SAS controllers, or Serial Attached SCSI controllers, are hardware components that manage data transfer between a computer's central processing unit and storage devices. They facilitate communication with SAS drives, which are high-performance hard drives or solid-state drives designed for enterprise environments. SAS controllers support multiple devices and provide features like error correction and data integrity. These controllers are essential in data centers and servers, where they enhance storage performance and reliability. They can connect to various storage devices, including SATA drives, and often support advanced features like RAID configurations, which improve data redundancy and performance.