But for those feeling good , here is something else to worry about: what happens to those beloved family photos or the extensive music collection if something should happen to your PC and backup? A fire, flood or earthquake could destroy the backup sitting inches from the PC.

For years, big firms have been storing their backed-up data in multiple locations to protect it from disasters. The data of consumers also has value, and it is not always just emotional. It is not hard to accumulate a few hundred dollars’ worth of content that needs protection.

The recognition of the monetary value of data is one force driving the sales of external hard drives. The NPD Group, the market research firm in New York, estimates that the market for external hard drives will grow 33 percent this year. That is largely because devices like the Western Digital My Book, Maxtor OneTouch or the Seagate Pushbutton Backup drives are easier to use and more stylish than past models.

Seagate, the leader of the hard-drive industry, is trying to solve the off-premises backup problem. It is pushing a device from its newly acquired Maxtor unit that allows consumers to back up data at home and off premises. The 500-GB device, called Fusion, allows consumers to link the external drive to the home network so any computer on the network can grab content there.

Access is also possible from outside the home. The device comes with software created by Fabrik, a start-up company in San Mateo, California, that turns the hard drive into a personal version of Flickr or YouTube. Some of the content on the drive can be designated public and the rest remains protected. The data can also be stored on Fabrik’s servers for a small cost for 1 GB—enough room to store 250,000 pages of text, 200 songs or about a thousand photos.

There are other solutions. Apple offers a backup service to Mac users who sign up for a .Mac account. It sells a one-year membership that entitles a user to 1 GB of storage for $100. There are several online backup services that work with the backup program on Microsoft’s XP operating system. Xdrive.com, for instance, or Backup.com.

Google offers 2.7 GB of storage space for anyone with a Gmail account. Although most people use it for archiving their e-mail messages, that is enough space to store 500 songs or 2,500 photos and a few spare Word files. You can do that by sending yourself an e-mail message with the files as attachments.

IBM sees an opportunity in this consumer market for backup. It sells a consumer program named Tivoli that automates backup. Every time a file is changed, a copy is stored on the PC’s drive and a copy is sent to a backup device or a remote server. Symantec, when it was done surveying the backup habits of users, decided it needed to jump in. Its new protection program for consumers, Norton 360, will include a function for backing up data online. (DAMON DARLIN)