A SATA controller is a hardware component that manages the connection between a computer's motherboard and its storage devices, such as hard drives and solid-state drives. It uses the Serial ATA (SATA) interface, which allows for faster data transfer rates compared to older interfaces like PATA. The SATA controller is responsible for sending and receiving data between the storage devices and the computer's processor. It also handles tasks like error correction and device management, ensuring that the storage devices operate efficiently and reliably within the system.