One of the things I've done is set up the Open Firmware password to prevent the machine from being booted from anything but its internal hard drive. It also prevents the machine from going into Target Disk mode, and it also prevent booting to single user mode (command-S at startup). The machine will always boot to the login window.
This presented a problem for a while, because I couldn't figure out how to fsck my disk when I suspected problems. But there is a way ... rather than booting directly into single user mode, we're going to go further than that and then go backwards to it. It's like going two steps forward and one step back. Here's how:
- Boot the machine to the login window
- Login as >console
- From the console, login as an administrator
- Then type 'sudo shutdown now'
- Supply your admin password

