Manual for GeniuX 1
Installation Instruction
10
Expansion Cards
PCI1, PCI2, PCI3, PCI4
The PCI bus uses its own internal interrupt system for dealing with requests from the
cards on the bus. These interrupts are often called “PIRQ#A”, “PIRQ#B”, “PIRQ#C”, “PIRQ#D”
to avoid confusion with the normal numbered system IRQs (IRQ0~15). These interrupts, if
needed by cards in the slots, are mapped to the normal system IRQs. The following table
shows how the onboard devices such as onboard SCSI or LAN, and PCI slots connect
these internal interrupts.
According to the above table, AGP and PCI slot 2 occupy PIRQ#A of the PCI interrupt,
onboard LAN and PCI slot 1 occupy PIRQ#B, onboard SCSI and PCI slot 4 occupy PIRQ#C,
USB and PCI slot 3 occupy PIRQ#D. With the advent of the PCI bus and its associated PCI
bus devices, shareable interrupts have become a common occurrence. However whether
or not the PCI bus devices can successfully share interrupts have relationship with OS or
device driver. If you encounter problems regarding PCI devices, refer to the above table in
order to deal effectively with the problems created by shareable interrupts.
Since PCI slot 1 and PCI slot 4 occupy the same arbitration signal lines (REQ#/GNT#),
therefore PCI bus master devices can not be simultaneously installed in PCI 1 and PCI 4
slots.
Narrow SCSI
Narrow SCSI interface uses an 8-bit bus and a 50-pin connector. It supports Ultra narrow
SCSI peripherals and supports data transfer rate of 20MB/S. Be sure the red side of the cable
is aligned with the end of the connector which is marked with “ ”. We provide internal 50-
pin narrow SCSI cable with 3 heades for user.
Wide SCSI
Wide SCSI interface uses a 16-bit bus and a 68-pin connector. It supports Ultra Wide SCSI
peripherals and supports data transfer rate of 40MB/s. We provide external 68-pin wide
SCSI cable with bracket for user.
Ultra 2 SCSI
Ultra 2 SCSI interface use a 16-bit bus and a 68-pin connector. It supports Wide Ultra2 SCSI
peripherals and supports data transfer rate of 80MB/S. We provide internal 68-pin Ultra 2
SCSI cable with 5 headers for user.
PCI Interrupt PIRQ#A
PIRQ#B
PIRQ#C
PIRQ#D
Onboard Device
LAN
SCSI
AGP AGP
USB
USB
PCI Slots (Refer
to above chart)
PCI 2 PCI 1 PCI 4
PCI 3
