The Highpoint Technology Inc. HPT368 Ultra DMA 66 Controller is a hardware device used in computer systems to manage the connection between the motherboard and storage devices (such as hard drives or optical drives) that use the Ultra DMA (Direct Memory Access) standard. The "Ultra DMA 66" refers to the data transfer rate (66 MB/s) of the interface, which was commonly used in the late 1990s and early 2000s to connect IDE (Integrated Drive Electronics) hard drives.

In terms of a Windows driver, it's a software component that allows Windows to communicate with the HPT368 controller hardware, ensuring the operating system can properly interact with storage devices connected to the Ultra DMA 66 interface.