an off-site location. Might want to get one of those custom foam carrying cases to put the USB drive in. I'd recommend getting the USB drives that have built-in power supplies (take standard computer cords) which gives you one less thing to lose or carry around. Peer II sells a nice, compact USB 2.0 enclosure (CA-405U2) that supports large format drives (if you get the latest models).
Consider a tape backup that holds 50Gb native. Tapes are nice because they're small/portable. Downside is that tapes are expensive and backup software on Windows machines is usually proprietary.
You'll still want to do the DVD-R method as well, which is a very good way to take snapshots of projects. Protect it with parity files, but don't depend on it as your only backup method.
Wolde you bothe eate your cake, and have your cake?
Check out the freeware win32 tool Nero CDSpeed which has many excellent functions for measuring the quality of optical discs (CD, CD-R, CD-Rw, DVD, etc) and tools for verifying the integrity of stored data. Its scandisc function test the drive's ability to read each file at the filesystem level and read each sector at the physical level, telling you which sectors are good, which are failing and which are dead.
An interesting side effect of using this tool is that I've noticed that the manufacture of pressed DVDs is highly variable! Some discs are excellent, some are crap. And it seems to be pretty consistent with the company that distributed them too. Some discs read very smoothly while others require all kinds of speed adjustments by the drive to get data out of them.