Stupid Question?

Hi, 

I feel like this is a stupid question. But I actually don't know the answer 
to it. If I'm going to make a Software RAID array with a bunch of identical 
disks, do the disks have to have at least one partition on them? Or can I use 
disks with NO partitions? 

Similarly, if I have made a hardware RAID array (say, with a 3ware 8506 
card), do I have to create at least a single partition on it before I put a file 
system on it? 

If partitions aren't necessary, is there any advantage or disadvantage to 
having a single partition on a disk versus having none? Is having no partitions 
faster? 

Andy Liebman