crash(8)                       DG/UX R4.11MU05                      crash(8)


NAME
       crash - what to do when the DG/UX system crashes

DESCRIPTION
       This entry tells you what to do if the system crashes.  Two kinds of
       crashes can occur:  halts and hangs.  A halt, a system-detected
       crash, sends a halt message to the operator's console.  A hang, a
       crash not detected by the operating system, is an infinite loop or a
       deadlock.

   How to shut the system down
       If your system halts, be sure to record the halt number.  Then dump
       the system memory as described below in "Taking System Dumps."  You
       will automatically enter the system dump dialogue.

       If your system returns to the SCM prompt without issuing a halt code,
       type START 1000 at the SCM (prom) prompt.  This command puts you in
       the system dump dialogue.  Take a dump of the system memory as
       described below in "Taking System Dumps."

   Taking System Dumps
       If your system halts, you will automatically enter the system dump
       dialogue.  If the system hangs, you will have to manually enter the
       dialogue as described above.  The dialogue will read as follows:

       Do you want to take a system dump? [Y]

       Accept the default or enter N.

       Limit the main memory dump to kernel memory only (no user memory)? [Y]

       Choose the default. (Under rare circumstances, you may be told by a
       DG representative to respond No.)

       Dump destination device? [st(cisc(),4)]

       If you requested a system dump, this prompt appears: accept the
       default, or enter the dump device in DG/UX common device
       specification format.  You will then be prompted to mount a tape:

       Mount tape.  Type newline when tape is ready.

       If the system memory image is too large to fit on one tape, you will
       be prompted to load subsequent tape volumes:

       Tape volume 1 completed.
       Mount tape.  Type newline when tape is ready.

       If any tape volume write fails, you will be allowed to restart the
       dump at the beginning of that volume:

       Hard error on tape volume 1.  Restarting volume from checkpoint.
       Mount tape.  Type newline when tape is ready.

       The final volume will be rewound upon completion of the dump:

       System dump completed successfully.

       In all cases, when you provide a dump, you should also provide a copy
       of the tailored system image (usually named /dgux) that was running
       at the time of the crash.  This image contains vital information
       necessary for interpretation of the memory dump; the memory dump is
       useless without the system image.  See the "DG/UX System Release
       Notice" on how to send dumps to Data General.

SEE ALSO
       cp(1), crash(1M), fsck(1M).


Licensed material--property of copyright holder(s)