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Using Device Path Names to Identify System Devices
Eliminate the Guesswork
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Managing hardware devices such as I/O boards and disks can be challenging,
especially for Sun Microsystems products with many devices attached.
Using industry-standard OpenBoot firmware, you can determine the
hardware configuration of your system. With this information, you can perform
hardware administration tasks, such as replacing disks and controller boards.
This tutorial helps to eliminate the guesswork by showing how you can
interpret the full device path name to establish the location of a particular
device on your system.
| Note -
To familiarize yourself with OpenBoot terminology and concepts used in this article,
consult the OpenBoot 3.x Command Reference Manual in the OpenBoot
Collection on docs.sun.com.
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Use this table to locate subjects in this tutorial:
You can determine the hardware configuration of your Sun Microsystems server or workstation
by inspecting the OpenBoot device tree (a hierarchy of
interconnected buses and their attached devices). To identify the card and slot
configuration using this method, you must map driver names, unit addresses,
and device arguments to the physical devices and their locations on the system.
Each hardware device on the system has a full device path name -- a
unique name representing the device and where that device is located in the
system addressing structure. The full device path name (hereafter referred
to simply as the device path) is a series of
node names separated by slashes (/):
/sbus@1f,0/SUNW,fas@e,8800000/sd@3,0:a
To quickly establish your hardware configuration (for example,
the slot location of a SCSI I/O controller card), you can use the device path
along with the look-up tables provided here.
You can examine the device path in a number of ways:
- /devices directory
This directory contains the physical device names for devices attached to the system
- OpenBoot ok prompt
- prtconf -vp command
Also, the device path may logged by the syslogd daemon when
it is associated with a device error. These messages appear in the system
console, and they are also written to the messages logs in the /var/adm
directory.
We'll use the following device path to identify the slot location of a card for
a Sun Microsystems Ultra Enterprise 3000:
/sbus@3,0/SUNW,fas@3,0/sd@0,0
In this example,
- sbus@3,0 represents the I/O board in slot 1 located on the back of
the system. We establish this designation by consulting table 1,
which describes the board slot and SBus slot assignments and their locations
(front or back of the system).
- SUNW,fas@3,0 is the onboard fast/wide SCSI controller of this same board.
This designation is determined using table 2, which describes onboard
controllers, the I/O board (SYSIO ASIC A or SYSIO ASIC B) to which they belong, and their locations
(front or back of the system). Table 3
provides common device driver names and their descriptions.
- sd@0,0 is the SCSI disk (sd) set to target id 0
(in this case, it is an internal disk, since only internal disks should be controlled
by the onboard SCSI controller of the I/O board in slot 1).
Table 1: Board Slot-SBus Slot Assignments -- Sun
Microsystems Ultra Enterprise 3x00-6x00 Servers
| Front |
Back |
| board slot |
sbus@ |
sbus@ |
sbus@ |
sbus@ |
board slot |
| 0 |
0 |
1 |
2 |
3 |
1 |
| 2 |
4 |
5 |
6 |
7 |
3 |
| 4 |
8 |
9 |
A |
B |
5 |
| 6 |
C |
D |
E |
F |
7 |
| 8 |
10 |
11 |
12 |
13 |
9 |
| 10 |
14 |
15 |
16 |
17 |
11 |
| 12 |
18 |
19 |
1A |
1B |
13 |
| 14 |
1C |
1D |
1E |
1F |
15 |
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Remarks: The Sun Microsystems Ultra Enterprise 3x00 has board slots in the back of system only
(the internal disks are located on the front). The Sun Microsystems Ultra Enterprise 4x00, 5x00, and 6x00
have board slots in the front and back of the system.
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Sun Microsystems Ultra Enterprise I/O boards are split in two halves - SYSIO ASIC A and SYSIO ASIC
B.
Table 2 identifies on-board
controllers and slots and the SYSIO ASIC board to which they belong:
Table 2:
Onboard Slot Assignments -- Sun Microsystems Ultra Enterprise 3x00-6x00 Servers
| Front |
Back |
| Sys I/O A |
Sys I/O B |
Sys I/O A |
Sys I/O B |
| soc@d |
fas@3 |
soc@d |
fas@3 |
| socal@d |
hme@3 |
socal@d |
hme@3 |
| sbus@1 |
sbus@0 |
sbus@1 |
sbus@0 |
| sbus@2 |
|
sbus@2 |
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Table 3: Common Sun Microsystems Device Driver Names
Device
Driver |
Description |
| fas |
fast/wide SCSI controller |
| hme |
fast (10/100 Mb/sec) Ethernet |
| isp |
differential SCSI controllers and the SunSwift card |
| glm |
UltraSCSI controllers |
| scsi |
Small Computer Serial Interface (SCSI) devices |
| sf |
soc+ or socal Fiber Channel Arbitrated Loop (FCAL) |
| soc |
SPARC Storage Array (SSA) controllers |
socal |
serial optical controllers for FCAL (soc+) |
Let's try another example. Consider the following:
/sbus@6,0/SUNW,socal@d,0/sf@0,0/ssd@2200002136bcd49,0 (ssd27)
In this example:
- sbus@6 represents the I/O board in slot 3 of a Sun Microsystems Ultra Enterprise server
(table 1)
- socal@d is the onboard serial optical controller
(table 2 and table 3)
- sf@0 is the GBIC port on the right (table 3)
- ssd@2200002136bcd49,0 (ssd27) is a disk in a Sun Microsystems StorEdge
A5x00 disk array.
The long number after the @ sign is the worldwide (unique) number of this particular disk.
| Note -
sf@0 is the GBIC port on the right and sf@1 is the GBIC port
on the left for a soc+ (socal) I/O board.
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This simple example shows the location of a SCSI tape drive:
/sbus@5,0/scsi@2,0/st@5,0
In this example:
- sbus@5 is the I/O board in slot 2 located in the front of the system
(table 1)
- scsi@2,0 is a SCSI controller card in slot 2 on the I/O board
(table 3)
- st@5 is a SCSI tape (st) drive at target id 5 attached to the controller
Identifying the Location of PCI Cards
Using the device path and simple math, you can determine the location of a
PCI card installed on a PCI I/O board on a Sun Microsystems Ultra Enterprise 3x00-6x00 server.
Consider the following example:
/pci@x,4000/scsi@2
In this example, x is the portion of the node address that is the
key to establishing the location of the PCI card.
First, divide x by 2. The whole number quotient indicates the slot location of the PCI
board in the Sun Microsystems Ultra Enterprise server. If there is a remainder of 0, the PCI card is located in the PCI 0
slot of the I/O board. If the remainder is 1, it is located in the PCI 1 slot of the I/O
board.
Table 3 shows the most common driver names that appear
in a device path. Use this table to identify different cards that may be installed.
Other useful information:
- /pci@x,4000/SUNW,isptwo@3 is the device path representing the onboard
UltraSCSI port on a PCI I/O board. This port is controlled by the PCI 1 Psycho chip
on the board.
- /pci@x,4000/SUNW,hme@1,1 is the device path representing the onboard
fast ethernet port on a PCI I/O board. This port is controlled by the PCI 0 Psycho chip
on the board.
| Note -
This information is correct as of OBP version 3.2.14 and above.
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Consider the following example:
/pci@6,4000/scsi@2
According to table 4, this device path represents
the card occupying slot 3:
Table 4:
Sun Microsystems Ultra Enterprise 450 PCI Slot Assignments
| Full Device Path Name |
PCI Slot/Device |
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/pci@1f,4000/device@4
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10
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/pci@4,4000/device@2
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9
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/pci@4,4000/device@3 |
8 |
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/pci@4,4000/device@4 |
7 |
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/pci@4,2000/device@1 |
6 |
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/pci@1f,2000/device@1
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5 |
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/pci@6,2000/device@1
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4 |
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/pci@6,4000/device@2
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3
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/pci@6,4000/device@3
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2 |
| /pci@6,4000/device@4
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1 |
| /pci@1f,4000/scsi@2/sd@6,0
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Internal CD-ROM |
| /pci@1f,4000/scsi@2/device
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External SCSI port |
Remarks:
- The device path /pci@1f,4000/scsi@3 may be reported.
This device path references the disk controller
built onto the system board that controls the first four internal disk slots in a
Sun Microsystems Ultra Enterprise 450 (bottom four slots).
- The device path /pci@1f,4000/scsi@2
may be reported. This device path references the controller built onto the
system board for the internal CD-ROM and/or tape drive, as well as the onboard SCSI
port on the system board.
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In this table, device is the device driver name of the card
occupying the slot (for example, scsi). Depending on the type of card,
other device driver names may be displayed
(see table 3).
Understanding Shared Device Paths
In some cases, two device paths are displayed for a single card.
For example, a system can be configured with a dual PCI SCSI card
occupying one or more slots. Since this card has two SCSI controllers,
it uses two device paths. Consider the following:
/pci@4,2000/scsi@1
/pci@4,2000/scsi@1,1
In this example:
- Both device paths refer to the same dual SCSI controller card
occupying slot 6 of a Sun Microsystems Ultra Enterprise 450 server.
- scsi@1 is the first controller
- scsi@1,1 is the second controller
Identifying the PCI Slot Speed
To identify the speed of a Sun Microsystems Ultra Enterprise 450 PCI slot,
you can also use the full device path. For example, Any full device path containing the node
pci@x,2000 indicates a 66 MHz slot (three total).
Any full device path containing the node pci@x,4000
indicates a 33 MHz slot (seven total).
| Tip -
Please see infodoc 16735 on SunSolve
for information on how to set the disk-led-assoc
variable (authorization required). Using this variable, you can easily identify the slot location of
an internal disk using the full device path.
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For your convenience, we have summarized the device paths that
refer to PCI slots or devices for popular Sun Microsystems workstations
and midrange servers.
Table 3
provides common device driver names and their descriptions.
Sun Microsystems Ultra 5
| PCI Slot/Device |
Device Path |
| PCI Slot #1 |
/pci@1f,0/pci@1/device@1 |
| PCI Slot #2 |
/pci@1f,0/pci@1/device@2 |
| PCI Slot #3 |
/pci@1f,0/pci@1/device@3 |
| Internal Disk |
/pci@1f,0/pci@1,1/ide@3/dad@0,0 |
| Internal CD-ROM |
/pci@1f,0/pci@1,1/ide@3/atapicd@2,0 |
Sun Microsystems Ultra 10
| PCI Slot/Device |
Device Path |
| PCI Slot #1 |
/pci@1f,0/pci@1/pci@1/device |
| PCI Slot #2 |
/pci@1f,0/pci@1/pci@2/device |
| PCI Slot #3 |
/pci@1f,0/pci@1/pci@3/device |
| PCI Slot #4 |
/pci@1f,0/pci@1/pci@4/device |
| Internal Disk |
/pci@1f,0/pci@1,1/ide@3/dad@0,0 |
| Internal CD-ROM |
/pci@1f,0/pci@1,1/ide@3/atapicd@2,0 |
Sun Microsystems Ultra 30
| PCI Slot/Device |
Device Path |
| PCI Slot #1 |
/pci@1f,2000/device@1 |
| PCI Slot #2 |
/pci@1f,4000/device@2 |
| PCI Slot #3 |
/pci@1f,4000/device@4 |
| PCI Slot #4 |
/pci@1f,4000/device@5 |
| Internal Disk |
/pci@1f,4000/scsi@3/sd@0,0 |
| Internal CD-ROM |
/pci@1f,4000/scsi@3/sd@6,0 |
| External SCSI Port |
/pci@1f,4000/scsi@3/device |
Sun Microsystems Ultra 60
| PCI Slot/Device |
Device Path |
| PCI Slot #1 |
/pci@1f,2000/device@1 |
| PCI Slot #2 |
/pci@1f,4000/device@2 |
| PCI Slot #3 |
/pci@1f,4000/device@4 |
| PCI Slot #4 |
/pci@1f,4000/device@5 |
| Internal Disk |
/pci@1f,4000/scsi@3/sd@0,0 |
| Internal CD-ROM |
/pci@1f,4000/scsi@3/sd@6,0 |
| External SCSI Port |
/pci@1f,4000/scsi@3,1/device |
Midrange Servers
Sun Microsystems Ultra Enterprise 250
| PCI Slot/Device |
Device Path |
| PCI Slot #0 |
/pci@1f,4000/device@5 |
| PCI Slot #1 |
/pci@1f,4000/device@4 |
| PCI Slot #2 |
/pci@1f,4000/device@2 |
| PCI Slot #3 |
/pci@1f,2000/device@1 |
| Internal Disk Slot #0 |
/pci@1f,4000/scsi@3/sd@0 |
| Internal Disk Slot #1 |
/pci@1f,4000/scsi@3/sd@8 |
| Internal Disk Slot #2 |
/pci@1f,4000/scsi@3/sd@9 |
| Internal Disk Slot #3 |
/pci@1f,4000/scsi@3/sd@a |
| Internal Disk Slot #4 |
/pci@1f,4000/scsi@3/sd@b |
| Internal Disk Slot #5 |
/pci@1f,4000/scsi@3/sd@c |
| Internal CD-ROM |
/pci@1f,4000/scsi@3/sd@6,0 |
| External SCSI Port |
/pci@1f,4000/scsi@3,1/device |
Sun Microsystems Ultra Enterprise 450
See table 4.
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