The software architecture implemented on current Macintosh computers follows the standard defined by the Open Firmware IEEE 1274-1994 specification. Three Technical Notes provide an introduction to Open Firmware on the Macintosh platform. They are
TN 1061: Open Firmware, Part I, available on the technical note web site at
http://developer.apple.com/technotes/tn/tn1061.html
TN 1062: Open Firmware, Part II, at
http://developer.apple.com/technotes/tn/tn1062.html
TN 1044: Open Firmware, Part III, at
http://developer.apple.com/technotes/tn/tn1044.html
Other technical notes provide additional information about Open Firmware on the Macintosh.
TN 2000: PCI Expansion ROMs and You, at
http://developer.apple.com/technotes/tn/tn2000.html
TN 2001: Running Files from a Hard Drive in Open Firmware, at
http://developer.apple.com/technotes/tn/tn2001.html
TN 2004: Debugging Open Firmware Using Telnet, at
http://developer.apple.com/technotes/tn/tn2004.html