This article is from the Introductory Macintosh FAQ, by Elliotte Rusty Harold firstname.lastname@example.org with numerous contributions by others.
This is one part of preventive maintenance that should be
done a *LOT* more often than every three months. The simplest back
up is merely to copy all the files on your hard disk onto floppies
or other removable media. If you keep your data files separate
from your application and support files then it's easy to only back
up those folders which change frequently. Nonetheless every three
months you should do a complete backup of your hard disk.
A number of programs are available to make backing up easier. Apple
included a very basic full backup application with System 6. Apple
ships the Apple Backup utility with all Performas that can backup
the entire disk or just the System folder onto floppies. The
previously mentioned Norton Utilities for the Mac and MacTools Deluxe
include more powerful floppy backup utilities that incorporate
compression and incremental backups. Finally the usual ftp sites
should have Diversified I/O's $35 shareware SoftBackup II, a full
featured backup program that will do full, image and incremental
backups to floppies, tape drives, WORMs, Syquest drives, hard disks,
servers and other media. See
About the only thing thing SoftBackup II can't do is replace old
versions of files in a backup set with newer versions. If you want
to do that, check out the more flexible payware utilities Redux ($49
street, doesn't support tape drives) and Diskfit Pro ($74 street).