Resources - Interrupt Requests (IRQs)

An interrupt is a message from one part of the computer to another that tells it that it needs to stop what it is doing, and do something else instead. Interrupts play a key role in how the processor   performs.    It   interfaces   with   every 

peripheral in the computer. The table below provides summary information in a typical computer. You may find this table useful when considering how to configure your system or for resolving IRQ conflicts.

IRQ	Bus	Priority	Default Use	Optional Uses
0	none	1	System timer	None
1	none	2	Keyboard controller	None
2	rerouted	n/a	Programmable Replaced by IRQ 9	(EGA) video cards
3	8/16-bit	11	COM2 (Serial Port)	COM4 (Serial Port) Network cards
4	8/16-bit	12	COM1 (Serial Port)	COM3 (Serial Port), Modems Network cards
5	8/16-bit	13	Sound card LPT2 (Parallel Port)	Network cards Sound cards SCSI adapters Tape controllers
6	8/16-bit	14	Floppy Controller	Tape controllers
7	8/16-bit	15	LPT1(Parallel Port)	Network cards Sound cards Tape controllers
8	none	3	Real-time clock	None
9	16-bit	4	Rerouted IRQ2	Network cards Sound cards SCSI adapters Video cards
10	16-bit	5	Trtiary IDE PCI devices/USB	Network cards Sound cards SCSI adapters Video cards
11	16-bit	6	SCSI adapters Video cards Trtiary IDE PCI devices/USB	Network cards Sound cards
12	16-bit	7	PS/2 Mouse	PCI devices/USB
13	none	8	Floating Point Unit Math Coprocessor	None
14	16-bit	9	Primary IDE channel	SCSI host adapters
15	16-bit	10	Secondary IDE channel	SCSI host adapters