Hp COMPAQ PROLIANT 3000, COMPAQ PROLIANT 1500, COMPAQ PROLIANT 4500, COMPAQ PROLIANT 1600, COMPAQ PROLIANT 5000 PCI Bus Numbering in a Microsoft Windows NT Environment

...

Integration Note

December 2000 13UK-1200A-WWEN

Prepared by OS Integration Engineering

Compaq Compute r Corporation

Contents

Executive Overview.....................3

PCI Bus Architecture

Terminology.................................4

PCI Hot Plug Terminology..........5

PCI System Overview..................5

PCI Architecture and Bridged

Controllers..................................6

PCI BIOS ...................................8

PCI Bus Numbering...................8

PCI BIOS Discovery...................8

Configuration Changes............11

Windows NT and PCI Bus

Numbering..................................11

PCI Bus Numbering and

Network Controllers..................11

Disk Renumbering....................12

Hardware, Software, and

Configuration Tools...................13

Compaq Servers and Option

Hardware .................................13

Planning a PCI System

Configuration.............................17

Before Modifying an Existing

System.....................................18

Planning the New

Configuration............................18

Step-By-Step Review...............19

PCI Test Configurations with

ProLiant Servers........................19

Configuration A, ProLiant

ML530......................................20

Configuration B, ProLiant

8000.........................................23

Configuration C, ProLiant

DL580 ......................................29

Compaq Support Software

and Utilities ..............................36

Additional Troubleshooting

Tips.............................................39

Summary....................................40

Appendices A-D.........................41

PCI Bus Numbering in a Microsoft Windows NT Environment

Abstract: Computing environments change rapidly to support business requirements. Typical network PCI-based servers contain a large number of expansion slots on multiple buses to allow for system growth. This means that multiple network and disk controllers of the same type may be installed in one server, with the intent that each installed controller supports a separate unique function. This can make it difficult to understand the physical and logical implications of PCI bus numbering.

This document provides information to help systems engineering professionals understand how Microsoft Windows NT handles PCI bus numbering when controllers are physically added, moved, or removed from a server configuration. This document also includes ideas and suggestions that can help systems professionals avoid network downtime due to configuration changes.

IMPORTANT: During the development of Microsoft Windows 2000, Compaq and Microsoft worked closely together effectively implementing Windows 2000 on Compaq hardware. Through this partnership, device detection improved, eliminating PCI bus numbering issues in the Windows 2000 environment. Windows 2000 checks and resets registry settings automatically, unlike its predecessor that does not reset the registry settings after discovering unbound devices.

The following documents were either used as references to produce this white paper or are mentioned as recommended related reading material:

• PCI System Architecture, Third Edition, MindShare, Inc. Tom

Shanley and Don Anderson, November, 1995.

• PCI Bus Balancing and Optimization on Compaq ProLiant

Servers, March, 1998 – Doc ID ECG073/0398.

• Where Do I Plug the Cable? Solving the Logical-Physical Slot

Numbering Problem, December 1996 – Doc ID 209A/1296.



• Deploying PCI Hot Plug on Compaq



Windows NT

Environment, July 1997 - Doc ID 064A/0797.

Servers in a Microsoft

Help us improve our technical communication. Let us know what you think about the technical information in this document. Your feedback is valuable and will help us structure future communications. Please send your comments to:

CompaqNT@compaq.com

PCI Bus Numbering in a Microsoft Windows NT Environment 2

Notice

Trademark Office. SoftPaq is a trademark and/or service mark of Compaq Computer Corporation. Netelligent is a trademark and/or service mark of Compaq Information Technologies Group, L.P. in the

U.S. and/or other countries. Microsoft, Windows, Windows NT, and Windows 2000 are trademarks and/or registered trademarks of

Microsoft Corporation. Pentium, Xeon, Pentium II Xeon, and Pentium III Xeon are registered trademarks of Intel Corporation. Adobe, Acrobat, and the Acrobat logo are trademarks of Adobe Systems, Inc. Other product names mentioned herein may be trademarks and/or registered trademarks of their respective

companies. The information in this publication is subject to change without notice and is provided “AS IS” WITHOUT

WARRANTY OF ANY KIND. THE ENTIRE RISK ARISING OUT OF THE USE OF THIS INFORMATION REMAINS WITH RECIPIENT. IN NO EVENT SHALL COMPAQ BE LI AB LE FOR ANY DIRECT, CONSEQUENTIAL, INCIDENTAL, SPECIAL, PUNITIVE OR OTHER DAMAGES WHATSOEVER (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION OR LOSS OF BUSINESS INFO RMATION), EVEN IF COMPAQ HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

The limited warranties for Compaq products are exclusively set forth in the documentation accompanying such products. Nothing herein should be construed as constituting a further or additional warranty.

This publication does not constitute an endorsement of the product or products that were tested. The configuration or configurations tested or described may or may not be the only available solution. This test is not a determination or product quality or correctness, nor does it ensure compliance with any federal state or local requirements.

PCI Bus Numbering in a Microsoft Windows NT Environment Integration Note prepared by OS Integration Engineering

Fourth Edition (December 2000) Document Number 13UK-1200A-WWEN

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PCI Bus Numbering in a Microsoft Windows NT Environment 3

Executive Overview

The term Peripheral Component Interconnect, commonly known as PCI, refers to the bus architecture standard. The PCI bus technology has become an industry standard; today’s servers provide a large number of expansion slots and can be populated with a greater number of PCI disk and network controllers. PCI buses provide fast access between controllers and/or system memory and the host processor. PCI buses offer a significant performance advantage over EISA buses.

The PCI Special Interest Group (SIG) is an unincorporated association of members of the microcomputer industry set up for the purpose of monitoring and enhancing the development of the PCI architecture. The PCI Steering Committee is a group of nine companies that oversees SIG activities and reviews formal recommendations for changes to PCI Specification(s). Compaq is a member of the SIG Steering Committee and actively proposes and contributes new design functions for future revisions to the PCI Specification.

Later in this document, examples are provided in two test scenarios, illustrating what happens to PCI bus numbering when configuration changes occur.

during system start up. Windows NT uses these numbers to identify bridged controllers. If controllers are added to an existing system, the PCI bus numbering might change. This change might affect the operation of your system.

This white paper provides information to help systems professionals understand how the PCI Specification addresses server bus numbering assignments. This document discusses:

• How the PCI BIOS detects and numbers PCI buses and bridges.

• What happens to PCI Bus numbering at each system start up.

• How adding or removing PCI devices might cause a renumbering of PCI buses.

• How Windows NT handles bus numbering in the Windows NT Registry.

• How to prevent PCI bus numbering mismatches from occurring.

This document contains several examples to demonstrate PCI bus numbering. After reading this document, you should be able to properly configure and/or reconfigure a Windows NT system when PCI bus numbers are reassigned with minimal interruption to the network.

PCI bus technology development continues to advance at a rapid pace to meet customer’s business requirements. Server technology includes equipment, such as the ProLiant 8000 with multiple PCI buses. The computing capabilities of these servers can be further expanded through PCI controllers and PCI bridged devices such as the Smart Array 4250ES Controller. Each PCI bus in the system is numbered by the PCI BIOS

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PCI Bus Numbering in a Microsoft Windows NT Environment 4

PCI Bus Architecture Terminology

Table 1 lists some terms related to PCI Bus Architecture terminology. Some of the terminology defined in this table was referenced from PCI System Architecture, Third Edition, MindShare,

Inc. Tom Shanley and Don Anderson. (November, 1995.)

Table 1. PCI bus architecture standard terms

Bridge Bridge is the device, providing connectivity between two independent

Bus Number Bus number is a number in the range 0…255 that uniquely selects a PCI

Device ID Device ID is a number in the range 0…31 that uniquely selects a device

Downstream When a transaction is initiated and is passed through one or more PCI-to-

Dual-Peer PCI Bus A system architecture providing high-bandwidth I/0 because two buses

Highly Parallel Architecture

PCI Peripheral Component Interconnect refers to a bus based on the PCI

PCI BIOS PCI BIOS functions provides a software interface to the hardware used to

PCI Bridge The device that provides the bridge between two independent buses.

PCI-to-PCI Bridge PCI-to-PCI bridge is a system architecture where an additional PCI bus is

buses.

bus.

on a PCI bus.

PCI bridges flowing away from the host processor, it is said to be moving downstream.

can operate simultaneously (i.e., in parallel) is called a dual-peer-PCI bus. A system architecture using dual memory controllers, dual-peer-P CI

buses to deliver optimized multiprocessing support to deliver increased system throughput and increased system performance when compared to traditional x86-based designs is said to be highly parallel.

Local Bus Specification, through which industry-standard peripheral controllers connect to computer systems.

implement a PCI based system.

PCI bridges can reside on the system and can reside on controllers. PCI bridges help with signal integrity and allow more devices to be added per system.

bridged off another PCI bus (i.e., in series).

Peer-to-Peer PCI Buses PCI buses that occupy the same ranking in the PCI bus hierarchy (with

Primary Bus The PCI bus closest to the host processor that is connected to one side of

Secondary Bus The PCI bus detected after the Primary Bus is called the Secondary Bus. Tertiary Bus The Tertiary bus resides furthest from host processor that is connected to

Triple-Peer PCI Bus System architecture operating with three PCI buses on a single server is

Upstream When a transaction is initiated and is passed through one or more PCI-to-

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respect to the host bus) are referred to as Peer PCI buses.

the inter-bus bridge is the Primary Bus (numbering always starts at 0).

one side of the inter-bus bridge.

referred to as a Triple-Peer PCI Bus.

PCI bridges flowing towards the host processor, it is said to be moving upstream.

PCI Bus Numbering in a Microsoft Windows NT Environment 5

PCI Hot Plug Terminology

Table 2 lists some terms related to PCI Hot Plug Terminology; however, this is not a complete list. The terms described here are those that relate to Hot Plug capabilities experienced in this document.

Table 2. PCI hot plug standard terms

*Hot Add

Hot Plug Aware Indicates that a piece of software, such as a device driver, can take

Hot Plug Slot A PCI slot capable of being powered down without interfering with the other

Hot Replacement The ability to remove PCI controllers from a system while the system is

*Hot Upgrade

PCI Hot Plug The ability to physically insert or remove industry-standard PCI adapters

* Not available in initial release of PCI Hot Plug technology for Windows NT

The ability to add existing PCI controllers and drivers to next generation controllers and drivers while a system is running, without shutting down the system.

advantage of the PCI Hot Plug capabilities of a system.

slots in the system, and without shutting the system down.

running and replace them with equivalent PCI controllers, without removing power to the server and without reconfiguring or reloading software support.

The ability to upgrade existing PCI controllers and drivers to next generation controllers and drivers while a system is running, without shutting down the system.

while the system is running without disrupting the operation of other devices in the system.

PCI System Overview

This section reviews some of the basics of buses including PCI architecture and bridged controllers, PCI BIOS, PCI bus numbering, PCI BIOS discovery, and configuration changes to the bus numbering.

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PCI Bus Numbering in a Microsoft Windows NT Environment 6

PCI Architecture and Bridged Controllers

There are four primary bus expansion schemes for PCI systems, namely the PCI-to-PCI bridge architecture, Dual-Peer PCI Bus architecture (see Figure 1), Highly-Parallel Bus architecture (see Figure 2), and Triple-Peer PCI Bus architecture (see Figure 3). The Compaq servers discussed in this white paper and used in the Integration Lab testing include these PCI architecture system designs. Refer to the “Compaq Server and Option Hardware” section of this white paper for more information.

133MHz FSB

Pentium III

133MHz

1.06GB/s

133MHz

1.06GB/s

133MHz

SDRAM

DIMMs

OSB4

SuperIO

Controller ISA Slot

Figure 1. Dual-peer PCI bus architecture in the ProLiant ML350

RCC 3.0

PCI/Memory

Controller

133 MB/s

4 x 32-Bit PCI Slots

133MHz FSB

Pentium III

267 MB/s

2 x 64-Bit PCI Slots

Server Feature Card

in 32-bit PCI slot

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PCI Bus Numbering in a Microsoft Windows NT Environment 7

Pentium III

Xeon

133MHz

SDRAM

DIMMs

33MHz/32-bit

Figure 2. Highly parallel PCI bus architecture in the ProLiant ML530

133MHz 133MHz

PCI slot

RCC 3.0

controller

66MHz/64-bit

PCI slots

Pentium III

Xeon

RCC 3.0

controller

SDRAM DIMMs

33MHz/64-bit PCI slots

Figure 3. Triple-peer PCI bus architecture in the ProLiant 8000

PCI bridges are not limited to the computer system; controllers can include them also. Hardware manufactures such as Compaq include PCI bridges on controllers to help with signal integrity, enabling more devices to be added per system. Data transfers from the host bus, through the primary PCI bus, through the PCI-to-PCI bridge on the controller, and finally to the PCI device. For example, an intelligent device such as a Smart Array 4250ES Controller contains a PCI bridge.

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PCI Bus Numbering in a Microsoft Windows NT Environment 8

PCI BIOS

The PCI BIOS specification defines the rules regarding implementation of the PCI BIOS and the software that it calls. The PCI BI OS supplies servic es t o the hardw are pla tf orm, such as determining the range of PCI buses present in the system and searching for all instances of a specific PCI device. The PCI BIOS for each hardware manufacturer is platform-specific. The operating system, application programs, and device drivers do not directly access the PCI configuration area. On Compaq servers you can review system configuration information by accessing the Compaq System Configuration Utility during system startup before the operating system initialization (by pressing F10). The System Configuration Utility may be installed on a server with the Compaq SmartStart and Support Software CD or from a diskette to update the server configuration.

PCI Bus Numbering

At startup time, the PCI BIOS is aware only of the existence of PCI bus 0, the first bus number detected on the Primary PCI Bus. The PCI BIOS assigns numbers to each PCI bus and bridge it detects during system initialization. PCI bus numbers reassign each time the system starts and the discovery process begins again. Each PCI device receives the same PCI bus number if no changes have been made.

Each time the server restarts the PCI BIOS must walk the base PCI bus (starting at bus 0), subsequent bridges, and bridged devices to search and identify other PCI buses as if it were the first time. Each time the PCI BIOS discovers another PCI bus after a physical configuration change is made, it increments the bus number and continues to walk the bus until all other buses are discovered.

As it discovers each bus and/or bridge, the PCI BIOS:

• Records each unique bus number

• Associates the bus number to a bus or bridged PCI device

When the System Configuration Utility runs it builds a picture of the bus “tree” that represents the overall system topology. The System Configuration Utility displays the slot and bus number assignment for each PCI device in the server. Since controllers are physically installed in numbered slots, the PCI BIOS does not detect the numbers assigned to the slots, only the PCI devices installed in the slots. Systems professionals typically use slot numbers to identify and record the physical placement of controllers when configuring network systems. This document should help you predict how the PCI BIOS assigns and/or reassign bus numbers and how to associate these assignments to the physical slot numbers. Slot number assignments remain constant with a controller for as long as the controller is installed in a particular slot.

PCI BIOS Discovery

The following examples illustrate the PCI BIOS discovery and bus number assignment process for PCI buses, non-bridged controllers, and bridged controllers. The actual discovery process includes other components not shown here that reside on the PCI bus, such as video or embedded SCSI devices. However, this document omits these other components to simplify the example.

PCI Bus numbering is determined by the order of detection of each PCI bus discovered in a server configuration. The manufacturer defines the detection order for each server. Refer to “Table 11. PCI Bus Number Order of Detection Matrix” for Compaq ProLiant servers.

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PCI Bus Numbering in a Microsoft Windows NT Environment 9

IMPORTANT: PCI Bus numbers are assigned in “device detection order,” not by slot numbering.

Bus numbers are assigned during bus initialization according to predefined hardware designators. The bus numbers may not appear to follow a set increment and some numbers may be skipped. However, by this method, these hardware designators prevent overlays in bus numbering from occurring.

process continues until all PCI controllers and controllers with bridged buses on the Primary Bus are detected. The PCI BIOS then continues the discovery process on the Secondary Bus until all PCI buses are detected.

The diagram in Table 3 shows an example of the discovery process. Table 3 does not represent all the PCI slots and bus assignment possibilities, it depicts snapshot of what occurs when controllers are loaded in the server.

Table 3. Example of PCI bus number detection order for the ProLiant ML350 (a dual-peer system)

ProLiant ML350 PCI Server Architecture PCI BIOS Discovery Process

! Host Bus " Primary PCI Bus First 0 ! Slot 1 – Server Feature Card Second 0 ! Slot 4 – Empty Third 0 ! Slot 5 – Empty Fourth 0 ! Slot 6 – NC3131 Fast Ethernet NIC Fifth 1

" Secondary PCI Bus Sixth 5

! Slot 2 – Smart Array 5300 Controller Seventh 5 ! Slot 3 – Empty Eighth 5

End of bus

discovery

Dual-Peer PCI Bus – The Compaq ProLiant ML350 server, an example of the dual-peer PCI architecture, begins the PCI BIOS discovery process at the Host Bus. When it detects the primary bus, it assigns bus 0 to it. The PCI BIOS then looks for PCI controllers in slots on the Primary Bus. PCI controllers detected without bridged PCI buses are assigned bus 0, the number of the bus in which it is seated. However, if the PCI Bios detects a bridged PCI device, it increments the bus number to 1 and assigns that bus number to the PCI bus detected on the bridged controller. (The next PCI bus detected is assigned a bus number according to the hardware designation for that system). This discovery

Controller Bus Detection Order

Bus Number Assignment

As indicated in Table 3, the order of detection on the ProLiant ML350 server is Primary Host-toPCI Bridge, followed by PCI controllers and bridged controllers on the Primary Bus in slots beginning at 1, skipping 2-3, and ending at 6. The bus discovery process continues with the Secondary Host-to-PCI Bridge, followed by PCI controllers and bridged controllers in slots beginning at 2 and ending at 3.

Highly Para l lel PCI Bus – The Compaq ProLiant ML530 provides an example of highly parallel PCI architecture. This architecture uses dual memory controllers, dual-peer-PCI buses to deliver optimized multiprocessing support to deliver increased system throughput, and increased system performance when compared to traditional x86-based designs.

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PCI Bus Numbering in a Microsoft Windows NT Environment 10

Triple-Peer PCI Bus – The Compaq ProLiant 8000 is an example of the triple-peer PCI architecture. The PCI BIOS begins the discovery process at the Host Bus. In a triple-peer PCI bus architecture the Primary Bus is the first bus detec ted an d it is assig ned bus 0. The PCI BIO S then looks for PCI controllers in slots on the Primary Bus. PCI controllers detected without bridged PCI buses are assigned bus 0, which is the number of the bus it is seated in. However, if a PCI controller is detected with a bridged PCI device, the PCI BIOS increments the bus number to 1 and assigns that bus number to the PCI bus detected on the bridged controller. This discovery process continues until all PCI controllers and controllers with bridged buses on the Primary Bus are detected. The PCI BIOS then continues the discovery process on the Secondary Bus until all PCI buses are detected, and then on to the Tertiary Bus until all PCI buses are detected.

The diagram in Table 4 is an example of the discovery process.

Table 4. Example of PCI bus number order of detection for ProLiant 8000 (a triple-peer system)

ProLiant 8000 PCI Server Architecture

PCI BIOS Discovery Process

! Host Bus

" Primary PCI Bus First 0

! PCI Slot 1 – Pri Bus Empty Second 0

! PCI Slot 2 – Pri Bus Empty Third 0

! PCI Slot 3 – Pri Bus Empty Fourth 0

! PCI Slot 4 – Pri Bus Empty Fifth 0

" Secondary PCI Bus Sixth 6 ! PCI Slot 5 – Sec Bus Empty Seventh 6 ! PCI Slot 6 – Sec Bus Empty Eighth 6 ! PCI Slot 7 – Sec Bus PCI Controller (no bridge) Ninth 6 ! PCI Slot 8 – Sec Bus PCI Controller (integrated PCI bridge) Tenth 7 ! PCI Slot 9 – Sec Bus Empty Tenth 6

" Tertiary PCI Bus Eleventh 13 ! PCI Slot 10 – Ter Bus PCI Controller (no bridge) Twelfth 13 ! PCI Slot 11 – Ter Bus PCI Controller (integrated PCI bridge) Thirteenth 14

End of bus discovery

Controller Bus Detection Order

Bus Number Assignment

The “Additional Troubleshooting Tips” section of this document contains a matrix titled “Table

11. PCI Bus Number Order of Detection Matrix”. This matrix lists the PCI Bus detection order for several Compaq ProLiant servers.

In this scenario, PCI BIOS assigns the Primary Bus as bus 0. Since it detects no devices in the Primary Bus, the discovery process continues to the Secondary Bus, assigned bus 6. The first PCI controller detected downstream from the Secondary Bus does not contain a bridge, this controller is assigned bus 6, the same as the Secondary PCI bus. The discovery process continues with bus number assignments for other controllers on the Secondary Bus based on the order of detection. Once again, if the PCI controller is a bridged PCI device, the bus number increments, if the PCI controller is a non-bridged device then the controller is assigned the same number as the bus it is seated in. After detection on the Secondary Bus completes, the Tertiary PCI Bus is assigned the bus 13.

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PCI Bus Numbering in a Microsoft Windows NT Environment 11

For example, the order of detection on the ProLiant 8000 is Primary Host-to-PCI Bridge, followed by PCI controllers and bridged controllers on the Primary Bus in slots beginning at 1, 2, 3 and ending at slot 4. The bus discovery process continues with the Secondary Host-to-PCI Bridge, followed by PCI controllers and bridged controllers in slots beginning at 5, 6, 7, 8, and ending at slot 9. Then, the process moves forward to the Tertiary Host-to-PCI Bridge, followed by PCI controllers and bridges controllers in slots beginning at 10 and ending at slot 11.

Configuration Changes

Bus number assignments for controllers with bridged devices are assigned to the PCI bus on the controller.

subsequent controller in the discovery process (containing a bridged PCI bus) receives an incremented bus number assignment, regardless of whether it is new or it was previously configured.

The PCI BIOS assigns resources at power-up, the server must be restarted before the PCI BIOS can assign PCI bus numbers to each bus discovered in the new configuration. The PCI BIOS assigns PCI bus numbers to each PCI device in the order of discovery without any concern for prior bus assignments or the physical slot location. Several bus-numbering scenarios included in this white paper demonstrate how the PCI BIOS discovers PCI buses and assigns numbers.

From time to time, network administrators add disk and network controllers to existing configurations to address the requirements of growing server networks. Adding a bridged controller earlier in the discovery order than other existing controllers can change the PCI bus number assignment of all bridged PCI controllers detected after it. Each

Windows NT and PCI Bus Numbering

During the initial installation of Windows NT, all network controllers in the server automatically add to the registry along with the bus number assignment. This is the only time that Windows NT automatically adds the PCI bus numbers in the registry. If no physical configuration changes are made to the system in the future, Windows NT continues to detect the controllers after future system restarts.

PCI Bus Numbering and Network Controllers

When you modify a server by adding a new controller, removing a controller, or moving a controller to a different slot, Windows NT might not detect the change in the server configuration. Configuration changes only occur when you insert or remove a bridged device. The PCI BIOS renumbers PCI bus numbers assigned to PCI buses and PCI bridged devices during the discovery process, based on the new configuration. Windows NT does not automatically check for new bus number assignments. Windows NT retains the original controller slot number and bus number assignments in its registry after the server restarts. However, the bus number assignments in the Windows NT registry can be updated using the appropriate network configuration tool for your controllers. The Compaq TLAN Teaming and Configuration Utility supports Compaq NetFlex-3 and Netelligent Controllers (see Appendix C for usage information),

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PCI Bus Numbering in a Microsoft Windows NT Environment 12

where as, the Compaq Network Teaming and Configuration Utility supports Compaq 10/100 and Gigabit NICs, discussed in this document.

Note: When configuration changes are necessary due to server maintenance or upgrade, Compaq recommends that you plan your changes carefully, document all original settings and bindings, and backup the system.

Physical controller modifications made after the initial configuration can adversely affect the original bindings. To make the controller functional again, you must reset the controller and device driver bindings. Network controllers must bind to device drivers to be functional and provide connectivity on a network. System Administrators unaware that new bus number assignments were made after a configuration change might falsely believe that the hardware is broken.

Compaq and Microsoft provide several utilities you can use to reset device driver and controller bindings. As long as the System Administrator knows bus numbers are assigned in a server, the Windows NT registry can be reset with minimal effort. See the section titled “PCI Test Configurations with ProLiant Servers” in this document.

Disk Renumbering

Disk reordering can complicate an administrator’s ability to identify what a particular disk volume contains when the numbers change in Disk Administrator. Howe ver, disk number reordering does not affect the contents of the disk volume.

partition and that loads as Disk 0. Compaq recommends running the Disk Administrator after completing a Windows NT installation to ensure that the boot drive receives a signature properly (Drive C:) and locks the drive letter to the partition.

The Compaq SCSI and Array Disk Controllers have a Windows NT Registry entry used to determine disk controller-loading order. If disk numbers/drive letters become reordered because of a changed drive load order, the operation of the applications on the disk should not be affected. When you create a partition on a disk drive; Windows NT Disk Administrator should be run to permanently lock the drive letter to the partition even if Drive C: is the only disk in the system.

In simple configurations, identifying contents on a particular drive or volume might not be an issue. In more complex configurations consisting of multiple drives and volumes, the order in which the drives/volumes are listed can change when a physical modification is made to the disk configuration. As mentioned earlier, Windows NT Disk Administrator lists drives and volumes in the order they are discovered.

Disk ordering in a simple example:

Order of detection (Before Change) Drive Letter and Label

Disk 0 C: NT OS Disk 1 D: ACCT files

The Windows NT Disk Administrator located under

#Programs#Administrative Tools (Common) contains a graphical

Start tool provided with the operating system to manage disk drives. This tool allows Disk Administrators to display and track disk devices. Windows NT lists drives and volumes in this utility in the order discovered at system startup. Each drive detected during discovery shows in the Disk Administrator with a disk number (starting at 0). The hard drive that boots the system must have one partition designated as the active

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PCI Bus Numbering in a Microsoft Windows NT Environment 13

Add two more drives to the system and the order of detection changes:

Order of detection (After Change) Drive Letter and

Label

Disk 0 C: NT OS

Disk 1 Unknown (not

formatted)

Disk 2 E: ENG files

Active System Partition

New

Disk 3 D: ACCT files

Windows NT orders disk volumes in the order of discovery at boot time. Adding more drives to an already configured system can change the order of detection. Descriptively labeling the disk volumes using the Disk Administrator can eliminate frustration and prevent unnecessary confusion identifying the contents of a disk volume. Labeling the volume ensures that you can easily identify its content.

Hardware, Software, and Configuration Tools

This section identifies the Compaq servers and option hardware used to create test scenarios in the Compaq Windows NT Integration Lab. All tests ran under the Windows NT 4.0 operating system. In addition to the operating system, several Compaq utilities and Windows NT administration tools were used to aid in the testing process. Testing included slot identification, bus number assignments, disk number assignments, and resetting the configuration after a system modification.

Compaq Servers and Option Hardware

This section provides a brief description of the servers and option hardware used to test PCI bus numbering and slot configurations for this document.

Disk order changed

Compaq Servers

This white paper details the PCI bus numbering scheme of five Compaq ProLiant server models. Note: The features discussed in this section should not be considered a complete description for

any of the server or option hardware. Refer to the specification for each product to learn more about the complete feature set. This information is available on the Compaq website at

http://www.compaq.com/products/servers

The ProLiant ML350 contains the dual-peer PCI bus architecture. Two other servers, the ProLiant DL380 and the ProLiant 530, have a highly parallel architecture, whereas, the ProLiant 8000 has a triple-peer PCI bus architecture as documented in Configuration B.

The ProLiant ML530 results are described in Configuration A, and the ProLiant ML350 server’s PCI bus numbering results are detailed in Configuration C.

The “PCI Bus Number Order of Detection Matrix” provided in this document lists the PCI BIOS discovery process for all servers mentioned up to this point.

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PCI Bus Numbering in a Microsoft Windows NT Environment 14

ProLiant 8000

The ProLiant 8000 has 11 PCI slots: ten 64-Bit slots and one 32-Bit PCI slot (see Figure 4).

Figure 4. Slot view of the ProLiant 8000

Primary Bus: Slot 1 is the first PCI slot

detected in this server configuration. Bus numbering starts here and continues to slots 2, 3, and 4.

Secondary Bus: Bus numbering continues

down to slots 5, 6, 7, 8, and 9.

Tertiary Bus: Then, bus numbering

completes after reaching slots 10 and 11.

ProLiant ML530

ProLiant ML530 contains a highly parallel bus and has 8 PCI slots: two 64-Bit 66MHz slots, five 64-Bit 33MHz slots, and one 32-Bit 33MHz slot (see Figure 5).

Figure 5. Slot view of the ProLiant ML530

Primary Bus: Slot 1 comprises the

Primary Bus. Secondary Bus: Bus numbering continues

down level to slots 7 and

8. Tertiary Bus: Bus numbering continues

down level to slots 6, 4, 3, and 2, completing after assigning a bus number to slot 5.

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PCI Bus Numbering in a Microsoft Windows NT Environment 15

ProLiant ML350

ProLiant ML350 is a dual-peer bus and has 7 PCI slots: two 64-Bit 3V slots, four 32-Bit slots, and one Non-Shared ISA slot (see Figure 6).

Primary Bus: Bus numbering begins

on slot 1 and continues to slots 4, 5, and 6.

Secondary Bus: Slots 2 and 3 comprise

the Secondary Bus and complete the bus numbering in this server configuration.

Figure 6. Slot view of the ProLiant ML350

ProLiant DL580

ProLiant DL580 is a triple-peer bus and is comprised of 6 PCI slots: two 64-Bit/66MHz slots, three 64-Bit/33MHz slots, and one 32-Bit/33MHz slot (see Figure 7).

Figure 7. Slot view of ProLiant DL580

Primary Bus: The Primary Bus

completes bus numbering after assignment to 6.

Secondary Bus: Bus numbering begins

with slot 1 and continues to 2 and 3.

Tertiary Bus: Bus numbering begins

with slot 4 and completes with slot 5.

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PCI Bus Numbering in a Microsoft Windows NT Environment 16

ProLiant DL380

ProLiant DL380 contains a highly parallel bus and has 4 PCI slots: three 64-Bit slots and one 32Bit slot (see Figure 8).

Primary Bus: Slot 1 is the only slot on

the Primary Bus. Secondary Bus: Slots 2, 3, and 4 complete

bus numbering on this server configuration.

Figure 8. Slot view of the ProLiant DL380

Option Hardware

The following listing in Table 5 identifies the types of Compaq controllers that are categorized as either PCI bridged or non-bridged.

Table 5. PCI bridged and no-bridged controllers

PCI Bridged Controllers Non-Bridged Controllers

Compaq Smart Array Controllers

RAID LC2 Controller Smart Array 5300 Controller Smart Array 221 Controller Smart Array 4200 Controller Smart Array 431 Controller Smart Array 3100ES Controller Smart Array 3200 Controller Smart Array 4250ES Controller -

Compaq SMART-2 Array Controllers

SMART-2SL Array Controller SMART-2 Array Controller SMART-2DH Array Controller -

Compaq SCSI Controllers

- Dual Channel Wide Ultra SCSI-2 Controller

- Dual Channel Wide-Ultra SCSI-3 Controller

- Wide-Ultra SCSI-3 Controller

continued

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