System Utilities for Jaguar and Panther
More important than any utility is a backup utility and a supported hard drive. Keep at least two backups of all important data that are untouched by the system except in special need of recover. Defragmenting is simply a matter of making a mirror copy of your existing hard drive to another, checking the mirror copy is bootable, and erasing the original and copying back the backup. Both http://www.dantz.com/ Retrospect Desktop and http://www.bombich.com/ Carbon Copy Cloner offer this ability.
Regarding the ability to boot drives. Most USB drives are presently not bootable, though many SCSI and Firewire drives are. For Firewire drives, only machines with AGP graphics slots/chips can boot off Firewire. The Blue and White G3 is not possible to boot from Firewire, and neither is the PCI graphics PowerMac G4. To tell a PCI graphics from an AGP graphics PowerMac G4, check the article below:
It is possible to boot off a second internal drive on those PowerMacs that are not bootable via Firewire. Thus if you want to keep a mirror backup for simplifying defragmenting and reinstalling, you can use an internal second drive. The only danger is that you can't as easily protect such a drive from a potential power surge which impacts the computer from a thunderstorm or power outage, thus the advantage of keeping a second external backup which is detached from the power at the same time as the computer is lost. Depending on your needs for backup this may or may not be a good idea.
You will need to use repair permissions if you run Classic a lot. For more about that visit http://www.macmaps.com/macosxnative.html
You will need to fix your directory if you get a kernel panic, or can't force quit any applications and are forced to restart. http://www.macmaps.com/directoryfaq.html explains how to do that.
Every night the computer goes through some maintenance scripts. However, if Energy Saver is on, or the computer is off, it can't run those scripts. They are called the Cron scripts and most freeware and shareware Mac OS X utilities have the ability to run them. For more about the other kinds of things you may want to do to X, but aren't always necessary, visit: