To configure a SCSI channel, you must verify the type of SCSI protocol required (differential and data transfer rate), identify each component in the SCSI channel, and obtain any missing components.
Because the system controller negotiates independently with the devices on a bus to establish the acceptable transfer rate of each device, you can mix fast and slow devices on the same bus. However, mixing narrow Fast-20 and wide Fast-20 devices on the same single-ended SCSI bus is not recommended.
These guidelines reflect the dependencies among SCSI bus bandwidths, types, and data transfer rates. Follow these guidelines to help to minimize inconsistent or inoperable SCSI buses:
Include all cable length inside devices, components, and chassis in calculating SCSI bus length.
Install wide and narrow SCSI devices on different buses for maximum performance.
Always use a terminator at the end of a bus.
The speed of the devices in the daisy chain is determined by the speed of the active device. If a slow device is active, the bus runs at a slow speed; if a high-speed device is active, the bus runs at a high speed.
After installing the Ultra SCSI XIO option board in the OCTANE workstation, use the information in this chapter for cabling and configuration information.
Before you can connect cables, you need to map the logical port numbers to the physical port locations. Follow these instructions:
Choose Toolchest > Desktop, and open a UNIX® shell.
Read all of this section, “Mapping the Logical Port Numbers to the Physical Port Locations,” before beginning your mapping task.
You see a listing similar to the example in Table 3-1.
Table 3-1. Identification of Information in ioconfig.conf File
Logical
Controller
NumberHard-
wareNode
XIO (xtalk) Bus Type
Physical ID
PCI Bus Type
Bus ID
Port Type (Abbreviation)
Serial Port ID or SCSI ID
2
/hw
/node
/xtalk
/10
/pci
/0
/ef
3
/hw
/node
/xtalk
/10
/pci
/1
/ef
4
/hw
/node
/xtalk
/10
/pci
/2
/ef
5
/hw
/node
/xtalk
/10
/pci
/3
/ef
3
/hw
/node
/xtalk
/10
/pci
/4
/tty
/1
4
/hw
/node
/xtalk
/10
/pci
/4
/tty
/2
5
/hw
/node
/xtalk
/10
/pci
/5
/tty
/1
6
/hw
/node
/xtalk
/10
/pci
/5
/tty
/2
7
/hw
/node
/xtalk
/10
/pci
/6
/tty
/1
8
/hw
/node
/xtalk
/10
/pci
/6
/tty
/2
2
/hw
/node
/xtalk
/9
/pci
0
/scsi_ctlr
/0
3
/hw
/node
/xtalk
/9
/pci
1
/scsi_ctlr
/0
4
/hw
/node
/xtalk
/9
/pci
2
/scsi_ctlr
/0
5
/hw
/node
/xtalk
/9
/pci
3
/scsi_ctlr
/0
The Logical Controller Number refers to the number assigned to a port on an optional board by the operating system. These numbers will always be higher than that of a port on the System Module. Ports of the same type are assigned incrementing port numbers. For example, because there is one Ethernet port on the System module, the logical number assigned to the first optional Ethernet port the software sees is 2. Because there are two serial ports on the System Module, the first logical number assigned to an optional serial port is 3. Subsequent optional serial ports are labeled, 4, 5, 6, and so on.
Ignore the Hardware, Node, and Communication Type columns when looking for information in Table 3-1. They appear in the ioconfig.conf file to report that hardware is being probed, on one node, using crosstalk as the communication tool within the workstation.
Use Figure 3-1 to determine the physical XIO ID number. If the board is in the XIO module, determine the physical ID number by the following rule: XIO module, quadrant A = 12, quadrant B = 11, quadrant D = 10, and quadrant C = 9.
 | Note: Physical port numbers are assigned in descending XIO probing order. Example: an Ethernet board in the PCI module (13) will be assigned logical port 2 before an Ethernet port in quadrant C (9) of the XIO module because 13 is probed before 9. |
This column is read only in conjunction with the Physical ID column that comes before it. (See Table 3-3.) If the Physical ID number is 13, this means that the board is in the PCI module.
The Bus ID column refers to the number of the physical port on the option board.
Table 3-2. Example of an ioconfig.conf File
Logical | Hard | Node | XIO (xtalk) Bus Type | Physical ID | PCI Bus Type | Bus ID | Port Type (Abbreviation) | Serial port ID |
|---|---|---|---|---|---|---|---|---|
1 | /hw | /node | /xtalk | /13 | /pci | /3 | /ef |
|
4 | /hw | /node | /xtalk | /10 | /pci | /2 | /ef |
|
3 | /hw | /node | /xtalk | /10 | /pci | /4 | /tty | /1 |
2 | /hw | /node | /xtalk | /9 | /pci | 0 | /scsi_ctlr | /0 |
3 | /hw | /node | /xtalk | /9 | /pci | 1 | /scsi_ctlr | /0 |
4 | /hw | /node | /xtalk | /9 | /pci | 2 | /scsi_ctlr | /0 |
5 | /hw | /node | /xtalk | /9 | /pci | 3 | /scsi_ctlr | /0 |
In Table 3-2, Logical controller number 3 (XIO module quadrant C, Physical ID 9), is an option board (with multiple SCSI ports) specifying port number 0, labeled on the option board as port 0. The abbreviation in the Port Type column identifies this port as a SCSI (scsi_ctlr) port.
The ioconfig.conf file records and saves option board and port information after the board is installed in the OCTANE workstation. However, the file reserves the board and port spaces if the option board is removed, and begins assigning new ID numbers when a new board is inserted. For example, if a board was in quadrant B (11) and was removed, and another Ultra SCSI board was placed in quadrant C (9), the file would begin numbering for the new board beginning with the next number after the last used for the previous board in quadrant B (11). This reporting pattern is desirable under some circumstances.
However, if you wish to have a listing of only what is currently installed, remove the ioconfig.conf file, and restart your system. The file is rebuilt with information about the current hardware configuration reflecting what is currently installed.
Determine your Logical Slot ID number.
Use the Logical slot number to determine the port number on the option board.
Use the abbreviation to help you determine the type of port.
Find the Logical controller number (x) for the port you have located (listed in the first column).
For instructions on installing cables, go to “Installing the Ultra SCSI Cables.”
Before installing the cables, read the previous sections beginning with “Mapping the Logical Port Numbers to the Physical Port Locations”. Then return here.
Open another UNIX shell, and at the prompt type hinv
Use the Hardware Inventory file to find the port you are interested in. Look for the Integral (SCSI) Controller number (x) that matches the Logical Controller number in the ioconfig.conf file (first column.)
Under the Integral (SCSI) Controller information, find the port you want.
Two Y cables included in the Ultra SCSI XIO board shipment connect the two double ports on the board to as many as four SCSI channels.
Connect the single end of the Y connector to the Ultra SCSI board connector, making sure the wide and narrow keys align.
The wide key is close to and is on the same side of the single cable connector as the B and A label. See Figure 3-2.
The high-density double cable connectors are labeled A and B on the narrow-keyed side of the cable connector.
A corresponds to channel 0 or channel 2
B corresponds to channel 1 or channel 3
Note: The connectors on the Ultra SCSI board are designed so that only the Y cables can be used with these connectors. 
Caution: The cables can be forced to attach incorrectly. The cables are keyed with a wide and narrow side on both the cable connector and Ultra SCSI board connectors. The Ultra SCSI bus times-out during system start-up if a cable is in backwards. Connect the A and B ends of the Y cable to SCSI cables that attach to a SCSI device.
Note: You connect the Y cable to another cable, not to the SCSI device.
After you have installed the Ultra SCSI option board in the OCTANE workstation, follow these instructions for assigning a SCSI address to an external device.
You must shut down your system to install an external device, but before doing so you must assign an address to the device.
Example: SCSI bus addresses appear as two numbers. The first number is the bus number, the second is the number of the device. The second number is the number the user sets. For example: 1, 5 is bus 1, and device number 5.
If you currently do not have any external devices attached to your system, you can assign any number between 1 and 15 (for wide SCSI devices) or 1 and 7 (for narrow devices) to the new device. Do not use address 0, as this is the default system SCSI ID.
If you have at least one external device attached to your system and you are adding another device, you must check which addresses are assigned to the existing external devices and then choose a number between 1 and 15 (for wide SCSI devices) or between 1 and 7 (for narrow SCSI devices) that has not already been assigned.
Note: Although the OCTANE workstation allows up to 15 addresses for SCSI devices, the devices themselves may have dials that allow you to set a number only between 1 and 9.
To check available addresses for external devices, follow these steps:
If the OCTANE workstation is powered off, turn on the system power.
Open the door on the front of the OCTANE workstation.
Press and release the power button to power on the system.
Log in to your account. For more information on logging in, refer to the OCTANE Workstation Owner's Guide.
When the system comes up, choose Toolchest > System > System Manager > Hardware and Devices, About This System.
You see a listing of your system's hardware devices and their address numbers.
Power off the OCTANE workstation and the device.
Choose a number between 1 and 15 (for a wide SCSI device) or between 1 and 7 (for a narrow SCSI device) that is not assigned to your current devices.
Set the number on the device.
Power on the device.
Power on the OCTANE workstation. (Be sure to power on the OCTANE workstation after you power on the device so that the device is recognized.)
To determine assigned SCSI addresses, choose Toolchest > System > System Manager > Hardware and Devices > About This System.
To access information about SCSI devices, open a UNIX shell, and at the prompt enter hinv or scsiha
Also see other reference material such as the IRIX Admin guides or man pages for scsiha or ioconfig