From the serial port, you'd just type "exit", which would restart the player application. Rebooting while the player is in RW mode is going to cause it to run an fsck, which is going to take a looooong time with two 80GB drives.

However, doing a "SITE Q" won't work, because "Q" isn't a command to the OS, it's a command to the player application. Let me think about the easiest way to solve that problem.