CHAPTER 4

Enabling a Hardware Timer

This chapter explains how to do the following:

• Enable a hardware timer that will reset the system if it times out
• Display system configuration and diagnostic information
• Reset and power cycle the system from a remote console

Hardware Watchdog

The Sun Enterprise x000 family of servers provide the ability to enable a hardware timer that will hard-reset the system if it times out. To enable the use of this feature, watchdog_enable must be set to 1 in /etc/system.

History Log Option of prtdiag(1M)

· To display system configuration and diagnostic information, use the prtdiag(1M) command.

The -l option of prtdiag(1M) logs its output to syslogd(1M) only if failures or errors exist in the system.

Resetting and Power Cycling the System From a Remote Console

You can reset the system or power cycle from the remote console under these conditions:

• The console must be connected to port A on the clock board.
• The key switch must be in either the On or Diagnostic setting. If it is in the Secure or Off position, the remote key sequences and button resets are ignored.
• Security features (such as OpenBoot security-mode) are disabled.
• Type slowly, no faster than 0.5 seconds and no slower than 5 seconds between characters.

TABLE 4-1 lists the remote console commands, which are useful for resetting the system under general conditions. The remote XIR reset command is useful in software development and debugging. For a discussion of this command, see "Externally Initiated Reset XIR" on page 3 in Chapter 1.

TABLE 4-1

Command	Keyboard Key Sequence
Remote power off/on	Return Return ~ Control-Shift-p
Remote system reset	Return Return ~ Control-Shift-r
Remote XIR (CPU) reset	Return Return ~ Control-Shift-x
Key: Return = ASCII 0d hexadecimal ~ = ASCII 7e hexadecimal Control-Shift-p = 10 hexadecimal Control-Shift-r = 12 hexadecimal Control-Shift-x = 18 hexadecimal

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Note - The remote console logic circuit continues to receive power, even if you have commanded system power off.

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Since the remote console logic looks for certain patterns on the ttya line in the hardware that can be used to reset the machine, it is important that only authorized personnel have access to the ttya serial port.