PATH
The Open Firmware startup process in Power Macintosh computers with a PCI bus conforms to IEEE Standard 1275 and to the PCI Bus Binding to IEEE 1275-1994 specification. These standards evolved from the OpenBoot firmware architecture introduced by Sun Microsystems. The PCI Bus Binding to IEEE 1275-1994 specification is available at http://bootrom.apple.com/1275/home.html#OFDbusPCI. The IEEE Std 1275-1994: IEEE Standard for Boot Firmware (Initialization Configuration) Firmware: Core Requirements and Practices is available at http://standards.ieee.org/index.html.
The 1275 Working Group continues to update the PCI Bus Binding to IEEE 1275-1994 specification. For latest information, you can access the FTP site listed in the note under Institute of Electrical and Electronic Engineers.
Additional information about the Open Firmware startup process for PowerPC computers can be found in the PowerPC Microprocessor Common Hardware Reference Platform (CHRP) System binding to: IEEE Std 1275-1994 Standard for Boot (Initialization, Configuration) Firmware, Revision: 1.8 [Approved Version] at http://bootrom.apple.com/1275/