haltsys/reboot vrs. shutdown (was Re: init's untimely death.)

[Karl Denninger]

In article <2049 at egvideo.UUCP> edhew at egvideo.UUCP (Ed Hew) writes:
>In article <132 at tridom.uucp> you write:
>>haltsys or reboot is SCO's way of telling shutdown where to stuff it!
>>It might not be nice for servers or off-hokk comm lines, but it WILL
>>shut the system down RIGHT AWAY.
>
>You are correct in the above statement.
.....
>Even then, you probably will still have to run fsck to clean up, as neither
>haltsys or reboot take you to single user mode, do any sync's, or cleanly
>terminate all those processes that are spawned when you are multi-user.
>Odds are that you'll still have a bunch of temporary files sitting around,
>and any number of unflushed buffers.

Wrong!

Try doing that "haltsys" right after copying a big file -- notice how long
it takes, and how your nice disk light is on for several seconds before the
system comes to a halt?

Notice as well that your system doesn't fsck all the disk partitions on the
way back up -- because the "file system ok" flag is set!

Haltsys is a clean shutdown.  It doesn't terminate processes -- which means
that any programs that were running don't get the chance to get signalled
and quit cleanly -- but it DOES sync the disks, unmount them (effectively
though not though the "umount" system service), and take the system down 
cleanly.

I use this method all the time for shutdowns, and have never had a problem
with it.  Then again, our system is set up to remove all the rogue lockfiles
and the contents of /tmp (AFTER "recover"ing for those caught in "vi") on 
the way back up -- preventing problems with things like Usenet!

--
Karl Denninger (karl at ddsw1.MCS.COM, <well-connected>!ddsw1!karl)
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