Interrupt Requests

Question 1

What are interrupt requests (IRQ)?

Answer 1

A hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Interrupts are used to handle such events as data receipt from a modem or network, or a key press or mouse movement.

Question 2

What is the interrupt request level (IRQL)?

Answer 2

The priority of an interrupt request

Question 3

What are the two types of interrupt requests?

Answer 3

Master PIC (0-7)
Slave PIC (8-15)

Question 4

IRQ 0

Answer 4

System timer (cannot be changed)

Question 5

IRQ 1

Answer 5

Keyboard controller (cannot be changed)

Question 6

IRQ 2

Answer 6

Cascaded signals from IRQs 8-15

Question 7

IRQ 3

Answer 7

Serial port controller for serial port 2 (shared with serial port 4 if present)

Question 8

IRQ 4

Answer 8

Serial port controller for serial port 1 (shared with serial port 3 if present)

Question 9

IRQ 5

Answer 9

Parallel port 2 and 3 or sound card

Question 10

IRQ 6

Answer 10

Floppy disk controller

Question 11

IRQ 7

Answer 11

Parallel port 1. It is used for printers or for any parallel port if a printer is not present

Question 12

IRQ 8

Answer 12

Real-time clock

Question 13

IRQ 9

Answer 13

Advanced configuration and power interface system control interrupt on Intel chipsets.
Other chipset manufacturers might use another interrupt request for this purpose.

Question 14

IRQ 10

Answer 14

The interrupt is left open for the use of peripherals. Open interrupt / available or SCSI or NIC

Question 15

IRQ 11

Answer 15

The interrupt is left open for the use of peripherals. Open interrupt / available or SCSI or NIC

Question 16

IRQ 12

Answer 16

Mouse on PS/2 connector

Question 17

IRQ 13

Answer 17

CPU co-processor or integrated floating point unit or inter-processor interrupt (use depends on OS)

Question 18

IRQ 14

Answer 18

Primary ATA channel

Question 19

IRQ 15

Answer 19

Secondary ATA channel