Three Technotes provide an introduction to Open Firmware on the Macintosh platform. They are:
TN 1061: Open Firmware, Part I, available on the Technote web site at
http://developer.apple.com/technotes/tn/tn1061.html
TN 1062: Open Firmware, Part II , available on the Technote web site at
http://developer.apple.com/technotes/tn/tn1062.html
TN 1044: Open Firmware, Part III , available on the Technote web site at
http://developer.apple.com/technotes/tn/tn1044.html
The New World software architecture follows some of the standards defined by the Open Firmware IEEE 1274-1995 specification and the CHRP binding.
The basis for the bootinfo file format and use is the document PowerPC Microprocessor Common Hardware Reference Platform (CHRP ) System binding to: IEEE Std 1275-1994 Standard for Boot (Initialization, Configuration) Firmware . A bootinfo file contains Open Firmware script, a description, information for individual operating systems, icons, along with other information.
Other Open Firmware references of possible interest include:
IEEE 1275-1994 Standard for Boot (Initialization, Configuration) Firmware: Core Requirements and Practices
IEEE Std 1275-1994 Standard for Boot (Initialization, Configuration) Firmware (Version 1.7)
Open Firmware Recommended Practice: Device Support Extensions (Version 1.0)
Open Firmware Recommended Practice: Interrupt Mapping (Version 0.9)