various boot-related questions.

[Jim Barton]

In article <1989Sep13.183918.8050 at helios.physics.utoronto.ca>, sysruth at helios.physics.utoronto.ca (Ruth Milner) writes:
> I have also suggested that there should be a way for it to i) automatically
> reboot after a crash, without depressing its belly button :-), and ii) have
> it actually HALT after the shutdown sequence has completed, rather than
> rebooting if you aren't there in time to press <ESC>. I often initiate
> shutdowns from my desk, and then go to the machine room a minute or two
> later. In the IRIS' case, it had cleverly rebooted by this time and I had to 
> shut it down again. There have been some hints that new PROMs might fix at
> least one of these problems, but it has been like pulling teeth to get any
> concrete information.

The system will halt after the shutdown sequence if you shut down to init
state 0, for instance 'shutdown -i0', or 'init 0'.  This works, I've done
it alot.  We don't autoreboot after an OS crash because there may be
important data sitting on the screen that would be lost in this case - like
the error message which tells you what happened.  There aren't any 'bugs'
to be fixed here, although we can argue about reboot after crash ...

> While I can live without ii), part i) is absolutely vital. If it crashes
> due to power problems or greedy people filling up swap or something, there
> is no reason why it shouldn't go ahead and reboot. And in other situations,
> I can get the information from /usr/adm/SYSLOG (or from the console if it
> can't reboot).

You can't get the final crash messages from SYSLOG!  The kernel just crashed,
how can it write reliably to the filesystem?  If you have the PROM environment
variable 'bootmode=c', the machine will reboot after a power fail.  And
filling up swap won't crash the machine, the OS will instead start gunning
down processes.  This would seem to answer most of your concerns.

> -- 
>  Ruth Milner          UUCP - {uunet,pyramid}!utai!helios.physics!sysruth
>  Systems Manager      BITNET - sysruth at utorphys
>  U. of Toronto        INTERNET - sysruth at helios.physics.toronto.edu
>   Physics/Astronomy/CITA Computing Consortium

-- Jim Barton
Silicon Graphics Computer Systems    "UNIX: Live Free Or Die!"
jmb at sgi.sgi.com, sgi!jmb at decwrl.dec.com, ...{decwrl,sun}!sgi!jmb