Unteroffizier wrote:I have had experiences with bad CD-rs in the past. Data just went unreadable in less than a year after burned. No doubt the choice of the right media is important.
Sticking to name-brand media is a good idea if you value your data.
I have also read that certain types of permanent marker and adhesive CD labels can be problematic. The ink from the marker or the adhesive on the back of the label can react with the top coating on certain brands of CD-R, eventually "rotting" it to the point where the data layer is damaged.
Your best bet is to label CDs using a marker that has been specifically designed for writing on CDs. Although FWIW I have never had problems using a plain old "Sharpie" permanent marker either.
What are your views of the dye and material used on CD-rs for consumers? What are the difference in theirs manufacture and material used as compared to the CD albums that we see in music/ movies stores?
CD-Rs are actually completely different technology from commercial audio CDs and CD-ROMs. They just happen to have similar optical properties after they are burned, which allows them to be read just like a commercially pressed disc.
In a commercially pressed disc, the data is encoded in a spiral track containing pre-pressed bumps that encode the digital 1s and 0s. This is then coated with a thin layer of reflective aluminum (so the laser can easily "see" the bumps), and the aluminum is then coated with a layer of protective resin. There is no dye layer in a pre-recorded CD.
In a CD-R, there is still a pre-pressed track, but it contains no data; it only supplies timing information that is used by the burner (this is the "ATIP", or Absolute Time In Pregroove). This is then coated with a layer of dye; on top of the dye there is a layer of reflective material (typically silver alloy or gold); and then the resin topcoat. During the burning process, the laser burns holes in the dye layer to form the pattern of 1s and 0s by selectively exposing the reflective layer.
The type of dye, and the thickness (and composition) of the resin topcoat can both vary on CD-Rs. AFAIK current dyes all have pretty decent projected lifetimes. The topcoat can be very thin on cheap/generic media though; I've seen cheap CD-Rs where you could literally flake the coating off with your fingernail!
The proprietary dark blue dye used in Verbatim's "DataLife Plus" line of CD-Rs supposedly has a longer lifetime than most other dyes; the DataLife Plus discs also have an extra thick topcoat, which should make them more durable. They cost a little more, but may be worth the extra expense for stuff you plan to keep for a long time.