On Fri, Jun 09, 2006 at 07:30:12PM +0100, Ted Harding wrote:
Is this the case? If so, does it vary with the brand/type of CD? And does something similar apply to DVDs?
My opinion is don't worry about it. My evidential data on this is recently (in the past 3 months) I destroyed some old backups that were taken in 2000 (the data was either moved to newer backups and put on different storage first, obviously) and they all worked *perfectly* despite many of them being abused. The other test data was that of some mp3 CD's I burned for listening to on the in car mp3 player. I purchased the in car player 3 years ago and recently stuck it in my new car, I also grabbed some of the CD's that had been in the old car for 3 years, all of them were ok apart from one that had a *big* scratch in it. Given that these discs have survived living in a car (on the floor, in the door pockets etc.) mostly without cases and the extremes of heat/cold that they were subjected to in there and that they had dozens of scratches on them told me not to worry about archival backups, which certainly don't have such a hard life. I think the main problem with the dyes used in CD-R discs is that they are not "light fast" so you may want to make sure they are in a dark place (inside the fire safe suits me fine), it also does apply to DVD's but I think that the more modern compositions of dyes used in the discs are better than the original dyes used for the very early burners/discs.
Current strategy for me is to put backups into the fire safe designed for computer media (this will help wrt to big fires and environmental concerns like humidity and light) burn 2 sets of discs onto different brands of media "just in case" and make sure I take a full backup every so often and keep the older copies to hand. I also test the old backups when they need to be replaced to make space in the safe and so far all of them have been fine. I also only write on the sleeves (I use sleeves to minimise the risk that the discs get scratched) that the discs go into just in case the ink in the pens I use decided to have a chemical composition that eats plastic. I'm certain that this strategy is a bit OTT for what I need, but in the case of backups I'd rather overspecify a bit than to try to be a cheapskate.
Thanks Adam