Information Technology Reference
In-Depth Information
6.
Determine the run level(s) at which the service should stop (typically,
0, 1, and s), meaning that the script needs to be linked to one or more
of the rc directories.
7.
Determine the two-digit number to control the stop sequence (00
through 99). Look at the other stop
rc
scripts in the appropriate
rc
directories and choose a number that is less than any required services
but greater than any services that were using the service.
8.
Link the new script from the
/etc/init.d
directory to the appropriate
rc
directories, giving it a name starting with
K
followed by the selected
two-digit number and then the service name.
Be sure to understand the procedure for adding
rc
scripts the system, especially the
use of different directories, the
K
and
S
prefixes, and the selection of script numbers.
Summary
The OpenBoot is firmware used to perform basic system operations such as
booting the system, running hardware diagnostics, and storing boot-related
parameters in NVRAM.
OpenBoot commands such as
banner
and
printenv
are used to display
NVRAM parameters. The
setenv
,
set-default
parameter
, and
set-defaults
commands are used to set NVRAM parameters.
The eight run levels are 0 (power down), s (single user), 1 (administrative), 2
(multiuser without NFS server (NFS client only)), 3 (multiuser with NFS
server), 4 (not used), 5 (power down), and 6 (reboot). The init command
supports changing to any run level, whereas the
shutdown
command can be
used change to run levels 0, 1, 5, 6, and s.
The
/etc/inittab
file contains information on which programs should be
started or stopped at each run level.
