Interrupt
<programming> 1. An
asynchronous event that suspends normal processing and temporarily diverts the
flow of control through an "
interrupt handler" routine.
Interrupts may be caused by both
hardware (I/O, timer, machine check) and
software (supervisor,
system call or
trap instruction).
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
interrupt handler. This is usually a
kernel level privileged 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 process table) updated. This first-level handler may then call another handler, e.g. one associated with the particular device which generated the interrupt.
2. Under
MS-DOS, nearly synonymous with "
system call" because the
OS and
BIOS routines are both called using the INT instruction (see
interrupt list) and because programmers so often have to bypass the operating system (going directly to a BIOS interrupt) to get reasonable performance.
[
Jargon File]
