Asus P/I-P55SP3AV - Manual (Page 14)

Feature Guide
System IRQs
In this manual you'll see something called an "IRQ" mentioned.
If you're not familiar with these, this is a short explanation of what
they are and why you may need to know about them if you upgrade
your system. If you are running Windows 95, your system should,
in principle, be able to deal with any IRQ requirements that occur in
the process of changing or upgrading your system configuration and
you will probably not need to concern yourself with them. Windows
3.x or other users, will need to be aware of IRQ use in the system
configuration.
An IRQ, or interrupt request, is the process whereby an input or
output device tells the CPU to temporarily interrupt whatever it is
doing and immediately process something from the source of the
interrupt. When finished the CPU goes back to what it was already
processing. This happens very quickly. There are 16 IRQs, IRQ 0
through IRQ 15. Devices that need an IRQ line to operate sometimes
must have the use of that line exclusively Some IRQs are already in
use by parts of your system. This is a design standard common to
IBM-compatible personal computer.
Some expansion cards require the use of an IRQ line, for example,
network interface cards and sound cards. When you install a card that
uses an IRQ, it probably will have a default IRQ setting that you
might need to change if that IRQ is already in use and cannot be
shared. There are different ways of setting an IRQ assignment in hard­
ware, with jumpers being the most common.
"Plug and Play" expansion cards have their IRQ assigned by the
system under Windows 95, or, without Windows 95, can be config­
ured using an ISA configuration utility.
There is some IRQ setup to do in the BIOS Setup utility. This is
explained in detail in Chapter 3.
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