Appendix D. Challenge IO4 PROM, Mezzanine, and Troubleshooting

This appendix supplies information about the Challenge IO4 PROM (programmable read-only memory) Command Monitor. This information is separated into hardware configuration commands, environment variables, and known bugs. Basic mezzanine board configurations on the IO4 and troubleshooting tips are also covered.

Hardware Configuration Commands

The IO4 PROM allows you to examine and modify the hardware configuration of your system using a variety of commands.

Checking and Updating the Hardware Inventory

When the system first powers on, the IO4 PROM automatically examines all of the installed boards to determine if any of the components have failed. During this process, the IO4 PROM reads a copy of the system's hardware inventory from nonvolatile RAM and compares it to the system's current configuration. If there are differences between the current and stored hardware inventories, the IO4 PROM inventory checker will generate a warning message. When a difference is detected during this comparison of the hardware inventory, the PROM pauses to allow you to examine the error messages. In the following example, the PROM detected a missing processor on a CPU board:

Checking inventory...
*** Slice 1 on the IP19 in slot 2 isn't visible
Press <Enter> to continue

If system uptime is critical (for example, if your system is the central server) and operators are not available around the clock, you may not want the PROM to wait for operator intervention when the inventory checker notices a problem. You can configure the system so that it continues to boot in spite of nonterminal failures by setting the nonstop environment variable (see the “Environment Variables” section that follows).

Because the PROM's hardware inventory checker cannot detect the difference between missing and broken hardware, you must explicitly update the system's hardware inventory whenever you change the system configuration. Update the hardware inventory as follows:

  1. Enter the PROM Command Monitor by selecting the “Enter Command Monitor” option from the PROM menu.

  2. When the PROM Command Monitor prompt (>>) is displayed, type update and press <Enter>. This tells the PROM that the system's current hardware configuration is correct.

  3. Type reset and press <Enter> to reset your machine.

If you see error messages when there have been no modifications to the system's hardware inventory, you may be experiencing a component failure. Call your service provider and do not update the hardware inventory until a field engineer has examined the system.

Displaying Information About the Current Hardware Configuration

Display a list of the boards currently installed in your system by typing hinv -b. The “-b” causes bus-specific information to be displayed. The “-v” (verbose) option, when used in conjunction with “-b” causes more detailed information about the boards to be displayed. For example, typing

hinv -b -v <Enter>

displays the configuration of all of the processors, memory banks, and I/O adapters in the system.

POD (Power-On Diagnostics) Mode

In the unlikely event of an extreme hardware failure, the system may drop down into a low-level diagnostic environment known as POD mode. This mode is used as an aid to system diagnosis and is not intended for use by customers. If your system enters POD mode, contact your service provider.

Environment Variables

This section describes procedures that you can use to customize certain aspects of the PROM Command Monitor. Many aspects of the system startup process can be individually tailored by changing the PROM environment variables. These variables are changed using the setenv command while in the Command Monitor. Enter the Command Monitor by first selecting the “Stop for System Maintenance” option during the system startup. When the System Maintenance menu is displayed, enter the Command Monitor by typing 5.

Some common modifications are described in the following subsections. Additional information is provided in the prom(1M) reference (man) page.

Booting From an Alternate Device

There are three environment variables in the PROM that are used to specify which device to boot from: the “SystemPartition,” the “OSLoadPartition,” and the “root” variable.

The “SystemPartition” variable specifies the location of the device volume header. Its default value is “dksc (0,1,8),” which specifies SCSI controller 0, disk 1, and partition 8 (by convention, the volume header is always
partition 8).

The “OSLoadPartition” variable specifies the device from which the IRIX kernel should be loaded. Its default value is “dksc (0,1,0),” which tells the PROM to look for the kernel on SCSI controller 0, disk 1, on partition 0 (by convention, the kernel location is always partition 0).

The root variable tells IRIX the name of the device that holds the root filesystem. Because this variable is used by IRIX, rather than by the PROM, its format is different from the “SystemPartition” and “OSLoadPartition” variables. The default value for root is “dks0d1s0,” which specifies that the root filesystem is stored on SCSI controller 0, disk 1, on partition 0.

The following three examples show you what the command line looks like when you change the boot device.

To boot from disk number 2 on controller 0, enter the following:

setenv SystemPartition dksc (0,2,8)
setenv OSLoadPartition dksc (0,2,0)
setenv root dks0d2s0

To boot from disk number 1 on controller 1, enter the following:

setenv SystemPartition dksc (1,1,8)
setenv OSLoadPartition dksc (1,1,0)
setenv root dks1d1s0

To boot from disk number 3 on controller 2, enter the following:

setenv SystemPartition dksc (2,3,8)
setenv OSLoadPartition dksc (2,3,0)
setenv root dks2d3s0

Starting the System Automatically

Each time the system is powered on, the PROM pauses briefly before starting the operating system. If the “Stop for System Maintenance” option is not selected, or if the <Esc> key is not pressed, the system loads the operating system from memory and begins to execute it. Setting the environment variable autoload to “yes” enables this feature. Setting autoload to “no” inhibits the automatic startup and causes the PROM to display the System Maintenance menu after running the power-on diagnostics.

Allowing the System to Boot in Spite of Nonterminal Hardware Failures

By default, the PROM stops and generates a warning message if it finds that a component has failed. However, the failure of a single processor or bank of memory may not be serious enough to prevent the system from coming up. To prevent a nonfatal hardware problem from stopping the system, set the nonstop variable to 1:

setenv nonstop 1

To ensure that the system displays a notification message in the event of any hardware failure, set the nonstop variable to 0:

setenv nonstop 0

Restoring Defaults

The PROM environment variables can be reset to their factory defaults by using the resetenv command while in the PROM Command Monitor. Since resetenv also resets the netaddr environment variable, note the machine's IP address before using this command.

Known Bugs

The following subsections describe all of the known IO4 PROM bugs. Since the IO4 PROM is software-writable, these bugs will be fixed by PROM updates in future releases of the operating system.

A Spurious CD-ROM Medium Is Displayed During Startup

A bug in the CD-ROM volume size code causes the SCSI driver to display an erroneous “No Medium Found” message if the CD-ROM caddy is empty when the system is booted. This message can be ignored.

Disk Formatting Fails Using Standalone fx

Systems running IRIX release 5.2 or earlier have a PROM problem that causes failure to format in the standalone version of fx. The PROM's SCSI driver improperly calculates the duration of timeout requests and the PROM times out prematurely. This terminates the formatting process before completion and leaves the disk in a corrupt state. In this case, attempts to read or write the disk will fail.

Always use the IRIX version of fx when formatting disks if the system is running operating system release 5.2 or earlier.

If the disk has been corrupted by use of the standalone fx process, it can be repaired by reformatting using the IRIX version of fx.

Mezzanine Board Configurations

Each Challenge deskside system comes with one standard IO4 interface board. See Chapterá1 for a technical overview of the IO4. The first IO4 in the system always supports either the VME Channel Adapter Module (VCAM) board or the Graphics Channel Adapter Module (GCAM) board.

If you are unsure of the system's hardware configuration, enter the hinv command at the console. You should see something similar to the following:

% hinv <Enter>

2 75 MHZ IP21 Processors
CPU: MIPS R8000 Processor Chip Revision: 2.1 
FPU: MIPS R8010 Floating Point Chip Revision: 0.1 
Data cache size: 16 Kbytes
Instruction cache size: 16 Kbytes
Secondary unified instruction/data cache size: 4 Mbytes
Main memory size: 256 Mbytes, 2-way interleaved
I/O board, Ebus slot 5: IO4 revision 1
Integral EPC serial ports: 4
Integral Ethernet controller: et0, Ebus slot 3
Integral SCSI controller 2: Version WD33C95A
Tape drive: unit 6 on SCSI controller 2: DLT 
Integral SCSI controller 1: Version WD33C95A
Disk drive: unit 1 on SCSI controller 1
Graphics board: GU1-Extreme 
CC synchronization join counter
Integral SCSI controller 0: Version WD33C95A
Disk drive: unit 4 on SCSI controller 0
Disk drive: unit 3 on SCSI controller 0
Disk drive: unit 2 on SCSI controller 0
Disk drive: unit 1 on SCSI controller 0
VME bus: adapter 0 mapped to adapter 3
VME bus: adapter 3
Integral IO4 parallel port: Ebus slot 5

Note: The GCAM board is used only on POWER Challenge systems that have the visualization console (Extreme) option installed.

Each system is slightly different, but all systems have at least one IO4 installed. The number of IO4s installed in your system determines the number of HIO mezzanine option boards it can support. It also determines the type of mezzanine options you can order. The VCAM or GCAM on the first IO4 precludes you from using “long” mezzanine boards. Long mezzanine boards stretch nearly to the backplane and do not fit on the IO4 when a VCAM or GCAM is installed. TableáD-1 describes some of the HIO mezzanine option boards and their lengths.

Table D-1. Optional Mezzanine Board Descriptions

Board Name


Number of Connectors

Flat Cable Interface



Flat Cable Interface



Three-Channel SCSI



Mezzanine Options Available With One IO4

FigureáD-1 shows the two possible configurations of the Challenge equipped with a single IO4. In the standard server configuration, the IO4 uses a VCAM and the IO4 may use up to two optional short mezzanine boards. With the POWER Challenge visualization console option and graphics, use of the GCAM allows only one optional short mezzanine board.

Figure D-1. IO4 With VCAM and GCAM

Mezzanine Options Available With Two IO4s

You can always have one or two short optional mezzanine boards installed on the primary IO4. This is determined by whether you have the visualization console option installed in your POWER Challenge system. When you order a second optional IO4 you can choose the option of having one of the following mezzanine configurations installed:

  • up to two long mezzanine option boards

  • up to two short mezzanine option boards

  • one long and one short mezzanine option board

FigureáD-2 shows the optional second IO4 and the potential configurations for additional optional mezzanine boards that might be installed.

Figure D-2. Mezzanine Types Available With Optional Second IO4

Mezzanine Options Available With Three IO4s

You can have one or two short optional mezzanine boards installed on the primary IO4. When you order a third optional IO4 you can choose the option of having one of the following mezzanine configurations installed:

  • up to two long mezzanine option boards

  • up to two short mezzanine option boards

  • one long and one short mezzanine option board

FigureáD-3 shows both optional IO4s and the potential configurations for additional optional mezzanine boards that might be installed.

Figure D-3. Optional Second and Third IO4 Configuration

IO4 Troubleshooting

There are a number of troubleshooting steps you can use to identify if the IO4 is the cause of system level faults. Always check for loose connections or damaged cables when trouble with IO4 peripherals occurs.

Never plug the Ethernet connector in while the system is powered on. This action may result in a current surge that blows a fuse on the I/O adapter or IO4. Symptoms resulting from this problem include:

  • Ethernet not working

  • keyboard and mouse not working

  • powered peripheral ports not working

This problem requires a visit from a trained field service engineer.

There is no mechanical connection available for the RS-422 connector on an optional second or third IO4.

Ethernet and RS-232 connectors connected to additional optional IO4 boards may need to be initialized to work properly after installation. See “Enabling Additional Serial Ports” in Chapterá2 for an example of how this is done.

Additional parallel printer ports on optional IO4s may also need to be initialized before they will work properly. For information on this topic see “Parallel Printer Ports” in Chapterá2.