[CentOS] A question about RAID and partitions

[Miguel Medalha]

>>> - Create a single RAID 1 device with both entire disks and then 
>>> partition on top
>>> - Create several RAID devices, one for each partition (md0, md1, md2 and 
>>> so forth)

> The latter is the way the installer will let you do it.

You pretty much gave a final answer to my question :-)
I was thinking in the abstract, but the facts speak louder (for now).

Yet, maybe I am being stupid but it seems to me that there still is 
something to my original question...

Under hardware RAID, a dedicated processor on the RAID controller does all 
the job of RAID calculations.
Under software RAID, as you said, "you create partitions on the disk, then 
combine them into md devices".

Isn't there any space for something in which the disks are made parts of 
RAID arrays *before* the partitions are created and yet all the RAID 
operations would be made by the main CPU and so it would still be considered 
software RAID? What would happen if the equivalent of mdadm was *included* 
in the OS kernel?

Thank you.

(Ok, I just noticed that my question is now O.T. and this is now a general 
Linux question rather than a specific CentOS question... Excuse me!)