After flashing the installed Sony optical drive back into the NEC drive hiding under the label, and also installing a flashed Pioneer 111 into the Mac Pro's lower bay—both of which support DVD-RAM writing—I tried to use Disk Utility to format my discs. But Disk Utility can't format them. Toast can erase them, but they then become unmounted and won't mount again. Apparently the version of 10.4.8 for Intel processors doesn't let one use RAM discs in the same way as the version that ran on my G4.

I've tried terminal commands with diskutil, with no luck. Any suggestions?