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golem · 8th March 2011

I still don't understand how the IRQ and device prioritization works in current computers and Windows 7.

Look at the list of one of my machines:

M-AUDIO - Knowledge Base

1. How can you see and identify in a current computer the priority order of devices, which device has higher priority? I suppose traditionally the priority order was 0,1,2,8,9,10,11,12,13,14,15,3,4,5,6,7. But I see that most of my devices are assigned to interrupts that are not in this list (16-23, and -2!)

2. is even nowadays so that with ACPI and APIC, first audio interface throws IRQ and processor starts processing and moving data from memory to audio buffer, and if there becomes a higher priority interrupt in the middle (e.g. WLAN), processor will interrupt the data moving and start serving the higher priority device..?

3. Is there any other way to change device priorities than switching to different PCI slots or USB ports..?, a friend claimed that prioritization is done in software and I read from somewhere that you can set a priority in windows registry (e.g. IRQ13, priority 1, IRQ10, priority 2, etc..), but it seems too dangerous to me. Any safer way to do this?

4. What is the most desirable way to prioritize the following devices in a DAW: Audio Interface, Hard Disk, MIDI-controller, Display Adapter, ATA channels, SATA controller?

I really would want to know that e.g. if there comes IRQ 10, 16, 19 and -2 all at the same time, which one is processed first and which one last..?

Still one thing, is it better to choose plug&play OS Yes or No from BIOS in a dAW?

8th March 2011	#21
golem Gear Head Joined: Dec 2010 Posts: 35	I still don't understand how the IRQ and device prioritization works in current computers and Windows 7. Look at the list of one of my machines: M-AUDIO - Knowledge Base 1. How can you see and identify in a current computer the priority order of devices, which device has higher priority? I suppose traditionally the priority order was 0,1,2,8,9,10,11,12,13,14,15,3,4,5,6,7. But I see that most of my devices are assigned to interrupts that are not in this list (16-23, and -2!) 2. is even nowadays so that with ACPI and APIC, first audio interface throws IRQ and processor starts processing and moving data from memory to audio buffer, and if there becomes a higher priority interrupt in the middle (e.g. WLAN), processor will interrupt the data moving and start serving the higher priority device..? 3. Is there any other way to change device priorities than switching to different PCI slots or USB ports..?, a friend claimed that prioritization is done in software and I read from somewhere that you can set a priority in windows registry (e.g. IRQ13, priority 1, IRQ10, priority 2, etc..), but it seems too dangerous to me. Any safer way to do this? 4. What is the most desirable way to prioritize the following devices in a DAW: Audio Interface, Hard Disk, MIDI-controller, Display Adapter, ATA channels, SATA controller? I really would want to know that e.g. if there comes IRQ 10, 16, 19 and -2 all at the same time, which one is processed first and which one last..? Still one thing, is it better to choose plug&play OS Yes or No from BIOS in a dAW?