IRQs and DMA in Win2k

  • Thread starter Thread starter Kilo Bravo
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Kilo Bravo

Does windows 2000 spoof IRQs? on some machines I see IRQs up to 20. I thought IRQs at the hardware level were numbered 0-15.

Also, why would a hardware device need an IRQ if it also has a DMA channel. For example my floppy disk controller is using IRQ 6 and DMA 2.

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K.Brown
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PCI systems have 4 hardware interupt lines(or 8 in some instances)
called A,B,C and D. The CPU has 1 interupt line, so the 1-x IRQs you see
are only a software carryover from the old ISA hardware system.
 
Bob I said:
PCI systems have 4 hardware interupt lines(or 8 in some instances)
called A,B,C and D. The CPU has 1 interupt line, so the 1-x IRQs you see
are only a software carryover from the old ISA hardware system.
Click to expand...

It's part of the MPS specification. Multi-cpu systems can
have IRQs over 15.

Hardware can use a combination of IRQs, DMA channels,
I/O addresses and memory ranges. It depends on the design
of the hardware.

Rick
 
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