System initialization and boot management

System initialization and boot management
The numeric 1 key (F1 on graphical display), when pressed during POST (double beep), starts the SMS interface.
The numeric 5 key (F5 on graphical display), when pressed during POST, initiates a system boot in service mode using the default service mode boot list. Sequence:
1. diskette (if installed)
2. CD-ROM (if installed)
3. hard disk
4. tape drive (if installed)
5. network (a. Token ring, b. Ethernet)

The numeric 6 key (F6 on graphical display) works like the numeric 5 key, but uses the customized service mode bootlist. This is the preferred method of loading AIX diagnostics from the boot hard disk.


ipl_varyon * Used to vary on the root volume group during system boot processing.


ipl_varyon -i : Inquiry mode - skips ipl device processing. Checks which disks are already bootable.


bosboot

Creates boot image. It does not update the bootlist in the NVRAM.
bosboot -a -d /dev/hdisk0 : Re-create boot image on hdisk0.
bosboot -a -d /dev/ipldevice -D : creates a boot image with the KDB debugger enabled.


mklv
Creates a logical volume.
mklv -y hd5 -t boot rootvg 1 : re-create boot LV (BLV) hd5.


lslv
Displays information about a logical volume.
lslv -l hd5 : determines the boot disk.


mkboot
Creates the boot image, the boot record, and the service record.
mkboot -c -d /dev/hdisk0 : clears the boot record of PV hdisk0.


chpv
Changes the characteristics of a physical volume in a volume group.
chpv -c hdisk1 : clears the boot record of PV hdisk1.


bootinfo Determines and displays various boot information, including boot device type and boot device name (NOT supported in AIX 4.2 or later).
bootinfo -b : returns the last boot device.
bootinfo -B hdisk0 : returns 1 if disk is bootable, 0 if not.


bootlist
Displays or alters the list or ordering of boot devices available to the system.
Normal boot list: possible boot devices for normal mode.
Service boot list: possible boot devices for service mode.
Previous boot device: last device from which the system booted.
Support of these boot lists is model dependent.
bootlist -m normal -o : displays the normal boot list.
bootlist -m service -o : displays the service boot list (if available).
bootlist -m normal cd0 hdisk0 hdisk1 : makes changes to the normal boot list.
bootlist -m prevboot : invalidates the last device from which the system booted.


halt or fasthalt
Writes data to disk (sync) and then stops the system. The system does not restart. Do not use this command if other users are logged into the system.


reboot or fastboot
Restarts the system. Can be used if no other users are logged into the system.


shutdown
Halts the operating system. Checks the existence of the executable /etc/rc.shutdown file (added by the administrator) that specifies all the applications and other user processes to close down.
By default the shutdown command powers down the system (if supported and issued).
shutdown -Fr : fast system shutdown and restart.
shutdown -m +1 : brings the system down to maintenance (single user) mode after waiting one minute.
shutdown -l : logs the output during the shutdown to /etc/shutdown.log.


last
Displays information about previous logins using the /var/adm/wtmp file.
last reboot : displays the time between reboots.
last shutdown : lists last shutdowns of the system.


uptime
Shows how long the system has been up.
uptime : displays the current time, the length of time the system has been up, the number of users online, and the load average.


sync
Updates the i-node table and writes buffered files to the hard disk.
sync;sync;sync;reboot : writes everything from the buffer to the hard disk and reboots the system.


lsfont
Lists the fonts available for use by the display.


chfont
Changes the default font selected at boot time.


mkfont
Adds the font code associated with a display to the system.


mkfontdir
Creates a fonts.dir file from a directory of font files.


chlang
Sets LANG environment variable in the /etc/environment file for next login.


chtz
Changes the system time zone information in the /etc/environment file.


chhwkbd
Changes the low-function terminal (LFT) keyboard attributes stored in the Object Data Manager (ODM) database.


lskbd
Lists the keyboard maps currently available to the low-function terminal (LFT) subsystem.


chkbd
Changes the default keyboard map used by the low-function terminal (LFT) at system startup.


chkey
Changes your encryption key.


lslicense
Displays the number of fixed licenses and the status of floating licensing. There are two types of user licensing, fixed and floating. Fixed licensing is always enabled. Floating licensing can be enabled or disabled.
lslicense -A : displays the number of available fixed licences on the system.


chlicense
Changes the number of fixed licenses and the status of the floating licensing (updates login.cfg).
chlicense -I -u 50I -u 50 : changes the fixed license number immediately to 50 (without rebooting).
chlicense -f on : enables the floating licensing.


lsitabLists records in the /etc/inittab file.


chitab
Changes records in the /etc/inittab file.


mkitab
Adds records to the /etc/inittab file.


rmitab
Removes records from the /etc/inittab file.


telinit or init
Initializes and controls processes.
0-9 Tells the init process to put the system in one of the run levels 0-9. S,s,M,m Tells the init process to enter the maintenance mode. a,b,c Tells the init process to examine only those records in the /etc/inittab file with a, b, or c in the run-level field. Q,q Tells the init process to re-examine the entire /etc/inittab file. N Sends a signal that stops processes from being respawned.
telinit q : requests the init command to re-examine the /etc/inittab file.


who

Identifies the users currently logged in.

Identify Runlevel

who -r : displays the runlevel.

who /var/adm/wtmp : displays a history of logins, logouts, system startups, and system shutdowns.


restbase

Restores customized information from the boot image. Attention: The command is executed only during system boot phase 1. Do not execute it in a run-time environment.


savebase
Saves base customized device data in the ODM onto the boot device.
savebase -d /dev/hdisk0 : save the ODM to the boot logical volume.