xxsk8er101xx :
...You can ignore RAID 0 as that isn't even used now a days and doesn't even perform redundancy so it'll just confuse things.
Excuse me, xxsk8er101xx. I am using RAID 0 for performance, and it works quite nicely. I do not care about losing my data - it is backed up to another storage location. The speed is what I desire, and striping gives it to me. I am not alone by any means.
For the new guy, RAID 0 has two or more hard drives in a line. The RAID controller chops the data up into blocks, and each block sent to a different drive. Looking at it simply, two drives means two blocks, almost twice as fast. Three drives, three blocks, almost three times as fast. See where this is going?
Here is a video of a guy that took 24 Samsung Solid State Drives and built a very very fast RAID 0 Array. Why? Just for fun!
http://www.youtube.com/watch?v=26enkCzkJHQ
Are you ready for RAID 1, now? Instead of making separate blocks, the controlloer writes the data two times - that is the redundancy part. So, if one of the hard drives breaks, as they all do eventually, then you still have the other one for an automatic back up. Pretty simple, isn't it?
The other forms of RAID mix and match the splitting and duplicating functions, but it is all pretty much the same theme as RAID 0 and RAID 1.
I know this explanation is simplified, and the other experts may try and argue that I don't have it all perfect, but that is my version of RAID, and I sure hope it helps.