So ... I did a Linux install on the SCSI hard drive. And it worked. But the guy who sold me the drive asked me to try some stuff to get it working properly, and those things didn't work.
So I pulled the drive.
Which is okay except that left me with no working operating system on Dualie. So I did another Linux install.
And it seems to work. I'm running under Gnome built on a Debian foundation. My Matrox G450 is operating sorta correctly. The two monitors are both working okay, but they're not running dual-headed. They're working in clone mode instead. So I continue to search for the solution.
I hate the beast that's done this to me.