Introduction to AIX system startup and shutdown

The Rs/6000aix boot is divided into multiple user (normal) mode and Single-user (service) mode. Under normal circumstances, a multiuser boot mode is generally selected, and single user mode is selected for system maintenance.

1. Multi-user Boot mode

After the system is properly installed, it takes only two steps to perform a multiple-user mode boot:

Turn the key switch on the front panel to the Normal position (counterclockwise head).

Power down the system (on a multiprocessor system, you can type in the console and then enter).

After the system automatically run, and finally into multi-user mode, waiting for the login interface. During multiuser mode, the system boot process passes through the following stages:

Phase 1: Guided import of Read-only memory (ROS IPL)

This phase includes the Power On Self Test (POST), locating the boot device, and loading the boot core into memory.

Phase 2: Configuring Basic devices

This stage system runs/etc/rc.boot 1. Rc.boot creates the Object Data Manager (ODM) database, guarantees that the basic device is set up, then initializes the logical Volume Manager (LVM), activates the root volume group (ROOTVG), and checks and installs the root file system.

Phase 3: Configuring Other Devices

This stage system runs/etc/rc.boot 2. Load ODM data and device files into the root file system and configure other devices that are not configured in Phase 2.

Phase 4: System initialization

This phase starts/etc/init, and the process number (PID) is 1.

Phase 5: Run phase

This stage init runs the entries in the/etc/inittab file and calls/etc/rc.boot 3. Then, install the/tmp file system, the ODM database is saved for the next boot, and the running state is set to multiuser, and if entries in/etc/inittab such as TCP/IP and NFS are not commented, these systems will be started.

The following is a typical/etc/inittab file

Init:2:initdefault:

Brc::sysinit:/sbin/rc.boot 3 >/dev/console 2>&1 # Phase 3 of System boot#★ Stage 5

Powerfail::p owerfail:/etc/rc.powerfail 2>&1 | Alog-tboot >/dev/console # Power

Failure detection

RC:2:WAIT:/ETC/RC 2>&1 | Alog-tboot >/dev/console # Multi-User checks #★ multi-user mode

Fbcheck:2:wait:/usr/sbin/fbcheck 2>&1 | Alog-tboot >/dev/console # run/etc/firstboot

SRCMSTR:2:RESPAWN:/USR/SBIN/SRCMSTR # System Resource Controller #★ start SRC

Rctcpip:2:wait:/etc/rc.tcpip >/dev/console 2>&1 # Start TCP/IP daemons #★ boot TCPIP

Rcnfs:2:wait:/etc/rc.nfs >/dev/console 2>&1 # Start NFS daemons #★ start NFS

Cron:2:respawn:/usr/sbin/cron

Piobe:2:wait:/usr/lib/lpd/pio/etc/pioinit >/dev/null 2>&1 # PB cleanup

Qdaemon:2:wait:/usr/bin/startsrc-sqdaemon

Writesrv:2:wait:/usr/bin/startsrc-swritesrv

Uprintfd:2:respawn:/usr/sbin/uprintfd

Logsymp:2:once:/usr/lib/ras/logsymptom # for System dumps

Infod:2:once:startsrc-s Infod

DIAGD:2:ONCE:/USR/LPP/DIAGNOSTICS/BIN/DIAGD >/dev/console 2>&1

DT:2:WAIT:/ETC/RC.DT #★ Universal Desktop Environment

Cons:0123456789:respawn:/usr/sbin/getty/dev/console #★ to start the ASCII terminal waiting process

As you can see,/etc/inittab starts the Universal Desktop Environment (CDE) at LFT (Low function terminal) by running the/etc/rc.dt script. You will see an interface similar to XDm, which is completely different from the login interface shown in the ASCII terminal.

Before phase 5 (run phase), the guide sequence can be understood through the LED display on the front panel of the machine. The LED has 3-bit code flashing when the boot sequence is in progress. If you want to know what the code means, look it up in the diagnostics Guide. At a certain stage, you will see code C32 or C33, which shows that the runtime is allocating the console. C32 is a low function terminal (LFTs), and C33 is a serial terminal (TTYs).

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