In computer hardware, a controller may refer to: Memory controller, a unit that manages access to memory Game controller, a device by which the user controls the operation of the computer Host controller Network controller Graphics controller or video display controller SCSI host bus adapter Network interface controller (NIC) Parallel port controller Microcontroller unit (MCU) Keyboard controller Programmable Interrupt Controller Northbridge (computing) Southbridge (computing) Universal asynchronous receiver/transmitter (UART) communications controller chip Peripheral DMA controller Floppy disk controller Disk array controller, also known as a RAID controller, a type of storage controller Flash controller, or SSD controller, which manages flash memory Terminal Access Controller IBM 2821 Control Unit, used to attach card readers, punches and line printers to IBM System/360 and IBM System/370 computers IBM 270x and IBM 37xx, used for telecommunications IBM 3271, 3272, 3271, and 3174, used to attach terminals (display devices) MIDI controller Programmable logic controller