Interrupt

In computing, an interrupt is an event that suspends normal processing and temporarily diverts the  through an  routine.

Description
Interrupts may be caused by both hardware (I/O, timer, machine check) and software (, or trap instruction). At Apple Computer in 1983, the Macintosh development team was known to use trap instructions, which used less memory than Lisa system calls on similar Motorola 68000 processors.

In general the computer responds to an interrupt by storing the information about the current state of the running program; storing information to identify the source of the interrupt; and invoking a first-level. This is usually a kernel level process that can discover the precise cause of the interrupt (e.g. if several devices share one interrupt) and what must be done to keep operating system tables (such as the ) updated. This first-level handler may then call another handler, e.g. one associated with the particular device which generated the interrupt.