(Or "hard disk controlLER", HDC) The circuit which allows the CPU to communicate with a {hard disk}, {floppy disk} or other kind of {disk drive}. The most common disk controlLERs in use are IDE and SCSI controlLERs. Most home personal computers use IDE controlLERs. High end PCs, workstations and network {file servers} mostly have {SCSI adaptors}. (1998-03-16)