A interrupt request / IRQ is in which instructions are sent to Cpu and uses an interrupt handler to run distinct program . Hardware interrupts are used to manage occurrences such as obtaining modem or network card information, important presses, or mouse motions.
Interrupt request 0. – it is a system timer (can not be altered)
Interrupt request 1 – keyboard controller (can not be changed)
Interrupt request 2 – cascaded IRQ 8–15 signals (any device configured to use IRQ 2 will genuinely use IRQ 9)
Interrupt request 3 – serial port 2 controller
Interrupt request 4 – serial port 1 controller
Interrupt request 5 –parallel port 2 and 3
Interrupt request 6 - floppy disk controller
Interrupt request 7 –parallel port 1. If a printer is not present, it is used for printers or for any parallel port. It can also possibly be shared with a secondary sound card with cautious port management.
As interrupt number increases priority level decreases, Priority level 0 is the highest priority level .
