Controllers, when used in Computing and especially in computer hardware, often occur when interface with peripherals. See for example:
disk array controller (a type of storage controller)
disk controller (a type of storage controller)
graphics controller or video display controller
network controller (in Ethernet)
computer keyboard controller
Interrupt controller
redundant array of independent disks controller
SCSI controller
Terminal Access Controller
=See also=
*Microcontroller
*Programmable logic controller
*[
http://www.webopedia.com/TERM/c/controller.html Controller description] at Webopedia, a computer term dictionary.