Developers of FireWire peripherals are required to provide device drivers. A driver for DV (digital video) is included in QuickTime 4.0.
The Power Mac G4 computer can boot from a FireWire storage device that implements SBP-2 (Serial Bus Protocol) with the RBC (reduced block commands) command set. Detailed information is available only under non-disclosure agreement; contact Developer Technical Support at dts@apple.com.
It is possible to connect two computers to each other using a FireWire cable, but no software is provided to make use of such a connection.
For additional information about the FireWire interface and the Apple APIs for FireWire device control, refer to the resources available on the Apple FireWire website at
http://developer.apple.com/hardware/FireWire/index.html