CertiGuide to A+ (Core Hardware)  9  Chapter 0001:  Power Supplies - System Board       9  XV  Demanding Attention Digitally

Interrupting 1 IRQ Conflict

The use of these interrupt channels to make a request carries the term Interrupt ReQuest and is abbreviated IRQ. From this you will hear the term, IRQ #.

Depending on the priority of what is happening in your PC, a request can be temporarily ignored if the PC has something going of a more critical nature. This state is known as masking the interrupt.

Suppose all heck is breaking out in your PC. Say, your memory has just gone brain dead. Since this is a (not good) condition that is more serious than anything else (to prevent data loss), your PC will report a Non-Maskable Interrupt (NMI).

Interrupting 1 IRQ Conflict