Corporate data backup is automatic and reliable and the data is stored off-site for disaster recovery and redundancy. Home data backup is infrequent, untested and one hard disk failure away from useless. Yet family photos and personal e-mail mean more to people than any corporate sales report. Family and friends often don't know how to protect that data.

With downloaded music costing about 99 cents per song, hundreds of hours of music can add up to about $1,500 - more expensive than the computer holding the files. A 160G-byte hard drive can store more than $40,000 of digital music. That's a serious dollar loss, and it should get your family and friends to think about backup, especially because that music is worthless if the licensing file gets lost.

What to backup

Home users don't need snapshot disk images so they can recreate a system within an hour. Help them collect their operating system and application CDs and keep them in one place, so in case they must format or replace a hard disk, they can reinstall everything easily, if not immediately.

Most people want to back up the following:

• Financial records
• E-mail from family and friends
• Music
• Genealogical data
• Photos

Financial records are easy because they don't take tons of room. After a decade of using Quicken, my backup folder is less than 60M bytes. That will fit on a USB thumb drive or CD, and will even fit on any Iomega Zip disk format (they start at 100M bytes).

E-mail causes more problems. Microsoft's Outlook and Outlook Express are the most popular products, and they encourage people to keep everything inside those applications. Unfortunately, the Outlook PST file grows fat, fragmented and fragile over time. Worse, copying the open PST file is difficult for many back-up applications, so users often must close Outlook for a good backup (close all applications, reboot the computer, then back up to get those open files).

Users who rip music from their own CDs already have a backup - the CD itself. Users who rip music from their old albums might want to protect those files because of the extra hassle getting the music from vinyl.