RAID 1 consists of an exact copy of a set of data on two or more disks
RAID 2 stripes data at the bit level, and uses a hamming code for error correction.
RAID 3 consists of byte-level striping with a dedicated parity disk.
RAID 4 consists of block-level striping with a dedicated parity disk.
RAID 5 consists of block-level striping with distributed parity.
RAID 6 uses block level striping with two parity blocks distributed across all disks.