| OpenBoot 4.x Command Reference Manual |
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| OpenBoot 4.x Command Reference Manual |
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| A P P E N D I X C |
Troubleshooting Guide |
What do you do if your system fails to boot properly? This appendix discusses some common failures and ways to alleviate them.
Familiarize yourself with the system power-on initialization messages. You can then identify problems more accurately because these messages show you the types of functions the system performs at various stages of system startup. They also show the transfer of control from POST to OpenBoot to the Booter to the kernel.
The example that follows shows the OpenBoot initialization sequence in a Sun Ultra TM 1 system. The messages before the banner appear on TTYA only if the diag-switch? parameter is true.
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Note - The actual OpenBoot initialization sequence is system dependent. The messages on your system may be different. |
Some OpenBoot systems provide the capability of commanding OpenBoot by means of depressing a combination of keys on the system's keyboard (i.e. a "keyboard chord").
When issuing any of these commands, press the keys immediately after turning on the power to your system, and hold the keys down for a few seconds until the keyboard LEDs flash.
The following paragraphs describe how to perform the functions of the Stop commands on systems that have USB keyboards.
Stop-A (Abort) works the same as it does on systems with standard keyboards, except that it does not work during the first few seconds after the system is reset.
1. After turning on the power to your system, wait until the front panel power button LED begins to blink.
2. Quickly press the front panel power button twice (similar to the way you would double-click a mouse).
A screen similar to the following is displayed to indicate that you have successfully reset the NVRAM contents to the default values:
Note that some NVRAM configuration parameters are reset to their defaults. They include parameters that are more likely to cause problems, such as TTYA settings. These NVRAM settings are only reset to the defaults for this power cycle. If you do nothing other than reset the system at this point, the values are not permanently changed. Only settings that you change manually at this point become permanent. All other customized NVRAM settings are retained.
Typing set-defaults discards any customized NVRAM values and permanently restores the default settings for all NVRAM configuration parameters.
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Note Note - Once the power button LED stops blinking and stays lit, pressing the power button again will power off the system. |
The Stop-F functionality is not available in systems with USB keyboards.
The Stop-D (diags) key sequence is not supported on systems with USB keyboards, however, the Stop-D functionality can be closely emulated by using the power button double-tap (see Stop-N Functionality), since this temporarily sets diag-switch? to true . If you want the diagnostic mode turned on permanently, type:
The sync command forces any information on its way to the hard disk to be written out immediately. This is useful if the operating system has crashed, or has been interrupted without preserving all data first.
sync actually returns control to the operating system, which then performs the data saving operations. After the disk data has been synchronized, the operating system begins to save a core image of itself. If you do not need this core dump, you can interrupt the operation with the Stop-A key sequence.
This section describes some common failures and how you can fix them.
Problem: Your system screen is blank and does not show any output.
Here are possible causes for this problem:
Refer to your system documentation.
If the keyboard is not plugged in, the output goes to TTYA instead. To fix this problem, power down the system, plug in the keyboard, and power on again.
Check the power cable on the monitor. Make sure the monitor cable is plugged into the system frame buffer; then turn the monitor on.
This means the NVRAM parameter output-device is set to ttya or ttyb instead of being set to screen . Connect a terminal to TTYA and reset the system. After getting to the ok prompt on the terminal, type: screen output to send output to the frame buffer. Use setenv to change the default display device, if needed.
If your system has several plugged-in frame buffers, or it has a built-in frame buffer and one or more plugged-in frame buffers, then it is possible that the wrong frame buffer is being used as the console device. See Setting the Console to a Specific Monitor .
Problem: Your system is supposed to boot from the disk; instead, it boots from the net.
There are two possible causes for this:
Interrupt the booting process with Stop-A . Type the following commands at the ok prompt:
The system should now start booting from the disk.
Interrupt the booting process with Stop-A . Type the following commands at the ok prompt:
Note that the preceding commands cause the system to boot from the disk defined as disk in the device aliases list. If you want to boot from another service, set boot-device accordingly.
Problem: Your system is booting from a disk instead of from the net.
Interrupt the booting process with Stop-A . Type the following commands at the ok prompt:
Problem: Your system is booting from the wrong disk. (For example, you have more than one disk in your system. You want the system to boot from disk2 , but the system is booting from disk1 instead.)
Interrupt the booting process with Stop-A . Type the following commands at the ok prompt:
Problem: Your system fails to boot from the net.
The problem could be one of the following:
Report the problem to your system administrator.
Plug in the ethernet cable. The system should continue with the booting process.
Report the problem to your system administrator.
Refer to the troubleshooting information in your system documentation. (Note: systems that do not have Twisted Pair Ethernet will not have the tpe-link-test parameter.)
Problem: You are booting from a disk and the system fails with the message: The file just loaded does not appear to be executable.
Problem: You are booting from a disk and the system fails with the message: Can't open boot device.
Turn on power to the disk, and make sure the SCSI cable is connected to the disk and the system.
Problem: Your system has more than one disk installed, and you get SCSI-related errors.
Unplug all but one of the disks.
At the ok prompt, type:
Plug in another disk and perform Step 2 again.
If you get an error, change the target number of this disk to be one of the unused target numbers.
Repeat Steps 2, 3, and 4 until all the disks are plugged back in.
Problem: You have more than one monitor attached to the system, and the console is not set to the intended monitor.
If you have more than one monitor attached to the system, OpenBoot always assigns the console to the frame buffer specified by the output-device NVRAM parameter. The default value of output-device is screen , which is an alias for one of the frame buffers found by the firmware.
A common way to change this default is to change output-device to the appropriate frame buffer:
Another way of setting the console to a specific monitor is to change the sbus-probe-list NVRAM parameter.
If the frame buffer that you are choosing as the console is in slot 2, change sbus-probe-list to probe slot 2 first:
If a non-SBus frame buffer is installed, this second method may not work.
| OpenBoot 4.x Command Reference Manual | 816-1177-10 |
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Copyright © 2002, Sun Microsystems, Inc. All rights reserved.