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 start-up. They also show the transfer of control from POST to the OpenBoot firmware to the Booter to the kernel.
The example that follows shows the OpenBoot initialization sequence in a SPARCstation 10 system. The messages before the banner appear on TTYA only if the diag-switch? parameter is true.
Note - The displayed kernel messages may vary depending on the version of the operating system you are using.
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... ttya initialized (At this point, POST has finished execution and transferred control to the OpenBoot firmware) Cpu #0 TI,TMS390Z50 (Probe CPU module) Cpu #1 Nothing there Cpu #2 Nothing there Cpu #3 Nothing there Probing Memory Bank #0 16 Megabytes of DRAM (Probe memory) Probing Memory Bank #1 Nothing there Probing Memory Bank #2 Nothing there Probing Memory Bank #3 Nothing there Probing Memory Bank #4 Nothing there Probing Memory Bank #5 Nothing there Probing Memory Bank #6 Nothing there Probing Memory Bank #7 Nothing there (Before probing the devices, the firmware executes NVRAMRC commands - if use-nvramrc? is true - and checks for Stop-x commands Keyboard LEDs flash) Probing /iommu@f,e0000000/sbus@f,e0001000 at f,0 (Probe devices) espdma esp sd st ledma le SUNW,bpp SUNW,DBRIa Probing /iommu@f,e0000000/sbus@f,e0001000 at 0,0 Nothing there Probing /iommu@f,e0000000/sbus@f,e0001000 at 1,0 Nothing there Probing /iommu@f,e0000000/sbus@f,e0001000 at 2,0 Nothing there Probing /iommu@f,e0000000/sbus@f,e0001000 at 3,0 Nothing there SPARCstation 10 (1 X 390Z50), Keyboard Present (Display banner) ROM Rev. 2.10, 16 MB memory installed, Serial #4194577. Ethernet address 8:0:20:10:61:b5, Host ID: 72400111. Boot device: /iommu/sbus/espdma@f,400000/esp@f,800000/ (The firmware is TFTP-ing in the boot program) sd@3,0 File and args: (Control is transferred to Booter after this message is displayed) root on /iommu@f,e0000000/sbus@f,e0001000/espdma@ (Booter starts executing) f,400000/esp@f,800000/sd@3,0:a fstype 4.2 Boot: vmunix Size: 1425408+436752+176288 bytes (Control is passed to the Kernel after this message is displayed) Viking/NE: PAC ENABLED (Kernel starts to execute) ... (More kernel messages) ---------------------------------------------------------------------------------------------------------------------
Table D-1 describes commands that are useful in some failure situations. When issuing any of these commands, hold down the keys immediately after turning on the power to your system, and keep them pressed for a few seconds until the keyboard LEDs flash.
Table D-1 Emergency Keyboard Commands
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Command Description ------------------------------------------------------------------------------------------------------------
Stop Bypass POST. This command does not depend on security-mode. (Note: some systems bypass
POST as a default; in such cases, use Stop-D to start POST.)
Stop-A Abort.
Stop-D Enter diagnostic mode (set diag-switch? to true).
Stop-F Enter Forth on TTYA instead of probing. Use fexit to continue with the initialization sequence.
Useful if hardware is broken.
Stop-N Reset NVRAM contents to default values.
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Note - These commands are disabled if the PROM security is on. Also, if your system has full security enabled, you cannot apply any of the suggested commands unless you have the password to get to the ok prompt.
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. You can do one of the following:
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" on page 114.
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:
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ok setenv diag-switch? false ok boot ---------------------------------
The system should now start booting from the disk.
Interrupt the booting process with Stop-A. Type the following commands at the ok prompt:
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ok setenv boot-device disk ok boot -------------------------------
Note that the preceding commands cause the system to boot from the disk defined as disk (target 3) in the device aliases list. If you want to boot from disk1 (target 1), disk2 (target 2), or disk3 (target 3), 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:
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ok setenv boot-device net ok boot ------------------------------
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:
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ok setenv boot-device disk2 ok boot --------------------------------
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.
Install a new boot block.
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.
Try the following procedure:
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ok probe-scsi-all ----------------------
Note the target number and its corresponding unit number.
Problem: You have more than one monitor attached to the system, and the console is not set to an intended monitor.
A common way to change this default is to change output-device to the appropriate frame buffer:
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ok nvalias myscreen /obio/cgfourteen ok setenv output-device myscreen ok reset ---------------------------------------
Another way of setting the console to a specific monitor is to change the
sbus-probe-list NVRAM parameter.
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ok show sbus-probe-list (Display the current and default values) sbus-probe-list f0123 f0123 (Your system may have a different number of SBus slots) ok ---------------------------------------------------------------------------------------------
If the frame buffer that you are choosing as the console is in slot 2, change sbus-probe-list to probe slot 2 first:
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ok setenv sbus-probe-list 23f01 ok reset -----------------------------------
