November 03, 2003
Data CDs: Here Today, Gone Tomorrow?
CDs have long been a popular standard for delivering new programs and backing up important information. I've got a shelf in the basement stacked with old program CDs and backups from my own PCs.
But what if they turned out to be worthless when I tried them in the future?
That's the concern raised in Fred Langa's latest Langa Letter in Information Week. Is he right? Well, looks like too like data to be absolutely sure, but, happily, I've always been reluctant to stick labels on a circular disc that's spun at high speed so can at least rest easy that this won't be the reason my CDs fail.
...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 [see http://www.langa.com/backups/backups.htm] , no essential data was lost (what was missing on one CD was available on another.)
I'd used two different brands of CD label-makers in the past, and (alas) have no way of knowing whether only one or both caused the problem. But the bottom line is that while some CDs with glue-on labels had problems, none--not one--marked with a permanent ink felt-tip pen did.