Re: [tlug] HELP cannot connect to the sound daemon

[Josh Glover <jmglov@example.com>]

Martin Arballo wrote:
> Mauro and Matt,
> 
> Now I know how can I make my sound card work, but,
> what happen if I do both things......or do they have exactly same result 
> and efficiency?  in that case, I would like to understand why?

OK, here is the answer in a nutshell:

When your system starts up, it goes through the mysterious SysV init 
scripts. (SysV == System V, the Other Unix, AT&T's official one, as 
opposed to the rebel BSD from Berkley.) I Googled for a link that 
explains how this works (thus saving me the typing), but I could not 
find anything, so here goes (correct me if I misspeak, anyone!).

Your system has a default runlevel (usually 5 on Linux systems in 
multiuser mode). It executes the scripts in the /etc/rc.d/rcX.d/ (where 
X is the numerical runlevel--run 'runlevel' with no arguments to see 
which runlevel your system is currently in, 'man runlevel' for more 
interesting stuff) directory, in alphabetical order. To facilitate the 
starting of scripts in the correct order, they are named using the 
convention ('K'|'S')XXservice (where XX is a number between 00 and 100, 
exclusive and service is the name of a service). Filenames starting with 
'K' (Kill) stop a service, filenames starting with 'S' (Start) start a 
service. Therefore, on startup, the system executes the S* scripts, in 
order, from the aforementioned rc directory. When it is done with this, 
it executes /etc/rc.d/rc.local script. So, anything there gets executed 
last in your startup procedure.

Similarly, on shutdown, the system executes all the K* scripts in that 
rc directory.

Do an ls -l on /etc/rc.d/rc5.d, however, and you will see that 
everything is just a symlink (symbolic link, 'man ln') to scripts in the 
/etc/[rc.d/]init.d/ directory.

This is an oversimplified explanation. 'man 8 init' for the full details.

chkconfig is a Redhat tool to manage all those symlinks. That way, you 
do not have to create, name and delete a bunch of links to change your 
startup configuration.


-- 
Josh Glover <jmglov@example.com>

Associate Systems Administrator
INCOGEN, Inc.