On few consumer laptops I have noticed that the laptops **firmware** provides an option for Raid.

Firmware --> Sata Operation --> RAID ON or AHCI (AHCI and RAID ON are mutually exclusive).

The laptops configuration allows only one HDD and this is what puzzles me.
From my understanding, RAID configuration is only possible when there are at least two HDD's in the setup and the few of the laptops I have seen have provision for just one HDD.

**So what is the significance of "RAID ON" here and what does it mean????**