Up To 10% of CD-Rs Fail Within a Few Years 317
Whatever you think about the likelihood that a new kind of DVDs could last for 1,000 years, this note from reader crazyeyes should give you pause about expecting current CD-Rs to be reliably readable for decades. TechARP found a failure rate near 10% for CD-Rs recorded 7 to 9 years ago, after storage in ideal conditions. On some, one or more individual files could not be recovered; others were not reliably readable on two separate drives. "In the past, hard disk drives were small (in capacity) and costly. To make up for the lack of affordable storage, many turned to CD-Rs. As it became common to store backups and personal pictures, videos, etc. on CD-Rs, the lifespan of these discs became a concern. According to manufacturers, CD-Rs should last for decades. Some even quoted an upper limit of 120 years based on accelerated aging tests! That sure is a long time, isn't it? But will CD-Rs really last that long?"
According to... (Score:5, Insightful)
According to manufacturers, CD-Rs should last for decades.
According to their marketing dept., rather.
Follow the Orange Book (Score:4, Insightful)
120yers, lets start with archive rated CD-R, and use a decent recorder with a tray. Then write according to the orange book specifications.
Not sure that hard drives are any better... (Score:5, Insightful)
In the past, hard disk drives were small (in capacity) and costly. To make up for the lack of affordable storage, many turned to CD-Rs.
Though I'm not convinced many consumer hard drives have shelf lives on the same order as the optical media that some of us are backing up to. Add to that the fact that hard drive interfaces do change fairly often (some of us still have systems in the transitional period between IDE and SATA), and you could have potentially more irritating problems if you were to back up to hard drives instead.
I suspect for paranoid user it may be more cost effective to backup multiple times to CD-R rather than to a hard drive. And on top of that, if one CD of your backup set goes, you are only out 700 MB or so. If you have a series of backups on a single 100+ GB hard drive, and it fails, you may be out everything that was on that drive.
Re:Not sure that hard drives are any better... (Score:5, Insightful)
Re:i have entire 1993 CD-R spindle (Score:1, Insightful)
Buy Quality Blanks!!! (Score:5, Insightful)
"Studies" like this are useless if they don't include information from the codes off the CD's (not the label on the box!) as to who the manufacturer is.
Get the Taiyo Yuden and MAM-A Gold blanks and you won't have issues like this.
Also please read the Wikipedia article on CD-ROMs, and expecially the references. You WILL end up with better burns if you do.
Re:10% Fail within a few years (Score:3, Insightful)
Re:According to... (Score:3, Insightful)
What are you talking about? AFAICT (quick google and wikiread) the only type of error correction you get on CD-Rs is inherent in the format of the disk, so it doesn't cost you any storage space (for data anyway). If you start adding extra layers of ECC (e.g duplicate all files and keep a hash table)then your not dealing with anything CD specific anyway.
And up to 100% of TFA is anecdotal (Score:1, Insightful)
TFA mentions that there were various brands that exhibited failures, but this ultimately tells us nothing. CD-R branding is completely meaningless. What matters is the material/dye composition and the OEM, and the author did not control for this criteria.
What you are most likely to find is that discs made from early materials are more prone to failure, as are discs from disreputable OEMs. These are the relevant facts for quality, and the lack of understanding about what determines the quality of a CD-R is what leads to popular myths, my favorite being the one about writing slowly to have a better or longer-lasting copy. If you have to do that, it means your burner and/or media is junk, and you are merely performing the voodoo that is necessary to make sub-specification parts work. A quality burner and media will write at 100% speed and it will be just as good as writing it at 2X or 4X or whatever other number people care to pull out of their collective ass.
I have written hundreds of CD-Rs myself, and the only archival failures I've had have been due to cheap media -- and those tend to fail fairly quickly, it doesn't really take 9 or 10 years, and there's a pretty good chance that the bad discs in TFA died a long time ago, shortly after burn, but he's only gotten around to checking them now. Some of the cheap discs in my collection actually started turning color, as after a couple of years there was a visible gradient going from the outside towards the inside. If you can see the physical degradation of the disc then you know the data doesn't really have a chance.
As always, backing up doesn't mean making one copy and then putting it somewhere forever until it's needed. Backing up means making copies on a periodic basis. If you wait 9 or 10 years between backups, you might as well have kept your data on the hard drive the whole time.
Re:According to... (Score:5, Insightful)
I would suggest as the cost per unit fell through the floor, so did any regard for quality control as well as the consumers lack of motiviation to drive all the way back to the store and get a replacement.
Re:i have entire 1993 CD-R spindle (Score:1, Insightful)
Arguing this isn't true is like saying magnetic media doesn't lose a charge.
You mean, a non sequitor? Since when does magnetic media hold charge?
Re:According to... (Score:3, Insightful)
Two observations:
1) You've been lucky. Others have not faired as well (and some of those others have tried very hard to only buy quality media)
2) CDs and even DVDs are too small.
Who wants to copy 222 DVDs to fill up just one terabyte drive? Who's got the time to sit there shuffling disks? I store backups on external hard disks. They cost roughly double what you'd spend on quality media and while it takes hours to copy across a terabyte of data you don't have to babysit it.
Video only still belongs on DVD because most players read the discs. Other data simply doesn't. The only exception is a temporary low cost solution for mailing or passing a few GB to a friend. If you don't expect to get the media back it'd be too expensive just giving them USB thumb drives so CD/DVD fills this niche. Other than those two uses I can't think of a good use for DVD/CD. Certainly not archival storage.
Re:According to... (Score:4, Insightful)
So you run 1000+ CD & DVDs through a "checker" once a year just to see if they're still working? Or do you just not have a lot of stuff to back up? :)
Re:According to... (Score:3, Insightful)
The thing is, it's a lot easier (and probably cheaper) to buy two 1.5TB SATA drives and just back up from one to the other every now and then, instead of burning 1500/4.7 discs once a month. I've moved to a completely hard-drive based backup solution, where I have every piece of important data on two separate hard drives. (Incremental) backups take 5 minutes instead of half a month, and all I need to store is two 3.5" hard drives... far better than hundreds of optical discs...
As for optical media failures: I've had _a lot_. Sure, I never used archival quality media or a top-of-the-line burner, but I hardly think that most people who backed up their family photos on CDs or DVDs use archival media or top-of-the-line burners... Hard drive failures? Not so much. In ten years or so, one failure (so about one out of thirty), which is OK if you're aware of it and use some sort of backup scheme or RAID1 to protect against mechanical failure.
Re:According to... (Score:1, Insightful)
while CD-ROMs use pits that are physically pressed into the disc and will easily last your entire lifetime (unless you toss them around like frisbees)
Except for the ones where the metal layer develops tiny holes right the way through (visible when held up to the light) - i.e. CD rot. These are typically nearly or entirely unreadable. Not very common (3 out of 400 in my collection) but it does happen, regardless of the storage conditions or use. So it is a good idea to back up pressed CDs now disk storage is cheap.