[lug] X, Window Managers and KDE/gnome 101

[Michael J. Hammel]

Thus spoke Aaron Crane
> Use of sysvinit doesn't in and of itself imply anything much about how
> system startup works.  Sysvinit does little more than define the existence
> of certain runlevels (0 = halt, 1 = single-user, 6 = reboot, 2..5 = normal,
> S = `special' or `system' or `single') and the interpretation of the
> /etc/inittab file.  Apart from that, it's up to the system integrator how to
> actually manage startup in a sensible way; different Linux distributions can
> and do select slightly different procedures.

Perhaps - I've never read the spec.  But implementation of sysvinit is pretty 
common and ....

> Debian adopts what I consider a straightforward and consistent scheme.  For
> each runlevel R, there is a directory /etc/rcR.d which contains files whose
> names match [SK][0-9][0-9]*.  Each one should be a program accepting one
> argument -- normally either "start" or "stop", but "restart", "reload", and
> "force-reload" also have defined meanings.  When entering a runlevel, all
> the Knn files for that runlevel are executed with an argument of "stop", and
> then all the Snn files are executed with an argument of "start".  [This is a
> slight simplification, but that's essentially what happens.]

... that is sysvinit.  SVR4 did this 10 years ago, right out of Bell Labs.
I think SVR3.2 also did it, but those memory cells were long ago burned.
In fact, all of the scripts under rcX.d, where X is a run level, are just
symbollic links to the actual scripts under /etc/rc.d/init.d.  The
symbollic links starting with "S" are run upon entering that run level and
the ones with "K" are run when leaving that run level.  At least that's how
it worked in SVR4.  I haven't bothered checking the specifics of the
Linux-based implementations.  It's pretty close, if it's not exactly the
same.

> If you want your Debian box to have an X-less runlevel and a default, X-ful
> one, then the easiest thing to do is to rename /etc/rc3.d/S99xdm to
> /etc/rc3.d/K99xdm.  Now runlevel 2 is still the default, and still runs xdm.

Just remove the symbollic link (assuming Debian does like everyone else - I
don't run Debian so can't say for sure if they are the same).

-- 
Michael J. Hammel                               The Graphics Muse 
mjhammel at graphics-muse.org                      http://www.graphics-muse.com
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