November 2004

Saved!

There are plenty of ways to back up your data. So no more excuses.

By Simson Garfinkel

My twins love cd-roms but don't know how to take care of them. They destroyed their prized copies of Dr. Seuss's ABCs and Arthur's Birthday, two discs that Broderbund's wizards made back in the 1990s. I tried polishing the CDs and largely failed. So I threw them away and burned myself new ones.

Copying CDs is an activity that most people associate with illegal music distribution and downloading. But there's nothing wrong, morally or even legally, with making backup copies of my own CD-ROMs for my own use -- provided that I don't start sharing those backups with all of my friends.

The easiest way to back up a CD or CD-ROM is to copy its contents onto a recordable CD (CD-R). The danger with this approach is that CD-Rs are more fragile than commercial CD-ROMs: many have thinner-than-paper labels that are easily damaged, especially by little hands. Moreover, most CD-Rs are not archival, meaning that they can lose data as they age and deteriorate. But the biggest danger with archiving a CD on a CD-R is that it is simply too tempting to use the backup when the original dies -- rather than making a copy of the copy.

Instead, I prefer to "rip" the CD-ROM, making a byte-for-byte copy of the entire disc on a 200-gigabyte hard drive that I keep specifically for this purpose. There are several disk-imaging tools available to do the copying; on my Mac, I use Apple's own Disk Utility, while on Windows, I use WinImage 6.1. These programs create a single file that's several hundred megabytes long. When the CD-ROM is inevitably damaged, I burn the image onto a fresh CD-R.

Computer hard drives die as well, of course. In the old days the standard way to back up a disk drive was onto magnetic tape. These days if you're storing less than a few terabytes, it's cheaper per gigabyte to buy external hard drives with USB or Firewire interfaces than to buy high-capacity magnetic tapes and drives. Although tape should be cheaper, disk drives have economies of scale in their favor. So I actually have two 200-gigabyte hard drives; each backs up the other.