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System Management Guide: Operating System and Devices
This procedure describes two
methods for changing system run levels for multi-user or single-user
systems.
When the system starts the first
time, it enters the default run level defined by the initdefault entry in the
/etc/inittab file. The system operates
at that run level until it receives a signal to change it.
The following are the currently
defined run levels:
0-9
| When the init command changes to run
levels 0-9, it kills all processes at the current run levels then restarts any
processes associated with the new run levels.
|
0-1
| Reserved for the future use of the operating system.
|
2
| Default run level.
|
3-9
| Can be defined according to the user's preferences.
|
a, b, c
| When the init command requests a change to run levels
a, b, or c, it does not kill processes at the
current run levels; it simply starts any processes assigned with the new
run levels.
|
Q, q
| Tells the init command to reexamine the
/etc/inittab file.
|
- Check the
/etc/inittab file to confirm that the run level to which you are
changing supports the processes that you are running. The getty process
is particularly important, since it controls the terminal line access for the
system console and other logins. Ensure that the getty process is
enabled at all run levels.
- Use the wall command to inform all users that you intend
to change the run level and request that users log off.
- Use the smit
telinit fast path to access the Set System Run Level menu.
- Type the new run level
in the System RUN LEVEL field.
- Press Enter to implement
all of the settings in this procedure.
The system responds by telling you
which processes are terminating or starting as a result of the change in run
level and by displaying the message:
INIT: New run level: n
where n is the new run-level number.
- Check the /etc/inittab file to confirm that the run level to
which you are changing supports the processes that you are running. The
getty process is particularly important, since it controls the terminal line
access for the system console and other logins. Ensure that the getty
process is enabled at all run levels.
- Use the smit telinit fast path to access the Set System Run
Level menu.
- Type the new system run
level in the System RUN LEVEL field.
- Press Enter to implement
all of the settings in this procedure.
The system responds by telling you
which processes are terminating or starting as a result of the change in run
level and by displaying the message:
INIT: New run level: n
where n is the new run-level number.
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