INIT.D(7)						       The SuSE boot concept							 INIT.D(7)

NAME

       INIT.D - The SuSE boot concept

SYNOPSIS

       /etc/init.d/*

       /etc/sysconfig

DESCRIPTION

       The scripts for controlling the system are placed in /etc/init.d/ (they have been moved according to the Linux Standard Base (LSB) specifi-
       cation).  These scripts are executed directly or indirectly by /sbin/init, the father of all processes. The configuration of /sbin/init	is
       given by the file /etc/inittab (see inittab(5)).

       At boot time, the boot level master script /etc/init.d/boot is called to initialise the system (e.g. file system check, ...).  It also exe-
       cutes some hardware init scripts linked into /etc/init.d/boot.d/.  Then it calls /etc/init.d/boot.local, which executes the local commands.

       After system startup, /sbin/init will normally switch on the default run level given in /etc/inittab.  It calls the run level master script
       /etc/init.d/rc to start or stop services provided by the other scripts under /etc/init.d/.

       Both  scripts,  then  boot level master script /etc/init.d/boot and the the run level master script /etc/init.d/rc starts all other boot or
       runlevel scripts either sequential or partial parallel within their dependencies order.

       To control the services of a run level, the corresponding scripts  are  linked  into  run  level  directories  /etc/init.d/rc<X>.d/,  where
       <X>=0,1,2,3,4,5,6,S is the run level number.

       There  are two kinds of symbolic link: start links, which are called when entering a run level, and stop links, which are called when leav-
       ing a run level.  Note that each service in the run levels 2, 3, 4, and 5 consists of a start and a stop link.  Within SuSE boot concept  a
       differential link scheme is used to be able to change a runlevel in comparision with the former level.

       If parallel executing of the boot scripts is enabled (see /etc/sysconfig/boot variable RUN_PARALLEL) then both master scripts uses the pro-
       gram startpar(8) which starts or stops multiple services in parallel.   Startpar(8)  will  look	for  the  files  /etc/init.d/.depend.boot,
       /etc/init.d/.depend.start, and  /etc/init.d/.depend.stop  to  get the dependencies for each service.  The files will be written, beside the
       symbolic links in the boot and runlevel directories, by the program insserv(8).

       To avoid redundant starts when changing run levels, only those services are started which have no start link in	the  previous  run  level.
       And  to	avoid  redundant stops when changing run levels, only those services are stopped which have no start link in the current level. To
       control this behaviour, the names of the scripts are added on the names of the start and stop links.

       To control the order of service starts and stops, the start and stop links include a number in their link name.

       The system configuration files in /etc/sysconfig contain most of the variables used to configure the installed services.   These  variables
       can  easily  be	changed by YaST or by using an editor. After using an editor, the script /sbin/SuSEconfig must be called to distribute the
       settings into the system.

   Some details
       The script /etc/init.d/lpd starts or stops the line printer daemon for the printing service, according to the flag used:

	      /etc/init.d/lpd start
       and

	      /etc/init.d/lpd stop

       To do this automatically in run level 3, this script is linked into /etc/init.d/rc3.d/ with these two symbolic links

	      /etc/init.d/rc3.d/S20lpd -> ../lpd
       and

	      /etc/init.d/rc3.d/K20lpd -> ../lpd

       The corresponding link with the letter S is used to start a service. For the printing service the number between the letter S and the  name
       should  be  greater  than  the number of the start link of the network service.	The corresponding link with the letter K is used to stop a
       service. The number of the stop link for the printing service should be less than that of the stop link for the network service so that the
       printer daemon is stopped before shutting down the network service.

   Run levels and their services
       0      This  level  is  used  for  halting  the	system.  The  only  valid  service for this level is the script halt, which is linked into
	      /etc/init.d/rc0.d/.  The script halt executes /etc/init.d/halt.local.  Special system issues for halt  or  reboot  should  be  added
	      there.

       6      This  level  is  used  for  rebooting  the  system. The only valid service for this level is the script reboot, which is linked into
	      /etc/init.d/rc6.d/.  The script reboot executes /etc/init.d/halt.local.  Specials system issues for halt or reboot should  be  added
	      there.

       S      This mode is used to switch from boot phase into single user mode.  The last valid service for this mode is the script single, which
	      is linked into /etc/init.d/rcS.d/.  In this mode you have only one console.

       1      According to the Linux Standard Base (LSB) specification this runlevel is used to switch from normal runlevel into single user mode.
	      This is different from former SuSE Linux versions!

       2      The run level 2 is without remote networking. Note that on some other systems this is identical with the single user mode.  This run
	      level can have more than one virtual console.

       3      The run level 3 is with network. This run level is for server stations not automatically running X.

       5      The level 5 is with network and xdm(1).  You should have a configured and perfectly running X Window System for  this  work  station
	      run level.

       4      The run level 4 is not (yet) used.

       /etc/init.d/skeleton
	      This script is a model for writing your own.  You can use insserv(8) to include your own script into a run level.

FILES

       /etc/init.d/*
       /etc/init.d/boot
       /etc/init.d/boot.local
       /etc/init.d/halt
       /etc/init.d/halt.local
       /etc/init.d/rc
       /etc/init.d/reboot
       /etc/init.d/skeleton
       /etc/init.d/single
       /etc/init.d/boot.d/S[0-9][0-9]*
       /etc/init.d/rc0.d/{K,S}[0-9][0-9]*
       /etc/init.d/rc1.d/{K,S}[0-9][0-9]*
       /etc/init.d/rc2.d/{K,S}[0-9][0-9]*
       /etc/init.d/rc3.d/{K,S}[0-9][0-9]*
       /etc/init.d/rc4.d/{K,S}[0-9][0-9]*
       /etc/init.d/rc5.d/{K,S}[0-9][0-9]*
       /etc/init.d/rc6.d/{K,S}[0-9][0-9]*
       /etc/init.d/rcS.d/{K,S}[0-9][0-9]*
       /etc/init.d/.depend.boot
       /etc/init.d/.depend.start
       /etc/init.d/.depend.stop
       /etc/inittab
       /etc/sysconfig/boot
       /etc/sysconfig

SEE ALSO

       insserv(8), startpar(8), init(8), inittab(5), and the SuSE Linux handbook, chapter The SuSE boot concept.

COPYRIGHT

       1996-2005 SuSE Linux AG, Nuernberg, Germany.

AUTHORS

       Florian La Roche <http://www.suse.de/feedback>, Werner Fink <werner@suse.de>, Burchard Steinbild <http://www.suse.de/feedback>.

4.4 Berkeley Distribution					   Nov 15, 2000 							 INIT.D(7)