Ayumi Hamasaki Sekai

Ayumi Hamasaki Sekai (http://www.ahsforum.com/forum/index.php)

- General Music Chat (http://www.ahsforum.com/forum/forumdisplay.php?f=45)

- - CD rot (http://www.ahsforum.com/forum/showthread.php?t=17041)

Some excerpts from a news article:

Quote:

Dan Koster was unpacking some of his more than 2,000 CDs after a move when he noticed something strange. Some of the discs, which he always took good care of, wouldn't play properly.

"I was kind of shocked to see a constellation of pinpricks, little points where the light was coming through the aluminum layer," he says.

His collection was suffering from "CD rot," a gradual deterioration of the data-carrying layer. It's not known for sure how common the blight is, but it's just one of a number of reasons that optical discs, including DVDs, may be a lot less long-lived than first thought.

"We were all told that CDs were well-nigh indestructible when they were introduced in the mid '80s," Koster says. "Companies used that in part to justify the higher price of CDs as well."

He went through his collection and found that 15 percent to 20 percent of the discs, most of which were produced in the '80s, were "rotted" to some extent.

The rotting can be due to poor manufacturing, according to Jerry Hartke, who runs Media Sciences Inc., a Marlborough, Mass., laboratory that tests CDs.

The aluminum layer that reflects the light of the player's laser is separated from the CD label by a thin layer of lacquer. If the manufacturer applied the lacquer improperly, air can penetrate to oxidize the aluminum, eating it up much like iron rusts in air.

But in Hartke's view, it's more common that discs are rendered unreadable by poor handling by the owner.

"If people treat these discs rather harshly, or stack them, or allow them to rub against each other, this very fragile protective layer can be disturbed, allowing the atmosphere to interact with that aluminum," he says.

Part of the problem is that most people believe that it's the clear underside of the CD that is fragile, when in fact it's the side with the label. Scratches on the underside have to be fairly deep to cause skipping, while scratches on the top can easily penetrate to the aluminum layer. Even the pressure of a pen on the label side can dent the aluminum, rendering the CD unreadable.

Quote:

DVDs are a bit tougher than CDs in the sense that the data layer (or layers _ some discs have two) is sandwiched in the middle of the disc between two layers of plastic. But this structure causes problems of its own, especially in early DVDs. The glue that holds the layers together can lose its grip, making the disc unreadable at least in parts.

Users that bend a DVD to remove it from a hard-gripping case are practically begging for this problem, because flexing the disc puts strain on the glue.

Rewriteable CDs and DVDs, as opposed to write-once discs, should not be used for long-term storage because they contain a heat-sensitive layer that decays much faster than the metal layers of other discs.

http://asia.news.yahoo.com/040506/ap/d82cojhg0.html

hmm... I remember hearing about a similar thing about CD degradation some time ago. I've heard that CDs can last anywhere from 5-20 years, if not more, but after reading this article, it seems that it may be a bit more towards the 5-10 year mark. I have about 100 CD-Rs which are silver on both sides (it looked cool at the time), but the slightest scratches on the obverse side of the discs sometimes messes them up or makes them unreadable, so with "CD rot", they may last even less that anticipated :(

I've lost cds and some important data because of that -_-;;;;;;;;;;;;;;;;;; My worst nightmare ever!!

oh dear...i throw my burnt CDs around and stack em' -__-" although i keep my originals extremely well~~

moi aussi... o my goshhh when will my ayu's cds decay?? (frightened)

I don't think it's that common of a problem...none of my dad's CDs seemed to have decayed yet :rolleyes

I've heard the same thing on TechTV's The Screen Savers. They are saying a CDR might last about 2 years stored well and taken care of, according to a study done on them. That is REALLY a LOT less then we thought. Commercial CDs and DVDs should fair a lot longer.

Quote:

Originally Posted by ~K+

oh dear...i throw my burnt CDs around and stack em' -__-" although i keep my originals extremely well~~

I'm the same way. I freak out if there's a scratch on my Ayu cases. :laugh

Quote:

Originally Posted by PickleCookies

I'm the same way. I freak out if there's a scratch on my Ayu cases. :laugh

I actually go to the trouble of replacing the case if there's a crack o_o" but if it's one of those Avex trays I replace it with a less-liked Avex CD tray and give the good one to the CD i like more XD

apparently most of my old CDRs are 2 years old now...