PCI Bus Numbering in a Microsoft Windows NT Environment

PCI Bus Numbering in a Microsoft Windows NT Environment 22
13UK-1200A-WWEN
Configuration A – Test 2 – Adding a Device
The example in Table 7 illustrates the PCI BIOS discovery and bus number assignment process in
the same ProLiant ML530 server. However, the configuration changes slightly by adding a
bridged PCI network controller on the Tertiary Bus.
Table 7. PCI BIOS bus detection in a ProLiant ML530–after adding a bridged controller
Bus
Detection
Order/
Controller
Discovery
Slot
Number
PCI Bridge/
Controller
Type – Test 1
Bus Number
Assignment
Description of PCI BIOS Discovery
Process
1st
Primary
Bus (O)
Host to PCI
Bridge
Bus 0
2nd Slot 1 Empty N/A
3rd
Secondary
Bus (2)
Host to PCI
Bridge
Bus 2
4th Slot 7 Empty N/A
5th Slot 8 Empty N/A
6th
Tertiary
Bus (5)
Host to PCI
Bridge
Bus 5
7th Slot 6 NC3131 Bus 6
8th Slot 4 Empty N/A
9
th
Slot 3 Empty N/A
10th Slot 2 Empty N/A
11th Slot 5 NC3132 (non-
bridged)
Bus 5
The PCI BIOS discovers the Primary Bus
and assigns it bus 0.
Discovery process continues to PCI slot 1.
No PCI controller detected, no bus number
assigned.
The PCI BIOS discovers the Secondary
Bus and increments the bus number to 2.
Discovery process continues to PCI slots 7
and 8. No PCI controller detected, no bus
number assigned.
The PCI BIOS discovers the Tertiary Bus
and increments the bus number to 5.
Discovery process continues to PCI slot 6,
and detects a bridged NIC, incrementing
the bus number by one to become bus 6.
Discovery process continues to PCI slots
4, 3, and 2. No PCI controller detected, no
bus number assigned.
PCI BIOS detects a NIC (no PCI bridge) in
slot 5, it is assigned the same bus number
as the PCI Bus where it resides.
*Bus number is different than previous configuration