Using Mac OS 9 on Power Mac G4 Mirrored Drive Door systems

"After confirming the system booted normally and Jaguar worked, I set about repartitioning the drive into 2 33gig partitions and an 8 gig partition which was to become a stand alone bootable OS9. A day and a half later, after myriad attempts to install OS9 from a number of different sources, searching the Apple knowledgebase, and 3 calls to Apple's tech support, I finally found a senior tech who confirmed what I was already suspecting. The only version of OS9 that can successfully boot one of these new G4s is a special release of 9.22 that is used for Classic.

"The new IDE bus cannot be found by "older" releases of OS9. Symptom, no hard drive found by install disk. The installers will also refuse to run on this computer when you boot from the CD.

"The solution offered by the Apple tech was to create the partitions then drag the OS9 system folder onto the 8 gig partition. That worked sort of. When I booted to that partition, I got a desktop and icons but no finder menus visible. I removed the 3 Classic entries in the system folder and rebooted to a normal OS9 desktop which is selectable as a boot drive now.

"My next attempt was to try to install OS9 on a firewire drive and boot from that. The only way to get a retail 9.2.1 installer to run, was inside Classic and it placed a system on the firewire drive. The system did not end up being bootable. Next step was dragging the system folder containing 9.2.2 from the OSX drive onto the firewire drive. This caused startupdisk to see the firewire drive as a 9.2.2 drive and I could select it for restart but the system would not boot from it.

"These limitations don't apply to eMacs or current iMacs because they use the older IDE bus technology. So if you are buying a new G4 desktop be aware your ability to use pure OS9 is going to be tricky to set up and limited in scope."