Ah, I see....
Thanks for your time & reply, I'm going to find time to try this as it could be useful for simpler disk repair / antivirus scans.
I was saying I've been brought-up on Mac's, since 1989, and getting onto the second hand LC475's the college had 
I've worked with RAM disks [notably with Softimage 3.9, on Win2000, on VPC4, on a G4 with 1.5G RAM installed
-just to prove it's possible], 'suppose I've never re-booted as opposed to shutting down whilst using one....
hence my apparent ignorance.
-It's only since I became the owner of a Wintel box that I've learnt the joys of mid-session re-booting.