Too Slow To Stop
Rick Stevens
rstevens at internap.com
Wed Aug 8 00:22:18 UTC 2007
On Tue, 2007-08-07 at 17:39 -0400, Mike - EMAIL IGNORED wrote:
> On Tue, 07 Aug 2007 16:27:20 -0500, Mikkel L. Ellertson wrote:
> [...]
>
> >
> > For example, random.init has these three lines:
> > # chkconfig: 2345 20 80
> > # description: Saves and restores system entropy pool for \
> > # higher quality random number generation.
> > This says that the random script should be started in levels
> > 2, 3, 4, and 5, that its start priority should be 20, and
> > that its stop priority should be 80. You should be able to
> > figure out what the description says; the \ causes the line
> > to be continued. The extra space in front of the line is
> > ignored.
> >
> > Mikkel
> [...]
>
> Yes, but what about my original problem? How can a process
> tell when the system has begun to shut down down?
>
> BTW, in looking around, I found:
>
> [root at mbrc32]# runlevel
> N 3
>
> Now this surprises me; it was run from a KDE Shell Konsole.
> While I start my system at level 3, I then type startx.
> I thought that the GUI runs at level 5. Am I wrong about
> this?
Yes. Well, sort of. If you start the machine at run level 5, the
inittab fires off X. However, you can start X at any run level. It
may be that some of the stuff needed to support X aren't running at
a lower level, on Fedora everything you need is running at level 3.
Since your machine booted to run level 3, that's what it's running at.
You ran X as an application.
For the most part, run levels are really advisory. They allow you to
group different things to different levels of functionality.
Historically, run level 1 was "maintenance" mode and only the minimum
stuff needed to run was used...on some machines, only the root
filesystem was even mounted.
Level 2 was "multiuser" mode--run level 1 with other _local_ filesystems
mounted and multiple consoles. Level 3 was "multiuser mode"--run level
2 with network enabled, inetd/xinetd started as well to allow telnet,
rlogin, rsh and ftp access, and NFS shares mounted. Level 4 was
user-defined and level 5 was GUI. Level 6 is a restart or reboot.
None of this stuff is necessarily cast in concrete. You can play with
the inittab and the stuff in the /etc/rc.d/rcX.d directories to your
heart's content. Just make sure you keep a virgin copy of everything
you mess with in case you do something...uh...silly. :-)
----------------------------------------------------------------------
- Rick Stevens, Principal Engineer rstevens at internap.com -
- CDN Systems, Internap, Inc. http://www.internap.com -
- -
- To err is human, to moo bovine. -
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