Dell OptiPlex GX1 Service Manual page 32

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IRQ8 Generated by RTC alarm event.
IRQ9 Available for use by an expansion card.
IRQ10 Available for use by an expansion card.
* NIC/default PCI IRQ.
IRQ11
IRQ12 Generated by keyboard controller to indicate that mouse's output
buffer is full.
IRQ13 Generated by math coprocessor to indicate coprocessor error.
IRQ14 Generated by device connected to primary EIDE port to indicate
that device requires service. If the EIDE controller is disabled,
this line is available for other use.
IRQ15 Generated by device connected to secondary EIDE port to indi-
cate that device requires service. If the EIDE controller is
disabled, this line is available for other use.
* If an ISA expansion card is configured for IRQ11, the optional NIC or PCI IRQ is assigned
to another available IRQ line.
DREQ0 Available
DREQ1 Available
DREQ2 Generated by super I/O controller to initiate DMA cycle for
attached diskette drive
DREQ3 Available
DREQ4 Generated by bus controller chip to activate second DMA
controller
DREQ5 Available
DREQ6 Available
DREQ7 Available
NOTE: The built-in audio controller, NIC (optional), and video controllers are assigned available
DMA channels automatically during system start-up.
The following subsections provide service-related information about hard-disk
drive options for the OptiPlex GX1 (low-profile, midsize, and mini tower) and
OptiPlex NX1 computers.