Thursday, August 28, 2014

Content of BLV in aix

What is the content of BLV in aix?

The following is the content of BLV
ü  Aix Kernel
ü  Rc.boot
ü  Reduced ODM
ü  Boot commands

AIX kernel
The kernel is always loaded from the BLV. There is a copy of the kernel in
/unix (soft link to /usr/lib/boot/unix_mp or unix_up). This version is used to
build the hd4 file system where the kernel image is read during system
boot.

rc.boot
         This is the configuration script that will be called three times by the init process during boot.

Reduced ODM
          Device support is provided only to devices marked as base devices.

Boot commands

          For example, cfgmgr and bootinfo.

Boot process in aix

Boot process in aix

If you are going to attend any interview, there might be the chance of asking the question about boot process at that time you can explain the boot process like the below. (Instead of telling all the detailed steps, we can tell the important thing to make the interviewer understand easily)

 Remember this is only for interview purpose


1.       Three phases are there in the boot process
1.       Ros kernel init phase

2.       Base device configuration

3.       System boot phase


1.       ROS (Read only storage) kernel init phase:

        Problem of the mother board checked

        POST (Power on self test) {all the peripheral devices are checked}
        Boot list is found and boot image is loaded into memory

        System initialization start 

2.       Base device configuration:

         All the devices and FS are configured with the help of cfgmgr.



3.       System boot phase:

         All the logical volumes are ‘varied on’

         Paging is getting started

         Process defined in /etc/inittab file are initiated by init process
         The system is getting up with the default runlevel 2.

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Notes:
ü  After the BLV is loaded into RAM, the rc.boot script is executed three times to configure the system.
ü  During rc. Boot1, Base devices to activate rootvg is configured
ü  During rc.boot 2, rootvg is varied on.
ü  In rc.boot3, remaining devices are configured.
ü  Content of BLV: AIX Kerne, Boot commands, rc.boot, Reduced odm