If the system has hung you may be able to shutdown by logging in as SYSTEM and trying one of the following commands:
If you cannot log in, then you should halt the processor at the console with CTRL-P.
You should then issue the following console commands:
>>> E -N F R0 >>> E PS >>> D PC FFFFFFFF00000000 >>> D PS 1F00 >>> CONTINUE
This sequence will cause the system to bugcheck.
You should write down the information displayed by the two E (examine)
commands, as they will be needed when analysing the dump file.