Dying CDs

[dimitrius]

I am guessing this might be of interest to other people as well...

I have around 50-60 CD-Rs with data, mainly divx/xvid movies. Some of these are upto 4 years old. In the last couple of months I found that some of the older discs are developing errors. As you all know when an avi gets a byte or two corrupted in the wrong place then a whole keyframe block could die. Now some of these cds are good, branded ones and some are generic. In the last 4 months I found 5 cds have developed faults. I found that all of these faulty cds seem to develop faults closer to the outer rim rather than inner - I guess that would be because there's more area to develop a fault in, around the edge. I play these cds very rarely, perhaps once every 3-4 months. There are no scratches or marks. It becomes really difficult to recover the data - even nero's cd copy with error corrections strugles. This is not just avi (avis are just more annoying) other datafiles also become corrupted.

so...
What's the average lifespan of a medium qulity branded CD-R?
Is and how the lifespan affected by the speed of writing? I normally write branded cds at 12x and unbranded at 8x (my burner is 12x).
What about the temperature and humidity - my flat is fairly warm and as dry as SouthEastern UK weather allows. I keep my cd-s in cases.
These faults have only been developing on cd-rs, normal cds donot develop them.


As far as I know it is recommended to play CD-Rs on cd writers since they have a more powerfull laser and are able to read CD-Rs (which are slightly less reflective) better. On my burner these faulty cds only have a couple of unreadable bytes often in rather difficult places in the avi :sly: . On my DVD drive, windows XP even strugles to read the directory structure.

So any ideas on what to do?
Have you any similar experiences?

[Minas]

from what i belive, cds should last forever, as long as there kept in good condidtion. i keep all mine in a cd folder. also dont use gereric cds, you will regret it. i went to a computer fair and founf 100 cd for $20, so i bought them. for the most part they worked ok, but i found that even when it finishes burning, often times it would not even read what on the cd! example: so i burn 'the professional' on a cd, it would finish burning, but(this was before i started to use data varification) i would go to watch it, and on the cd would be 'The Professional,' double click, and wmp would come up and just hang there. i could not read the file in any way. later found 100 spindle of TDK cds at a local store, regular price, i used to buy memorex, but $30 for 50 cds seems expansive now. also i would burn things for friends at school, and i had the generic cds in my backpack, and i found the top layer would chip rather easily. after i saw that i rushed home to burn everything back on real cds. sorry if i was rambling on, but i dont think cds really 'fall apart,' just be careful with them.

[dimitrius]

hmm, I've also had that problem with generic cd's when the top layer comes off so I've long abandoned generic ones. The thing is that some of my oldest cds are generic and they are still fine as long as you make sure to handle them by the edges. Suprisingly most of the cds that developed faults were good, branded ones. Also I just checked with some of my friends for whom I've burnt cds a long time ago and their's were fine. Of course since I have many more of them the likelyhood of 1 or 2 dying is higher.

[malum]

There was a big article recently (I forget where) that put most CD failures down to putting labels on them. It interacts with the dye and causes problems. On unprotected silver topped CDs it can also delaminate them.

[r6d2]

Originally posted by Minas
[B]from what i belive, cds should last forever, as long as there kept in good condidtion.
Unfortunately, s**t happens, even with branded-care taken CDs. However, there is an interesting solution to this problem, creating redundant parity files and store them somewhere else.

A good tool for this is QuickPar (search for PAR2 in the forum for some users experiences).

[Father Ted]

Originally posted by malum
There was a big article recently (I forget where) that put most CD failures down to putting labels on them. It interacts with the dye and causes problems. On unprotected silver topped CDs it can also delaminate them.

i looked for it, but i can't find it now. there is a good article on CD stability in cd world here: here at CD media world (http://www.cdmediaworld.com/hardware/cdrom/cd_quality.shtml#Conclusion)

it has some links to other pages. i found the dye discussion page interesting. i'd not seen a list of the dye numbers before.

[malum]

http://www.informationweek.com/story/showArticle.jhtml?articleID=15800263




That was certainly the case in my tests: I did discover bad CDs, but not one--zero--was traceable to a specific brand or dye type. Instead, for me, the only disks that failed were those that I had covered with a glue-on paper label from a print-it-yourself CD label-maker kit. Several of these labeled CDs were, in fact, totally unreadable by every means I tried (including special data-recovery software); all the data on those CDs is just plain gone. My best guess is the glue on these do-it-yourself labels interacted with either the foil or the dye, rendering the CDs useless.

Fortunately, although I have more than 1,000 data CDs in storage, only a handful have these labels. All my other CDs were hand labeled using an ordinary permanent-ink felt-tip marker, and all of these that I tested--all of them, including the very first CD-R in my collection--remain intact and fully readable. Plus, because I make multiple backups of important files http://www.langa.com/backups/backups.htm , no

[dimitrius]

hmm, very interesting article especially the one about the dye.

Here's a snippet (I always heard that gold cd-rs were better but I thought it was just an urban myth):

The gold-colored CD-R uses the PhthaloCyanine pigment and a gold reflection layer. As the pigment is transparent, the golden reflection layer shines through the bottom side giving the `golden' look. Compared to the other colored media, the reflection contrast of the golden medium is the highest and the durability of such CD-R's is said to be over 100 years. As the golden medium's reflective property is the highest, if your friends or customers have problems reading data from any other burnt media, try using the gold medium CD-R.

http://www.cdmediaworld.com/hardware/cdrom/cd_dye.shtml

Most of my cd's are blue (of all the cd's that developed faults, ref. first post, all were blue but one which was silver and generic). From all most of the articles about cd-rs that I've read in the last couple of days it seems that Phthalocyanine is the best kind of dye for length of storage, and Cyanine is better for wider compatibility.

Cyanine discs use a Long Write Strategy, and phthalocyanine discs use a Short Write Strategy. That is, a longer laser pulse produces a more accurate 3T optical mark on cycanine media, and a shorter laser pulse creates a more accurate 3T optical mark on phthalocyanine media. Write strategy, in the currently available generation of CD-Recordable media and drives, is not adjustable for media type. However, a group of engineers, called OSJ (Orange Book Study Group of Japan) has proposed that all CD-R media manufactured include information in the pregroove of the disc that identifies the type of media and tells the CD Recorder which write strategy to use. This proposal will soon be implemented by the manufacturers of CD-R media and the manufacturers of CD recordable drives.

http://www.cd-info.com/CDIC/History/Commentary/Parker/stcroix.html

funny thing is that the cd-r brands I used 3-4 years ago were all recommended to me by people who used them alot - Verbatim, Ricoh and TDK. Amongst the faulty cds Verbatim has highest count.

[ca321]

Have anyone used vinyl recordable discs? How reliable are they?

Verbatim CD-R (http://www.verbatim.com/products/products.cfm?pc_parent=76F06320-48F1-485E-8E286B6E0039C276&pc_id=02E800A7-686F-4C56-A49A19BBBCA55994)
Verbatim DVD±R (http://www.verbatim.com/products/products.cfm?pc_parent=1DC9DF5C-C0D4-4AEC-BE4352D34D71B4EB&pc_id=0098E470-9414-434E-9FE31CB39036E07B)

[smiller667]

It isn't vinyl. It's meant to look like it, though.

[dimitrius]

haven't tried their vinyl types, but their oridinary cd-rs are among the ones that died on me inside of 4 years. I'd be careful of using verbatim.