Kill -9

[rbottin at atl.calstate.edu]

This message is a reply from rbottin

===============================================

No there is no more powerful kill than -9. There is no real
hierarchy implied by the numbering - just different reasons
for sending a message to a process. Its just that it is
either impossible or very bad practice for a program to catch the -9
signal and ignore it....

On some UNIXes any hardware interupt hard a higher priority than the
signals that the software could send, and so once a process hangs up waiting
for a tape drive then ONLY an interupt from the TAPE wakes it up.
(your milage may vary)
In one case the processor in the tape drive was waiting for a signal
from the CPU and ignoring most of its buttons, while the
UNIX was wouldn't talk to the tape untilt the hung process was
not using the tape drive - deadly embrace.....
The only thing to do was to shutdown, ignore the complaints about
hung processes (or don't panic about them)....and reboot with tape
turned on...
dick botting (rbotting at atl.calstate.edu, dick at realsoonnow.csubnet.edu,...)
 


This is the original messsage
===============================================

Subject:  kill -9

Is there a stronger kill than kill -9?  I had a process which attached
itself to my tape drive and then locked up.  I couldn't kill it no
matter what I tried.  This caused me great concern, backups are very
important to me and I couldn't access the tape drive with this process
on it.  I shut down the system (two of my file systems didn't unmount
because of the process and shutting down didn't kill the process either) 
and rebooted.

Any suggestions.

Norm Frech < frech at mwraaa.army.mil >

 
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