Dell R410, PERC s300(RAID controller), Hard Drive replacement 

PERC is stand for Power Edge Raid Controller. Hard Drive replacement.
a scsi controller type, allowing more devices to connected then a SATA type of controller found on desktop PC sell at Best Buy.
This PERC S300 has 4 HD that allows to set up RAID possible. And it’s setup as RAID 5 array.
What is a RAID setup?
Allow you to combined HD for speed or for fault tolerance (if one HD die the computer still functions). RAID act like an expensive backup program.
When you set up RAID you combined more then one HD together. This is known as creating the first Array, by throwing all your hard disk into this array is known as RAID.