[HM] Volume Scheme, RAID questions

[Chris Beamis]

Hi,
   I'm using disk utility, and I have two identical hard drives.  One  
is the boot drive, and it has a single volume.  My hope is to do a  
mirror RAID setup so that the second drive always mirrors the first.   
When I try to follow the instructions in 10.4.8 help I get to the  
point where I'm supposed to click 'create' but it is greyed out.  So  
I thought maybe I need to format the second drive first.  I want to  
format it identical to the boot drive, but when I click on the boot  
drive, then the 'partition' tab, under Volume Scheme it says  
Current.  But when I do the same for the second drive, setting Volume  
Scheme to Current, everything else is greyed out, I can't type the  
volume name or format or size.  The stuff gets ungreyed if, under  
Volume Scheme I click on 1 partition, but then I'm not doing it  
exactly like the boot drive.

   Can anyone explain to me what the terms "Current" and "1  
Partition" mean in this context?

Thanks,
Chris