Rebooting Sys V/386

[John G. DeArmond]

src at scuzzy.in-berlin.de (Heiko Blume) writes:

>>Is there a way to force a sys V/386 3.2 system to reboot?
>>I need to cause a reboot from a remote login after changing
>>the kernel with idbuild. Is there a way to do this with
>>just shutdown? Can it be done with a call to reset the system?

>'init 6' will shutdown the system cleanly and reboot *without*
>waiting for a keypress. of course the floppy drive must be
>open/empty.

I've found that on more systems than not, this does not work and
instead hangs the computer when it prepares to reboot after shuting down.
Why?  Got me.  Also, one should note that executing "uadmin 2 1", which
is what run state 6 does by default does not do a clean shutdown.  A much
better way is to take /etc/rc1 which is a script, and modify it to
orderly shut the system down.

On a related issue, a useful technique to recover a system unresponsive
to terminal or console input (a tcp/ip bug will do this, as will a  modem
chatting with a dumb port) is to place a powerfail entry in /etc/inittab,
have it run /etc/rc1 with the proper arguments, and then put up a small
daemon that will trap SIGHUP on a spare port and fire a SIGPWR at init
(process 1).  This is a trivial C program.   Then when you need recover
the system, you simply toggle carrier detect on that port and wait for
the system to shut down. 

John
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