Typical uses

Typical interrupt uses include the following: system timers, disks I/O, power-off signals, and traps. Other interrupts exist to transfer data bytes using  UARTsor Ethernet; sense key-presses; control motors; or anything else the equipment must do.

A classic system timer interrupt interrupts periodically from a counter or the power-line. The interrupt handler counts the interrupts to keep time. The timer interrupt may also be used by the OS's task schedual to reschedule the priorities of running processes. Counters are popular, but some older computers used the power line frequency instead, because power companies in most Western countries control the power-line frequency with a very accurate atomic clock.

A disk interrupt signals the completion of a data transfer from or to the disk peripheral. A process waiting to read or write a file starts up again.

A power-off interrupt predicts or requests a loss of power. It allows the computer equipment to perform an orderly shutdown.

Interrupts are also used in typeahead features for buffering events like keystrokes.