Installing YDL 4.0
There are some areas that need to be thought out before you install. YDL does not work like Virtual PC, in which you boot OS X and then launch a PC clone. When you boot the Mac, YDL needs to come up first. You have to partition the install hard disk to accept YDL. There is an automatic tool to do this, but you may have to do it manually, depending on your configuration. In any case, the boot program messes around with the Mac's Open Firmware (OF). Resetting PRAM via option-control-P-R or though the Mac's Startup Disk utility wipes out the changes YDL inserts, so the first partition that OF sees must be one containing the boot program for YDL, or else it does not boot. (The install program does not currently support external firewire or USB disks.) If you boot into OS X, there's no way to back up and get into YDL. So the first disk in the chain that OF sees must be that YDL boot partition.