Redundant Array of Independent (or Inexpensive) Disks. A collection of 2 or more disks that work together to increase performance and safety. The disks form one logical storage unit. The most used RAID levels are: RAID 0: striping only, RAID 1: mirroring only, RAID 5: striping with error correction information on all disks.
the BIOS is simply as you put it "a control panel for the system" but the options can be way more advanced then what the control panel options are