Inside your computer
Selecting IRQs for cards
The table below lists the interrupts available on the
motherboard and their default functions. The notes explain
whether the default function can be disabled, if so how, and
under what circumstances it is safe to do so.
A/6 XEN OWNER'S HANDBOOK
These interrupts are not used by
the motherboard and are available
for expansion cards.
IRQ7 is not normally used, and can
be used by expansion cards without
affecting the operation of the
parallel port. It is possible for
software to enable the parallel
port's use of IRQ7. This is rare but
could cause problems with a card
If you are not using the parallel port
it can be disabled using SETUP,
freeing IRQ7 to be used by an
This interrupt can be used if a
secondary IDE interface is disabled,
or not fitted.
Serial port 2
Each of the serial ports, can be
Serial port 1
individually disabled using SETUP.
When a port is disabled, the
interrupt assigned to it is free and
can be used by an expansion card.
You should only disable a port if you
are certain that you will not be
These interrupts cannot be used
Floppy disk controller by an expansion card under any
Real time clock
Hard disk controller