Hard disk controller
1. Abbreviated as HDC, the hard disk controller is a circuit that enables a computer to read and write information to a hard drive. The HDC also acts as a bus, connecting the hard disk to the rest of the computer's components. Today, hard drives have the controller built on to them, usually a circuit board that covers the bottom or on the back portion of the drive.
2. The term hdc is also the device name for the master ATA device on the second channel.