Posted on 1999-11-10
Medium Priority
Last Modified: 2010-04-27
I need someone to list down all the hardware interrupts
1) which interrupts are used? normally by what?
2) which interrupts are free for use (e.g sound card, network card, etc)
I am using a Intel Pentium III system.
Question by:recce

Expert Comment

ID: 2197262
free interrupts are usually 5,7,9,10,11,12. You can free up 3 and 4 if you don't have any com port devices (serial mouse, modem) 7 is usually the printer port. 14 and 15 are for the two ide hard drive channels so you can free up one of these if you don't have more than 2 ide devices. Irq 2 is cascaded to irq 9, so they are in essence the same port. You can't use 6, 8, or 13.
Under 98 it is possible to share interrupts with some devices but it is best to avoid this if possible

Author Comment

ID: 2197390
how about irq 1?
why can't use 6, 8, 13?

Expert Comment

ID: 2197572
Here is a complete rundown.

0 System Timer
1 Keyboard Controller
2 Second IRQ Controller
3 COM Port 2 (or COM 4, if installed/enabled)
4 COM Port 1 (or COM 3, if installed/enabled)
5 Parallel Port (LPT 2, if installed/enabled)
6 Floppy Disk Controller
7 Parallel Port (LPT 1)
8 Real-Time Clock
9 Available (Redirected IRQ 2)
10 Available
11 Available
12 PS/2 Mouse Port (if installed/enabled)
13 Math Coprocessor
14 Hard Disk Controller
15 Normaly Hard Disk Controller
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Expert Comment

ID: 2198023
For IRQ information on your particular system, you can check out the Microsoft System Information in your Programs-accessories-systemtools folder.

Choose Hardware Ressources-IRQ's.

 Here you will find info on which IRQ's are taken by your hardware-components and which are free.

Or you can check this page out for all your IRQ-questions:

LVL 12

Expert Comment

ID: 2198337
There is also the NMI (Non-Maskable Interrupt) that is wired directly to the memory parity circuits. This will bring your system to a *FULL STOP* immediately if there is a hard memory pariity failure.

(Haven't seen one of these in YEARS...)


Expert Comment

ID: 2199665
"I am using a Intel Pentium III system."

I don't matter at all, all PC compatibles use the same IRQ system.

Expert Comment

ID: 2202092
Right click on My Computer, select Properties.  Click Device Manager tab.  Click once on Computer (at the top of the list) to make sure it is highlighted.  Click on Properties button.  You should see four radio buttons to select more information for interrupts, I/O ranges, DMAs, and memory.  In this way you can identify what resources are already in use by your system, and which ones are available.

Good luck!

Author Comment

ID: 2203310
sorry turner, but  i think Jason s has answer exactly what i want.
Jason s, can u lockin

Accepted Solution

Jason_S earned 200 total points
ID: 2203329
Sure.  Glad to help.

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