help removing extra devices after failed RAID setup

I've been trying to set up a RAID 10 with 4 volumes... the first time I tried this with disk utility and it failed, leaving behind 4 "ghost" volumes/devices which I cannot seem to get rid of. I've found out now how to set up the RAID correctly, but I cannot get rid of these devices which appear when I run "diskutil list" (booted from system DVD).

If I get info on one of these devices with "diskutil info disk3" I get

I'm guessing this image was going to be turned into the RAID set somehow. But they can't be unmounted/ejected with diskutil, and even removing the hard disks physically from the machine does not make them go away.

So I'm wondering where the list of devices is stored, is there something in PRAM for instance? How does the device table get created, and how does the machine know what the RAID sets are? How can I get rid of the phantom devices?

 

ok I think I've figured this out. There isn't a problem at all... these volumes only appear when booted from the system DVD - I can only assume they're meant to be there, some disk images for running the installation etc.

I'm still wondering however if anyone can provide insight into the processes going on with a RAID boot disk... how the system knows how to mount a software RAID array at startup? Are all the details stored in the partition tables on the constituent drives themselves or something?