OP/SYS: OpenVMS AXP Versions 1.0, 1.5
COMPONENTS: Shutdown, Bugcheck
SOURCE: Digital Equipment Corporation
SUBJECT:
This article outlines the steps required to force a crash on an Alpha AXP system.
This procedure applies to the following systems:
DEC 2000 Model 300 AXP DEC 3000 Model 400 AXP DEC 3000 Model 500 AXP DEC 3000 Model 600 AXP DEC 4000 Model 610 AXP DEC 7000 AXP DEC 10000 AXP
You may need to force a crash of the system if the system is hung, that is, if it does not respond to input from any terminal. You could just reboot the system, but when you force a crash, OpenVMS AXP writes the contents of memory to the dumpfile, SYS$SYSTEM:SYSDUMP.DMP. The cause of the system hang or crash can sometimes be determined by examining the dumpfile.
The Customer Support Center recommends using these steps instead of SYS$SYSTEM:OPCCRASH.COM, because OPCCRASH requires using a terminal, scheduling the process, and then executing the command file properly, which may not be possible due to whatever is hanging the system.

PROCEDURE
Issue the following commands from the system console device.

1. Halt the system:
1. For a DEC 7000 AXP or DEC 10000 AXP system:
   ^P
2. For DEC 2000, DEC 3000 AXP and DEC 4000 AXP systems:
   Press the Halt button.
   In either case, a PC (Program Counter) will be displayed. Type "C" to continue and halt the system again, displaying another PC. Repeat this cycle 8-10 times to get a good sampling of the PC values. The PC samples will help determine the location of the code that caused the problem.
2. Display all registers. This display provides information which may help diagnose the system hang:
   >>> E -N F R0
3. Display the current Processor Status (PS) information. This display provides information which may help diagnose the system hang:
   >>> E PS
4. Force a crash by loading the following values into system registers:
   >>> D PC FFFFFFFF00000000 <- invalidates the current PC.
   >>> D PS 1F00 <- elevates IPL to 31.
   >>> CONTINUE
   The system will then crash with the following bugcheck:
   INVEXCEPTN, exception while above ASTDEL or on interrupt stack
   When the system reboots, you can analyze the crash dump by invoking the System Dump Analyzer Utility:
   $ ANALYZE/CRASH SYS$SYSTEM:SYSDUMP.DMP
   EXAMPLE:
   This example shows the user input and system responses from a forced crash:
   ^P <------------------- halted CPU 0 \ \ halt code = 1 \ \ operator initiated halt / ----- Repeat this cycle PC = FFFFFFFF800602F8 / 8-10 times / >>> C