Technical data

Server Software and Utilities
2-10
In BIOS Setup [F2], PCI IRQ lines 1 to 4 can be mapped to any one of the IRQs (3,
4, 5, 7, 9, 10, 11, 12, 14, 15) that are displayed in the Setup menu. However, there
are certain rules that must be followed to avoid IRQ conflicts.
1. Use “Auto Select” (the default) for most Window NT installations, unless an ISA legacy
card is installed. Do not choose “Auto Select” if an ISA legacy card is installed in the
server.
2. ISA assignments take priority over PCI assignments.
3. A PCI device cannot use the same IRQs that is already used by an ISA device.
4. In the 5220 and 5225 series servers, IRQ14 and 15 are fixed for the dual channel IDE.
Limitations: The following limitations are only for DOS and Novell operating
systems.
5. SCSI and Ethernet cards cannot share the same PIRQ line in a uniprocessor
environment; therefore, do not insert a SCSI board into a slot with the same PCIRQ
assignment as the Ethernet. Likewise, do not insert an Ethernet card into a slot that
has the same PCIRQ assignment as a SCSI controller.
Examples:
A. The E-Net controller in the Proprietary slot uses PIRQB; therefore, do not
install a SCSI controller into slots 3, 4, or 8, because the first IRQ in these slots
are also assigned PIRQB. In addition, do not install a SCSI adapter that uses
multiple IRQs in slots 9 and 10, because the second IRQ in these slots is also
assigned PIRQB.
B. The on-board SCSI uses PIRQC, so do not use slot 5 and 6 for an E-net card,
because these slots are also assigned PIRQC. In addition, do not install an E-
net card that uses multiple IRQs in slots 7 and 8, because the second IRQ in
these slots is also assigned PIRQC. These two examples are summarized in
the following table. Do not install the type of card in the left column in the PCI
slot marked with “NO.”